An X-Band Doppler Motion Sensor With a Two-Ports Oscillator

In this paper, we propose an X-band Doppler motion sensor based on a high-efficiency dual-output oscillator circuit integrated with a common resonator and a passive mixer. The oscillator provides two output signals with different power levels. The oscillator and mixer circuits are implemented in a 0.5 μm AlGaAs/InGaAs depletion-mode pseudomorphic high electronic mobility transistor process. The oscillator shows a high output power of 21.15 dBm at 11.2 GHz and a peak efficiency of 41.1 % at 10.7 GHz. For a 10.3 GHz oscillation, a phase noise of -132 dBc/Hz is obtained at a 10 MHz offset. The output power centered at 10.58 GHz is 11.67 dBm at one port and 9.12 dBm at the other port, and a phase noise of -105.8 dBc/Hz at 1 MHz offset when providing a 2.55 V supply with 28 mA consumption for practical Doppler motion sensor application that detects human motion at a distance of 13 m. A detection range of 30 m has been proven for human motion. This paper demonstrates the feasibility of a compact high efficiency Doppler motion sensor without a bulky power divider or amplifier by monolithic combining the proposed oscillator and mixer circuit.