Abstract: A phase shifter for electrically adjusting the down-tilt of an antenna, based on rotating at least one phase wheel having a specially shaped dielectric. Each phase wheel is rotatably mounted between a stripline and the metallic ground plane of a feed system for an RF signal communicating the RF signal between each element of the antenna and a common terminal. The dielectric distributed on each phase wheel is shaped so that as the phase wheel is turned mechanically, the amount of dielectric directly beneath the stripline and above the metallic ground plane either increases or decreases in some proportion to the amount (angular displacement) the wheel is turned. All the phase wheels used in a system can be arranged, oriented, and tractively coupled so as to rotate in synchrony under the action of a single drive, which may itself be driven by a stepper motor for accurate, fine control.

Abstract: A land mobile radio system (110) includes a plurality of radio channels (112), each radio channel (112) being interconnectable (115) to any one of a number, N, of combiners (114), and each combiner (114) being associated with a corresponding transmit antenna (120). A combiner output signal at the output of each combiner (114) is connected to a transform matrix (133) which divides each combiner output signal into a number, N, of transformed signals, each transformed signal containing an equal power level part, 1/N, of each combiner output signal. Each transformed signal is provided to an amplifier (135) for amplification thereof, and the amplified transformed signals are provided to an inverse-transform matrix (138) which recombines the equal parts of each amplified transformed signal into amplified combiner output signals which are provided to the antennas (120) for transmission thereof. The land mobile radio system (110) includes N antennas (120), and where N is a power of m, e.g., N=m.sup.

Abstract: A self clamping connector 10 for a radio frequency coaxial cable having a helically corrugated outer conductor 14 which does not require flaring of the outer conductor of the cable is disclosed. The connector includes a clamping back nut 30 having a plurality of resilient fingers 32 at one end. Each of the resilient fingers 32 have an outer conductor matching threaded portion 38. A cup shaped collet 40, further including a base 42 having an opening 44 therein, is positioned over the resilient fingers 32 to clamp the fingers 32 onto the helically corrugated outer conductor. The cup shaped collet 40 also enables the connector to collapse part of the outer conductor corrugation. The collapsed corrugation is held between the collet and the resilient fingers. A body 50, having threading to enable coupling to the clamping back nut 30, forces the cup shaped collet to remain over the resilient fingers when the connector is in the assembled state.

Abstract: A modular interconnect matrix (200) interconnects a plurality (M) of radio channel units (203) with a plurality (N) of antennas (202). Each radio channel unit (203) is connected to a first connector (222) on a corresponding first switching module (217) having a plurality (N) of seconds connectors (225). Each antenna (202) is connected to a first connector (212) of a corresponding antenna interface module (205) having a plurality (X) of second connectors (215). The second connectors (215,225) on the modules (205,217) are arranged for interconnection of at least one second connector (225) on each of the first switching modules (217) with at least one second connector (215) on each of the antenna interface modules (205).

Abstract: A land mobile radio system (110) includes a plurality of receive antenna (120) for receiving RF signals transmitted from mobile units. Each receive antenna (120) is connected to a transform matrix (133) which divides each received RF signal into a number, N, of transformed signals, each transformed signal containing an equal power level part, 1/N, of each received RF signal. Each transformed signal is provided to an amplifier (135) for amplification thereof, and the amplified transformed signals are provided to an inverse-transform matrix (138) which recombines the equal parts of each amplified transformed signal into amplified received RF signals which are provided to an RF signal processing section (125). The amplified RF signals are thereafter provided to corresponding radio channel units (127).

Abstract: A modular interconnect matrix (200) interconnects a plurality (M) of radio channel units (203) with a plurality (N) of antennas (202). Each radio channel unit (203) is connected to a first connector (222) on a corresponding first switching module (217) having a plurality (N) of seconds connectors (225). Each antenna (202) is connected to a first connector (212) of a corresponding antenna interface module (205) having a plurality (X) of second connectors (215). The second connectors (215,225) on the modules (205,217) are arranged for interconnection of at least one second connector (225) on each of the first switching modules (217) with at least one second connector (215) on each of the antenna interface modules (205).

Abstract: An apparatus for linearizing the output of a wideband amplifier by digitally predistorting the input to the amplifier in a way that just compensates for the distortion in the amplified signal, comprising a pipeline controller (12), for providing pipeline controller signals, and a pipelined predistorter (11), consisting of several stations, serially connected to each other, wherein each station performs one or more tasks concurrently, under the direction of the pipeline controller (12). The result is a digital predistorter with a bandwidth large enough to linearize, by itself, the entire output of a wideband amplifier. More generally, an apparatus for linearizing a wideband amplifier by using digital signal processing performed using a pipeline architecture, as opposed to using a sequential processing architecture, under the supervision of a pipeline controller.

Abstract: An improved antenna system for use at high frequencies such as cellular communication and PCS frequencies, having a steerable, multi co-linear array antenna in which the number of radiating elements per co-linear array increases monotonically from the periphery of the antenna to the middle of the antenna, and wherein the antenna is connected to a Butler matrix feed network, thereby providing steerability of the radiation pattern associated with the antenna. The improved antenna system achieves significantly lower sidelobe generation as compared to antenna systems using multiple co-linear arrays of radiating elements in which the number of radiating elements per co-linear array is constant. The Butler matrix feed network is implemented via a microstrip fabricated printed circuit board without crossovers.

Abstract: A system (10) for combining a plurality of transmission channels within a multiple channel communication system includes a master computer (20) that controls the transmission frequency and schedule of a plurality of channel transmitters (18). Each channel transmitter (18) is electrically connected to a channel transmitter combiner filter (12). Each channel transmitter combiner filter (12) is fixedly tuned to a unique bandwidth window along the electromagnetic spectrum, and two sets (24), (26) of channel transmitter combiner filters are formed of the channel transmitter combiner filters (12) whose unique bandwidth windows are adequately spaced for electrical isolation along the electromagnetic spectrum. Each set (24), (26) of channel transmitter combiner filters is electrically connected to a common antenna (28) by means of a three decibel (3 dB) coupler (22).

Abstract: A hollow center conductor connector assembly having an expandable plug (12), a plug-expanding-conductor-coupler (14) and a bolt (15) provides a connector for smooth wall hollow center conductors and corrugated wall center conductors. The expandable plug (12) is provided with fine teeth (34) for gripping a smooth wall type center conductor and a helical groove (36) for gripping a corrugated wall type center conductor. The diameter of the expandable plug (12) is expanded when the plug-expanding-conductor-coupler (14) and expandable plug (12) are drawn together by a bolt (15).

Abstract: A circularly polarized microcell antenna 10 that requires only a single feed-line to radiate circularly polarized electromagnetic energy therefrom. The antenna 10 comprises a reflector box 14 having a bottom 15 and side walls 17 to which an electrical connector 20 is mounted. The center conductor 24 of the connector 20 is electrically connected to a conductor bar 22 upon which a first dipole assembly is mounted at a designated one-quarter wavelength location. The shell of the connector 20 is electrically connected to the reflector box 14 upon which a second dipole assembly is mounted at a designated one-quarter wavelength location. Each dipole assembly comprises a primary dipole arm 52 and a secondary dipole arm 68 which are electrically connected by a phasing loop that introduces a 90.degree. phase shift between the primary dipole arm 52 and the secondary dipole arm 68.

Abstract: In a feed forward amplifier (100), a main amplifier (125) is coupled between an input (102) at which an input signal is received and an output (173) at which an output signal is provided. The output signal is an amplification of the input signal. A sample of the output signal is compared (144) with a sample of the input signal to produce a difference signal indicative of distortions introduced by the main amplifier (125). An error amplifier (165) provides a distortion signal which is an amplification of the difference signal, and the distortion signal is combined (169) with the output signal to compensate for main amplifier distortions. A random frequency, constant amplitude sine wave pilot signal is combined (117) with the input signal, and a correlation power detector (194,195,202,212,213) is provided to determine the magnitude of the pilot signal in the output signal. The gain and phase of the difference signal is then adjusted (155) to minimize the magnitude of the pilot signal in the output signal.

Abstract: Male and female radio frequency cable connectors 64 and 13 have corresponding circumferential grooves 80 and 44 which are aligned and face each other when the connectors 64 and 13 are in a connected state so as to form a channel. The connectors 64 and 13 are held together by a canted-coil spring 11 residing in the channel formed by the two aligned and facing circumferential grooves 80 and 44. Deformation of the canted-coil spring 11 residing in the channel allows the male and female counterpart RF cable connectors 64 and 13 to resist separation as well as provide a primary electrical contact between the two connectors. If a substantial tensile force is placed on the cables 12 and 85, the spring 11 will deform sufficiently to allow separation of the two connectors 64 and 13.

Abstract: A transistor mounting clamp assembly for ensuring reliable electrical connection of a power transistor electrical connector tab (typically the collector tab) to a metallized portion of an associated printed circuit board. The transistor mounting clamp assembly comprises a top and bottom clamp dimensioned for sandwiching therebetween the transistor tab. The clamp assembly uses a machine screw and associated Belleville washer for maintaining this urging relationship even when the components expand and contract. The bottom clamp preferably has a stepped region or other surface discontinuity for securing the connector tab thereto. The clamp assembly further comprises an extending tab which is secured to the top clamp and which has a second region for providing electrical connection to the metallized portion of the printed circuit board by soldering, or other means.

Abstract: A multi-cavity dielectric filter 30 having a single housing 32 for a plurality of resonant cavities 65. The dielectric filter 30 has a plurality of dielectric resonators 42 placed inside housing 32, instead of in individual housings, wherein the resonators 42 are spaced a quarter wave apart and are electrically isolated from one another by conductive isolation plates 44 positioned therebetween. The isolation plates 44 do not make continuous mechanical contact with the interior conducting surface of housing 32, but rather are spaced from the inner surface 77 of housing 32, thereby making assembly of the filter much simpler than if a solid RF connection had to be made. The resonators 42 are positioned inside the housing 32 between the isolation plates 44 and are supported by low loss, low dielectric constant spacers 46. End walls 59 complete the cavity formation at the termination ends 79 of housing 32.

Abstract: A TE.sub.101 mode cavity resonator housing 60 has a truss 70 securely mounted to one of its broadwalls 72. The truss 70 is fabricated from a material having a lesser coefficient of expansion than that of the material from which the housing 60 is fabricated. The difference between the coefficients of expansion results in a difference in expansion and contraction of the materials over temperature. The thermal expansions and contractions in the housing 60 material result in variations in the natural resonant frequency of the housing 60. These variations in natural resonant frequency are compensated by offsetting thermal expansions and contractions in the truss 70 material.

Abstract: A technique for directly coupling multiple high frequency resonant cavity filters includes a common port 62 that is directly coupled to a coupling rod 76 that is mounted within a first high frequency resonant cavity filter housing 64 of a housing assembly 60. The coupling rod 76 is directly coupled by a conductor 74 to an coupling rod 72 that is mounted within a second high frequency resonant cavity filter housing 66. The conductor 74 passes through an opening 78 in a common wall 80 between the first 64 and the second 66 high frequency resonant cavity filter housings. Thus, both filters 64, 66 are directly coupled to the common port 62.

Abstract: A broadband antenna array, formed of pairs of horizontally-spaced dipoles that are balun-fed, uses an air dielectric microstrip binary-feed network to optimize antenna bandwidth. Each dipole is fed by a three-wire balun which maintains the proper current distribution on the dipoles over the operating bandwidth. The binary-feed network feeds each dipole individually to further optimize the antenna's pattern bandwidth. The binary-feed network is formed using a conductive ground plane with spaced conductors to utilize an air dielectric, thereby minimizing antenna losses in the feed network. The feed network impedances are chosen to give a broadband impedance match to the dipoles, and the entire assembly of binary-feed network and dipoles is mounted in a reflector box, the dimensions of which are chosen to control the antenna beamwidth. Vertically stacked pairs are used to compress the vertical radiation pattern for greater antenna gain.

Abstract: A folded high frequency resonant cavity filter 30 includes a filter housing 32 that contains a half-wave resonator rod 36, 64 and a plurality of evanescent mode resonator rods 34, 34'. The half-wave resonator rod 36, 64 and plurality of evanescent mode resonator rods 34, 34' are mounted to the filter housing 32 such that they all lie along a single plane. The filter housing 32 has an inner wall 42 that physically isolates two groups of evanescent mode resonator rods 34, 34' from each other. An aperture 40 is is formed in the inner housing wall 42 between two physically opposing evanescent mode resonator rods 34' to allow a capacitive cross-coupling to occur between the two evanescent mode resonator rods 34'. The capacitive cross-coupling is fine tuned by a tuning rod 44 that is positioned through the inner wall 42 and within the aperture 40.

Abstract: A vehicular multi-band antenna is adapted to receive signals in the AM/FM bands and to receive and transmit signals in a significantly higher frequency band such as that used for cellular telephone. The antenna is provided with a base section fixedly mounted on the vehicle and a removable antenna mast section removably received in the base section.