Abstract: An improved log periodic dipole antenna, adapted for use in a cellular telephone system, has a plurality of radiating elements with differing lengths. The sequence of lengths selected results in a horizontal beam width of about 65 degrees and a front-to-back signal strength ratio exceeding 45 dB. This combination of characteristics reduces interference among adjacent cellular telephone transmitter sites, and reduces waste of transmission energy from the back of the antenna. A preferred sequence of radiating element lengths is long-short-long-short-long, which may be described as a “double stacked hourglass” configuration.

Abstract: An antenna control system is connected to an antenna in order to control the position of the antenna. The system includes a motor connected to the antenna for adjusting the position or vertical tilt angle of the antenna. A driver is provided for operating the motor. A sensor is also provided to detect the position of the antenna. In addition, an antenna controller is connected to an antenna memory, the driver, and the sensor, for reading the detected position of the antenna and for controlling the driver to adjust the antenna's position. A main controller is connected to the antenna controller for sending commands to and reading data from the antenna controller. In this manner, the main controller can interface with any number of antennas at a base station and control the position or down-tilt of each antenna. According to one embodiment of the control system, a user interface is also provided for entering commands to and reading data from the main controller.

Abstract: The invention provides a power sharing amplifier system for a cellular communications system, having with an 8th order transform matrix circuit, eight power sharing amplifiers and an 8th order inverse transform matrix circuit. The 8th order transform matrix circuit has six input ports and responds to six RF input signals for providing 8th order transform matrix RF input signals. The 8th order transform matrix circuit also has two input ports that do not receive input signals, but instead are coupled through a resistor to ground. The eight power sharing amplifiers respond to the 8th order transform matrix RF input signals, for providing eight amplified transformed RF signals. The 8th order inverse transform matrix circuit responds to the eight amplified transformed RF signals, for providing six inverse transform amplified RF output signals to six output ports.

Abstract: A microstrip antenna suitable for omnidirectional S-band operation is formed by the application of a plurality of microstrip radiating elements to the exterior surface of a dielectric tube. The microstrip radiating elements are fed by a branched microstrip input feed line connected to the elements. In the illustrated embodiment, the microstrip radiating elements are fed in-phase by feed line. A substantially cylindrical reflector tube is disposed within the dielectric tube.

Abstract: An isolation improvement circuit for a dual-polarization antenna, the dual-polarization antenna consisting of both a transmitter and receiver antenna for simultaneously transmitting a transmission signal and receiving a receiver signal, in which the transmitter and receiver antennas are configured so as to be mutually orthogonal either by physical or electrical orientation in order to reduce how much of the transmitter signal is picked up by the receiver antenna. The isolation improvement circuit reduces the level of transmitter signal appearing at the output port of the receiver antenna by providing a time-delayed transmission signal that destructively interferes with the transmitter signal picked up by the receiver element.

Abstract: The invention provides a log periodic dipole antenna having a microstrip center feedline and a log periodic hourglass dipole assembly. The microstrip center feedline means responds to an input radio signal for providing a microstrip center feed radio signal. The log periodic hourglass dipole assembly responds to the microstrip feed radio signal, for providing a log periodic hourglass dipole antenna radio signal.

Abstract: A coupling structure for coupling two resonant cavities, which may be dissimilar, based on providing a metallic surface, called here a guide surface, at an angle intermediate between the orientation of the magnetic field in the two cavities. The guide surface may be one surface of a non-rectangular window cut in a wall separating the two cavities or may be the surface of a coupling screw piercing, at the intermediate angle, a rectangular window in a wall between the two cavities. In the non-rectangular window embodiment, an adjusting tuning screw is provided that screws into a notch in the guide surface. In the angled coupling screw embodiment, coupling is adjusted by providing that more or less of the angled coupling screw extends into the rectangular window. The coupling structure couples any two cavities having mutually orthogonal magnetic fields by providing the guide surface at an orientation so the magnetic field in each cavity has a non-zero projection onto the guide surface.

Abstract: An antenna system producing a multi-beam antenna pattern having reduced sidelobe levels with a uniform beam pattern includes an antenna having a plurality of co-linear arrays of radiating elements including central co-linear arrays each of which has an identical number of radiating elements and a pair of outermost co-linear arrays each having a single radiating element. Each of the central co-linear arrays receives the full power output from a corresponding output of a Butler-matrix feed network except for two of the central radiating elements adjacent to the two outermost co-linear arrays, which each share the output power from a corresponding one of the outputs from the Butler-matrix feed network with one of the outermost co-linear arrays.

Abstract: The characterization and detection of an identifying bit sequence is performed without digital demodulation or bit synchronization. A waveform containing a digital bit sequence is correlated with waveforms corresponding to a set of known bit sequences. For each bit sequence, one of the inputs to a correlator is shifted through all possible values of correlation lag while the correlation match for each lag value is compared to the others so that a peak correlation between the two waveforms is determined. The peak correlation values for each of the known bit sequences are then compared to characterize how closely the received radio frequency signal corresponds to each of the known bit sequences. The bit sequence that most closely corresponds to the waveform of the received signal may then be identified. Applications include the identification of the N-AMPS DSAT and the GSM training sequence in a cellular radio scanning receiver.

Abstract: In a land mobile radio system including at least one base site having a system for interconnecting a plurality of radio channel units with a plurality of directional antennas and/or antenna beams, the base site further includes an interference avoidance system for controlling communications between each radio channel unit of the base site and mobile radio units communicating with the base site so as to avoid causing potential interference at the operating frequency of each radio channel unit at other base sites. The interference avoidance system monitors potential interference at the operating frequency of each radio channel unit on each antenna beam.

Abstract: A fixed radius tapered slot antenna (100) formed a dielectric substrate (10) with an electrically conductive layer (14) on one side. The slot is defined by two hemispherical shaped elements (12, 13). A common base (15) is also formed on the conductive layer behind the hemispherical shaped members. Preferably, a microstrip feedline (16) is formed on the side of the dielectric substrate to electromagnetically couple to the balun (18) adjacent the narrow end of the tapered slot. A contiguous array (102) of fixed radius tapered slot antennas (100) can be made on the same conductive layer of a dielectric layer. A reflector (30) can be integrated with the antenna array to improve the radiation pattern. The fixed radius tapered slot antenna has been proven to out-perform an exponentially tapered slot or Vivaldi antenna.

Abstract: A support system for an antenna having a pair of support arms (2) each secured at one end to a clamp (1) and having slots (3) formed at the other end to secure a support lug (4). The support lug has a first end (5) to receive a clamping mechanism (6) for securing the lug to a support pipe or column, and a second end (7) having at least three apertures (8,9) for attaching the lug to the support arms by means of fasteners (10). The slots in the support arms and support lug allow the support system to be secured to support pipes having a wide range of diameters by allowing each support arm to be secured to the support lug while forming any one of a range of angles therewith and while not requiring removal of the fastening bolts.

Abstract: A coaxial cable connector is disclosed. The connector includes a body, a backnut, a clamping insert and a deformable helical split washer. The deformable split washer, clamping insert, body and backnut provide a simple means for deforming and clamping the outer conductor. In one disclosed embodiment, the split washer is captivated in a tubular extension to facilitate installation on the outer conductor.

Abstract: A scanning and targeting system (100) interconnects a plurality of radio channel units (203) in a single trunk group with a plurality of antennas (202), each radio channel unit (203) having a receive section and a transmit section and the scanning and targeting system dynamically connecting the receive section of each one of the radio channel units with any one of the plurality of antennas which, on average during a sampling period, has the strongest received signal strength of RF signals at the operating frequency of the radio channel unit, and the scanning and targeting system dynamically interconnecting the transmit section of each of the plurality of radio channel units with any one of the plurality of antennas which, on average during the sampling period, is best suited for transmitting RF signals at the operating frequency of the radio channel unit in a direction corresponding to the desired destination for the transmitted RF signals.

Abstract: The present invention provides a microstrip collinear antenna having cable connector assembly means and a collinear microstrip printed circuit board means. The cable connector assembly means responds to a radio signal, for providing a cable connector assembly radio signal. The collinear microstrip printed circuit board means responds to the cable connector assembly radio signal, for providing a collinear microstrip printed circuit board radio signal. The microstrip line collinear antenna is constructed with a number of one half .lambda. printed circuit board elements on both sides of a double-sided board. These one half .lambda. sections are the radiators. On the other side of the board opposite each radiator is a respective section of corresponding microstrip transmission lines to provide radio frequency power to each radiating element.

Abstract: In a coaxial cable having a hollow inner-conductor, a connector assembly is provided for electromagnetically connecting the hollow inner-conductor and outer-conductor of the coaxial cable to a standard connector. In one disclosed embodiment, the connector assembly is formed from a body having an axial opening extending therethrough and an outer conductor contact portion. A dielectric cylinder is disposed within the axial opening of the body of the outer-conductor contact, the dielectric cylinder is provided with an axial opening extending therethrough.

Abstract: An antenna system comprises at least two dipole antennas (6) constituting an antenna module and is placed above and parallel with a common, artificial ground plane (5) in the form of an electrically conducting plate, for instance the bottom of a metal box (2). The dipoles (7) and the feed lines (8, 9, 10, 11) are designed as air dielectric strip-lines and are configured in one piece of a homogeneous material and extend mechanically and electrically in an uninterrupted manner from the dipoles to the antenna connector. The parts configured in one piece are produced by punching out sheet metal, and after suitable bending the parts are inserted in corresponding openings (16) in the ground plane (5).

Abstract: In a system for interconnecting a plurality of radio channel units in a single trunk group with a plurality of directional antennas and/or antenna beams, each radio channel unit has a receive section and a transmit section and the system dynamically connects the receive and transmit sections of each one of the radio channel units with any one of the plurality of antennas which, on average during a sampling period, is best suited for receiving and transmitting RF signals at the operating frequency of the radio channel unit. The system further includes traffic distribution monitor for monitoring, storing and displaying information on a periodic basis indicative of the usage of each antenna and/or antenna beam. The specific antenna or antenna beam being utilized by a radio channel unit is monitored on a periodic basis during communications between the radio channel unit and a mobile radio unit, and this information is stored in a memory associated with the radio channel unit.

Abstract: In a radiating coaxial cable, the outer-conductor having a plurality of radiating apertures is wrapped in a tape of conducting material which covers some of the apertures. In one embodiment of the invention, the conductive tape is combined with a fire retardant tape so that one winding procedure will result in winding both the conductive tape and the fire retardant tape over the outer-conductor.

Abstract: A circularly polarized antenna has an open reflector box, an array of crossed dipoles, and a single binary feed network. The open reflector box is formed of conductive material, has a ground plate and four side walls defining an opening, and has an input port for receiving an input signal. The single binary feed network is disposed within the open reflector box, is connected to the input port, and has a microstrip transmission line spaced from the ground plate. The microstrip transmission line has conductive bars mounted parallel to the ground plate and spaced therefrom forming an air dielectric low loss microstrip. Each pair of crossed dipoles has a first dipole comprising two downwardly bent radiating elements arranged at an angle with respect to the ground plate, and has a second dipole comprising two straight radiating elements arranged parallel to the ground plate.