Wideband Receive Beamforming Based on 4-D Antenna Arrays With Postmodulation

A wideband receive beamforming configuration and method based on four-dimensional (4-D) antenna arrays with postmodulation is proposed. Two pairs of single-pole-triple-throw switches are utilized for beamforming at the center frequency. Postmodulation is introduced to increase the degree of freedom of 4-D antenna arrays and achieve a deep null point at the steering direction of sidebands power pattern. The reception of 16 quadrature amplitude modulation signal, whose bandwidth is larger than the time modulation frequency, is implemented by a 16-element 4-D dipole array. The results of wideband beamforming show that the sidebands power at the steering direction can be eliminated ideally, whereas the sidelobes level of averaged radiated power pattern is suppressed to a low value. The 4-D array with postmodulation shows obviously improved bit error rates performance as compared to the 4-D array with conventional beamforming method and phased arrays, which confirms that the 4-D array with postmodulation has potential advantages in the application of wideband communication systems.