Simulation Study of Wideband Interference Rejection using Adaptive Array Antenna

Array antenna systems are often used to enhance the received signal to interference and noise ratio when the signal operates in heavily jammed environment. Proper modeling of the received data at different antenna elements is important when evaluating the performance of this system, especially when both the signal and interference have wide frequency bands. The received data has two dimensions: space, because different antenna elements are separated on the antenna face and time, because sampled data from each element is collected over time. Therefore received data processing can be regarded as space-time processing. The time sequence data is referred to as the received waveform of a given antenna element. The antenna output is the linear combination of data from all the antenna elements. In conventional narrowband beamforming, time sequences at different antenna elements are related by some fixed phase shift. The phase shift is determined by the waveform's direction of arrival (DOA). For a wideband waveform, time sequences at different antenna elements are delayed in time and not simply related by a phase shift. If a wideband waveform arrives at an off boresight angle, the time delays may not be integer multiples of the sampling time (fractional delay). Thus, to properly process the received data at each antenna element, interpolation is necessary to derive the correct time samples.