Smart Antenna Beamforming Network

Smart Antenna with RF beamforming capability can greatly improve the performance of the vehicle communication system by providing better link quality and high immunity to interference. Butler Matrix is a well-known beamforming network. It can be used for multibeam antennas. The Butler Matrix increases the system capacity and provides higher signal to interference ratio, consequently enhancing the overall system performance. Several studies have been conducted related to the cascading Butler Matrix. In an Multi Port Amplifier (MPA) application, a signal entering one port of the Butler Matrix is divided into equal parts. The signal is then amplified by all the amplifiers and then recombined by the combining Butler Matrix at the output port that corresponds to the particular input port.Suarez also reported that the introduction of the cascading Butler Matrices improves the performance of antenna parameters such as cross over and beam orthogonality. In this chapter, the RF front end system of cascading Butler Matrices are integrated with active elements such as Low Noise Amplifiers (LNAs) and High Linearity Low Noise Amplifiers (HL_LNAs). The first and second stage LNAs are mounted before and after the first Butler Matrix. The first Butler Matrix is used a power divider to divide the input signals. The second Butler Matrix is used to recombine the signals from the