A wideband Ka-band receiver with high gain flatness and slight group delay fluctuation

We report on the design consideration and experimental results of a wideband Ka-band heterodyne receiver with high gain flatness and slight group delay fluctuation. Flat gain performance is achieved by applying amplitude equalizers both in RF circuits and IF circuits. Small group delay fluctuation is fulfilled by making a trade-off between out-of-band rejection and group delay when designing the RF and IF BPFs. The measured results demonstrate that the receiver has a gain flatness less than ±0.5dB at a conversion gain of 55dB and a slight group delay fluctuation less than 2ns.