( I am working in GHz range and so the spacing of multiples of
wavelength means it will be only few cms.)
One more observation i have made is that i have placed my antennas on
a rectangular plate and then on a curved surface. The former setup
gives me around -20db gain at 270deg, i.e back side of the rectangular
plate whereas in the latter case there is no such diffraction effect.
Why is it so?