Single-Layer Magnetic Current Antenna Array with High Realized Aperture Usage Rate Based on Microstrip Line Structure

A new antenna structure is proposed to show that a single-layer magnetic current array based on the microstrip line structure can achieve a relatively uniform and large in-phase radiating aperture together with high realized aperture usage rate (RAUR). By alternatively and periodically loading the microstrip line with blocking stubs, the equivalent magnetic currents along one direction are suppressed while the currents along the other direction are left, forming a relatively uniform and in-phase 1-D magnetic current array. The electromagnetic wave is radiated into space while traveling forward along the line. By in-parallel concatenating a series of the 1-D arrays with adjacent arrays presenting mirror relations, a large in-phase radiating aperture is built with a relatively high RAUR performance. Moreover, the shorting walls at the interconnecting planes of the neighboring 1-Darrays can be removed attributing to the antenna arrangement style and the required feed network. Eight rows of the 24-element 1-D magnetic current array fed using a substrate integrated waveguide-based eight-way power divider fabricated using a single substrate board is simulated and built to demonstrate the design strategy. The prototype shows a measured bandwidth of 4.37% and a peak gain of 25.1 dBi at 20 GHz. The RAUR is 8.66/λ₀², which is higher than most of the single-layer high-gain antennas.