Beam Forming Network Design for Cluster Feeding of Highly Functional Scanning Antenna(Special Issue on Innovation in Antennas and Propagation for Expanding Radio Systems)

Electric beam scanning reflector antennas provide beam scanning and pattern control, and can create narrow beams efficiently. However, they are not popular because the beam control circuit is large and difficult to realize. This paper proposes a new BFN configuration for cluster feeding of highly functional scanning antenna. The Enhanced PAttern Control nonswiTch (EPACT) BFN simplifies the beam control circuit and its control algorithm by using a fast Fourier transform (FFT) circuit, phase shifters, and a power divider. Furthermore, this paper proposes a design technique that uses modules to implement the FFT circuit and a method that optimizes amplifier placement to improve antenna efficiency. The design technique facilitates the manufacuture of large-scale FFT circuits. The optimized amplifier location improves the antenna efficiency by eliminating the partial concentration of signal power.