Design of A Push-Push and Push-Pull Oscillator Based on SIW/SICL Technique

In this letter, the design of a Push-Push and Push-Pull oscillator based on substrate integrated waveguide (SIW) and substrate integrated coaxial line (SICL) technique is presented. Differential-phase lock of the sub-oscillators is realized with the SIW cavity at fundamental TE₁₁₀ mode, thus simplifying the oscillator design procedure. Based on the SIW and SICL technique, a broadband magic-T is utilized for combining the desired signal and cancelling the undesired signal for both Push-Push and Push-Pull output. The prototype of the Push-Push and Push-Pull oscillator is designed and fabricated. Measured results show that the proposed oscillator has f₀ suppression of -13.1 dBc at the Push-Push port, and 2f₀ suppression of -24.3 dBc at the Push-Pull port. Compared with the conventional single oscillator, the phase noise is improved by 2.5 ~ 3.2 dB at 100 kHz through 1 MHz offset for the desired f₀ and 2f₀ output signals.