Design and Implementation of a Quasi-Orthogonal Switching Beam-Former for Triangular Arrays of Three Radiating Elements

An innovative switching multi-beam network for triangular arrays of three radiating elements is proposed. This novel network provides three orthogonal beams in a desired elevation angle and a fourth one in the broadside steering direction. The network is composed of four-port 3-dB quadrature hybrid power couplers and fixed phase shifters. In this paper, a relation between network components, radiating element distance and beam steering directions is shown. Application of the proposed dissipative network to the triangular cell of three double stacked patches of 1.7 GHz and 60 ^° beamwidth that integrates the intelligent antenna GEODA with an array distance of 0.56 λ is exhibited. Measured scattering parameters of the network are compared with both, theoretical and simulated scattering matrices, validating the expected behavior. Besides, by combining two complementary single proposed networks, a matrix that supplies six orthogonal beams in a given elevation angle and a seventh one in the broadside steering direction has been built. Moreover, the whole system, dissipative network with GEODA cell array, has been measured in the anechoic chamber of the Radiation Group at Technical University of Madrid, demonstrating a successful performance.