Reconfigurable split ring resonator array loaded waveguide for insitu tuning

Abstract

Two linear arrays of split ring resonators (SRR) with broad side coupling and various relative positions are investigated for controllable wave transmission in a rectangular waveguide. Each array is designed to have a different unit size of SRRs. A rectangular waveguide with a cutoff frequency of 3.2 GHz shows an additional stopband between 3.4 GHz and 4.8 GHz when a five element SRR array with a unit SRR dimension of 18mm by 18 mm and a pitch of 25mm is loaded. The other five element array with a unit dimension of 10mm by 10mm and a pitch of 25mm is inserted adjacent to the first array with a broad side coupling resulting in another stopband between 5 GHz and 6.5 GHz, where the coupling gap between two arrays is approximately 3mm (120mil) and the dielectric constant is 2.55. The center frequency of the stopband is tunable depending on the degree of alignment between those two arrays. One of the SRR arrays has a piece of magnet attached to its edge, and in-situ tuning is achieved by moving it by a ferrite (or a permanent magent) from outside of the waveguide. The tuning results of numerical simulation show good agreement with those of measurement.