22.8 GHz Substrate Integrated Waveguide Analog Frequency Divide-by-3 Circuit

A 22.8 GHz analog frequency divide-by-3 circuit is presented based on an injection locked oscillator. Substrate integrated waveguide (SIW) technology is used to implement the input and output sections of the frequency divider circuit. The input SIW section at the gate of the active device permits the introduction of the injection signal at the third harmonic frequency of the oscillator, while the output section is designed to maximize the DC-RF conversion efficiency of the oscillator circuit. A prototype is fabricated presenting a measured DC-RF efficiency of 38.5% at 7.603 GHz output frequency with 3.7 dBm output power. An injection locking bandwidth of 301.4 MHz was obtained for a 1.5 dBm input injection signal at 22.8 GHz.