Design of a subharmonic mixer for millimeter-wave applications

In this paper, design methodology of a millimeter-wave subharmonic mixer is presented. The mixer circuit consists of GaAs based Schottky anti-parallel diode pair (APDP) from Rutherford Appleton Laboratory and is implemented on the quartz substrate using microstrip line. The RF and local oscillator (LO) signal is fed through rectangular waveguides and E-plane probe transitions are considered to launch the signal from waveguide to microstrip line. Co-simulations show that the maximum down conversion loss within the frequency band 88 GHz-102 GHz is 10.5 dB while the LO frequency is kept fixed at 42 GHz. The simulations include the parasitic effects of the diode by considering its 3Dmodel.