Compact Absorptive Dual-Beam Patch Antenna by Fusing Resistor-Terminated Defected Microstrip Structure

A compact absorptive dual-beam patch antenna is proposed by fusing the absorptive branch inside the patch antenna. The defected microstrip structure with a meander slot and the T-shaped shorted stub can make the absorptive branch achieve the absorptive function in a small size so that it can be fused into the dumbbell-shaped slot of the patch antenna. Furthermore, the dumbbell-shaped slot extends the current path of the patch operating at TM
₂₀
mode. Thus, the overall size of the patch antenna doesnot increase but decreases. Compared with other absorptive antennas, the proposed one realizes the out-of-band reflectionless characteristic in a compact size and dual-beam radiation. For demonstration, a prototype operated at 5.8 GHz was measured with the compact size of 0.31λ
₀
× 0.48λ
₀
, the out-of-band reflectionless bandwidth of 49.5% (3.50–5.72 GHz and 6.46–7.11 GHz), and the dual radiation beams directed at ±42°.