This thesis uses injection-locked oscillators to realize spectrum and vital sign sensor. At first, the thesis discusses the factors to affect the locking range based on Adler¡¦s equation, and adopts an increase of injection power to enlarge the locking range. Then, the circuit simulation using ADS is carried out to predict the output response of an injection-locked oscillator. As an implementation result, a CMOS chip of an injection-locked oscillator achieves 70 MHz locking range at -17.5 dBm injection power. In addition, a CMOS FM demodulator is realized with the injection-locked oscillator, showing that the chip can demodulate the FSK signal with a minimum frequency deviation of 350 KHz, a minimum input power of -39.5 dBm, and a maximum data rate of 40 Mbps. With the help of the above CMOS chips, a spectrum sensor and a vital sign sensor are realized. In the test, the spectrum sensor can measure a minimum signal power of -100 dBm at a scan speed of 100 MHz/0.5 ms, while the vital sign sensor can detect the breathing and heartbeat rate at a sensing distance of 80 cm.

This paper presents a novel power management analysis method to reduce the power consumption for the non-contact vital sign sensor. The sensor consisting of the class-E power amplifier (PA), low noise amplifier (LNA), single pole double through (SPDT) switch, and circularly polarized antenna (CPA) is integrated on the Flame Retardant Class 4 (FR-4) epoxy-glass laminate substrate. The appropriate pulse width and pulse period are determined to decrease the power consumption and accurately detect the human physiological signals (respiration and heartbeat). A simple direct down-conversion architecture with a tunable phase shifter is utilized to eliminate the null detection point and the direct current (DC) offset. The overall power consumption of the proposed sensor with the novel power management technique is only 40 % of the conventional system with the DC bias, which can be utilized for the green energy application.