Friday, September 30, 2011

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.