Self-Heating Study on a First Order Filter with Discrete and Continuous Tuning

In this paper, the study on self-heating of a first order filter with discrete and continuous tuning working at S-band is addressed. The filter is based on a simple structure formed by a shunted stub terminated in a pin diode to ground for discrete tuning and in a varactor diode for continuous one. It is demonstrated that, depending on the mode of working, the self-heating can drastically vary among states, due to the different electromagnetic field patterns presented by each one of the states. The study is performed with the aid of a multiphysics electro-thermal platform. A measurement campaign is also developed where the thermal maps of the implemented prototype filters working under medium power conditions are extracted. The measured results have confirmed the proposed analysis procedure as well as the performed study.