Millimetre wavelength variable focusing antenna for power beaming and active denial systems

A design of a millimetre wavelength antenna with adjustable focal length is demonstrated in this study. This antenna is designed to operate in the near field regime, and has the ability to change the focal plane position. The structure of the antenna is based on a Cassegrain configuration in order to deliver maximum power density to a predefined focal plane. Possible applications are radioactive power beaming and active denial systems. The analysis and development of this antenna were carried-out using the Gaussian beam model and the ABCD matrix method in order to find the focus position and spot size as a function of the axial distance. The development of the quasi-optical components of the Cassegrain antenna, simulation results and experimental results are described in this work.