| 摘要 |
An antenna has a resonant cavity 2 defined by electrically conducting plates 3, 4 and a sidewall 5, and has sixteen helical antenna elements 6 each with five turns in the helical section and a probe 7 at the opposite end, the stem of probe 7 passing through an aperture in upper plate 3 so that its end 6 is within the resonant cavity 2 common to all elements 6 in that module. Cavity 2 has a cross-section parallel to the plates 3, 4 essentially square in shape except for the presence of four inwardly-protruding buttresses 8, one situated mid-way along each side of the cavity to promote the formation of standing waves of different mode, and thereby enhance the frequency range of the array 1. |
