High accuracy feedback control system for a phased array antenna

DETAILED DESCRIPTION OF THE INVENTION FIG.
2 illustrates a first embodiment of the present invention.
The distribution system, phase shifters, and method of supplying the antenna elements are similar to that of FIG.
1; however, the control system is significantly different.
The signal to be applied to the antenna element is first received by the antenna distribution system 212 at port 201, where it is passed along the distribution system and through a series of phase shifters 203A through 203D to a termination 213 located at the end 202 of the distribution system.
The signal is coupled to the antenna element 204A through 204D by individual couplers positioned along the distribution system between phase shifters.
In the operation of this system, the signal to be transmitted is supplied to the antennas by way of the distribution system and phase shifters.
The phase shifters are identical with each receiving the same control signal and accordingly imparting the same phase shift.
The signal arriving at any antenna element is shifted in phase with respect to the previous element along the distributing system by the phase shift of a single phase shifter.
As noted earlier, this is the requirement for steering the beam off boresight by a spatial angle which is directly related to the phase angle imparted by each phase shifter.
The control and feedback circuitry of FIG.
2 comprises directional coupler 207 located at the input of the distribution system, directional coupler 208 located at the end of the distribution system, phase detector 206 which receives the output of the directional couplers and phase shifter 209 which is in series with one input of the phase detector.
In the operation of the control circuitry, a command signal indicating the desired total phase shift across the phase shifters 203A through 203D, is applied to the control port 210 of phase shifter 209.
A portion of the signal applied to the distribution system is coupled through directional coupler 207 and passed through phase shifter 209 to a first input port of phase detector 206