A high-impedance dual-mode SAW resonator for ultra low power and high data rate FSK modulator

This paper reports on the design and experimental realization of a dual-mode surface acoustic wave (SAW) resonator with two high-impedance resonant peaks for ultra low power binary frequency-shift-keying (FSK) modulator applications. The single-device structure of the dual-mode resonator is believe to be a promising solution to eliminate the loading effect and noise as a result of multiple switches and other parallel connected resonators, and has the potential to reduce the size and complexity of packaging, compared with the multi-resonator multi-frequency approaches. The dual-mode SAW resonator concept is realized by an in-house, two-mask process that delivered symmetric-mode resonators at 404.9 MHz with trans-impedance values of 1,100 Ω and quality factor of 3134, and anti-symmetric mode resonators at 407.6 MHz, with 900 Ω trans-impedance and 4014 quality factors. Based on the experimental results, we propose a FSK modulator that integrates this high-transimpedance dual-mode resonator and reaches data rates up to 1.5 Mbps. The FSK modulator can be used for low power transmitters in body area network (BAN) and wireless sensor networks (WSN).