Abstract: A matching network for coupling an OEM vehicle antenna to communications equipment operating at two different frequencies without any physical modification of the antenna mast and base. The network comprises a first transmission line section connected at one end to the antenna, a first stub tuner connected to the opposite end of the first transmission line section, a second transmission line section connected at one end to the junction of the first transmission line section and the first stub tuner, a second stub tuner connected to the opposite end of the second transmission line section, and a feedline connected to the junction of the second transmission line section and the second stub tuner for connection to the communications equipment operating at the two different frequencies.

Abstract: A tunable antenna includes separate radiator parts coupled to one another. The coupling between the parts is changed by rotating and/or displacing the parts with respect to one another such that the antenna exhibits a radiation pattern associated with a respective degree of a rotation and/or displacement. A process for manufacturing such antennas includes constructing parts for a respective antenna, coupling the parts to one another to permit them to rotate and/or displace, measuring the radiation pattern of the parts, and adjusting the radiation pattern by rotating and/or displacing the parts with respect to one another to set a nominal radiation pattern of the respective antenna formed by the parts. The couple is changed by rotation and/or displacement of the parts. A respective degree of rotation and/or displacement creates a corresponding change of a radiation pattern of the parts.

Abstract: A transmission system delays a carrier wave and program audio in the digital domain. The carrier wave and the program audio are converted to analog and the carrier wave is modulated by the program audio. The system includes a master oscillator that generates a digital carrier wave. The digital carrier wave is transmitted to a delay stage that delays the digital carrier wave by a certain delay value. The system further receives an analog or digital signal that is representative of programming. If an analog signal is received, the signal is transmitted to an analog-to-digital converter where it is converted to digital audio. The digital audio is then transmitted to a delay stage that delays the digital audio by the same delay value. The digital carrier wave and the digital audio are converted to an analog carrier wave and analog audio respectively. A modulator modulates the analog carrier wave by the analog audio and sends the amplitude modulated carrier wave to a power amplifier.

Abstract: A transmission line 2 to one end of which an electric signal is inputted has &lgr;/4 transmission lines 3, 4 connected to the other end thereof. An element antenna la is connected to the other end of the &lgr;/4 transmission line 3 via a transmission line 5, and an element antenna 1b is connected to the other end of the &lgr;/4 transmission line 3 via a transmission line 6. An element antenna 1c is connected to the other end of the &lgr;/4 transmission line 4 via a transmission line 7, and an element antenna 1d is connected to the other end of the &lgr;/4 transmission line 4 via a transmission line 8. Impedances of the transmission lines 2-8 and the &lgr;/4 transmission lines 3, 4 are set to 50 &OHgr;, respectively.

Abstract: First and second spaced apart in-phase current loops at least partially overlap in the axial direction. The first and second current loops may be first and second arrays of in-phase current loops that are spaced apart and at least partially overlap in the axial direction. First and second arrays of arrays also may be provided that are spaced apart from one another and that at least partially overlap in the axial direction. Desirably high mid-field strength may be provided without violating guidelines for far field radiation in the axial direction or in the plane of the loops. A third array of in-phase current loops, an array of third in-phase current loops and/or an array of arrays of third in-phase current loops also may be provided that spaced apart from and at least partially overlapping the second loops in the axial direction, opposite the first loops.

Abstract: A radio frequency identification transponder (RFID tag) in accordance with the principles of the present includes a tag antenna having a gain and an input impedance. The tag also includes RFID circuitry, which may be in the form of an RFID tag integrated circuit, the RFID circuitry also being characterized, in part, by an input impedance. According to the principles of the present invention the tag's read distance is maximized by tuning the tag antenna impedance and gain. In general, the imaginary part of the antenna impedance is chosen as the negative of the imaginary part of the RFID circuitry's impedance. Additionally, the real part of the tag antenna's impedance is selected by tuning those geometrical antenna parameters that affect both the antenna's gain and impedance. For RFID tags wherein the geometrical parameters of the tag antenna do not affect the gain G.sub.

Abstract: The diversity antenna circuit comprises a first antenna for receiving a vertical plane of polarization of an electric wave, a second antenna for receiving a horizontal plane of polarization thereof, a receiving means for detecting the electric field strength of a received signal, a first matching means for matching the first antenna to the receiving means, a second matching means for matching the second antenna to the receiving means, a first transfer means, a second transfer means, a first switching means, a second switching means, and a switching control means for connecting one of the first and second antennas to the receiving means and separating another one from the receiving means according to ON/OFF control of the first and second switching means based on received electric field strength.

Abstract: A radiotelephone matching switching system and associated antenna and printed circuit board contact configurations for a retractable antenna employs at least two contacts which are traversely spaced apart in the radiotelephone housing so as to reduce the space used therein. One embodiment also allows reactive components of the circuit to be disconnected thereby increasing the operational bandwidth of the radiotelephone.

Abstract: A technique for optimizing the impedance match between a plurality of pulse generators and a high-Q tuned load by equally advancing and retarding the phase of equal groups of pulse generator modules with respect to the load voltage. The sum output current is in phase with the coupling network voltage and produces alternating pulse generator sinewave outputs of successive plus and minus equal phase shifts with respect to the load voltage.

Abstract: A disguised broadband antenna system for use with a broadcast radio receiver and communications apparatus in a vehicle wherein the antenna system comprises a standard broadcast antenna mounted to the vehicle by means of a base, a distributed matching network for coupling the antenna to the broadcast receiver and the communications equipment in the vehicle and a broadcast coupler connected between the matching network and the broadcast receiver and communications equipment for providing isolation between the broadcast receiver and communications equipment. The distributed nature of the matching network provides the broadband frequency response required while at the same time providing the highest Q factor available in a limited size and spreads any power dissipation over a relatively larger area. A series reactive element is connected electrically to the antenna through the base to cause the antenna to operate closer to resonance through the broadband frequency range of interest.

Abstract: A dual band MDS/MMDS down converter receiving system wherein the support boom of a semi-parabolic antenna contains the down converter electronics. Located at the focal area of the semi-parabolic antenna are a pair of driven feed elements which are connected to the printed circuit board carrying the dual band down converter electronics. The dual band down converter is formed in an elongated shape to fit entirely within the formed hollow interior of the support boom. The down converter comprises a first printed circuit board which contains a low noise amplifier, two RF filters, and two diplexer filters located at the input end of the printed circuit board. The RF filters are mounted on opposite sides of the printed circuit board. The input is directly connected to the pair of driven feed elements. The RF filters are surrounded by input ground shields.

Abstract: An antenna device shared by three different waves has a single two-stage collinear antenna constituted by half-wave dipole antennas which are adapted for a vehicle telephone signal and are stacked one upon the other. The device allows an AM-FM radio receiver to receive AM and FM broadcast signals via a first coaxial cable and a vehicle telephone transceiver to receive a telephone signal via a second coaxial cable. A first impedance converting circuit is implemented as a field effect transistor and connected to the base end of the antenna for matching the antenna and the first coaxial cable in the event of reception of the AM broadcast signal. A second impedance converting circuit matches the antenna and the first coaxial cable at the time of reception of the FM broadcast signal. The impedance converting circuits convert the input/output impedances of the AM and FM signals.

Abstract: A dual mode broad band antenna especially designed to provide simultaneously high and low angle radiation patterns relative to a horizontal ground plane is disclosed herein. This particular antenna utilizes four wire radiators in the form of an inverted conical log-spiral supported in a vertically extending fashion a predetermined distance above the horizontal ground plane. In order to operate the antenna in its high and low angle modes simultaneously, first and second oppositely phased AC currents are applied to the radiators in two different ways through specifically connected hybrid isolating transformers.

Abstract: An antenna system is disclosed for plural band radio receivers having a common antenna. The system is especially adapted for AM/FM automobile broadcast receivers and may be used with a CB transceiver with a tri-band antenna. An impedance transforming means is provided at the base of the antenna and a single transmission line or lead-in cable extends from the impedance transforming means to the AM/FM receiver. The impedance transforming means has a high input impedance for the AM and FM bands and a relatively low output impedance to minimize the signal loss in transmission from the antenna to the receiver. The impedance transforming means includes a field effect transistor in a common source configuration and means are provided to produce substantially 100% voltage degeneration for both AM and FM signals.

Abstract: An antenna for simultaneous connection to a citizen's band transceiver, an AM receiver and a FM receiver, particularly suitable for use on a vehicle such as an automobile. The antenna proper is a center-loaded upstanding rod which, in the preferred form, telescopes downwardly to a retracted position where it does not protrude above the ground plane. The antenna proper is connected to a T-connected open stub transmission line and to a FM resonant relatively high impedance signal-carrying transmission line. The former has inductive reactance in the FM band which offsets the capacitive reactance of the relatively short effective length of the antenna proper in the FM frequencies. The signal-carrying transmission line is substantially half wave in length in the FM band so as to reflect impedance at its far end substantially equal to the impedance present at the T-connection.

Abstract: An isolation system adapted to permit simultaneous operation of at least colocated radio transceivers operating at different frequencies into at least one antenna by means of a single hybrid transformer having said at least one antenna coupled to one conjugate port, at least one broadband impedance simulator coupled to the other conjugate port and wherein said transceivers are respectively coupled to sum and difference ports of the hybrid transformer.

Abstract: A horn of circular or rectangular cross-section has a multiplicity of circumferential grooves on its diverging inner peripheral wall; these grooves have a depth on the order of a quarter wavelength, at the upper end of the band of operating frequencies, and are separated by distances up to half a wavelength. Other discontinuities in this peripheral surface, serving to pick up odd modes for divergence-measuring purposes, are in the form of probes transverse to the horn wall disposed in one or more grooves or throughgoing slots lying between certain grooves or within same. The discontinuities may be arranged in pairs of diametrically opposite probes or slots, e.g. with two mutually orthogonal pairs disposed in a common transverse plane; probes in adjoining grooves may be interconnected by a transmission line.

Abstract: An antenna has two output terminals and is operative for receiving electromagnetic radiation and converting the same into electrical signals appearing across the two antenna output terminals. There are provided a first and a second transmission channel, each having a respective input comprised of a pair of input terminals, and respectively operative for transmitting electrical signals having frequencies lying in a predetermined first frequency range and in a predetermined higher second frequency range, one of the input terminals of the first channel being connected to one of the two antenna output terminals. A transformer includes a primary winding connecting the other of the input terminals of the first channel to the other of the two antenna output terminals. The transformer further includes a secondary winding connected across the two input terminals of the second transmission channel.