An Ultra-Broadband Doubly Balanced Monolithic Ring Mixer for Ku- to Ka-band Applications

A novel 12-40 GHz ultra-broadband doubly balanced monolithic ring mixer with a small chip size covering the Ku- to Ka-band applications implemented by a 0.15-mum pseudo- morphic high electron-mobility transistor process is presented. The proposed mixer consists of two spiral transformer baluns and a band-reject filter. The use of the spiral baluns leads to the achievement of a chip size less than 0.8 times 0.8 mm². The radio frequency (RF) spiral balun with a band-reject filter served by an L-C resonator is used to improve the bandwidth of the mixer and to provide an output port for the intermediate frequency (IF) extraction as well. The mixer exhibits a 6-12 dB conversion loss, high isolation over 12-40 GHz RF/local oscillation bandwidth, a DC-8 GHz IF bandwidth, and a 1-dB compression power of 14 dBm for both down- and up-converter applications.