The effect of perforating the corner reflector on maximum radar cross section

Passive point targets such as trihedral and dihedral corner reflectors are commonly used for synthetic aperture radar calibration because of their large radar cross section and wide radar cross section pattern. These types of passive point targets are not expensive to manufacture comparing to active point targets such as transponder and they are easy to deploy in the field without using power to work. Perforating the corner reflector is an important factor in building the corner reflectors to allow quick drainage from heavy rain, cleaning from dust and reduce the effect of wind as well as reducing the weight of the corner reflectors. In this paper, we analysis the effect of perforating the corner reflector on maximum radar cross section using square trihedral corner reflector with four different hole sizes and three varying hole centre spacings. The results showed that a hole size of one-tenth of the wavelength reduced the maximum radar cross section by less than 1 dB from the theoretical radar cross section and the spacing between the two holes did not have much effect while one-sixth of the wavelength reduced the maximum radar cross section by about 1 dB and the reduction between the spacing is very small about 0.10 dB. Finally, a hole size with one-fourth of the wavelength reduced the maximum radar cross section by more than 2 dB and the reduction between the spacing increased while one-third of the wavelength has a reduction of about 4 dB.