Modeling and Characterization of a Compact In-Line Filter with Transmission Zeros

This paper introduces an innovative method for generating transmission zeros within a circuit model, eliminating the necessity for extra resonators. It capitalizes on employing posts within a cavity to produce transmission zeros, thereby improving selectivity without enlarging the overall size of the circuit. Through this approach, precise control over the positioning of transmission zeros becomes achievable. The process commences with the development of a single resonator, and then progresses to crafting a third-order filter with a bandwidth of 400 MHz, focused at 3 GHz. This novel framework bears significant implications for the creation of compact and effective filters in high-frequency applications, promising enhanced efficiency and performance.