Bzn Varactor-based Microwave Devices

This dissertation researches on VCO in X-band and tunable bandstop filte tuned by BZN varactor. The VCOs are designed on the basis of the distributed parameter circuit and semi-distributed parameter circuit. And this dissertation compares the phase noise and tunability of the two circuits with each other. This dissertation utilizes the relations between the bandstop filte and the lowpass prototype filte to design the bandstop filte. In order to change the centre frequency, the BZN varactor is used in the microsrip circuit.This dissertation finished the design and physical production of VCOs and tunable bandstop filter. The phase noise of the distributed parameter VCO is–91.83dBc/Hz@100KHz,– 116.8dBc/Hz@1MHz, The tuning bandwidth of the distributed parameter VCO is 95MHz; And the phase noise of the semi-distributed parameter VCO is–91.67dBc/Hz@100KHz,–114.3dBc/Hz@1MHz, The tuning bandwidth of the semi-distributed parameter VCO is 1.013GHz according to the measurement; For the tunable bandstop filter, through the simulation, when changes in capacitance vary from 0.1 pF to 0.7 pF, the centre frequency changes from 10.94 GHz to 7.99 GHz, the tuning bandwidth of the tunable bandstop filter is 2.95 GHz. Some advices are proposed for the problems in this dissertation.