Patent ID: 7095373

Claim:
A planar array antenna, comprising: a multi-layer substrate having an intermediate layer conductor in a laminated face; first and second slot lines formed in said intermediate layer conductor, and intersecting each other; first and second microstrip lines formed on said multi-layer substrate, and traversing said first slot line, respectively, at a position corresponding to both end sides of said first slot line; third and fourth microstrip lines formed on said multi-layer substrate, and traversing said second slot line, respectively, at a position corresponding to both end sides of said second slot line; a first antenna element coupling to one end of said first microstrip line and one end of said third microstrip line; a second antenna element coupling to the other end of said first microstrip line and one end of said fourth microstrip line; a third antenna element coupling to one end of said second microstrip line and the other end of said fourth microstrip line; a fourth antenna element coupling to the other end of said second microstrip line and the other end of said third microstrip line; a fifth microstrip line provided on said multi-layer substrate, a top end side of said fifth microstrip line traversing said first slot line in a center region of said first slot line so as to be electromagnetically coupled to said first slot line; and a sixth microstrip line provided on said multi-layer substrate, a top end side of sixth microstrip line traversing said second slot line in a center region of said second slot line so as to be electromagnetically coupled to said second slot line; wherein each of said first to fourth antenna elements is an antenna element excitable in two directions.