A compact LTCC semi-lumped highpass filter with vialess structure

A new type of semi-lumped highpass filter (HPF) based on multilayer technology is presented in this letter. Capacitive coupled stripline stubs are utilized as semi-lumped resonators in the structure without using any means. Hence, undesired parasitic effect in the multilayer interconnections is minimized while high quality factor and stopband rejection are realized simultaneously. In this research, a HPF works from 5.15 to 5.95 GHz has been designed and fabricated on a low temperature cofired ceramic (LTCC) substrate. The proposed topology has been validated through a series of tests. By virtue of the LTCC multilayer technology, the proposed HPF is compact, occupying only a volume of 2.5 mm x 2.0 mm x 1.0 mm.