Low cost W-band sub-harmonic mixer using quasi-MMIC technology

In this paper, a high performance sub-harmonic mixer for W-band application using a low cost approach is developed. By flip-chip bonding a high performance schottky diode onto a separately fabricated passive circuit having a quartz substrate, a quasi-monolithic millimeter-wave integrated circuit (Q-MMIC) mixer is achieved. Compare to MMIC, the discrete device and passive circuitry of the Q-MMIC are fabricated separately, thus the fabrication process is simplified and the cost is reduced. The measurement results show the conversion of the developed mixer is less than 13 dB over the full W-band, as a 46 GHz LO signal with a 10 dBm power is pumped, which means the IF bandwidth can up to 18 GHz. A minimum conversion loss of 8 dB at an RF of 90 GHz and LO of 46 GHz is also observed from the measurements. The total size of the mixer is 2.2 mm× 4.0 mm.