A C-band GaAs pHEMT single-balanced resistive mixer with miniaturized balun is presented.By using lumped-distributed structure

the coupled-line length was reduced by a factor of 11 compared with the conventional

λ/4

coupled-line balun.This balun was then used in a resistive mixer to transform the input single-ended signal into differential.The mixer achieved good linearity and port isolation performance with zero power consumption.Test results showed that

with a fixed IF of 160 MHz and 0dBm LO power

the minimum conversion loss is 8.3dB in 3.5~5GHz RF frequency range.The measured 1dB compression point is 8dBm and the LO-to-IF isolation is better than 38dB.