Design of high directivity compact parasitic array for beam-steering applications

In this paper, two synthesis methods to design directive and compact parasitic antenna arrays with beam-steering capabilities are compared. The two methods are used to calculate the complex excitation coefficients associated to each array element needed to synthetize the antenna radiation pattern in a given direction. The analysis is principally focused on the antenna directivity and has been validated using a nine-element compact array at 1.75 GHz. The antenna is composed of nine monopoles (length 0.21λ), with only one driven element connected to a transceiver. This element is surrounded by eight parasitic monopoles arranged on a finite circular ground plane with a radius of 0.6λ and forming a circular (radius 0.1λ) array. The antenna has been prototyped and evaluated in a radio anechoic chamber. The measurement results are in excellent agreement with full-wave electromagnetic simulations.