An Improved Interdigital-based Parallel-Coupled Microstrip BandPass Filter

This paper presents a microstrip bandpass filter using an interdigital structure. The filter is designed at a center frequency of 36GHz, while the bandwidth is 4GHz. In the traditional coupled microstrip filter, especially working in the Ka band, the distance between the first coupled microstrip is a little close, so, it can be a little difficult to produce. However, the interdigital structure provides a closer coupling, and thus, it performs better than the first coupled microstrip. This paper based on the traditional coupled microstrip bandpass filter and designed a bandpass filter using interdigital structure optimized by HFSS.