A Compressed Planar Band-Pass Filter using Microstrip Square Resonators with Interdigital Capacitor

Decreasing the size and physical dimensions of a planar filter in telecommunication and mobile systems has high importance. Most of the filters with planar structure are designed using electric, magnetic and mixed coupling models. Like as ring resonators, in this paper a new compact planar band pass filter using interdigital capacitor is introduced. This new filter is compared with a four-pole square open-loop resonators filter. The performance of this filter is comparable to a four-pole square open-loop resonators filter and size of this filter is reduced about 36%.