Design of Tunable Edge Coupled Microstrip Bandpass Filterss: A Transmission Line Theory Approach

Microstrip edge coupled ¿lters perform well as bandpass ¿lters with a decent skirt rate. Coplanar waveguide (CPW) ¿lters have been developed because of the good isolation they provide. Development of tuning techniques for these passive ¿lters is becoming increasingly necessary to improve the robustness and reliability of microwave receiver designs. For example, in a high Q ¿lter, a slight shift of the center frequency in a fabricated ¿lter results in a very large change in the resulting gain at the frequencies of interest. This book explains the design of tunable microstrip edge-coupled filters and introduces three new tuning techniques for edge coupled filters. MATLAB codes for analyzing tunable edge-coupled filters are also provided.