Design of low -power super-regenerative receivers.

Abstract

The rapid growth of wireless communication is enhancing our lives in many ways. Applications such as implantable neuroprosthetic devices, robotics, and home automation, require short range, low data rate, and wireless communication, but for these applications power consumption must be very low and size must be small. In our research, super-regeneration is re-examined for its simplicity and efficiency when used for low-power, short-range communication and implemented as a single CMOS chip. We first present a complete study of super-regeneration theory. Different control modes and the limitations of super-regenerative receivers are discussed. We also propose a new system model to explain the theory. Based on this theory, we design two fully integrated CMOS super-regenerative receivers using several digital processing techniques to enhance performance. We use a synthesizer for multi-band operation and introduce a novel auto-calibration scheme to improve the system performance. We also present a new receiver architecture that incorporates a high-Q silicon micro-electro-mechanical systems (MEMS) resonator. Frequency selectivity is dramatically improved by taking advantage of the extremely high quality factor (Q > 10,000) of MEMS resonators. This design is one of the first demonstrations of a radio based on silicon MEMS components. Two fully integrated prototypes were fabricated using IBM's 0.13mum mixed-mode CMOS process. The first is a low-power wireless receiver that has a data rate of 500 kbps for on-off keying (OOK) modulated data on a 2.4 GHz carrier, has 9 channels, and consumes 3.6 mW. The second prototype is an auto-calibrated wireless receiver, which employs the successive approximation register (SAR) algorithm to eliminate external control. The receiver shows the same receive performance as the first prototype, consuming only 2.8 mW, but does not require any off-chip control. The third prototype is a super-regenerative core incorporating a MEMS resonator. It detects and demodulates 4 kbps OOK data modulated on 104 MHz carrier and consumes only 360 muW.