Design of A Compact Quad-channel Diplexer using Stepped-Impedance Resonators

In this paper, an efficient EM-based design approach for designing miniaturized quad-channel diplexer is presented. Asymmetric stepped impedance resonators are exploited in the presented design for size reduction. Dualband coupling matrix is used to synthesize the dualband branch filters in the presented quad-channel diplexer. Space mapping technique is applied to efficiently optimize the EM-based design. The design procedure of channel dualband filter and input T-junction is discussed in detail in section II. An EM-based quad-channel diplexer is designed and optimized in Sonnet em simulator to validate the proposed design approach. It is shown that the quad-channel diplexer occupies small area. Good agreement is achieved in EM simulation.