A high performance self-oscillating sub-harmonic mixer (SO-SHM) incorporating compact microstrip resonant cell (CMRC) for wireless sensor application

Abstract

A new self-oscillating sub-harmonic mixer (SOSHM) is developed for low-cost wireless sensor application. The

mixer employed an improved compact microstrip resonant cell (CMRC) and its open-short dual band stub (DBS).

Incorporating the in-line CMRC and DBS into our new SOSHM, we can provide suitable oscillation for the LO

frequency and terminations to all major unwanted mixing products, leading to a unique high conversion gain

design. Our SOSHM with a measured 8.5-dB single side-band (SSB) down-conversion gain at 8.2 GHz RF signal

outperforms typical designs of 3 dB conversion gain, and represents a recorded high performance for a planar

X-band harmonic active mixer. Measured LO-RF isolation is better than 50 dB for RF ranges of 7.5-10 GHz. The

novel design achieved state-of-the-art performances at a much-reduced complexity and power consumption,

definitely making it a viable candidate to low-cost high performance wireless sensing subsystems.