Synthesis of Triple-Band and Quad-Band Bandpass Filters Using Lumped-Element Coplanar Waveguide Resonators

Abstract

Abstract-This paper develops a novel design method for synthesizing the multi-passband filter with high flexibility in various passband location and fractional bandwidth. Using the proposed compensation technology in the equivalent circuit of multi-passband resonator, the cutoff frequencies and matching property in passband regions can be improved. Triple-and quad-band bandpass filters operating in both wireless local area network (WLAN) 802.11 a/b/g and worldwide interoperability for microwave access (WiMAX) systems are presented to verify the design method. The lumped-element coplanar waveguide stub fabricated by the split-ring resonator is established to realize filter with compact size. All the measured, full-wave simulated and equivalent-circuit modeled results illustrate a good agreement among them, which validates the multi-passband design methodology and shows the advantages of DC elimination and deep rejection between each passband.

Optimum Design of Lumped Filters Incorporating Impedance Matching by the Method of Least Squares

“…However, in this paper, we are concerned with the design of lumped filters, which have direct applications for microwave distributed filters, which may be realized through the application of appropriate transformation formulas [6][7][8][9]. To the best of our knowledge, the method of least squares has not yet been applied to the design of lumped filters.…”

A Novel Triple Passband Filter Design Method Based on Stepped Impedance Resonators

“…Resonators with controllable second and third harmonics and stubloaded resonators have been used to generate three passbands. And some other design procedures about multi-band filter have been discussed in paper [7][8][9][10][11][12][13].…”

“…Multi-band filters become quite popular. Therefore, they had been widely studied in several papers [2][3][4][5][6][7][8][9][10][11][12][13]. In [2], a tri-band filter was designed using three sets of resonators with a common feed circuit, but it has a large size due to a large number of resonators.…”

Design of High Order Suspended Stripline Bandpass Filter With Miniaturization

“…In this paper, we propose a 6th order BPF of the SSL structure. The concepts of quasi lumped element circuit given in [2,[6][7][8] are used to analyze the filter performance. Effort has been exerted on the circuit design to reduce the filter dimensions.…”