| Abstract: | This paper presents a new class of microstrip slow‐wave open‐loop resonator filters with reduced size and improved stopband characteristics. A comprehensive treatment of both ends loaded with triangular and rectangular ends is described, leading to the invention of a microstrip slow‐wave open‐loop resonator. Two‐resonator and four‐resonator bandpass filters are designed at the operating frequency of about 2 GHz, and a bandwidth of 60 MHz. The size of the slow‐wave open‐loop resonator is optimized from the standpoint of the unloaded Q‐factor. The filters are not only compact in size due to the slow‐wave effect, but also have a wider upper stopband resulting from the dispersion effect. The filter designs of this type are described in details. The experimental results are demonstrated and discussed. |
