AN/FPQ-6 RADAR ANTENNA GAIN DETERMINATION BY PATTERN INTEGRATION TECHNIQUES

The acceptance test gain determination for the 29 foot diameter Cassegrainian antenna of the AN/FPQ-6 radar was performed by antenna pattern integration techniques. This approach was used because of time limitations and difficulties of setting up an accurate boresight range for conventional gain comparison with a gain standard. By pattern integration of both the antenna and the feed patterns, the effective loss of near-in sidelobes and the spillover around the Cassegrainian sub-reflector could be determined separately with good accuracy. This approach gives considerable information on several characteristics of the antenna which led, in part, to changes for improving antenna performance. The less significant losses were estimated. The resultant gain determined by this technique averaged at 51.1-db over the band. This was confirmed at a later evaluation program where direct measurement gave an average gain of 51.2-db over the band.