Three-Dimensional Comer Reflector Antenna

A reflector antenna utilizing three planar reflectors and a 3/4 X-unipole radiator is proposed. Calculations based on image and EMF-methods predict that the gain is about 5 dB greater than that of the two-dimensional comer reflector antenna, and that the input impedance is roughly between 50 and 75 9. Experiments conducted on the three-dimensional corner reflector antenna with rectangular comers confirmed the predicted properties and also showed the sidelobe in the electric plane being suppressed by the effect of mact ion . This effect is explained by the calculated radiation pattern of 3/4 X-unipole on conducting half plate. PRINCIPLE OF THE ANTEXK-A The antenna consists of three planar reflectors and a 3/4 X-unipole (X is wavelength) located on one of the reflect.ors, as shown in Fig. 1. If the ground plane dimension I is infinitely large, the radiation pattern is exact.ly that of a 3/2 X-dipole inside the corner reflect,or, which becomes maximum a t 0 = e, ‘v ~ / 4 and @ = 4 2 , by choosing the corner angle a and t.he distance d between the apex and t.he unipole properly. The sidelobe at. 0 N r/2 will be suppressed if the ground plane dimension 1 is finite. ANALYSIS BY IMAGEAND EMF-METHOD Assuming a sinusoidal current for t,he unipole and infinite dimensions for the reflectors, we get the following far field when LY = ;./n Manuscript received July 1