Microstrip line antenna with crank-shaped elements and resonant waveguide elements

Claim 1

A plane antenna comprising: a microstrip line antenna including a plane dielectric substrate and a plurality of parallel conductor lines arranged on said substrate along a first direction, each of said conductor lines comprising a plurality of antenna elements sequentially connected together to form a crank-shaped conductor pattern, each of said elements comprising a relatively long first segment and a relatively long second segment with said first and second segments oriented in said first direction and a relatively short third segment oriented in a second direction normal to said first direction and connecting said first and second segments together in said crank-shaped conductor pattern, a plurality of half wavelength waveguide elements lying on a plane parallel to said substrate, extending respectively in said first and second directions and each waveguide element comprising a conductor resonant with a half wavelength of an electric wave to be used, and means for supporting said half wavelength waveguide elements in spaced relation to said conductor lines at at least one of a set of distances comprising about a half wavelength of said electric wave to be used and integral multiples of said half wavelength.