The design of RF front-end chip for typhoon monitoring radiometer

The paper presents the design and performance of a V-band radiometer MMIC with 0.1μm GaAs pHEMT technology. The circuit includes a frequency double LO chain and a resistive mixer. The resistive mixer with balance structure topology can improve the image-rejection ratio. Compared with other mixers, the sub-harmonic mixer can achieve high isolation. The typical isolation measured between LO to RF is almost 60dB. The measured conversion loss of the mixer is from 13dB to 15dB over RF frequency 50-60GHz. The bandwidth of IF reaches 1 GHz. The circuit also exhibits very good phase difference between I/Q within 90 ± 6°. The completed mixer show 25dB image-rejection ratio (IRR) over the whole band.