Abstract: A waveguide assembly for use in a radar. The waveguide assembly being fabricated from a di-electric material and comprising a beamsplitter which comprises a right circular cylinder having a quarter wave air gap substantially along a centreline of the right circular cylinder. The waveguide assembly further comprises a waveguide on a port of the beamsplitter. In at least one construction, the waveguide assembly comprises four ports: a transmit input arranged to receive a signal from a source, a receive output arranged to direct a return signal to a receiver, and output port, and a load port.

Abstract: A waveguide assembly for use in a radar, the waveguide assembly being fabricated from a di-electric material and comprising a beamsplitter which comprises a right cylinder having a quarter wave air gap substantially along a centreline of the right cylinder.

Abstract: Reflective means comprising substrates, selectively reflects electromagnetic radiation whose frequency lies between 3×109 Hz and 1013 Hz, and includes, for example, a layer of high resistivity silicon, on which the radiation is arranged to be incident, and means for selectively generating charge carriers in the layer to reflect the radiation, for example, by illuminating a face of the substrate with electromagnetic radiation whose wavelength lies between 5 ?m and 100 mn in order to generate the charge carriers. The reflective means may form part of an imaging device in which a scene to be imaged is illuminated by radiation which passes through the reflective means in a coaxial arrangement, the reflected radiation being received by the reflective element while the reflective region is scanned over its entire surface, to produce a stream of radiation reflected from the scene which can be detected and used to drive a display.

Abstract: Reflective means comprising substrates, selectively reflects electromagnetic radiation whose frequency lies between 3×109 Hz and 1013 Hz, and includes, for example, a layer of high resistivity silicon, on which the radiation is arranged to be incident, and means for selectively generating charge carriers in the layer to reflect the radiation, for example, by illuminating a face of the substrate with electromagnetic radiation whose wavelength lies between 5 ?m and 100 mn in order to generate the charge carriers. The reflective means may form part of an imaging device in which a scene to be imaged is illuminated by radiation which passes through the reflective means in a coaxial arrangement, the reflected radiation being received by the reflective element while the reflective region is scanned over its entire surface, to produce a stream of radiation reflected from the scene which can be detected and used to drive a display.