284 BELL S YSTEM TECH NIC A L JOURNA L 



dom available to us in the designing of the focussing element and the feed 

 motion to improve the performance. If the degrees of freedom are not 

 enough \vc must, if we insist on an optical solution introduce more. This 

 could in principle result in microwave lenses similar to the four and five 

 element glass lenses found in good cameras, but such complication has not 

 as yet been necessary in the radar antenna art. 



Since military release has not been obtained as this article goes to press 

 we must omit any detailed discussion of optically scanning radar antenna 

 techniques. 



PART III 



MILITARY RADAR ANTENNAS DEVELOPED BY THE 

 BELL LABORATORIES 



i3. General 



In the fuial jxirt of this paper we will describe in a brief fashion the 

 end products of radar antenna technology, manufactured radar antennas. 

 Without these final practical exhibits the foregoing discussion of principles 

 and methods might appear academic. By including them we hope to 

 illustrate in a concrete fashion the rather general discussion of Parts I 

 and II. 



The list of manufactured antennas will be limited in several ways. Severe 

 but obviously essential are the limitations of military security. In addition 

 we will restrict the list to antennas developed by the Bell Laboratories. In 

 cases where invention or fundamental research was accomplished elsewhere 

 due credit will be given. Finally the list will include only antennas manu- 

 factured by contract. This last limitation excludes many experimental 

 antennas, some initiated by the Laboratories and some by the armed forces. 



It is worthwhile to begin with an account of the processes by which these 

 antennas were brought into production. The initiating force was of course 

 military necessity. The initial human steps were taken sometimes by 

 members of the armed forces who had definite needs in mind and sometimes 

 by members of the Laboratories who had solutions to what they believed 

 to be military needs. 



With a definite job in mind conferences between military and Laboratories 

 personnel were necessary. Some of these dealt with legal or financial 

 matters, others were princi})ally technical. In the technical conferences 

 it was necessary at an early date to bring military requirements and tech- 

 nical {)ossibilities in line. 



As a result of the conferences a program of research and development was 

 oflen undertaken by the Laboratories. An initial contract was signed which 



