Design and Analysis of Microstrip Patch Antenna properties with Split-Ring Resonator Metamaterial as Superstrate at mmWave Frequency

Abstract

The Microstrip Patch antenna which is considered as low profile and easy to fabricate antenna incorporates drawbacks that include low gain and bandwidth. Using Metamaterials superstrate both bandwidth and the gain of patch antenna can be enhanced. This paper basically includes the study characteristics of rectangular patch antenna that is fed by microstrip line, with metamaterial as the two layers of superstrate is carried out at mmWave frequency ie 24GHz. The rectangular patch antenna is designed, that resonate at 24GHz, with copper as the radiating material put on Rogger 5880 substrate of 0.5mm thickness. The substrate dimension is taken to be 15mmx 15mm. The metamaterial structure exhibits negative permittivity and permeability at the same frequency as that of rectangular patch antenna ie at 24GHz. The substrate used for SRR structure design is Rogger 5880 of thickness 0.2mm. The unit cell dimension is 1.6mm x 1.6mm and the superstrate layer consists of a 9x9 SRR structure. Rectangular Patch characteristics are studied by placing the single layer and double layer of the superstrate at various distances (in mm). It is observed that placing a double superstrate layer with a gap of 1mm between them was placed at a distance of 1mm from the resonating rectangular patch antenna, making the antenna exhibit a multi-band feature along with an increase in the antenna gain. The Rectangular Patch antenna, SRR structure simulation is carried out in the CST simulation tool. Simulation results show that SRR characteristics are satisfied at 24GHz ie it behaves like a double negative structure and was verified using Matlab. The antenna shows multi-band resonance behavior at 24.033GHz, 25.36GHz, 25.285 GHz, 26.27 GHz when a double layer of 9x9 Split Ring Resonator is added above the radiating element. The gain offered by a single patch was 7.57dB and with the superstrate layer, the gain obtained was 9.01dB. The polarization component along the main lobe direction shows the cross-polarization component is found to be -85dB. The analysis of antenna with and without superstrate shows that there is improvement in gain and the multiband resonance can be achieved.