With Compact Filter Transmission Zeros

Recently, with the rapid development of the microwave and millimeter-wave technology, microwave apparatus are facing a huge market in many fields, such as microwave communication, navigation, and electro-counterwork. Moreover, the frequency channel distributed to multiple communication systems becomes narrow because of the limit of the frequency resource. As a result, the apparatus used for microwave and millimeter- wave receiver and transmitter are required to have a good performance to decrease the insertion loss and the noise interference. It becomes an important research subject to improving the performance of the filters through any methods.Transmission zeros play an important part in requirements of better rejection and the smaller size of filter. They can improve the frequency selectivity. They can provide better characteristics of the stopband. They can be used in the design of bandstop filters, and they can decrease the size of filter efficiently. In this thesis, new methods, new configurations and new technique of FSS shorting stubs filters will be analyzed and studied. The thesis includes the following content:First of all, a systemic research of FSS iris and waveguide E-plane shorting stubs will be done. It consists of the relationship between the resonance frequency and the dimension of the FSS iris and the relationship between the transmission zero frequency and the dimension of the shorting stub.Secondly, combining two FSS irises and a shorting stub into a small unit, bandwidth, resonant frequency and transmission zeros are obtained from simulation. Then integrated filters based on the above-mentioned units are designed, fabricated and measured. Furthermore, diplexers are also investigated and designed to verify this novel configuration. A sample diplexer is fabricated which realizes an over 100dB isolation.At last, by studying the effect brought out by the fabrication error, we suggest a new method to revise the error through computer aided. According to the experience of filter design and measurement, a speedy and effective means for the debugging of the filter 15 ProPosed.