High Selective Balanced Bandpass Filters Using End-Connected Conductor-Backed Coplanar Waveguide

Abstract

In this paper, an end-connected conductor-backed coplanar waveguide (CBCPW) balanced bandpass filter and a size reduction one with adjustable multiple transmission zeros have been developed by using the separated electric and magnetic coupling, and quarter-wavelength short-circuited stubs. The differential mode (DM) and the common mode (CM) equivalent transmission line circuits have been modeled and verified, and the DM/CM parts can be designed individually. The proposed CBCPW balanced bandpass filters have been fabricated and measured, and their advantages of multiple transmission zeros, high out-of-band suppression, and high common mode suppression characteristics have been demonstrated.

Keywords

• Conductor-backed coplanar waveguide
• balanced bandpass filter
• separated electric and magnetic coupling
• transmission zeros