| 摘要 |
A compact, low-profile broad-banded log-periodic antenna comprises a planar conductor (3) partially sandwiched by but electrically insulated from two substantially parallel spaced-apart ground planes (4, 8). The sandwich extends as far as an imaginary plane (15) that is orthogonal to conductor (3) and to the ground planes (4, 8). Conductor (3) comprises an alternating series of radiating loops (L(n)) and non-radiating transmission-line loops (L(j)). The non-radiating loops (L(j)'s) lie on the ground plane (4, 8) side of plane (15). The radiating loops (L(n)'s) lie on the other side of plane (15). Optional additional ground planes (6, 10) may be employed, in which case they lie in plane (15) and meet one of the primary ground planes (4 or 8, respectively) along a common edge. The length (d) of the loops (radiating or non-radiating), the spacing (D) between loops, and the height (h) and width (w) of the radiating loops (L(n)) are all scaled by a factor (S) which is less than 1 but greater than 0. The top members (B(n)) of the radiating loops (L(n)) converge towards a point P which defines the preferable termination point of the optional ground planes (6, 10).
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