Figure 48. CARAMBA II azimuth pattern, 3-bit phase-board feed, f . 



Some conclusions can be drawn from the results of the CARAMBA program: 



1. Low-side-lobe, circular-array antenna patterns can be achieved using the 

 R-2R lens fed with four input probes to obtain a tapered output distribution. Side 

 lobes on the resulting radiation patterns are on the order of -25 dB over a 20-percent 

 frequency band. 



2. The use of digital amplitude and phase distributions obtained by means of 

 diode techniques gives radiation patterns which can be predicted by computer tech- 

 niques, within the system errors. 



3. The digital method is valuable as a research tool. Many combinations of 

 amplitude and phase distributions .can be readily placed on the element terminals by 

 means of amplitude and phase-control panels. 



As an example of the versatility of the digital method, figure 49 shows the 

 difference pattern obtained from the array by simply advancing the phase-control 

 switches on the panel 180°. Strictly speaking, independent control of the digital 

 amplitude and phase is not possible, since a change of the amplitude bit results in 

 a slight change of the phase, because of the physical construction of the phasor 



43 



