DOUBLE SPIRAL TYPE SLOT ARRAY CIRCULAR ANTENNA

摘要

PURPOSE:To improve the aperture efficiency of a circular slot antenna by arranging a slot to a position of a 1/2 wavelength and tilting the slot to the opposite side to other slot by nearly 45 deg.. CONSTITUTION:The center of a circularly radiation disk 4 is taken as the origin of the X-Y coordinate, and 1st slots 1a, 2a, 3a...na whose slot length is nearly lambdae/2 are arranged on a 1st spiral R1 whose distance r1 with the origin is expressed in the relation of r1=delta+(theta/2pi)Xlambdag while being tilted by 45 deg. in the radial direction, where theta(in radian) is an angle between the X axis and the optional radial axis in the circular waveguide space, delta is an optional number, lambdag is a wavelength of the propagation mode spread uniformly in the axis symmetry in the radial direction of the circular waveguide space from a feeding section and lambdae is a wavelength in the free space. Moreover, 2nd slots 1b, 2b, 3b...nb whose slot length is nearly lambdae/2 are arranged on a 2nd spiral R2 whose distance r2 with the origin is expressed as r2=delta+lambdag/2+(+ or -delta+(+ or -theta/2pi)Xlambdag to opposite side to the 1st slot while being tilted by nearly 45 deg..