W-Band Broadband Single Balanced Waveguide Mixer

This paper describes the design and development of a broadband mixer at W-band using Schottky-barrier chip diodes in single balanced configuration. The mixer has been designed with rectangular waveguide and suspended stripline transmission line media on 0.127 mm Rogers RT duroid substrate. EDA tools like HFSS and ADS are used to optimize the performance of the mixer circuit. The mixer operates over radio frequency (RF) bandwidth (92 to 102 GHz) with local oscillator (LO) frequency at 91 GHz and it works in downconversion mode. Simulated conversion loss is less than 10 dB over 10.3 percent RF bandwidth for 10 dBm of LO power and measured conversion loss is less than 13 dB for 11 dBm LO power. Measured LO to RF isolation is greater than 35 dB.