Design of a tunable oscillator using a suspended-stripline resonator

In this paper, a new design method of a tunable oscillator using a suspended-stripline resonator is presented. The negative resistance of an FET mounted on microstrip line (MSL) is combined with a high Q suspended-stripline (SSL) resonator to produce a tunable oscillator with good phase noise. The new MSL-to-SSL transition facilitates easy connection between the MSL-based circuits and the SSL module. The proposed oscillator is also frequency-tunable using a tuner located on the top of the SSL housing. The measured phase noise of the implemented oscillator at 5.148 GHz is -104.34 dBc@100 kHz and -133.21 dBc@1 MHz with 125.7 MHz of frequency tuning.