PURPOSE: To obtain an ideal circularly polarized wave slot antenna, which is nearly a complete roundness, by specifying the inclination of a slot to be arranged in a double helix shape.
CONSTITUTION: To a slot board 5 of the conductor of the one side of a radial waveguide path, to which a feeding is executed by a coaxial line 14, a number of the slots are provided. Then, the slots are successively arranged so that the polar coordinates (R, θ) of the center of an odd numbered slot, which keeps a constant angle with the radial direction of the waveguide path, satisfies the equation R=b+λθ/2, where λ is the wavelength of an axisymmetric propagating mode in the radial waveguide path and (b) is an arbitrary length, and the equation R=λ/2+b+lθ/2 is satisfied by an even numbered slot. Thus, even when an intermediate metallic board is not used, a complete roundness polarized slot antenna can be obtained providing a gain of high performance.
KIKUCHI SHIGEO
MISUMI KATSUMI