Design and Fabrication of Low Phase Noise Oscillator Using $Q$ Enhancement of the SISL Cavity Resonator

In this article, an X-band low phase noise oscillator using a high-quality (Q) cavity resonator based on the substrate integrated suspended line (SISL) technology is proposed. To achieve a low phase noise, the partly dielectric substrate cutting off and double-metal structure are used to improve Q of the resonator. The principles of the proposed Q-enhancement techniques are analyzed theoretically and verified experimentally. Using the proposed techniques along with the electromagnetic shielding property of the SISL technology, the designed cavity resonator can achieve a high loaded Q up to 792. The measurement results indicate that the oscillator using the proposed highQ resonator features a low phase noise of -133.91 dBc/Hz at 1-MHz offset from a carrier frequency of 11.87 GHz. In addition to the low phase noise property, the proposed oscillator has the merits of low cost, high integration, and self-packaging.