Multi-technique broadband microstrip patch antenna design

Abstract

Microstrip patch antennas offer low profile and small footprint advantages, but limited operating bandwidth. Substantial research focuses on broadband techniques. This paper presents the design, simulation, fabrication, and characterization of a 30% bandwidth microstrip patch antenna that incorporates multiple broadband techniques while minimizing footprint area. Methods include patch shape, dielectric thickness, and coupling slot optimization, with capacitively-coupled L-probe feeds. The final design incorporates an electrically thick dielectric and circular-E patch geometry. Microstrip L-probe feed and coupling slot dimensions were optimized via HFSS simulations. The final design was fabricated, and then tested in an anechoic chamber. The new design has measured and simulated impedance bandwidths (VSWR <; 2) of 37.9% (7.9GHz to 11.6GHz) and 36.4% (8.1GHz to 11.7GHz), respectively. The minimum E- and H-plane measured main lobe gain is -3dBi from 7.9GHz to 9.0GHz, a 13.0% pattern bandwidth. The simulated pattern bandwidth is 11.8% (8.0GHz to 9.0GHz). Side lobe levels less than -4.7dB and a 3dB beamwidth of 15°±5° are maintained between 8.0GHz and 9.0GHz. At frequencies greater than 9.0GHz, the H-plane gain is less than -3dBi.