摘要 |
<p>A planar antenna includes a first slotted waveguide serving as a power-feed unit, and a second slotted waveguide of planar type coupled with the power-feed waveguide, for radiating circularly polarized microwaves into space. The second waveguide has a metal plate in which a two-dimensional slot array consisting of a plurality of rows of slots is formed. An insulative layer is provided on the second waveguide to cover the slot array. A plurality of rows of metal patch radiators are provided on the insulative layer. These patch radiators are electromagnetically coupled with the slots, respectively, in such a manner that each radiator is directly excited by the corresponding slot through the insulative layer, thereby radiating circularly polarized microwaves.</p> |