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The operational background and some of the possible single and dual lens antenna options for use in a millimetric sensor with approximately 3° beamwidth have been examined. A particular single lens antenna design gave a scan of more than ±3 beamwidths and compatibility with conical scan, beam broadening and monopulse operation.A dual lens antenna design was operated both with a single feed horn and with a rectangular matrix of plain waveguide radiators (with potential application in real time imaging). Good scan characteristics were obtained out to ±6 beamwidths with the single feed horn but the matrix feed assembly needed a group of elements to be fed in phase before equivalent performance could be obtained. The aim of the work was to simulate feeding the lens antenna with a monolithic array and whilst an array of waveguides can not accurately model all the properties of a monolithic array they are considered sufficiently representative to indicate some of the compromises that may have to be made.

A technique for using frequency scanning to give 360° electronic beam steering from a circular antenna array is described, using relatively simple hardware. A field focused filter is used as a frequency selected switch for a lens fed circular array.

A compact range for millimetre-wave frequencies is described using a dielectric lens. This configuration leads to a number of advantages such as reduced tolerance requirements and costs, and can be implemented into standard antenna test chambers.

A dielectric lens, designed to be fed by a wide-angle corrugated conical horn, is described. The radiation pattern of the horn-lens combination is similar to that of a much longer conical horn while retaining wideband characteristics.