Low-Phase-Noise Oscillator Using a High-Q_L Resonator with Split-Ring Structure and Open-Loaded T-Type Stub for a Tumor-Location-Tracking Sensor

Sensors in the medical field to detect specific tissues, such as radars, must provide accurate signals from frequency generators. In order to supply an accurate frequency signal, the oscillator must have a low phase noise. Therefore, the resonator used in the oscillator must provide a high Q_L. Therefore, in this paper, we have proposed a low-phase-noise X-band oscillator that used a resonator with a high value of Q_L as a sensor for tissue-locating applications. The resonator had a split-ring structure and consisted of an open-loaded, T-type stub with a high-Q_L; such high-Q_L levels were enabled by controlling the length of the open-circuit in the T-type stub. This led to the generation of only low-phase noise in the proposed oscillator. Experimental results showed that, at an operating frequency of 10.08 GHz, the output power was 18.66 dBm, the second harmonic suppression was −34.40 dBc, and the phase noise was −138.13 dBc/Hz at an offset of 100 kHz. This proposed oscillator can be used as a sensor to detect the location of tissues during laparoscopic surgery.