Microwaves in Manchester - EuMW 2011

Most of the MWJ editors and staff arrived in Manchester, UK on Sunday for the largest Microwave Conference and Exhibition in Europe, European Microwave Week. There are about 1400 delegates registered for the technical sessions this year and the content appears to be very good. I sat in on a few sessions ranging from emerging technology such as graphene FETs to more mature high efficiency GaN amplifiers.

The exhibition started on Tues and were well attended even through Wed. The Manchester Central facility has a nice layout where all the sessions are very close to the exhibition floor and entrance so finding your way around is relatively easy. The exhibition floor is wide open with a very high roof as it was an old rail station converted into an exhibition center. The major T&M companies like Agilent, R&S and Anritsu have the largest booths up front with other major players like CST, Ansys, AWR, NI, TriQuint, Sumitomo, Cobham, etc. having large booths right behind them. Over 200 companies are represented here . We see a lot of activity in GaN, non-linear modeling, wideband components and test systems, advanced materials and improved packaging.

There has been an emphasis on recruiting young engineers to the field, especially in Europe, including emphasis on more women as evidenced by the Women in Microwaves sessions. Several companies have applications that will engage young people such as Ansys' high frequency educational toolkit in conjunction with Anritsu and Eductika. We talked with Dr. T at NI about this subject, and he indicated that NI also has Labview based programs to engage young engineers in high school and college so several companies are doing something about the problem.

MWJ organized the Defence and Security Forum which was extended to a full day after its success last year in Paris. The morning sessions concentrated on security issues covering UWB and TeraHertz imaging for IED detection, through the wall imaging and detection of threats hidden on the body. The lunch and learn session was given by Strategy Analytics on the future budget trends in a declining budget atmosphere. The afternoon sessions were dedicated to an industry perspective on future challenges for radar and EW. A representative from Thales and Cambridge Consultants spoke first followed by an industry panel including representatives from Agilent, NI, NXP, RFMD and TriQuint. The day's events were concluded with an executive forum covering future needs and trends in defense related to microwave technology. Hundreds of attendees participated in the day's events.

The exhibition is wrapping up tomorrow and MWJ has shot about a dozen videos which will be posted online in a couple of weeks. The videos covered many product demos from the exhibition plus interviews with the president of EuMA, Dr. T from NI and representatives from AWR.

Tattoo Electronics Open Up Many Possibilities

It was recently announced that researchers from Northwestern University and the University of Illinois at Urbana-Champaign have developed “tattoo electronics”. These are wireless electronics so flexible and thin they can be applied to the skin and forgotten.

According to the release, the high-performance epidermal electronic system mounts directly onto the skin with the ease, flexibility and comfort of a temporary tattoo. The system could be used for monitoring brain, heart and muscle tissue activity; wound measurement and treatment; biological and chemical sensing; computer gaming and covert communications.

The challenge for Huang and his colleagues was to make the thickness and stiffness of the electronic system similar to that of skin. The researchers accomplished this through a serpentine design of electronic nanoribbons. The circuits for the various components are fabricated as tiny wires. When mounted on lightweight and stretchable membranes, the wavy, snakelike shape allows the wires to bend, twist, scrunch and stretch while maintaining functionality.

The electronics also can be removed easily. They adhere to the skin the same way it is believed a gecko’s foot adheres temporarily to a surface: through an electrostatic phenomenon called the van der Waals force. Tape or glue is not necessary.

Tattoo electronics could have medical applications from Northwestern News on Vimeo.

The system features electrophysiological and physical sensors and wireless power and communication modules. It is free of cumbersome wires, making it practical for use outside a research lab or clinic, in a natural environment. The researchers also show that their system’s EEG, ECG and EMG recordings are comparable to signals collected using bulky commercial devices that require tape for mounting to the skin.

They also demonstrate their system’s potential for use in human-machine interfaces. The electronics can be mounted on a person’s throat and, after training, the system can translate the simple spoken commands “up,” “down,” “left” and “right” into directions to control the video game Sokoban. This capability could prove useful to patients with muscular or neurological disorders, such as amyotrophic lateral sclerosis, or ALS, who could use the electronic patches to communicate or interface with computers. Another demonstration shows the electronics can be integrated with commercially available temporary tattoos, if there is a desire to conceal the electronics.

Avago and Skyworks Modules Show Up in Droid Bionic

I like to see the smartphone teardowns for the major new phone introductions to see who the RF/microwave winners are for the high visibility products that will represent significant volume. The latest (long anticipated) smartphone is the Motorola Droid Bionic with market leading specs in many areas. ABI Research (and a few others) have done teardowns and found some interesting findings.

According to ABI Research vice president of engineering James Mielke, “Motorola has mixed some of the latest technology with quite a few components now considered the norm and a few that have not been seen in phones for years.” One of the newer components, the OMAP4430, scored well in performance testing but not quite high enough to top the leaderboard.

Major changes include:

• LTE modem designed by Motorola
• A new LTE transceiver from Intel (Infineon)
• An interesting RF configuration supporting more than the advertised CDMA/LTE support
• Transition from Nvidia Tegra II to OMAP4430 application processor

But for us RF folks, the most interesting is the Avago Quad Band GSM/EDGE PA (ACPM-7868) indicated by red arrow and Skyworks 700 MHz LTE PA module (SKY77483) indicated by the red arrow. According to the Avago datasheet, the PA is a linear quad band/multi-mode PA for both GMSK and 8-PSK modulation schemes. There are two amplifier chains, one is to support the GSM850/900 bands and the other is to support the DCS1800/PCS1900 bands.

The LTE RF module is a Skyworks 700 MHz LTE load insensitive PA with an integrated coupler. ABI also noted that there is a ceramic filter which has not been really seen in modern handsets. I am guessing it might be to prevent interference with the many frequency bands near the LTE signals (could be from Trans Tech which Skyworks owns?).

Let me know if you have further information on these parts. Photo courtesy of ABI Research.

IBM to Publish 2 GHz Graphene IC at Upcoming Conference

IBM is set to publish a paper on a 2 GHz frequency doubler RF circuit in a CMOS-compatible manufacturing process technology at the upcoming International Electron Device Meeting, due to be held in Washington DC, Dec. 5 to 7. IBM researchers will deliver a paper that is a significant step toward moving graphene from the lab into a manufacturable technology. It will detail how using a 200 mm wafer-scale CMOS-compatible fabrication process can be used to make high-performance graphene FETs and RF passives.

A major obstacle with graphene is the difficulty of building a gate dielectric (insulating layer) on its inherently inert surface. However, graphene layers grown by controlled vapor deposition (CVD) can be transferred to many types of substrates. To take advantage of this property, IBM built silicon wafers containing pre-defined embedded gate structures, and then transferred CVD-fabricated graphene layers onto them. As an example they built a frequency doubler which demonstrated a conversion gain of ~-25 dB at an output frequency of 2 GHz. This performance was nearly constant from 25-200°C, indicating that both n- and p-transconductance are temperature-independent in this range, a new finding for CVD graphene-based devices.

The four images on the right show (a) an 8” graphene FET wafer; (b) single die; (c) SEM image of a typical fully processed device and (d) an enlarged view of the device showing the embedded gate structure with two-finger design. Except for the CVD graphene transfer, all processing was done in a conventional 200 nm fab. Graphene technology is finally making it into production.

New RFIC Greatly Mitigates LightSquared LTE Interference with GPS

There has been a lot in the news the last few months about LightSquared's proposed new broadband LTE network which is close in frequency to the GPS band and could cause interference in critical areas of navigation systems. LightSquared is seeking FCC approval for 40,000 basestations to support 260 million users across the country establishing a new LTE network. They were approved in Jan 2011 but recent tests have indicated that signals from the network could interfere (jam) nearby GPS receivers so the FCC has said they cannot launch their network until the problems are resolved.

LightSquared has indicated they will adjust the direction of their signals to minimize the strength near GPS stations and move the frequency a little farther away. There is a 10 MHz block near the GPS frequency that they will not use and move to another block of spectrum currently used by Inmarsat. They will also reduce the maximum power levels to provide additional protection.

But today Tahoe RF announced an RFIC solution to the problem with an integrated dual channel (L1 & L2) GPS RFIC that substantially mitigates interference from LightSquared and 4G L-Band LTE signals (and other jamming environments). The RFIC also includes a fractional-N synthesizer with a high performance VCO. The receive paths can be configured high linearity or low power operation by setting the ADC bit rate. The two independent receive paths are integrated with 12 bit analog to digital converters providing complete conversion of the GPS signals from RF to digital data. The RFIC has the ability to process L1 and L2 received signal data in the presence of a greater than 60 dBc jammer.

GPS devices are being improved against the backdrop of various 4G and other signals that can interfere with the relatively weak satellite signals with improved filtering and sensitivity. Infineon recently announced highly integrated GPS/GLONASS modules with improved sensitivity plus pre- and post- filtering around the LNA. These modules have out-of-band rejection of greater than 43 dBc in the cellular bands.

This is a very exciting area as another company is trying to bring broadband to the rural market around the country, something the Obama administration has been promoting and supporting for a while but has not seemed to meet expectations. Can all these signals co-exist as we squeeze more and more data into our limited spectrum?

How I developed the Sixth (or Twelfth) Wavelength Transformer

The following article was sent to us by Peter (B) Bramham, inventor of the sixth wavelength transformer (I never knew that in his first publication he was mistakenly listed as B. Bramaham so it has taken many years for people to realize it).

There have been various references in the last few years to a method of matching transmission lines, variously called the “alternated-line” and “twelfth-wave” and “Bramham’s” transformer. This is shown in the Figure below. It is usually compared with the quarter-wave stepped matching section and the half-wave taper, over which it has several advantages. It is shorter in length, and uses only lines of the same impedances as the lines which are to be matched.

Back in 1959 I was a member of the international group working at CERN, the European Laboratory in Geneva, on a proton linear accelerator. I had previously worked in Britain on electron accelerators for medical use, which used high-power RF at S-band (around 3000 MHz). For proton acceleration, lower frequencies were used, in this case 202.5 MHz. So I had to forget about waveguides, and get used to rigid lines and coaxial cable. The high-power feeds to the accelerating cavities used 3-inch line made from brass or copper tubes, and phase-shifters and power-dividers were required in the lines.

At that time, there were various standard impedances for coaxial lines and cables. In Britain, 75 ohm and 50 ohm impedances were largely used. Equipment we had from Germany used 60 ohms, while that from the USA used 50 ohms. CERN had a mixture of these. The linear accelerator design was based on a machine being built at AERE Harwell in Britain, and used high-power lines of 47.6 ohms. This seemed strange, but turned out to be the nearest you got to 50 ohms using standard (“Yorkshire Copper”) brass tubes. Rather than machine metric tubes to get 47.6 ohms, I changed our standard impedance to 50.4 ohms which corresponded to metric tube sizes.

So I had to fit impedance transformers all over the place. I started with half-wave tapers where there was space, or quarter-wave stepped lines where there was not. Then I started looking analytically at various matching systems. Hence my report CERN 59-37. As it seemed to be of interest in other labs, I offered it for publication to the journal “Electronic Engineering” in January 1961 (reference 1). (Due to a printer’s error, my initial appears as B instead of P). Only in recent years have I seen many references to my work, perhaps because the Internet makes it much easier look in the literature.

The main interest in my transformer seems to have been in the USA, among radio-amateurs (“hams”). A common problem was matching a 75 ohm feeder cable to a 50 ohm system. With my transformer you didn’t have to look for a quarter-wavelength of 61 ohm cable.

I have been pleased to see many references to my transformer on the Internet, thanks to L.B. Cebik (reference 2), Darrel Emerson (reference 3), and others. I have retired from CERN now (many years ago), and am living in France, close to the Swiss border and Geneva.

References

1. P. Bramham. A convenient transformer for matching coaxial lines. Electronic Engineering, Jan.1961. (Vol.33 no.395)

2. L.B. Cebik. Antenna application notes. Eagle.

3. Darrel Emerson. The twelfth-wavelength matching transformer. QST, June 1997 (Vol.81 no.6.)

RFID Enables Self Serve Draft Beer

My new favorite wireless product - self serve draft beer enabled by RFID technology. Coming soon to a bar near you, self service drafts using an RFID card, computer screen or maybe even your smartphone. According to their website, DraftMagik™ is the first hosted service of its kind to manage and deliver draft beer to the Point-of-Pour™ while also providing an interactive patron experience. The beer can be poured in full-service fashion by the bartender (behind the bar) or in a “pour your own beer” mode by age-verified patrons (in front of the bar at a table or wall). Each of these distinct Point-of-Pour™ locations are managed by DraftMagik to provide the establishments a secure and reliable system to control, measure and effectively deliver draft beer.

DraftMagik also meters and tracks patron consumption via secure RFID technology. These RFID loyalty cards or one-time use wristbands can manage pre-paid, declining balance; credit card secured or pre-loaded balances. DraftMagik monitors and centrally controls a wide variety of advanced sensors, flow meters and valves to ensure accurate and real-time display and reporting of all draft beer served at the client site.

I can't wait!

A Stellar Partnership

Those of you following me on twitter (@mwjournal) received a tweet yesterday as I was about to meet with the folks at Stellar Industries in Millbury Massachusetts –a quiet New England town blending residential homes and “old-school manufacturing” facilities on the outskirts of Worcester. Stellar Industries, a manufacturer with just over 30 employees specializes in custom designed substrates and direct bond copper for photonics and microelectronics. The company does a brisk business selling products to the Telecom, Biomedical, and Defense Industries.

The company believes there is a good business opportunity for their products in the RF market, thus they requested a meeting to see how the Journal could help spread the word. With the recent inflation in gold prices, their copper clad substrate technology offers excellent heat-sinking properties at very competitive prices. Company President Ron Visser is well acquainted with the Microwave industry and has been attending the MTT-S IMS for years. Exhibiting at last year’s show, Ron and his sales manager Eric Brown were pleased by the amount of interest exhibition attendees showed for their technology.

The astronomical price of gold (thanks to speculators and other investors looking for safe haven) would give their copper submounts a huge cost advantage. And the company’s double-digit growth last year vindicates their bullish enthusiasm for revenue growth in the immediate future. So we look forward to hearing more from this company in the future.

Another tidbit that I heard from Eric Brown during our facility tour concerned a successful government initiative to support Stellar’s growth as a business. The Mass Manufacturing Extension Partnership offers companies training in the Time Wise® Principles of Lean Manufacturing to help them become more competitive. I was very impressed by this story, especially considering the news this week about the California solar panel manufacturer that received federal seed money yet is now filing for bunkruptcy because they can't compete with their Chinese counterparts.

Too often the media reports on the government’s shortcomings and one can come to believe the public sector is incapable of getting anything right. But based on Eric Brown's praise for this particular state funded program, this just isnt the case. In an age where government is portrayed as “the” problem and a roadblock to capitalism and the free-market, this example illustrates how government can be get it right. As any investor knows, in business you win some and you lose some. This example tells me that we need continued government support for the private sector, even if every effort doesnt succeed.

From the Mass Manufacturing Extension Partnership website:
http://www.massmep.org/success_stories/stellar.html

Stellar also specializes in vapor deposited thin films and gold/tin solders on thick film and thin film as well as on semiconductor wafers. For small manufacturers, on-time delivery and high quality, long-lasting products are what separates them from larger companies and overseas competition.Stellar Industries, a manufacturer with just over 30 employees, makes a unique product which is good for business, but the types of custom requests it receives from customers can slow down delivery. The Millbury-based company makes miniaturized heat conductive ceramic blocks, similar to circuit boards, which are made-to-order for customers in the telecom, biomedical, and defense industries. Demand for their products is increasing and as the company grew, management recognized a need to more efficiently manage their production process. Stellar called on the Massachusetts Manufacturing Extension Partnership (MassMEP) to help streamline their performance on the production lines.

Utilizing the Time Wise® Principles of Lean Manufacturing, the MassMEP trained all 32 employees. Stellar Industries showed great progress in the time it takes to produce a product and improved their teamwork skills. "The MassMEP team opened our eyes to different ways of manufacturing," said Ron Visser, President of Stellar Industries. "We can now look at everything from a different standpoint. We take what the customer wants and break it down into smaller steps to increase productivity and product quality."Since the program was implemented, the dollar output per manufacturing employee has increased 8 percent to an all time high for the company. Product output has increased by 25 percent. For the first time ever, all weekly work orders were delivered on time."Communication is key. As a result of the training, we have opened up lines of communication that weren’t there before," added Visser.The company also conducts frequent Kaizen events, short bursts of activity to make small improvements with a goal of making large gains in efficiency and productivity, which will continue to wring out more waste from their operation. They now also have a Lean steering committee that monitors such activity."The next step for us is to be certified by the International Organization of Standardization (ISO), the world’s largest developer of production and manufacturing standards," said Visser. "Lean has allowed us to be more disciplined, so we should be able to go into ISO much easier than a year ago. Every day, we see improvements. It takes a continual effort."


About Stellar Industries

Stellar’s products include custom lapped and polished electronic grade ceramics composed of Alumina, Beryllium Oxide, Aluminum Nitride, or specialty ceramics. Stellar also supplies custom services for metalizations on these ceramics using a variety of thick film, thin film, refractory and Direct Bond Copper metalizations. Our ceramic substrates are used in a variety of electronic components including:
Laser Diode / Photodetector Submounts:
• Featuring precision machining and wrap-around metalization vapor deposited gold/tin solder alloys
High Power Microelectronic substrates:
• Featuring Copper Clad High Temperature DBC metalization
Microwave and RF thin film substrates:
• Featuring Precision Ion Etch geometries

Wireless Sensor Networks to Reach $2 Billion in 2021

According to IDTechEx research in the new report "Wireless Sensor Networks 2011-2021", WSN will grow rapidly from $0.45 billion in 2011 to $2 billion in 2021. These figures refer to WSN defined as wireless mesh networks, i.e. self-healing and self-organizing. Wireless Sensor Networks will eventually enable the automatic monitoring of forest fires, avalanches, hurricanes, failure of country wide utility equipment, traffic, hospitals and much more over wide areas, something previously impossible. It has started already with more humble killer applications such as automating meter readings in buildings, and manufacture and process control automation.

The market for non-mesh wireless sensor systems in general is far larger and some proposed standards apply to both. For example, in addition to the above, the market for Real Time Locating Systems is $0.38 billion in 2011 rising to $1.6 billion in 2021.

Mesh WSN - status today
By far the biggest success of WSN has been in smart meters. Lesson number one - the Governments can make things happen faster than industry. In many countries around the world Governments have mandated that so called "smart meters" need to be installed in certain circumstances, such as new house builds or retrofits. More than 50 million have been installed so far. Now meter reading data is sent wirelessly, and the power is taken from the electricity supply so no batteries are needed. This is seen as a starting point to home automation - wireless sensors embedded in the house that will automatically communicate with the smart meter, your thermostat etc. It is part of the smart grid activity. Here, the ZigBee protocol is being employed.

Lack of Standards Delays Adoption
However, those that supply WSN need to be aware. There is no single standard that has emerged as a clear winner. Indeed, many so called standards are not - many companies implementing ZigBee for example meet the basic criteria to use the ZigBee label but add further capability resulting in systems that are not interoperable with different sensors from different vendors. Many vendors, including giant system integrators that have their own proprietary wireless communications, hope that they may become the chosen default "standard". A small number may win. The industry is not gearing towards a more collaborative approach to allow many to win. This in turn is putting off adoption. Would you install tens of thousands of wireless sensors in your plant locations if it was a proprietary solution? What if that company would not exist in five years?

This reads on to the lack of scalability - party due to lack of multi vendors sensors working together - but no-one has really tested many tens of thousands of mesh wireless sensor nodes. Theory suggests key network paths may form and if they are removed the system can slow down to unacceptable levels.

Lack of Total Solution Delays Adoption
Another challenge that vendors need to address is that many only offer hardware. Adopters are often on their own for the software - which they need in order to make useful decisions on the data collected to give the system a payback. IDTechEx note that in wireless sensing, the big successes are those that offer complete solutions. One example is Savi Technology, part of Lockheed Martin, that offer a full solution to asset tracking/visibility and the other is Ubisense, a successful UK company that has recently listed (and oversubscribed in doing so) based on a real time locating systems (RTLS) solution offering. Those selling only hardware now take note.

Adoption Forecasts
In the new IDTechEx report "Wireless Sensor Networks 2011-2021", IDTechEx forecasts the market in great detail. We study how the average price per node will drop from $29 in 2011 per piece to $25 per piece in 2021. The report looks at the latest activity and sees how these challenges are being tackled.

US ahead but Asia catching up
The USA dominates the development and use of WSN partly because of the heavier funding available there. US industry sits astride the computer industry thanks to companies such as Microsoft and IBM and WSN is regarded as a next wave of computing, so US industry is particularly interested to participate. Add to that the fact that the US Military, deeply interested in WSN, spends more than all other military forces combined and creating and funding start-ups is particularly easy in the USA and you can see why the US is ahead at present.

Watch the Governments
It was the Governments that created the first killer market for wireless sensors in smart meters, even though in reality most do not use the wireless features of the smart meters yet. The US military have spent more than $21.5 Billion on RTLS/sensor asset tracking solutions. Industry usually prioritises rapid payback, Governments don't always have to as they seek better security, safety, longer term efficiency etc. One such new project in Europe is "Living planIT", focused on making smarter cities. 22% of the global population lives in 600 major sized cities, representing 50% of the global GDP. Improving quality of life is therefore a very important challenge but also represents a great opportunity for sustainable technologies. Living PlanIT's aim is to create an ICT platform through aggregating existing and proven technologies that will be blended into real estate development. That would have as a prerequisite to embed technology (e.g. wireless sensors) into the construction process rather than rely on retrofitting which becomes more cost intensive.

In the first wave of the project, 2, 897,640 sensors will be embedded in Living PlanIT's "test-city" in Portugal. Requirements for these include standardisation, open API, horizontal integration but also, zero maintenance for embedded sensors that would have to meet lifetime expectations of over 30 years. Living PlanIT will be presenting at the IDTechEx event "Wireless Sensor Networks & RTLS USA 2011" in Boston, USA on November 15-16. This is the only event on the topic to cover the latest progress with technology and adoption. You will hear the needs and experiences of many end users.

Source: IDTechEx report "Wireless Sensor Networks 2011-2021" www.IDTechEx.com/wsn

Industry leaders predict a 'White Space economy'

Cambridge Consultants has released a report discussing the foremost business opportunities in wireless technologies enabled by White Space frequencies, predicting the development of the first White Space consumer devices in the next five years. The report entitled is the result of a White Space workshop hosted by Cambridge Consultants, and brings together experts from across the wireless and broadcast industries including representatives from Nokia, Samsung, BBC, BSkyB, Neul and CSR to discuss White Space technology.

The report views the use of White Space radio as an inevitability, addressing a critical need for redressing methods of spectrum usage and opening up new possibilities for wireless devices. Much discussion of White Space to date has focused on the potential for helping meet rapidly increasing demand for mobile data on smartphones. However, the report emphasises that White Space technology has the potential to provide for a far broader range of applications and presents a solution for the ‘always on’ society.

Deemed the ‘White Space economy’, the report considers the expansive new business opportunities for a range of industries and suggests that initial market opportunities will emerge as a series of smaller, niche applications which would minimise dependency on multiple parties and require lower investment. In terms of revenue generation, White Space technologies could see returns both through direct data delivery or indirect revenue streams such as advertising. Data revenue may suit certain geographies for applications such as rural broadband, whereas advertising could be more suitable for applications such as local content broadcasting.

The report also examines the role of the UK as leading Europe in White Space development, and the role Ofcom has in creating a successful model that will set the blueprint for other countries to follow.

Specific opportunities highlighted:

Micro or localised wireless Internet service providers (WISP)
There is great potential for businesses (supermarkets or local government, for example) operating in more remote areas to supply Internet services and advertising to the local surrounding area. Delivery of personalised and location based services to very local clientele, for a very modest investment by the supplier, is an attractive new business model and the report speculates that delivery could cost as little as one tenth of the cost of copper.

Localised broadcasting
For broadcasters, there is now interest in using White Space for interactive ‘back-channel’ applications and the delivery of highly localised content and advertising.

The ‘Internet of Things’
Encompassing areas such as M2M, smart metering, and applications that require connectivity over a long-range but low data rate, White Space stands out as an enabler of the ‘Internet of Things’. White Space is especially appropriate firstly because the method for connecting can be optimised to meet the need for longer range and lower bit rate. Secondly, the data transferred is low rate and in some instances very infrequent, and for some applications the majority of data can be transferred at a time when it is less likely to cause interference.

The report predicts that we will see enterprise White Space devices developed by the end of 2011, and consumer devices entering the market in five years.

Product Highlights from EMC 2011

I spent the last two days in lovely Long Beach, CA at the IEEE EMC 2011 conference and exhibition. It is a great venue right on the harbor including the nice southern CA weather with the Queen Mary parked right across the harbor. The traffic in the exhibition was average with some busy times in the morning but typically slowing as the day went on. I visited all the microwave companies at the show and have noted below some of the more interesting products I came across. A full report will be coming in a couple of days highlighting all the companies I visited.

AR was showing off their DER2018 digital emissions receiver with continuous coverage from 20 Hz to 18 GHz with 140 MHz of instantaneous bandwidth. We shot a video to demonstrate its fast scanning performance as it displayed a full scan in 7 sec that would take a spectrum analyzer something like 10 minutes to produce.

For test and measurement, R&S had several displays but highlighted their RTO Oscilloscope in a video we shot. The touch screen display and noise floor are very impressive. Agilent was showing off their N9038A MXE EMI receiver which we also captured on video. It can scan 20 minutes of gap less data using its data recording function. Aeroflex was showing off their new S-Series fast, low noise signal generator operating from 100 kHz to 3 or 6 GHz.

There were many impressive amplifiers such as IFI's 1 to 6 GHz, single band amplifier which is unique to the industry, Ophir's family of 80 to 1000 MHz models ranging from 200 to 2000 W and CPI's 18 to 22 GHz 250 W model. Miteq had on display their family of fiber optic links to 22 GHz which are well suited for low loss equipment links that are immune to interference. 3M showed me a ribbon flex cable that performs to 12 GHz even when fully folded at a 90 degree angle.

I was able to attend the Gala Event on the Queen Mary which was spectacular and well put together. Hundreds of attendees were transported for a short ride to the other side of the harbor and enjoyed drinks and dinner on the majestic ship. The organizers did a great job this year! Next year's show is in Pittsburgh, PA - see you there.

RF Things to look for in the UK

At the Journal, we are currently working on our September European Microwave Week Show issue. This year the event takes place in Manchester, UK and so England is on our minds. The show is about six weeks away and early signs of heavy activity among Journal advertisers and EuMW exhibitors is indicating a strong show. If you are among the microwave professionals travelling to the UK keep your eyes out for the RFID way-finding system that is being deployed troughout the country to assist the blind and partially sighted.

According to RFID News, a UK-based charitable organization known as Guide Dogs is working with the University of Reading to employ RFID technology to provide the visually impared with the means to choose how they get about. The way-finding system consists of three main components: RFID tags, a handheld receiver, and a database of pre-recorded messages about each tag’s location.

The tags are embedded in the surrounding environment such as at bus stops or indoor shopping centers. When it comes into range, the handheld reader scans the tag and speaks to the user, telling exactly where he/she is. The system, dubbed Talking Tags can also provide additional information about the immediate environment around them. Users and potential service providers such as city officals, retail outlets, and transit providers recently tested the system in London and gave it positive reviews.

Electromagnetic Fish Hook Repels Sharks

This news is a couple of months old but I found it interesting and just now stumbled upon it. A New Jersey-based Shark Defense company developed the SMART (Selective Magnetic and Repellent-Treated) Hook that is intended to repel sharks but does not affect other types of fish. It is magnetic and coated with a metal that produces an electrical current when placed in seawater. Electromagnetic fields are known to affect sharks' sensory systems they try to steer clear of them when possible. Market-valuable fish, such as tuna, do not have this electrical sense and are not repelled by the hook. It requires no power source, and reportedly only costs slightly more than a traditional hook (an amount that should be made back through reductions in damaged equipment, wasted time, and unmarketable catches).

In a set of 50 tests using two different groups of sharks, it was found that smaller, recreational-sized SMART hooks with bait received 66 percent less shark strikes than their conventional counterparts. Larger, commercial-sized SMART hooks received 94 percent less, due to the fact that more of the shark-repellent metal was present.

As reported by Live Science, the original work was sponsored by NSF SBIR grant. "Combining a magnetic repellent with a galvanic repellent is very important, because many studies have shown that sharks behave differently to magnets or metals alone," said Craig O'Connell, who researches the effects of magnetism in sharks with Shark Defense and publishes on the subject. "There are many species of shark, and they seek out their prey differently. Having two repellents available increases the chances that the sharks will be deterred."

Magnetic and voltage-creating metals have separately been shown to reduce shark catches by 18 to 68 percent in past studies, although the Shark Defense researchers state that combining the two properties boosts the SMART hook's repellent properties.

EM waves have many uses!

Google Wallet and NFC Smartphones Starting to Take Off

ABI stated that recent developments in contactless payment technology are generating renewed interest, and suggest that the long-delayed dream of comprehensive contactless payment systems may finally be approaching reality. The introduction of Google Wallet and the expectation that several new NFC-enabled smartphones will reach consumer markets soon have created a sense of optimism.

According to ABI Research, in 2010 only about 10% of total POS terminal shipments included some form of contactless technology. While the analyst firm does not agree with some of the wilder media predictions for contactless POS growth – for example that within 12 months, one third of all terminals in the US will accept contactless payments – it does forecast that 85% of terminals shipped worldwide will be contactless-enabled in 2016, driven by increased proliferation of contactless cards and especially, rapid adoption of NFC-enabled cell phones.

Senior analyst Craig Foster comments, “Contactless has the potential to change the way we pay for goods completely, significantly reducing time spent queuing at the point of sale. It also represents an almost perfect fit for the vending industry, because:

• The increased speed and simplicity of check-out go hand-in-hand with the very essence of the vending machine – to provide goods quickly and conveniently;

• The fact that small-value transactions – typically under $25 in the US – do not need to be authenticated by signature or PIN entry is very appealing to vending machine operators.”

M2M practice director Sam Lucero adds, “Contactless technology is also in the very early stages of adoption in ATMs: rather than inserting the card, a customer waves it in front of the machine and enters a PIN.”

Ingenico, VeriFone, and Hypercom are the three leading vendors of POS terminals and command most of the market. VeriFone recently completed the acquisition of Hypercom after satisfying the antitrust concerns of the US Department of Justice. Contactless terminals have formed an increasingly significant part of Ingenico’s portfolio in recent years, accounting for a claimed 21% of the company’s shipments in 2010.

After Chinook Downing, RPG Defeat Should Get More Priority

It was very sad to hear about the recent downing of the Chinook helicopter in Afghanistan that killed 38 soldiers. Eastern Afghanistan has steep mountain ranges, providing shelter for militants with rocket-propelled grenade launchers creating a dangerous area for military aircraft and personnel. Large, slow-moving air transports like the CH-47 Chinook are particularly vulnerable, so the military should not be surprised that one was shot down especially if it is not equipped with countermeasures as it is a relatively defenseless aircraft.

The two greatest dangers faced in asymmetric warfare are improvised explosive devices (IED) and rock propelled grenades (RPG) as they are easy to obtain and widely used by insurgents. Large funding has gone into IED defeat systems in the US, such the Warlock and JCREW programs, with thousands of systems being fielded. These are RF based systems to jam wireless frequencies that remotely detonate the IEDs. The systems have been relatively effective but there are other ways to detonate IEDs (wires, pressure plates, etc.) so they are not a total solution to defeat them. However, there seems to be much less emphasis put on defeating RPGs as there are only a few systems available today.

Most solutions are deployed on land vehicles which have cages or nets around them that are designed to defeat RPGs but these would not be appropriate for airborne vehicles (photo courtesy of Polish military). There are a couple of active RPG defeat systems that have been developed for vehicles that use RF technology. Rafael Advanced Defense Systems and Israel Aircraft Industries' Elta Group developed an active protection system called Trophy. Trophy intercepts and destroys incoming missiles and rockets with a shotgun-like blast by using radar sensors to track the incoming RPGs. The system includes the Elta EL/M-2133 F/G-band fire-control radar with four flat-panel antennas mounted on the vehicle, that has a 360-degree field of view. A computer uses the signal from the incoming weapon and calculates an approach vector. The system then calculates the optimal time and angle to fire the neutralizers. The launchers fire the neutralizing agents, which are usually small metal pellets (like buckshot).

A few years ago it was reported that there was resistance to incorporating Trophy into the US Army. The US DoD had contracted with Raytheon to develop a similar system, Quick Kill, which at the time was several years behind Trophy in development so there were rumors they wanted their own system instead of the Trophy. Later, in February 2011, Rafael announced that the Trophy system completed a successful evaluation in the US. This system is primarily intended to be used on ground vehicles so these systems probably need to be adapted to be used on airborne vehicles.



Another system that is a non-lethal RPG defeat concept is the RPGNet from Qinetiq US that uses a net shaped "trap" made of super-high strength ballistic fiber, developed under a joint ONR/DARPA program. The net intercepts the flight trajectory at a safe distance from the vehicle and defeats the RPG by crushing its nose, rendering the fuse inoperable. This prevents the high-order blast effect by preventing the formation of the shaped charge plasma jet. The system is in development by Foster Miller from program for the Office of Naval Research (ONR).

Several US companies are working on systems to defeat RPGs but they seem behind several other countries like Israel and the UK. General Dynamics has developed the ShotScreen™ RPG Defeat System which is an active protection system that can be mounted on new or retrofitted on a variety of vehicles including helicopters. The system releases a wave of small diameter, low velocity non-lethal pellets from several non-slewing locations to defeat multiple anti-tank type RPGs. It provides 360° horizontal protection with variable inclination coverage and an option for full hemispherical coverage. As mentioned previously, Raytheon has also worked on active protection systems.

Asymmetric warfare presents different challenges than the military is used to dealing with over the years so priorities need to be assessed and new systems deployed quickly to meet these new challenges. Airborne vehicles operating in insurgent areas need protection/countermeasures such as RPG defeat systems which should be more of a priority for the military on vehicles performing critical missions such as the Chinook that was shot down.

NI Week: Austin in August

Every year in August, National Instruments hosts NIWeek, a truly impressive event that focuses on graphical system design and the company’s test & measurement and controller software. This conference attracts more than 3,000 of the world's brightest engineers, educators, and scientists. NIWeek 2011, the company's 17th annual customer and technology conference, opens August 2 at the Austin Convention Center in Austin, Texas, for three days of interactive technical sessions, targeted summits, hands-on workshops, and exhibitions on the latest developments for design, control, automation, manufacturing, and test. The conference also features keynote presentations and demonstrations that highlight how engineers and scientists can use NI graphical system design to test, measure, and fix inefficient products and processes to improve everyday life.

There are many benefits for attending NIWeek 2011, including the technical sessions, a chance to see NI collaborators and their products, and the opportunity to network, which is such a critical part of our careers. The conference provides opportunities to boost productivity through the three full days of interactive technical sessions, exhibitions, and hands-on workshops on the latest technologies for control, design, measurement, automation, manufacturing, and test. The company claims that most engineering professionals who attend the conference increase their productivity significantly.

This year's keynotes include founder Dr. James Truchard who will discuss the latest technologies, including timing and synchronization, streaming digital signal processor (DSP) design, and software-defined radios, to optimize graphical system designs around the world.Jeff Kodosky, coinventor and "Father of LabVIEW" with more than 30 patented LabVIEW technologies, sharing his vision for tackling challenging timing problems with LabVIEW, the future of graphical system design, and the possibilities it presents for engineers and scientists.

NI R&D engineers will also explore cutting-edge products and technologies that enable new applications and change the way engineers and scientists design, build, and test complex systems. I had the chance to attend NI Week several years ago and I have to say it is a great experience. The atmosphere is similar to the most advanced science fair you could ever imagine. When the R&D team shows off their stuff, they always put together a highly entertaining demo. When I attended there were chopper motorcycles, dunk tanks, archery, high-speed video capture and giant flat panel screens called into service to wow the audience. Not to mention the hyped-up sound system. It was a little bit like a Vegas production, a little bit Mac World.

If we wanted to get the next generation of kids excited about science, I would send them to NIWeek. Its that much fun. Unlike dedicated microwave shows like IMS, this event really lets engineers experience technology far outside their usual experience. It is very rewarding and eye opening. Of course their will be a dedicated RF pavilion for RF/microwave engineers that want to slip into their comfort zone while attending. I will also be there to meet Massachusetts Executive Fanny Mlinarsky of Octoscope and hear her talk about Over-the-Air Test solutions.

And the big acquisition of AWR and Phase Matrix this past spring should make this year's NI week especially relevant. Hope to see some of our readers there.

Industry Hardware Gets 15 Minutes of Fame

I get that this is entertainment and not real news, so please indulge my little rant, which is meant for your entertainment.

My "exposure" to the daily television show GMA (Good Morning America) occurs as a captive viewer stuck on a treadmill at the local gym. With no access to the TV controls, getting in shape usually means turning a little piece of my brain into mush on those days. Between the steady diet of "mind-numbing repetition of that day's big story with little depth or insight" or the "day after day reporting of nothing new in some long-drawn out soap-opera trial for some grizzly murder", it is hard for me to say great things about the programming of this or other similar shows. But the kicker for me is the health alert. You know the one. This segment warns the viewer that what you don’t know about some commonly found object, food/drink or activity could harm you and your family.

As mentioned, I’m just a captive audience on a treadmill. My intake is purely visual, no audio. And so what gets burned into my consciousness is the message suspended on the lower portion of the TV screen during the segment that is responsible for today’s rant, which reads, “Health Alert: Cell Phone Cancer Alarm, Rating your Radiation Levels”. Well that doesn’t look good. And I wonder, do most people understand the difference between non-ionizing microwave radiation and X-ray radiation? If you’ve ever watched the hilarious Jay Leno interviews with the average person on the street, it is hard to believe that they do. Certainly the appearance of the words “Cancer” and “radiation” next to each other doesn’t help clarify the distinction.

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This recent broadcast was a follow up to a statement from the World Health Organization this month that people should be “more cautious about how much we use our cell phones due to concerns about a link to brain cancer”. Wait, back-up. What statement? What was the link? What was the method used to determine a link? Could you explain/quantify “more cautious”? Not in this segment.

Here’s a little background on the WHO report, courtesy of CNN.

A team of 31 scientists from 14 countries, including the United States, made the decision after reviewing peer-reviewed studies on cell phone safety. The team found enough evidence to categorize personal exposure as "possibly carcinogenic to humans."

What that means is they found some evidence of increase in glioma and acoustic neuroma brain cancer for mobile phone users, but have not been able to draw conclusions for other types of cancers. "The biggest problem we have is that we know most environmental factors take several decades of exposure before we really see the consequences," said Dr. Keith Black, chairman of neurology at Cedars-Sinai Medical Center in Los Angeles.

"What microwave radiation does in most simplistic terms is similar to what happens to food in microwaves, essentially cooking the brain," Black said. "So in addition to leading to a development of cancer and tumors, there could be a whole host of other effects like cognitive memory function, since the memory temporal lobes are where we hold our cell phones." In February, a study by researchers at the National Institutes of Health, revealed radiation emitted after just 50 minutes on a mobile phone increases the activity in brain cells. The effects of brain activity being artificially stimulated are still unknown.

Wireless industry responded to the announcement saying it "does not mean cell phones cause cancer." CTIA-The Wireless Association added that WHO researchers "did not conduct any new research, but rather reviewed published studies."

"When you look at cancer development -- particularly brain cancer -- it takes a long time to develop. I think it is a good idea to give the public some sort of warning that long-term exposure to radiation from your cell phone could possibly cause cancer," said Dr. Henry Lai, research professor in bioengineering at University of Washington who has studied radiation for more than 30 years.

Results from the largest international study on cell phones and cancer was released in 2010. It showed participants in the study who used a cell phone for 10 years or more had doubled the rate of brain glioma, a type of tumor. To date, there have been no long-term studies on the effects of cell phone usage among children.

"Children's skulls and scalps are thinner. So the radiation can penetrate deeper into the brain of children and young adults. Their cells are at a dividing faster rate, so the impact of radiation can be much larger." said Black of Cedars-Sinai Medical Center. Of course, I rarely see children hold a phone up to their head, nobody can text that way.

Back to the GMA segment where electrical engineering associate professor, Dr. Michael Knox from NYU Polytechnic University (winner of the 2011 Distinguished Teacher Award) has been recruited to monitor the RF energy in a typical American home (husband, wife, 2 kids, 5 cell phones, Wi-Fi and microwave oven) using the N9340B Handheld Spectrum Analyzer from Agilent Technologies. I had to chuckle as the anchor described how the family allowed ABC to invade their home with a “Big machine that measures radiation”. Maybe I’ve seen too many handheld spectrum analyzers at various trade shows, but that one doesn’t look so big to me. In fact it looks kind of cute. Congratulations on making prime time TV, Agilent.

As Dr. Knox roamed the house (interrupting dinner time) with a “fancy machine that measures radio waves” aka spectrum analyzer, the family got a visual glimpse of the radio activity from their cell phones, Wi-Fi and microwave oven. While Agilent’s spectrum analyzer performed flawlessly detecting the RF signals from each, I’m not convinced the information meant anything to the on looking, non-technical family. I have to imagine the same was true for the majority of the TV audience paying attention. Nice try GMA. I wonder what’s on The Today Show?

The Mine Clearing Beast Autonomous Vehicle

Wireless controlled autonomous vehicles of all kinds are being developed by the military. An interesting type being developed are IED and mine clearing vehicles. They can safely clear areas for the military and civilians caught in war tore areas.

The Digger D-3 is a mine-clearing robot with a unique approach. Instead of poking around to locate mines and explosives, it shreds that area and eats them. It is a land tiller on steroids (and lots of them). At the front of the D-3 is a giant spinning metal pulverizer, which has tungsten hammers that beat down a quarter meter into the ground, turning everything into mulch. The mines do blow up but don't seem to damage the Digger at all. It is designed to width stand antitank mines and unexploded shells of sizes up to 81 mm and has been able to successfully ingest mines containing as much as 8 kilograms of explosive.

Here is the Digger D-2 in action:


An operator commands this beast from a safe distance using a remote control unit. The hull of the robot is made up of hardened steel plates in a "V" shape to help limit any damage from explosions. The only potentially vulnerable spots are the air intakes, which are protected from flying shrapnel by special grates. At full throttle, the D-3 can reliably clear a comforting 100 percent of landmines from the ground at a rate of 1,000 square meters per hour (about 10,000 square feet per hour), while also divesting the land of any unwanted shrubbery (I guess you can plant the field it leaves behind). I can't wait to try one in my back yard so I can plant new grass!

Is RF Radiation from Cell Phones Dangerous?

A very controversial subject is whether RF radiation from cell phones is dangerous to our health. There are studies showing that it might be and others that show is not dangerous. Many people do not realize that RF radiation at these frequencies is non-ionizing so it cannot damage the cell structure on the molecular level like solar radiation does. However, it can heat the cells (as a microwave oven does to food) but cell phones are relatively low power so does it do any damage to us? Nothing conclusive to date has shown that it is dangerous at the power limits set by the FCC or other international organizations. Below is a recent release about the subject.

The International Journal of Hyperthermia has unveiled a new special issue which addresses the thermal aspects of RF exposure on human health. This special issue resulted from a workshop born out of the controversies surrounding huge growth and use of wireless communication. In the issue, invited experts further refine a quantitative assessment of the effects of thermal energy on tissue damage, fetal development, immune function and neurocognitive behaviour. The special issue papers are available on: http://informahealthcare.com/toc/hth/27/4.

One of the key findings of the workshop and research papers is that while RF exposure standards can surely be refined further, it is fair to say that the present exposure limits set for the general public are far more protective against thermal hazards than recommended limits for the temperature of hot water in the home.

“The purpose of the workshop – and the resulting special issue – was to review current knowledge of the effects of heat on the body that are of potential relevance to setting limits for human exposure to RF,” explains the lead review author, Kenneth R Foster, of the Department of Bioengineering at the University of Pennsylvania. “Thermal damage to the body is clearly a very large topic; our discussion and this special issue focuses on thermal effects that are likely to be relevant to setting RF exposure limits.”

“We examined the most appropriate health endpoints for a given tissue or system, appropriate time periods for acute and chronic exposure, time-temperature thresholds for adverse effects, as well as cost effective and targeted research to help us better understand and define human exposure standards,” continued Foster.

“The upshot was that current RF limits, as recommended by the WHO and adopted by the majority of the world’s governments, are – in thermal terms – far below temperatures that could harm the body,” says Foster. “Indeed, under ordinary environmental conditions, exposure at the whole body limits for the general public, will lead to no detectable increase in core body temperature due to thermoregulatory responses.

That said, both sets of current guidelines on exposure to radiofrequency are subject to limitations, despite the fact that they form the basis for exposure guidelines throughout most of the world. The IEEE (Institute of Electrical and Electronics Engineers) and the ICNIRP (International Commission on Non-Ionizing Radiation Protection) limits set out basic restrictions in terms of power absorbed in tissue. However, the biologically significant quantity is the thermal exposure (increase in temperature and duration of exposure to elevated temperature).

Within the human body, time-temperature functions for thermal damage to different tissue types varies widely and current limit definitions are complex and difficult to explain to the public. In addition, new technologies employing high-power mmWave sources are coming into use and the possibility of human exposure to such energy at potentially injurious levels is increasing.

“If the limiting hazards of RF energy are indeed thermal, several questions must be addressed,” says Mark Dewhirst, Professor of Radiation Oncology, Pathology and Biomedical Engineering at Duke University. “Are current limits adequate to protect diverse tissues from thermal injury? Would it make sense to move to a time-temperature based limit? Are present standards adequately protective for exposures to the types of energy employed by modern electronic devices?”

I am sure there will be more to come on this subject. What do you think?

New Ga Tech Device Captures Ambient EM Energy to Drive Small Electronic Devices

This was published from Ga Tech a week or so ago - interesting research on energy scavenging:

Researchers have discovered a way to capture and harness energy transmitted by such sources as radio and television transmitters, cell phone networks and satellite communications systems. By scavenging this ambient energy from the air around us, the technique could provide a new way to power networks of wireless sensors, microprocessors and communications chips.

Georgia Tech School of Electrical and Computer Engineering professor Manos Tentzeris displays an inkjet-printed rectifying antenna used to convert microwave energy to DC power. This grid was printed on flexible Kapton material and is expected to operate with frequencies as high as 10 gigahertz when complete. (Click image for high-resolution version. Credit: Gary Meek).

“There is a large amount of electromagnetic energy all around us, but nobody has been able to tap into it,” said Manos Tentzeris, a professor in the Georgia Tech School of Electrical and Computer Engineering who is leading the research. “We are using an ultra-wideband antenna that lets us exploit a variety of signals in different frequency ranges, giving us greatly increased power-gathering capability.”

Tentzeris and his team are using inkjet printers to combine sensors, antennas and energy-scavenging capabilities on paper or flexible polymers. The resulting self-powered wireless sensors could be used for chemical, biological, heat and stress sensing for defense and industry; radio-frequency identification (RFID) tagging for manufacturing and shipping, and monitoring tasks in many fields including communications and power usage.

A presentation on this energy-scavenging technology was given July 6 at the IEEE Antennas and Propagation Symposium in Spokane, Wash. The discovery is based on research supported by multiple sponsors, including the National Science Foundation, the Federal Highway Administration and Japan’s New Energy and Industrial Technology Development Organization (NEDO).

Communications devices transmit energy in many different frequency ranges, or bands. The team’s scavenging devices can capture this energy, convert it from AC to DC, and then store it in capacitors and batteries. The scavenging technology can take advantage presently of frequencies from FM radio to radar, a range spanning 100 megahertz (MHz) to 15 gigahertz (GHz) or higher.

Georgia Tech School of Electrical and Computer Engineering professor Manos Tentzeris holds a sensor (left) and an ultra-broadband spiral antenna for wearable energy-scavenging applications. Both were printed on paper using inkjet technology. (Click image for high-resolution version. Credit: Gary Meek)

Scavenging experiments utilizing TV bands have already yielded power amounting to hundreds of microwatts, and multi-band systems are expected to generate one milliwatt or more. That amount of power is enough to operate many small electronic devices, including a variety of sensors and microprocessors.

And by combining energy-scavenging technology with super-capacitors and cycled operation, the Georgia Tech team expects to power devices requiring above 50 milliwatts. In this approach, energy builds up in a battery-like supercapacitor and is utilized when the required power level is reached.

The researchers have already successfully operated a temperature sensor using electromagnetic energy captured from a television station that was half a kilometer distant. They are preparing another demonstration in which a microprocessor-based microcontroller would be activated simply by holding it in the air.

Exploiting a range of electromagnetic bands increases the dependability of energy-scavenging devices, explained Tentzeris, who is also a faculty researcher in the Georgia Electronic Design Center at Georgia Tech. If one frequency range fades temporarily due to usage variations, the system can still exploit other frequencies.

The scavenging device could be used by itself or in tandem with other generating technologies. For example, scavenged energy could assist a solar element to charge a battery during the day. At night, when solar cells don’t provide power, scavenged energy would continue to increase the battery charge or would prevent discharging.

Georgia Tech graduate student Rushi Vyas (front) holds a prototype energy-scavenging device, while School of Electrical and Computer Engineering professor Manos Tentzeris displays a miniaturized flexible antenna that was inkjet-printed on paper and could be used for broadband energy scavenging. (Click image for high-resolution version. Credit: Gary Meek)

Utilizing ambient electromagnetic energy could also provide a form of system backup. If a battery or a solar-collector/battery package failed completely, scavenged energy could allow the system to transmit a wireless distress signal while also potentially maintaining critical functionalities.

The researchers are utilizing inkjet technology to print these energy scavenging devices on paper or flexible paper-like polymers – a technique they already using to produce sensors and antennas. The result would be paper-based wireless sensors that are self-powered, low-cost and able to function independently almost anywhere.

To print electrical components and circuits, the Georgia Tech researchers use a standard materials inkjet printer. However, they add what Tentzeris calls “a unique in-house recipe” containing silver nanoparticles and/or other nanoparticles in an emulsion. This approach enables the team to print not only RF components and circuits, but also novel sensing devices based on such nanomaterials as carbon nanotubes.

When Tentzeris and his research group began inkjet printing of antennas in 2006, the paper-based circuits only functioned at frequencies of 100 or 200 MHz, recalled Rushi Vyas, a graduate student who is working with Tentzeris and graduate student Vasileios Lakafosis on several projects.

“We can now print circuits that are capable of functioning at up to 15 GHz — 60 GHz if we print on a polymer,” Vyas said. “So we have seen a frequency operation improvement of two orders of magnitude.”

The researchers believe that self powered, wireless paper-based sensors will soon be widely available at very low cost. The resulting proliferation of autonomous, inexpensive sensors could be used for applications that include:

· Airport security: Airports have both multiple security concerns and vast amounts of available ambient energy from radar and communications sources. These dual factors make them a natural environment for large numbers of wireless sensors capable of detecting potential threats such as explosives or smuggled nuclear material.

· Energy savings: Self-powered wireless sensing devices placed throughout a home could provide continuous monitoring of temperature and humidity conditions, leading to highly significant savings on heating and air conditioning costs. And unlike many of today’s sensing devices, environmentally friendly paper-based sensors would degrade quickly in landfills.

· Structural integrity: Paper or polymer based sensors could be placed throughout various types of structures to monitor stress. Self powered sensors on buildings, bridges or aircraft could quietly watch for problems, perhaps for many years, and then transmit a signal when they detected an unusual condition.

· Food and perishable material storage and quality monitoring: Inexpensive sensors on foods could scan for chemicals that indicate spoilage and send out an early warning if they encountered problems.

· Wearable bio-monitoring devices: This emerging wireless technology could become widely used for autonomous observation of patient medical issues.