Parallel-coupled filter with improved rejection

SOH ZHONGSHENG JOHNSON

Publication

Parallel-coupled filter with improved rejection

SOH ZHONGSHENG JOHNSON

Abstract

In this thesis, a modified stripline parallel-coupled filter with improved upper stopband rejection slope using the design equations for coupling sections of arbitrary length is proposed. The proposed design is verified using a set of experimental filters that were designed, implemented and measured. For the 5 GHz filters implemented, the new design was able to provide up to 23 dB more rejection at +1 GHz offset from the centre frequency.A packaging method to allow the stripline filter proposed to be readily integrated onto hybrid microwave integrated circuits as a surface mounted device is also discussed. Finally, a yield analysis showed that based on commercial printed circuit fabrication tolerances, the proposed filter design offer a good yield of up to 80%.