| Microwave oscillator plays an important role in microwave and RF systems. Dielectric resonator oscillator (DRO) shows excellent characters of high stability, low noise, small system volume and low cost. This paper proposed a new type of DRO called push-push-like DRO based on push-push DRO. In push-push-like DRO, outputs of two parallel feed back DROs are combined by a power divider whose outputs are out of phase at fundamental frequency and in phase at second harmonic frequency. As with the push-push DRO, second harmonic is achieved from two circuits which work at fundamental frequency, thus cheaper very high frequency signal source could be available without signal quality worsening. This type of DRO should be easy realized and higher output power would be achieved because the primary part of push-push-like DRO is parallel feed back DRO.The main works and achievements are as follow:(1) The basic design theory of series feed back DRO, parallel feed back DRO and push-push DRO are introduced, and good results of harmonic balance simulation have been achieved;(2) The power of output signal of push-push DRO has been analyzed. To make the output power of second harmonic enhanced, dual-frequency complex impedance matching method is applied in DRO circuit. Results of simulation show that the power of second harmonic is enhanced by nearly 7dB.(3) A new power divider whose outputs are out of phase at fundamental frequency and in phase at second harmonic frequency has been realized after simulations on ADS and HFSS. Detailed design formulations and procedures of the power divider have been given, the measured results show that the phase difference between the output ports are 179.1° at fundamental frequency and 1.75° at second harmonic frequency. Push-push-like DRO has been proposed based on push-push DRO, and the measured results show that the output frequency is 19.50125 GHz, the output power is nearly 0 dBm, and the phase noise are -68.48dBc@10kHz and-95.13dBc@100kHz. |
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