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Compact Triple-Band Filter Using Multiple Split-Ring Resonators

A novel design for a compact triple-band filter using multiple split ring resonators is simulated and compared to measurements.

Planar Green functions are an ideal solution method for the analysis of microstrip networks.   The Method of Moments (MoM) formulation that underpins the planar Green function method is based on the solution of Maxwell’s equations in integral form.  This method results in a solution that is highly phase stable, enabling the analysis of proximity coupled microstrip structures that are closely spaced, such as  the rings of a split ring resonator (SRR) microstrip filter.

Filter_picture.jpg        
SRR_resonant_2GHz.jpg



SRR filter prototype
SRR filter resonant at 2 GHz

 

Dr. Riana Geschke of the University of Stellenbosch (SU) in South Africa, Dr Branka Jokanovic from IMTEL, Serbia and Prof Petrie Meyer (SU) have been working on the design of SRR filters [1]. They use FEKO extensively for the simulation of these devices. This work has lead to a number of filters being manufactured and then measured. Measured results show excellent agreement with FEKO simulation results. Given that the required manufacturing tolerances for these SRR filters are in the order of a couple of tenths of micron, it makes the agreement obtained between FEKO and measured results even more impressive. This work shows that FEKO is ideally suited to the simulation of complex microstrip filters, towards advancing the state of the art in microstrip filter design.

SRR_S_param_comparison

Measurement compared to FEKO simulation

 

[1]   
R.H. Geschke, B. Jokanovic, P. Meyer, “Compact Triple-Band Resonators Using Multiple Split-Ring Resonators,” Proceedings of the European Microwave Week 2009, held in Rome, Italy, 28 September to 2 October 2009.