Efficient Two-Element Array Antenna

A challenge in array antenna theory is to obtain an array with a maximally selective array factor implemented with minimum number of radiators. The simplest array antenna consists of two radiators only. This paper presents an approach for designing such an array antenna with an array factor with the following properties: two-dimensional selectivity of the main lobe with an arbitrary half-power beamwidth (HPBW), absence of side lobes, arbitrary distance between the elements, azimuthal steering of the main lobe without appearance of side lobes. The proposed theory is verified using numerical simulations. In addition, a new closed form expression for the HPBW for binomial array antennas is proposed.