Abstract: A radome for providing a relatively wide-band operation which in a preferred embodiment uses at least a pair of panel means mounted adjacent each other, each having a plurality of discontinuous conductive elements applied to a selected surface thereof in an array of parallel paths. The discontinuous elements in each path of the array are interconnected by diode means which can be biased in a non-conductive direction during a first transmit mode and in a conductive direction during a second non-transmit mode. The panels are separated by a distance which is substantially equal to one quarter wave length (.lambda..sub.s /4) at a selected frequency within the wide pass-band of electromagnetic energy which is to be transmitted.

Abstract: A "shutter" type structure for transmitting electromagnetic energy within a selected frequency range and preventing the transmission of such energy outside such range during a first open shutter mode of operation and for preventing the transmission of any electromagnetic energy during a second closed shutter mode of operation. The structure includes an insulative member having an array of symmetrical conductive elements on at least one surface, such elements being interconnected by diode elements in both vertical and horizontal directions. The diodes are placed in their conductive states during the first mode of operation and in their non-conductive states during the second mode of operation.

Abstract: A structure for selectively transmitting electromagnetic energy over a selected frequency range during a first operating mode and for substantially preventing the transmission of electromagnetic energy at any frequency during a second operating mode either by absorption or by reflection of such energy. The structure includes at least one shutter means comprising continuous and discontinuous elements and diode means interconnecting the discontinuous portions of the discontinuous element. The diode means are biased in a non-conductive direction during the first operating mode and are biased in a conductive direction during the second operating mode. The structure can further include filter means which include continuous and discontinuous elements arranged so as to be resonant over the selective frequency range during both operating modes.

Abstract: A multiple section telescoping police baton is disclosed. The baton has a locking mechanism which is activated upon twisting of one section relative to the other in order to prevent sliding motion of one section relative to the other.