2.45 GHz High Gain Self-Oscillating Mixer for Simple Short-Range Doppler Radar

摘要

A high gain self-oscillating mixer (SOM)for short-range Doppler radars, which meets the needs of simplicity, low power and low cost, is accomplished using a new optimization technique based on SOM's constant gain curves similar to those of amplifiers. Using the optimization technique, the maximally optimized value for conversion gain and corresponding circuit parameters can be obtained. The measured conversion gain is up to 21.2 dB with one FET, which is the highest value reported to date. For the SOM, a microstrip slotted-square-patch resonator (SSPR) with a high quality factor is adopted. The SSPR-SOM, which emits a low power of-3.64 dBm with a microstrip patch antenna of 3.8 dB gain at 2.45 GHz band, shows good performance as a proximity motion detector.