Some techniques for evaluating the bandwidth characteristics of adaptive nulling systems

Some techniques for evaluating the bandwidth characteristics of adaptive nulling systems are presented. The system performance is categorized according to its antenna characteristics and the post-antenna channel tracking characteristics. The former tend to be radio-frequency (RF) percentage bandwidth dependent and the latter on the achievable component tolerances used to implement the channel (whether at RF or some lower intermediate frequency (IF)). Measured results are also presented for a seven-beam paraboloid reflector-type multiple-beam antenna (MBA), and the effects of feed-reflector multipath inherent in this geometry on the cancellation bandwidth is evaluated in detail.