SPS Feasability Study SD76SA0239-2

2.3.3 Array Design and Waveguide Structures The fundamental theory of MW antenna operation and basic array technology development status was used in the design of the 1-km diameter 5-Gw SPS microwave antenna. However, the aperture size and the high efficiency requirements make the MW antenna extremely complex. Studies have shown that the slotted waveguide array is one of the most efficient radiators for the antenna. Subsequent analyses have shown that the temperature interface between waveguides and dc-RF conversion tubes can cause severe thermal design problems on the array. Radiating Element Design Conventional waveguide designs such as the TEjo mode waveguide slotted array made the amplitron installation concept very complex as shown in Figure 2.3-6. To solve this temperature interface problem and possibly increase the RF efficiency of the radiator, Rockwell developed the resonant cavity radiator (RCR). The RCR is a resonant cavity box excited with the TEmo mode. Physically, the RCR is a conventional standing waveguide radiator with the common walls removed. The RCR has three significant potentials. They are: 1. Improvement in efficiency. 2. Lighter weight. Figure 2.3-6. Raytheon MW Subarray Concept