Design and Simulation of a 2.5 GHz Rectangular Microstrip Patch Antenna

Abstract

Existing 2.5 GHz copper/FR4 Rectangular Microstrip Patch Antennas (RMPAs) achieve good impedance matching and wider bandwidth, but they do not simultaneously provide high gain, compact patch size, and precise resonance at 2.5 GHz, which the current simulation-based study seeks to address. This presents the design and simulation of a single-element RMPA operating at 2.5 GHz using the classical transmission-line model. The antenna comprises a copper patch of 38.2 mm by 25.5 mm on a 1.6 mm FR4 substrate, a copper ground plane of 45.88 mm by 57.2 mm, and a feed offset of 1.7 mm from the patch centre. The simulation resonates at 2.502 GHz, a deviation of only 2 MHz (0.08%) from the design target, with a return loss of 10.40 dB, a Voltage Standing Wave Ratio (VSWR) of 1.91:1, and a bandwidth of 60 MHz (2.40%), satisfying the conventional −10 dB and 2 VSWR acceptance criteria. The radiation pattern exhibits a boresight gain of 5.78 dBi, a front-to-back ratio of 15.88 dB, and a half-power beamwidth of about 80° with a mismatch efficiency of 90.24%. A clean main lobe with suppressed back and side radiation confirms RMPA suitability for directional point-to-point and point-to-multipoint links. Benchmarked against two reference designs, the proposed antenna achieves exceptional resonant-frequency accuracy, strong gain, directional radiation, and low-cost simple construction. Its weaknesses are weak impedance matching and narrow bandwidth.