Study On Microwave Components Of Wireless Communication Systems

With the development of communication technology, It become very valuable to study microwave active or passive components in wireless technology as excellent microwave components can enhance the capability of satellite communication systems or radar systems.The objects studied in the thesis involved microstrip bandpass filter,microstrip diplexers,low noise amplifier,power amplifier and the technology improving the power amplifier's power added efficiency .In traditional wireless transceiver,the most direct way to cascade a low pass filter after the bandpass filter in order to reduce spurious response effect to nonlinear microwave components such as mixer,power amplifier. The use of an additional low pass filter not only degrades the insert loss but increases the size of the filter.The bandpass filter that has spurious suppression characteristics can solve this problem and it has excellent bandpass symmetry and stopband attenuation characteristics at high frequency.So it becomes very practical value to study the bandpass filter that has sprious suppression characteristics.Based on the study for the spurious suppression technology of microstrip bandpass filter ,A capacitive coupled Stepped Impedance Resonators(SIR) microstrip passband filter is proposed according to transmission theory in chapter 2, the principle that spurious center frequency can be controlled by adjusting the SIR impedance ratio are analyzied and the results of passband filter simulation is given. On the other hand, highly selective bandpass filters have been comprehensively studied as the frequency resource become more and more scarce.Two microstrip bandpass filters with a pair of transmission zeros on both sides of the filter are proposed based on the principle that one transmission zero can be made if transmission line paralleled with a microstripλ/4 open stub . The reason that transmission zero produced is analyzed in detail. At the end of the chapter the simulation and measurement result of two microstrip bandpass filters have been presented.Diplexers is the critical microwave component in the transceiver.the design goal of diplexers is to make the receiving and transmitting channel bandpass filter has good inert loss performance and enchance the isolation to reduce mutual disturbance. Microstrip diplexers not only can reduce the size but minish the production cost ,So the study of microstrip diplexers becomes the import parts of the microwave diplexers research.In the chapter three ,a microstrip diplexers composed with two hairpin bandpass filter has been...