Impedance Characteristics Analysis of Two-Port Networks Based on A Reactive Component and A Ceramic Resonator

A ceramic resonator can form a well-performing bandpass filter. However, since the impedance of the ceramic resonator is capacitive below the resonant frequency and above the anti-resonant frequency, it is only suitable for constructing a bandstop filter. High-pass and low-pass filters cannot be realized with ceramic resonators alone. Therefore, reactive components must be introduced. In bandpass filters, inductors and capacitors are often needed to save resonators and to widen or compress the passband. This paper will study a ceramic filter with a reactive component. This paper focuses on key metrics such as bandwidth and the variation of resonant frequencies. Measurement results illustrate the effects of inductors and capacitors on these metrics, showing that their introduction can widen or compress the passband, thereby expanding the application range of ceramic resonators.