Performance analysis of conductive patch materials for the design and fabrication of microstrip patch antennas

In this paper, the performance of microstrip patch antenna has been analysed by employing different patch and ground conducting materials. The Flame Retardant (FR4) material having thickness of 1.5 mm, dielectric constant (ε_r) = 4.4 and loss tangent of 0.002 has been deployed as the substrate in the propounded antenna designs. The conducting materials employed as the patch and ground for the performance analysis of the printed antennas are copper, aluminium, brass and stainless steel having corresponding conductivities of 5.78 × 10⁷ S/m, 3.52 × 10⁷ S/m, 1.55 × 10⁷ S/m and 1.00 × 10⁶ S/m, respectively. The conducting materials employed in the antenna designs each are of uniform thickness of 0.45 mm. The antenna performance has been examined in terms of variation in the antenna characteristics - return loss, bandwidth, gain and directivity with the variation in the conductivity of patch and ground. The proposed antennas have been designed and simulated using CST Microwave Studio 2016. The designed antennas have been practically fabricated and tested using E-5071C Network Analyzer and Anechoic Chamber. It has been observed that the practical antenna results closely matches with the simulated results. It has been concluded that the antenna consisting of copper material as patch and ground provides the minimum return loss of -41.84 dB at corresponding resonant frequency of 8.55 GHz among the examined materials whereas the stainless steel having the minimum conductivity provides the maximum bandwidth of 0.656 GHz with the corresponding resonant frequency of 8.54 GHz. It has been concluded that the bandwidth and return loss decreases exponentially with increase in conductivity of patch and ground whereas the gain of antenna increases exponentially with increase in the conductivity of patch and ground.