Design of a Microstrip Bandpass Filter Using Metamaterials

Split ring resonators (SRR) are suitable for microwaves due to their unique properties. In this research, using metamaterials and SRR structures, a band-pass filter on the C band was designed. The main filter structure consisted of two SRRs connected with a microstrip line. The initial size of the structure, such as the radius of the rings, was estimated based on the central wavelength of the filter. In order to increase the bandwidth and the efficiency of the passage in the central frequency, genetic algorithm was used and the optimal dimensions of the filter were obtained. The change in the central frequency of the filter due to the change in the dielectric constant was investigated, and the filter stability was depicted in relation to the change in its dimensions. Compared to other existing filters, this filter, with its simplicity of structure and ease of construction, has better characteristics such as a high pass ratio at center frequency and wide bandwidth.