Isolator-Based Dielectric Waveguide Filter Cascade

This paper presents a new method of cascading bandpass filter using an isolator instead of the conventional transmission line. The primary objective of utilizing isolators is to safeguard other Radio Frequency (RF) components from the adverse effects of undesirable reflected signals. Particularly in the case of cascaded filters, these isolators mitigate the impact of reflected signals on overall performance. To validate this approach, third-order and sixth-order dielectric waveguide filters were designed. These filters were cascaded using isolators and subsequently subjected to simulation using circuit simulation software. The results indicate that the insertion loss of the filter is less than 0.05 dB, and the return loss is less than -20 dB, effectively meeting the design specifications of the filter.