A broad W-band detector utilizing zero-bias direct detection circuitry

In this paper, a broad W-band detector utilizing zero-bias direct detection planar circuitry with high voltage sensitivity and enhanced tangential signal sensitivity (TSS) is proposed, which is intended to apply for W-band radiometer. The commercially available GaAs detector diode Agilent^® HSCH-9161 is adopted to build an unamplified zero-bias direct detector, along with probe transition, broad band microstrip impedance matching network and low pass filter. Voltage sensitivity up to 1000 mV/mW from 75 GHz to 104.5 GHz (almost full W-band) is achieved. A self-manufactured video amplifier is used to set the video bandwidth (VBW) as approximately 70 Hz and the obtained TSS is better than -51 dBm in the full W-band. The whole circuit is based on microstrip circuits and is hence easy and cheap to fabricate, which satisfies the low cost requirements of assembling large passive millimeter wave imaging array.