A Low-Profile High Gain Filtering Antenna with Controllable Radiation Nulls Employing Engraved Sectoral Arcs

A high-gain circular patch-based filtering antenna having wide bandwidth with controllable radiation nulls by means of sectoral slots and rectangular slits is proposed in this communication. Introducing a pair of sectoral arcs on the radiating patch generates a configurable null near the lower band-edge frequency, while a pair of rectangular slots is loaded on the top surface to extract a controllable upper-band radiation null. In addition, a small air gap is introduced in-between the substrate and the ground plane to enhance the overall impedance bandwidth of the proposed filtering antenna. The prototype is designed, fabricated, and tested with good agreement between simulated and measured results. The measured results show the −10 dB impedance bandwidth ranges from 3.82 to 4.28 GHz (11.3%) with a peak gain of 8.63 dB and average gain of 8.1 dB over the operating bandwidth. The overall electrical size of the antenna is 0.67 λ0 × 0.67 λ0 × 0.048 λ0 which is reported as smallest amongst multiple state-of-the-art works achieving such high gain. Hence, the proposed filtering antenna is a potential candidate to be used in communication building blocks where high gain is required.