Variable focusing antenna for wireless power transmission and remote sensing at millimeter wavelengths

Summary form only given. The design of a cassegrain antenna with adjustable focus is described. This antenna consists of a millimeter wave (MMW) band cassegrain feed requiring the sub-reflector surface to be highly reflective at 94GHz. The cassegrain antenna is operating in the near field regime, and has the capability to change the size of the beam spot and so make the focus a function of the distance between the main dish and the sub-reflector. It is then possible to achieve the maximum power density. The focus of the beam was determined and the development of this antenna has been carried out using the Gaussian model. The approach was employed to find the distance between the main- and sub-mirrors using the ABCD matrix, and find the focus as function of the axial distance. This design is applicable to millimeter wave remote sensing and power beaming, where maximum power density is required at the target. We present the development of the quasi-optical system, simulation and experimental results.