Analysis and Exploitation of Diplexer-based Fully Passive Harmonic Transponder for 5G Applications

An analytical model for the conversion loss (CL) calculation of diode-based fully passive harmonic transponders is proposed in this work. Given diode’s SPICE parameters, the proposed model can accurately predict second-harmonic output based on RF input power. Thus, CL can be easily obtained. Such an accurate analytical model can be applied to evaluating potential CL performance of each diode candidate. Then, a novel diplexer-based fully passive harmonic transponder is designed, prototyped and measured. Through the introduction of the diplexer, traditional stringent antenna design restrictions can be alleviated. For an input power level of −30 dBm, measured CL of the proposed harmonic transponder is around 20.2 dB, which is more than 10 dB lower than the state-of-the-art counterpart.