Abstract: A wireless communication system for closed environments including a plurality of antennas parallel line coupled to the coaxial cable of a coaxial cable radio frequency transmission system. Each antenna includes a quarter wavelength long conductor positioned between the center and outer conductors of the coaxial cable. The conductor is axially aligned to the cable and insulated from the center and outer conductors by the cable's dielectric core. The conductor is connected to a quarter wavelength radiator supported by a conductive bar clamped to the exterior of the coaxial cable.

Abstract: A method and apparatus for frequency stabilization of cavity filters of the class including an outer tubular conductor and an inner conductor is effected by supporting the inner conductor of the resonant cavity by an apparatus comprised of a reference collar and an interface collar connected together by a means having a first coefficient of thermal expansion. The reference collar is structurally connected to the reference end of the outer tubular conductor by adjustable tuning means. It is not connected directly to the inner conductor. The inner conductor is structurally connected to the interface collar by a means having a second coefficient of thermal expansion. The first coefficient of thermal expansion and the second coefficient of thermal expansion are selected to provide compensation for the difference in thermal expansion between the outer conductor and the inner conductor of the cavity filter.

Abstract: A coaxial dipole antenna element which has omni-directional radiation characteristics in azimuth and can be incorporated into linear antenna arrays to shape the radiation pattern in the vertical dimension is fed by coaxial conductors built into a electrically integral center support extrusion.

Abstract: A ridged coaxial transmission line assembly including a plurality of parallel transmission paths is fabricated from an extrusion incorporating a plurality of slotted, longitudinal bores provided with centrally located conductors held in position by insulating stand-offs provides a structure performing the dual functions of electrically integral antenna mast and signal conductors for a linear array of antenna elements supported by the mast.

Abstract: A power divider directional coupler comprised of coupled transmission line sections at the beginning of each of a plurality of subdivided transmission lines wherein each subdivided transmission line has a unique characteristic impedance, even mode impedance and odd mode impedance. The coupled transmission line sections are shorted and function as quarter-wave transformers providing a center frequency electrical transmission phase of 90 degrees.

Abstract: A comb-line filter incorporating a plurality of bandpass resonators set off center between ground planes is provided with input and output coupling means comprised of dual notching resonators.

Abstract: An R.F. resonant cavity filter for connection in a transmission line and multicouplers utilizing same, said filter adapted to pass only signals of a predetermined frequency into and out of a branch transmission line, to block signals of said predetermined frequency from propagating down said transmission line in one direction but not the other, and to pass all other signals substantially undisturbed.

Abstract: A cavity notch filter (1) for series connection in a transmission line is disclosed which comprises a high Q cavity (2) containing therein an inductively coupled L-C series circuit (19). The notch filter (1) acts as a high series impedance at the resonant frequency of the cavity. At frequencies off resonance, the filter is characterized by low impedance so as to produce broad lateral pass bands.A multicoupler (18) for connection of a plurality of signaling devices (15) to a single antenna (16) may be assembled to comprise two or more of the filters (1) inserted into the transmission line (17); each being tuned to resonate so as to produce a notch at the respective frequency of the signaling device (15). A different signaling device (15) is connected to each of the series connected notch filters (1) at a junction (7). Energy at all frequencies is then permitted to propagate down the line except the energy at the frequency of the respective signaling device (15).

Abstract: An electrical filter network with improved characteristics is disclosed for selectively attenuating and passing two different, closely spaced frequencies. The notch filter network includes a low Q reactive circuit tuned to be parallel resonant at the frequency to be attenuated. A cavity resonator with a high Q is inductively coupled to the reactive circuit and is tuned to be resonant at the frequency to be passed. Utilizing these concepts, a multicoupler may be constructed to consist of two or more such filter networks in combination with a transmission line. In such a multicoupler, the network adjacent to the antenna terminal is separated therefrom by a multiple of a half wavelength. Additional filter networks are separated from one another by an odd number of a quarter wavelength. With this arrangement, each network passes a band around the frequency to which the high Q cavity is tuned and rejects a band of frequencies around the reactive circuit resonant frequency.