The X-band Dro And Stability,

Microwave solid-state frequency source is one important and basic component which are widely applied in microwave system like radar, communication and electron rivalry. Dielectric resonator (DR) is often used to design frequency synthesizer. In this paper, it is introduced about how to utilize digital frequency temperature compensation circuit (DFTCC) to improve DRO's frequency vs temperature range stability.Firstly the basic theory and the design method of DRO and buffer amplifier, as well as the principle of the DFTCC are presented in detail.Secondly the system pattern has been demonstrated thoroughly. By adding the resonance network on the gate of the FET rationally and the output and input matching network the oscillation criteria is satisfied. The harmonic balance method is used to analyze and optimize the output power and phase noise. To magnify the output power and enhance the load pulling ability a buffer amplifier is designed after DRO. According to the request of the system, the digital temperature sensor chip DS 1720, the voltage output digital to analog converter chip MAX5580, the integrated operational amplifier OP07C and so on, have been chosen to establish the DFTCC. In this system, MCU PIC12F629 is programmed with a look-up table which provides corrections directly to each digitized temperature code. Each new digital code is sent into a D/A converter by using a delay timer. The analog output voltage which is magnified with OP07C is then applied to the tunable varactor of the DRO to correct the frequency drift vs temperature.Finally through the EMC design of the layout and grounding, the system specification has been achieved by debugging all the whole circuits and programs time after time. In a conclusion, adopting the DFTCC to design the high frequency source with high frequency stability is feasible.