Quadrupole Illumination for Improving the Signal to Noise Ratio in Microwave Imaging

A quadrupole illumination scheme with specific phase distribution at the excitation elements is proposed in order to improve the noise performance of microwave imaging systems. In comparison with conventional single antenna illumination, the proposed system features simpler calibration while at the same time drastically improving the signal-to-noise ratio. An application with planar scanning is considered here; however, the quadrupole illumination is also applicable to cylindrical and spherical acquisition surfaces.