Synthesis and implementation of quadruplet filter with microstrip technology

Modern wireless communication transceiver applications often pose stringent out-of-band rejection requirements which necessitate steep and sharp narrow band rejection profile for microwave filters. The use of transmission zero inserted filters are very common to achieve such a response type. Microstrip filters are popular implementation option because of their compactness and low mass where Q-factor required is not so high. In this paper, a step by step methodology is presented for design and realization of a quadruplet filter with two finite real-frequency symmetric transmission zeros. The filter is realized in microstrip and results are presented.