A Dual-Beam Eight-Element Antenna Array With Compact CPWG Crossover Structure

In this letter, a dual-beam eight-element antenna array is proposed with compact coplanar waveguide with ground (CPWG) crossover structure. The feeding network is composed of a microstrip-line feeding network with four 90° hybrids and a CPWG feeding network with compact crossover structures. Compared to the conventional Butler matrix feeding network, the proposed network has fewer 90° hybrids and circuit is less complex. By exciting different port of the feeding network, the eight-element antenna can be excited by phase step of 22.5° or -22.5° and achieve two beams pointing at two different directions. The measured gain is 10.2 dBi, and beam directions of the two peaks are ±7° at 5.8 GHz.