Monolithic Ka to Ku-Band All Balanced Sub-Harmonic Resistive MHEMT Mixer for Satellite Transponder

This letter presents the design and measured performance of a novel Ka to Ku-band all balanced sub-harmonic resistive mixer monolithic microwave integrated circuit (MMIC). A new topology using 0.13 μm GaAs metamorphic high-electron mobility transistor (mHEMT) based mixing quad is implemented to reject mixing product spurious signals involving even order of radio frequency (RF). Measured performance shows more than 50 dB of isolation for the second harmonic of the local oscillator (LO) signal at the RF and intermediate frequency (IF) ports, which is better than earlier reported data for field-effect transistor (FET) based sub-harmonic resistive mixers to the best of the authors´ knowledge. In-band mixing product spurious of ( -2RF, +8LO) is found 70 dBc down with reference to the desired IF level for -10 dBm of RF input power. Effects of coupling on the mixer performance are also discussed through various electromagnetic simulations and measured results. Mixer exhibits conversion loss of about 9.5 dB.