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Design of multiple-passband filters using coupling matrix optimisation

Design of multiple-passband filters using coupling matrix optimisation

Shang, X., Wang, Y., Nicholson, G.L. and Lancaster, M.J. (2012) Design of multiple-passband filters using coupling matrix optimisation. IET Microwaves, Antennas & Propagation, 6 (1). pp. 24-30. ISSN 1751-8725 (Print), 1751-8733 (Online) (doi:

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This study presents the design of microwave filters based on the coupling matrix approach; determination of the matrix is based on a hybrid optimisation algorithm which may be applied to cross-coupled filters having diverse topologies. Various filter responses from dual-band to quad-band are given as examples of the approach. The optimisation is performed on the coupling matrix and a genetic algorithm (GA) is employed to generate initial values for the control variables for a subsequent local optimisation (sequential quadratic programming search). The novel cost function in this study measures the difference of the frequency locations of reflection and transmission zeros between the response produced by the coupling matrix and the ideal response. The ideal response in the form of characteristic polynomials is determined from the filter specifications and generated by a recently developed iterative technique which is capable of realising multi-band filters with different return loss levels. Convergence of the coupling matrix optimisation is fast, and no initial values for the control parameters are required by the GA. An eighth-order X-band dual-band waveguide filter with all-capacitive-coupling irises has been fabricated and measured to verify the design technique. Excellent agreement between simulation and experimental result has been achieved.

Item Type: Article
Additional Information: [1] Date of Current Version: 1 March 2012. Issue Date : January 11 2012.
Uncontrolled Keywords: coupling matrix optimisation, cross-coupled filters, eighth-order X-band dual-band waveguide filter, genetic algorithm, hybrid optimisation algorithm, microwave filters, multiband filters, multiple-passband filters, sequential quadratic programming search, subsequent local optimisation
Subjects: T Technology > T Technology (General)
Pre-2014 Departments: School of Engineering
School of Engineering > Mobile & Wireless Communications Research Laboratory
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Last Modified: 14 Oct 2016 09:23

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