| One of the objectives of this thesis is to demonstrate that the same building block and underlying design theory can be used to design both classes simultaneously. Cross-coupled resonators which have been used extensively to design bandpass filters in the past are shown to yield band-reject filters as well by simply adjusting the relative strength and nature of the coupling coefficients. Cross-coupled band-reject filters are designed and fabricated in microstrip technology to determine their experimental performance. It is found that this first class of band-reject filters is sensitive to manufacturing errors, especially for filters or orders 4 and higher. To overcome this limitation, a second class which is based on networks with Non-Resonating Nodes is then presented. Actual filters are designed, fabricated and measured. Excellent performance is demonstrated.; Another key objective of this research is the design of a new class of dual-mode bandpass filters specifically for implementation in microstrip line (strip line) filters. A triangular dual-mode microstrip loop resonator is introduced and used as a basic building block. Pseudo-elliptic bandpass filters with transmission zeros at real and imaginary frequencies are designed. Bandpass filters of 2nd and 4th orders are designed, fabricated and measured. Measured results validate the circuit models. To further enhance the robustness of these filters, the concept of Non-Resonating Node (NRN) is then used.; To the author's knowledge, the classes of filtering structures presented in this thesis have never been reported before. (Abstract shortened by UMI.)... |
