Microwave subsampler using cascaded cold pHEMTs

We propose a concept using cascaded cold pHEMTs to implement a microwave sampler for subsampling use. The MMIC concept supports slewed control voltages as well as digital square-wave control signals. As such, the control voltages could be from oscillator sources, or from logic signals that have poor fidelity caused by PCB parasitics, etc. Sampling losses of circa 14 dB have been simulated in subsampling mode with RF input at 10th harmonic of the sampling frequency.