High resolution three-dimensional microwave imaging of antennas

A procedure for imaging antenna currents that uses a relationship between the radiated far-field hemisphere and the Fourier transform domain of the source current density distribution is presented. The technique is applied to an array of two orthogonal waveguides, a slotted waveguide array and a reflector antenna. In each case the radiated far-field hemisphere is inverted to produce a high-resolution volumetric image of the antenna currents. Polarization discrimination is demonstrated as is the ability of the technique to `see behind´ blockages by defocusing the foreground. It is shown that accurate distribution is available from the reconstructed image. Selective editing of the Fourier domain of the current distribution is performed to suppress unwanted artifacts in the reconstruction