Design of Matching Circuits for Microstrip Triplexers Based on Stepped-Impedance Resonators

Abstract

New matching circuits for microstrip triplexers are proposed based on half-wavelength tapped-connected (or fed) stepped-impedance resonators. The stepped-impedance resonators play important roles for the matching circuits, either to serve as a through pass at the center frequency of a bandpass filter or to provide a short circuit at the center frequency of another bandpass filter. First, three tapped-connected stepped-impedance resonators together with suitable branch transmission lines are utilized to develop the matching circuits for a microstrip triplexer. The design procedure for these matching circuits is much simpler than that for the conventional triplexer structures due to the use of tapped-connected stepped-impedance resonators. Second, to reduce the number of stepped-impedance resonators and to improve the spurious resonances associated with the proposed matching circuits, modified matching circuits for the triplexer are also proposed. Agreement between measured and simulated results is observed and supports the usefulness of the design procedure.

A Compact Microstrip Quadruplexer Using Slotline Stepped Impedance Stub Loaded Resonators

“…To this end, various design approaches have been proposed [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17].…”

“…In [1], a novel high-isolation multiplexer utilizing steppedimpedance resonators (SIRs) was reported, which had a large circuit size due to the additional matching network. In [2], the authors presented low-temperature co-fired ceramic (LTCC) diplexer and triplexer, designed based on a parallel-coupled line filter connected with a capacitor.…”

“…Moreover, due to the limited coupling area available, this type of multiplexers only allows a small number of passbands to be implemented. Additionally, numerous techniques were proposed to design microstrip multiplexers [14][15][16][17][18][19][20][21][22][23][24][25].…”

Design of Compact Quadruplexer Based on Defected Stepped Impedance Resonators

“…In these communication systems, the multiplexers are an essential component for channel separation in microwave front-end systems. Recently, much research has been focused on developing various kinds of multiplexers [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19].…”

“…In [4], the authors presented a triplexer with high isolation at the cost of increasing circuit size due to the additional matching network based on the stepped-impedance resonators. In [5], novel microstrip line resonators were proposed to design a microstrip diplexer.…”