A compact HPF with attenuation poles by using quasi-lumped elements

A compact HPF with sharp attenuation by using quasi-lumped elements is proposed. The HPF consists of parallel plate- and gap type- capacitors and an inductor line. The one block of the HPF has two sections of a constant K filter and bridge T configuration. Thus, the HPF of one block is designed and the performance is optimized by circuit simulator. With the gap capacitor adjusted the proposed HPF illustrates the sharp attenuation characteristics near the cut-off frequency. In order to improve the stopband performance, the cascaded two block HPF is examined. Its measured results show the good agreement with the simulated ones giving the sharper attenuation slope.