Wideband Design of a Single-Layer Dual-Band Multi-Ring Microstrip Antenna Fed by an L-Probe with Separated L-shaped Elements

This paper presents wideband design of a single-layer dual-band multi-ring microstrip antenna (MR-MSA) fed by an L-Probe with separated L-shaped elements. The proposed antenna consists of an inner square split ring patch for a higher band, two outer separated L-shaped patches for a lower band, and a feeding L-shaped probe (L-Probe) to excite the radiating patches. The radiating patches and the L-Probe are arranged on a thick single-layer dielectric substrate with a thickness of approximately 0.1 wavelengths to obtain dual-band and wideband operation. The two design frequencies of the proposed antenna are about 9 GHz and 12.5 GHz. In order to achieve dual-band and wideband characteristics at the two design frequencies, dimensions of the proposed antenna are tuned by using ANSYS HFSS. It is confirmed by the numerical simulation that fractional bandwidths below −10 dB reflection are 10.1% for the lower band and 16.9% for the higher band, respectively. Stable unidirectional radiation pattern characteristics for the lower and higher bands are also confirmed by the simulation.