Teflon based hairpin type bandpass filters & asymmetric phase shifters

Abstract

In this thesis, three kinds of bandpass filters for 10.2GHz, 2.35GHz, 618MHz applications and two kinds of phase shifters for 2.3GHz, 2.2GHz applications on Teflon substrate were designed, fabricated and measured. The proposed bandpass filters can be divided largely into 2 types. The size of the first type was reduced by one more interchanging the coupling as compared to the conventional pseudo-interdigital type and therefore the coupling coefficient was improved. The size of the second type was also reduced by an extended resonator of which span and length are the same as the previous stage. As a result, the filter size was much reduced and the coupling coefficient was much significantly improved as compared to the conventional hairpin type. While the coupling direction of the conventional Schiffman phase shifter is perpendicular to the signal propagation, that of the proposed phase shifter is same to the signal propagation. In addition, low insertion loss, reflection loss and small VSWR were measured.