A 3mm band microstrip single-diode frequency doubler using feed-forward technique
A 3mm band frequency doubler design was formed by using a novel technique of feed-forward. The output fundamental frequency is reduced by employing a λ/2 feed-forward transmission line parallel with a diode, LPF at input hand and BPF at ouput hand instead of using balanced structure with more diodes. This mode of feed-forward line reduces the complexity and difficulty of matching circuit. The input signal was sent in by a WR-19 waveguide-to microstrip transition, and the output signal was sent out by a WR-10 microstrip-to waveguide transition. The simulated output power reaches maximum value of 8.5 dBm when the input power is 13dBm. The rejection of both fundamental and third harmonic is greater than 30dB.