PLANAR ANTENNA

PROBLEM TO BE SOLVED: To obtain a planar antenna with a higher antenna gain and higher efficiency than those of a conventional planar antenna which uses a dielectric body for a guide path. SOLUTION: In the planar antenna that uses an electromagnetic field where an electromagnetic wave is propagated in a surface wave mode on a dielectric board having a small dielectric loss characteristic and emits a circularly polarized wave by using a required number of thin and long conductors provided on the surface of the dielectric board as radiation elements, a couple of two orthogonal thin and long conductors are used for one radiation element and in the planar antenna that radiates a linearly polarized wave, a radiation element consisting of one thin and long conductor is placed in parallel with a polarization direction or at an angle not so high in the polarization direction on the dielectric board.