Abstract: A circuit assembly (200) is disclosed comprising a substrate (210) and conducting layers (250) on opposing sides of the substrate (210), there being at least one via (220) through the substrate (210), which via (220) forms a conductive path between the conducting layers, wherein the substrate (210) is a foam substrate, and wherein the via (220) is provided with a solid dielectric lining (270) plated with a conducting material (250).

Abstract: A circuit assembly (200) is disclosed comprising a substrate (210) and conducting layers (250) on opposing sides of the substrate (210), there being at least one via (220) through the substrate (210), which via (220) forms a conductive path between the conducting layers, wherein the substrate (210) is a foam substrate, and wherein the via (220) is provided with a solid dielectric lining (270) plated with a conducting material (250).

Abstract: A sensor (10) for detecting an incident RF signal having a carrier frequency, and for estimating said carrier frequency, comprises a plurality of filters (70-73), each allowing passage of signals over a different band of frequencies from the band of frequencies over which passage of signals is allowed by the others of the plurality of filters (70-73), and a plurality of detectors (80-83). Each filter (70-73) is associated with at least one of the plurality of detectors (80-83), and said at least one detector (80-83) is arranged in use to generate an output signal if the incident RF signal results in a signal in the band of frequencies passed by the filter (70-73) with which the detector (80-83) is associated. Generation of the output signal by the detector (80-83) indicates in which of the frequency bands the incident RF signal has been detected.

Abstract: A sensor (10) for detecting an incident RF signal having a carrier frequency, and for estimating said carrier frequency, comprises a plurality of filters (70-73), each allowing passage of signals over a different band of frequencies from the band of frequencies over which passage of signals is allowed by the others of the plurality of filters (70-73), and a plurality of detectors (80-83). Each filter (70-73) is associated with at least one of the plurality of detectors (80-83), and said at least one detector (80-83) is arranged in use to generate an output signal if the incident RF signal results in a signal in the band of frequencies passed by the filter (70-73) with which the detector (80-83) is associated. Generation of the output signal by the detector (80-83) indicates in which of the frequency bands the incident RF signal has been detected.

Abstract: The invention comprises a feed horn (10) illuminating a circular flat panel (12) formed from a high impedance surface structure. By controlling the resonant frequencies of the individual elements of the array, a controlled phase shift profile is applied across the surface of the panel to an incident phase front spherically spreading from the feed antenna so as to reflect that wavefront in a particular direction or impose a certain desired beam shape. The principles are reciprocal so a receiving system can also be achieved or indeed a simultaneous transmit and receive operation can be supported. The phase controlled reflecting plate advantageously performs focussing to the feed and beam scanning or beam shaping. This concept of feed to a phased reflector plate allows the power distribution to be implemented in free space.

Abstract: The invention comprises a feed horn (10) illuminating a circular flat panel (12) formed from a high impedance surface structure. By controlling the resonant frequencies of the individual elements of the array, a controlled phase shift profile is applied across the surface of the panel to an incident phase front spherically spreading from the feed antenna so as to reflect that wavefront in a particular direction or impose a certain desired beam shape. The principles are reciprocal so a receiving system can also be achieved or indeed a simultaneous transmit and receive operation can be supported. The phase controlled reflecting plate advantageously performs focussing to the feed and beam scanning or beam shaping. This concept of feed to a phased reflector plate allows the power distribution to be implemented in free space.

Abstract: An electron beam window 20 is formed with six diamond panes 21 to transmit an electron beam 15. The panes 21 are formed in a cylindrical disc 17 of single crystal or of polycrystalline diamond such that each pane 21 is surrounded by a thicker integral peripheral rim 22 which conducts heat away from the panes 21. A heat sink ring 35 can be fitted to the outer cylindrical surface of the peripheral rim 22. A scanning means 36 indexes the electron beam 15 sequentially through each pane 21. The use of diamond panes reduces the electron beam energy converted to heat in each pane 21, the thicker peripheral rim 22 increases cooling of the panes 21, and the scanning movement 37 reduces the temperature rise of the panes 21.