2003 – Energy-Efficient Circuits and Systems Group

Subthreshold Programmable FIR Filter Chip

A suite of programmable FIR filters designed for operation in the subthreshold region provides insight into sizing for minimum energy operation.

Differential and Single Ended Elliptical Antennas for 3.1-10.6 GHz Ultra Wideband Communication

The primary design is an ultra thin, low profile differential antenna with an incorporated ground plane for use with a UWB IC receiver. The differential capability eases the design complexity of the RF Front-End, and the incorporation of a ground plane enables conformability with small electronic UWB devices. Two single ended designs are also presented for use with a UWB IC transmitter. Both designs result in excellent bandwidth, efficiency, and nearly omnidirectional radiation patterns.

Ultra-Dynamic Voltage Scaling Test Chip

This 90nm test chip demonstrates ultra-dynamic voltage scaling using local voltage dithering for a suite of 32-bit Kogge-Stone adders. The adders function from VDD at 1.2V to below 200mV, extending the range of energy-delay scalability.

A 180mV FFT Processor Using Subthreshold Circuit Techniques

Minimizing energy requires scaling supply voltages below device thresholds. The fabricated 1024-pt fast Fourier Transform (FFT) processor operates down to 180mV using a standard 0.18µm CMOS logic process while using 155nJ/FFT at the optimal operating point.