A PROPOSED MODEL OF OPEN STUB HAIRPIN-COMB BANDPASS FILTERS WITH TWO ATTENUATION POLES

Abstract

In this paper, a proposed design of bandpass filter is introduced . A new stubs are applied to the bandpass filter to enhance the skirt selectivity on both sides of the upper and lower frequency band . Two attenuation poles are produced by this new structure. The upper band pole is introduced by the hairpin-comb structure. The lower band pole is introduced by the tapped open stubs. We fabricated a new structure using milling machine at the Lab in The University . two attenuation poles are realized at the upper band and the lower band respectively, one at 1.71GHz and one at 1.93GHz. Sharp roll-off on both sides of the passband is obtained. Measured results show good selectivity at both upper and lower bands