Phased arrays TTD question

Why is True Time Delay needed in a phased array, just for large bandwidth signals?

Can anyone recommend any good books on phased arrays and True Time Delay Systems?

thanks,
B

Hi B,

In order tu steer the antenna beam, the antenna elements must work with a time difference betwen them.
For narrow bandwidth, the time delay can be approximated with other means (phase shifters) that give the same result for a fixed frequency, and approximately the same result in some bandwidth.
With phase shifters, as frequency changes the steering angle changes and the beam pattern become distorted. These problems are avoided with true time delays.

Good phased array books are:

R. Hansen: Phased Array Antennas, Wiley, 1998.
R. Mailloux: Phased Array Antenna Handbook, Second Edition, Artech House, 2005.

Regards

Z