A W-Band High Intermediate-Frequency Subharmonic Mixer Utilizing a Novel T-Type Duplexer

This letter presents the design of a W-band subharmonic mixer (SHM) featuring a novel T-type duplexer structure. The structural modifications of the duplexer effectively reduce the discontinuities and parasitic effects in the microstrip lines, enhancing the transmission performance of both the local oscillator (LO) and intermediate-frequency (IF) signals. By optimizing the internal microstrip layout of the duplexer and shortening the length (L) of the open-circuited stub, the interference of the resonance point on IF output performance is eliminated. The SHM is fabricated and tested, and the results indicate that with the LO frequency fixed at 40 GHz, the conversion loss (CL) in the radio frequency (RF) range of 89–99 GHz is between 8.1 and 14.7 dB, with a minimum CL of 8.1 dB at 90 GHz, and a high IF output frequency range of 9–19 GHz, with an effective bandwidth of 10 GHz, is achieved. The potential application is as the first-stage frequency conversion module in the downconversion chain of a W-band multichannel transceiver.