| 摘要 |
PROBLEM TO BE SOLVED: To provide a circularly polarized patch antenna which is capable of easily adjusting an axial ratio in an operation frequency even if a dielectric substrate of a high dielectric constant is used.SOLUTION: The circularly polarized patch antenna includes: a dielectric substrate 4 including a first plane 41 and a second plane facing opposite to each other; a radiation element 5 disposed on the first plane 41 and smaller than the first plane 41; a bottom board 3 disposed on the second plane, larger than the second plane, and including an outside portion 37 which protrudes outside of the second plane in a plane direction including the second plane; and a second side 32 and a fifth side 35 which are formed in the outside portion 37 of the bottom board 3 and function as a bottom board side degenerative separation part. The second side 32 and the fifth side 35 are unlikely to be influenced by wavelength reduction effects by the dielectric substrate 4 since being provided in the portion protruding outside of the dielectric substrate 4. Therefore, even if the dielectric constant of the dielectric substrate 4 is varied, a possibility for a size of the second side 32 and the fifth side 35 to be settled within an allowable range is high and in addition, since an allowable range of trimming is widened, the adjustment of the axial ratio in the operation frequency is facilitated.SELECTED DRAWING: Figure 1 |
