| 摘要 |
A termination (20, 32) is placed in the opposing wall behind the center radiator (18c, 28c) of a multiple slot antenna array. The termination is inoperative when the array is excited for sum mode radiation patterns and is operative when the array is excited with difference mode radiation patterns. When the terminatrion is inoperative, the center slot radiator is excited along with the remaining slot radiators (18, 28) to produce the sum pattern. When the termination is operative, the center slot radiator is prevented from receiving excitation and a resultant difference pattern is produced by the remaining slot radiators (18, 28). Both E-plane and H-plane patterns can be achieved by the appropriate use of series slots and shunt slots. By eliminating the center slot (18c, 28c) in the difference pattern a reduction in side lobes results. This is an improvment over current practice where there are an even number of slots and no change of amplitude distribution-only a change of 180 DEG phase between the halves for the difference mode.
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