Triple-Band Circular Ring Microstrip Patch Antenna Enhanced by Nd:YAG Laser Processing at C-band for Wireless Communications

Abstract

This work presents the design and experimental validation of a compact circular ring microstrip antenna on Rogers RO4350B substrate. The initial slotless design exhibited dual-band performance at 4.44 and 5.8 GHz with return losses of –18.5 dB and –28.3 dB, gains of 2.3 and 5.5 dBi, and efficiencies of 48% and 83%. Introducing a 1 mm central slot enhanced bandwidth and generated triple resonances at 4.62, 5.82, and 6.2 GHz, with gains up to 6.8 dBi and 85.2% efficiency. Prototypes were fabricated and further processed using Nd:YAG laser treatment, which improved impedance matching and extended bandwidth to 550 MHz. The results highlight the effectiveness of slotting and laser processing in achieving compact, wideband, and efficient antennas for Wi-Fi, WLAN, and emerging 5G applications.