Active antenna with switchable beams for wireless sensor networks and IoT

Abstract

An active antenna capable of changing the beamwidth and pointing direction of its main radiating beam is presented. The design exploits the use of a novel frequency selective surface (FSS) and variable capacitance diodes (varactors) to control the main beam of an antenna. The main beam azimuthal pointing direction can be steered ±18° from boresight and the −3dB beamwidth varied from 100° to 140°. Narrower beamwidths can be achieved by changing the size and shape of the active ground plane. The design is suitable for applications where even small changes to the antenna parameters (gain, beamwidth and pointing direction) can have a positive impact on coverage and performance. Operating within the 2.4GHz ISM band, the proposed antenna design is suitable for adaptive indoor WiFi networks, dynamic wireless sensor networks and the internet of things.