An X-band Voltage-Controlled Oscillator Based on SIW Trisection Filter

This paper develops a voltage controlled oscillator (VCO) based on an SIW trisection bandpass filter (BPF). A three-cavities filter is proposed to act as a frequency stabilizing element. In addition, a phase shifter is added to the circuit to adjust phase to realize a VCO. In this paper, one transmission zero (TZ) appears near the upper passband of the proposed BPF, which can effectively enhance the phase noise performance. Experimental results indicate that the phase noise of the proposed VCO is greater than
$-121.3\ \text{dBc}/\text{Hz}$
at IMHz offset frequency over the whole frequency tuning range of 195 MHz.