Varactor-loaded inverted-F multiport parasitic array radiator antenna

In order to realize a compact low-profile antenna that can steer beam/null continuously in full azimuthal directions, this paper proposes a new configuration of beam-steering antenna with mutual coupling between inverted-F antenna (IFA) elements. The antenna array consists of two active and two passive IFA elements loading variable reactors, thereby realizing a low-profile antenna array within a small space. It is expected that the antenna possesses a high ability to form beam and/or null, since it behaves as both Yagi-Uda array and phased array. Furthermore, we derive here a general expression of equivalent weight [1] for multiport parasitic IFA arrays. Finally, the beam steering of the proposed antenna is demonstrated by the numerical simulation.