Low profile antenna study using the physical optics hybrid method (POHM)

POHM is applied to the design of the low-profile IFF (identification of friend or foe) airborne antenna whose height is less than 1 in. The basic idea of the POHM is that the physical optics technique is used to extend the application of the method of moments to a larger class of problems. The POHM program is tested with geometrical optics, geometrical theory of diffraction, and measured data. It is seen that the accuracy of the POHM is quite satisfactory for large ground plates. In the angular region, z>or=0, the accuracy of the POHM is very high because the physical optics currents on the body are included. However, the accuracy decreases because the POHM assumes that no currents exist on the shadow area (z<0) of the surface on the body.<>