In initiating the investigation reported here, advances in the basic design 

 approach (as noted briefly above) furnished valuable guidelines. Some techniques 

 successfully implemented for linear and planar arrays were adaptable for use in a 

 cylindrical configuration; and methods of beam-forming and steering already imple- 

 mented by NELC for various IFF and radar applications were incorporated 

 where possible. 



Techniques involved in the SAMB (Stationary Aperture Moving Beam) and 

 CARAMBA (Circular-Array Radar Agile Moving Beam Antenna) programs were im- 

 portant in the present study. However, they were of direct concern only as they 

 might be extended to a pencil-beam radar antenna having a circularly symmetric 

 configuration. Only such pertinent details are furnished here, except for some 

 aspects of the SAMB program which have not been previously reported. The com- 

 puter programs associated with the SAMB and CARAMBA antennas, and descrip- 

 tions of their circuitry and switching, are not of concern here and have not 

 been included. 



THE SAMB ANTENNA 



With the advent of the fixed-aperture scanning arrays of the AN/SPS-32 

 and SPS-33 types, the need for a rapid-scanning, highly agile antenna for the IFF 

 function became apparent. SAMB was part of the effort to fill this need. In con- 

 trast to the present need for wide-frequency-spectrum radar antennas, the IFF 

 requirements were less stringent in terms of beam shape in the elevation plane, 

 bandwidth, and power-handling capacity. The interrogators used for IFF operated 

 in a relatively narrow frequency band of about +3 percent. Since the elevation 

 position of the target to be interrogated is known from the radar data, a fan beam 

 in that plane is sufficient to give the required data. Although specifically designed 

 for the IFF band, many of the SAMB components maintain satisfactory character- 

 istics over at least a 25 percent frequency band. Hence, the techniques can be 

 used for other frequency bands and configurations. The wideband capability of 

 the SAMB antenna is of particular interest for the wide-spectrum cylindrical array 

 for the radar application. 



