Abstract: The present invention provides within three particular aspects thereof an isolating and matching device operable to enable an electrically heatable window of a motor vehicle to be used as an efficient VHF communications aerial or antenna; wherein isolating and matching circuitry is provided for Series VHF Matching, Shunt VHF Matching and Split Passband Matching of an electrically heatable window heating element to an aerial input impedance of an aerial feeder circuit of a radio frequency receiver or transmit/receive device.

Abstract: A transmitting and receiving radio frequency antenna of arcuate shape, serving as a radio frequency radiator of wave lengths between about 2 meters to about 160 meters. A tuning and loading coil is connected to one end of said antenna for tuning and matching said arcuate radiator. A capacitance is connected at the other, coupling to ground. Advantage of vertical and horizontal polarization is obtained.

Abstract: A discone antenna has a conducting cone having an apex and a conducting disc with a disc feed conductor extending from its center. The conducting disc is mounted at the apex of the cone in spaced relation therewith such that the disc feed conductor extends down into the cone through the cone's apex. A coaxial connector is mounted within the cone at the apex of the cone and defines a tuning cavity therein. A tuning slug is received in the tuning cavity through the apex of the cone and is vertically adjustable within the tuning cavity to tune the antenna.

Abstract: A mobile antenna system for use at frequencies in and above the 800 MHz band having a collinear radiator mounted on one surface of a dielectric such as the window of a vehicle and a tunable coupling circuit disposed internally of a conducted housing mounted on the opposite surface of the dielectric which acts as a counterpoise for coupling RF energy between the radiator and a transmission line connected to a suitable transceiver.

Abstract: A car phone antenna assembly which comprises a whip, a base mounted on a window of a car and a coupling unit having the structure for a capacitive tuning circuit. The coupling unit further comprises a coupling plate which acts as a coupling capacitor together with the base, first and second inductor members, and a variable capacitor member which can fine tune the resonant frequency of the antenna assembly.

Abstract: A mobile antenna circuit for resonant transmitting from an RF signal source may comprise: an antenna having a base and at least first and second conductive sections one of which is extendable and retractable to lengthen and shorten the antenna; a motor operatively connected to one of the conductive sections for extending and retracting the antenna in response to control signals thereto; an impedance matching circuit coupling the RF signal source to the base of the antenna for matching impedance thereof at a specified frequency; and control components connected to the motor to produce control signals for extending and retracting the antenna section so as to resonantly tune the antenna at a specified frequency. The circuit may include a phase angle detector connected between the RF signal source and the impedance matching circuit for developing a voltage differential being fed to the control components for producing the control signals for extending and retracting the antenna section.

Abstract: An impedance matching arrangement is suitable for use with a frequency hopping radio communications system which is operable over a wide frequency band, so as to match the operating impedance of the antenna at each of the frequencies used. As the frequency of the radio system hops from one frequency to another, a note of any impedance mismatch is noted and data derived therefrom is stored for future use when that frequency is next selected so as to reduce any impedance mismatch.

Abstract: The present invention is a moisture-insensitive system adapted to couple radio frequency energy at a low impedance from a matched two conductor transmission line, through a vehicle windshield and to an antenna in a manner which minimizes stray radio frequency radiation within the passenger compartment of the vehicle. The system includes two pair of conducting plates, one pair mounted on each side of the windshield, each pair opposite the other pair. A coaxial feed line is coupled to the inside pair of plates and a matching circuit is connected across the outside pair of plates. A full-size, unloaded antenna element is connected to the output of the matching circuit. A decoupling device, such as a decoupling sleeve or a RF choke, can be used to minimize RF current flow on the shield conductor of the coaxial feed line. The coaxial cable is coupled directly through the windshield, without an intervening matching network, so that RF energy at a low impedance is coupled to the outside pair of plates.

Abstract: A resonant double loop radio frequency (rf) antenna for radiating high-power rf energy into a magnetically confined plasma. An inductive element in the form of a large current strap, forming the radiating element, is connected between two variable capacitors to form a resonant circuit. A real input impedance results from tapping into the resonant circuit along the inductive element, generally near the midpoint thereof. The impedance can be matched to the source impedance by adjusting the separate capacitors for a given tap arrangement or by keeping the two capacitances fixed and adjustng the tap position. This results in a substantial reduction in the voltage and current in the transmission system to the antenna compared to unmatched antennas. Because the complete circuit loop consisting of the two capacitors and the inductive element is resonant, current flows in the same direction along the entire length of the radiating element and is approximately equal in each branch of the circuit.

Abstract: The present invention provides within three particular aspects thereof an isolating and matching device operable to enable an electrically heatable window of a motor vehicle to be used as an efficient VHF communications aerial or antenna; wherein isolating and matching circuitry is provided for Series VHF Matching, Shunt VHF Matching and Split Passband Matching of an electrically heatable window heating element to an aerial input impedance of an aerial feeder circuit of a radio frequency receiver or transmit/receiver device.

Abstract: Impedance matching between two conductor transmission lines and conventional antenna designs including a straight antenna element having an effective length of at least one-quarter wavelength in the operating frequency range and a zero impedance at one end is disclosed in which a straight coupling conductor having a length of about one-quarter wavelength in the operating frequency range is mounted in close spaced co-planar relation to such antenna element with one end electrically connected to the zero impedance end of the antenna element. The two conductors of the transmission line are coupled to the antenna element and coupling conductor, respectively, at the interconnected ends thereof and the spacing between the antenna element and the coupling conductor is adjusted along their coextensive lengths to achieve an impedance match at each frequency in the operating frequency range.

Abstract: A system for adjusting the antenna matching network of a radio system in the presence of an interfering signal in the matching network being adjusted comprises a loop from which the interfering signal is cancelled by an adaptive interference cancellation (AIC) system. The AIC system receives an interference sensor signal having the frequency of the interfering signal. Means responsive to the interference sensor signal and phase and amplitude control signals provides a modified interference sensor signal having a phase and amplitude determined by the control signals. This modified interference sensor signal is combined with a mismatch signal which is derived from the signal in the matching network to produce a modified mismatch signal.

Abstract: A whip antenna system for surface vehicles or the like. The antenna system's tuner has an LC tank circuit, into whose inductor is inserted a coil that is connected to the vehicle's transmitter/receiver, the coil being field coupled to the tank circuit's inductor. The inserted coil provides sufficient reactance that the vehicle need not serve as a counterpoise, thus providing an antenna of comparable size but electrically less close to the ground (i.e. one that has better "seeing"), and useable with non-metallic vehicles (e.g. fiberglass boats).

Abstract: A relatively short broad band monopole coaxial antenna is provided with a center conductor and an outer radiator. The antenna is mounted above a ground plane and comprises a bare outer radiator portion adjacent the ground plane and a portion remote from the ground plane which is covered with a variable thickness microwave absorbent material. The signal to be transmitted is applied to the base of the monopole antenna adjacent the ground plane. Non-radiated signals propagate up the antenna. The high frequency components are absorbed by the microwave absorbing material. A tip matching network and a base matching network are coupled between the outer conductor and the ground plane for attenuating and matching the low frequency components of the non-radiated signals. The resulting monopole coaxial antenna has no undesirable reflections and has the appearance of infinite effective length antenna.

Abstract: An active antenna system for an airborne high frequency single sideband receiver comprised of a shorted loop type antenna having an inductive characteristic over the frequency range of 2.0 to 10.0 MHz and which is tuned to resonance at a selected operating frequency by shunting the antenna at its feedpoint by selectively switched sets of voltage variable capacitors. Also coupled to the feedpoint is a field effect transistor which is adapted to provide radio frequency amplification. Impedance matching between the output of the field effect transistor and the input of a radio frequency receiver is further provided by a transistor configured as an emitter follower.

Abstract: A simple technique and circuit is disclosed to replace prior Z-.theta. type discriminators in supplying the loading and phasing control signals to the impedance matching network in an automatic antenna tuner. The new circuit samples forward and reflected voltage V.sub.f and V.sub.r (or equivalently I.sub.f and I.sub.r) in the RF input. The loading control signal is supplied according to the in-phase component of V.sub.r relative to V.sub.f. The phasing control signal is supplied according to the quadrature component of V.sub.r relative to V.sub.f. The magnitude of each of the in-phase and quadrature V.sub.r components is reduced to zero by the matching network to thus reduce the phasor amplitude of V.sub.r to zero and hence eliminate reflected voltage.

Abstract: An impedance matching network suitable for tuning an antenna includes a plurality of reactive elements and control circuits for selectively switching these elements into and out of the circuit. Each control circuit includes a pair of oppositely poled, normally reverse biased, PIN diodes connected in series across a reactive element and apparatus including a selectively controllable radiation responsive element for forward biasing the PIN diodes to thereby effectively switch a reactive element out of the network. In one arrangement, the reactive elements are formed from spaced, helically wound sections of a hollow conductive tube with the biasing voltages for the PIN diodes carried by conductors located within the tube.

Abstract: A low-profile survivable antenna suitable for military use is described. pite its small size, which might be one tenth of a wavelength, the antenna has reasonable transmission range for these applications. Very little operator attention is needed in use, since a special matching circuit within the antenna network enables effective impedance matching, over a 3:1 frequency range, without necessity of switching to different matching circuits over different frequency bands. By including resistive components along with other passive inductive or capacitive elements, the reactance of the single matching circuit is made to effectively compensate the antenna's impedance over the entire frequency range. The impedance of the circuit has a decreasing positive reactance which compensates for the decreasing negative reactance, with frequency, of the antenna.

Abstract: The orientable beam antenna comprises a fixed source, a fixed first reflector and a mobile reflector. The axis of the source is offset with respect to the focal aspect of the fixed reflector, and the mobile reflector connected to the elements through a universal joint device having two orthogonal axes, enabling the mobile connections to be limited to commercially available bearings.

Abstract: Television and FM radio antenna apparatus with a tuneable circuit to be coupled with a building wiring system and thus supplement or replace conventional interior or exterior antennas.

Abstract: A low-profile survivable antenna suitable for military use is described. pite its small size, which might be one tenth of a wavelength, the antenna has reasonable transmission range for these applications. Very little operator attention is needed in use, since a special matching circuit within the antenna network enables effective impedance matching, over a 3:1 frequency range, without necessity of switching to different matching circuits over different frequency bands. By including resistive components along with other passive inductive or capacitive elements, the reactance of the single matching circuit is made to effectively compensate the antenna's impedance over the entire frequency range. The impedance of the circuit has a decreasing positive reactance which compensates for the decreasing negative reactance, with frequency, of the antenna.

Abstract: A VHF monopole antenna unit, particularly adapted for operation in the 30 MHz frequency range, yet capable of embodiment in a compact structure only approximately 11/2 feet in height is described. Coarse tuning is accomplished in a number of switched bands, for each of which is provided a specially designed matching network comprised of inexpensive L-networks of inductors and capacitors. Tuning is accomplished through adjustment of inductor elements. The simple, inexpensive design of the matching circuits eliminates need for intricate mechanisms typically used for automatic impedance matching over a wide band and also for a broadband impedance matching transformer. The compactness made available by the unique top-load structure design is further made possible by provision of a specially designed dielectric filled vertical antenna element, accomplishing the same range and efficiency in an even more compact antenna.

Abstract: A circuit for coupling a citizens band transceiver and a broadcast band receiver to a standard automobile antenna. The circuit is comprised of an impedance transforming network connected in series with the standard automobile antenna and a parallel-tuned circuit in series with the broadcast band receiver. The series-tuned network is comprised of a split capacitance for stepping the impedance down from the citizens band transceiver to the lower impedance of a standard automobile antenna. The series-tuned circuit also includes a tuning coil for matching the output of the network to the particular automobile antenna. In series between the automobile antenna and the broadcast band receiver is a parallel-tuned circuit comprised of a capacitor and a tuning coil. To prevent multiplication and excessive voltages in the event the broadcast band receiver should become disconnected, a limiting resistor connects the parallel-tuned circuit to ground.

Abstract: A VHF whip antenna of reduced physical length comprising a whiplike electrical conductor mounted atop a hollow, plastic, sealed cylindrical housing having a coaxially mounted circuit support tube mounted therein, with a highly resonant circuit attached thereto. Resonance is achieved in the circuit from a U-shaped inductance of a predetermined length mounted on the inside support tube, the inductance being coupled in series electrically with a variable capacitor. The whip conductor is designed to be three half-wave lengths long and when in combination with the resonant circuit, radiates power in perfect phase relationship that accounts for a power gain in the order of ten DB.

Abstract: A wide band impedance matching device is described for matching the impedance of an antenna transmission line to a radio transceiver over a wide band of radio frequencies. The device includes an impedance matching network having an inductor and two capacitors that electrically interconnect in either a capacitance "T" mode or a capacitance ".pi." mode. The device also includes an efficient bypass circuit that is capable of electrically bypassing the impedance matching network to effectively directly interconnect the antenna transmission line to the transceiver.

Abstract: A matching coupler in an antenna system to power transfer in matching characteristic impedance of an antenna and a transmission line using a ganged variable capacitance with a resonate coil and another variable capacitance in series with a transmission line and an antenna.

Abstract: In accordance with the present invention, a single shunt feed mechanism, including a single gamma section and a single impedance matching circuit, is employed to enable an antenna tower as an effective radiator in plural wave length bands without having to alter the upper tie point of the gamma section to the antenna tower. In one embodiment, the shunt feed of the invention enables the antenna tower as an effective radiator in either two of the adjacent bands mentioned, namely the 40 and 80 meter bands or the 80 and 160 meter bands. In accordance with another embodiment of the invention, a single shunt feed mechanism, including a single gamma section, a single impedance matching circuit, and a filter, enables an antenna tower as an effective radiator in all three of the indicated bands.

Abstract: An antenna coil for use in radio frequency communications having a molded assembly of four components. The antenna coil includes a conductive top coil form insert, a conductive coil form center contact having a tap point, and a conductive bottom coil form insert disposed on a coil form inner core or placed on a removable core pin around which plastic is molded to form the antenna coil form. A plurality of grooves molded into the antenna coil form are provided to accommodate a coil wire. A whip antenna radiating element screws into a threaded inner portion of the top coil form insert and the bottom coil form insert is threaded to screw onto a base or mobile antenna mount which connects to communications equipment through a coaxial cable. The coil form center contacts has a number of alternating lugs and slots to allow a large number of coil variations.

Abstract: A portable transceiver antenna is provided with a base suitable for retention by a fishing rodholder or for hand held use and is pretuned to facilitate its use without a ground plane. The antenna includes an electrically conductive rod which may be covered by a dielectric and segmented, and would then include couplings fabricated from ferrules closely fitted over nipples to produce reliable electrical contact through the coupling. The antenna may be used with citizens band, very high frequency - frequency modulated, and similar applications.

Abstract: A three band monopole antenna with such length as to be of greater electrical length than a quarter wavelength of the two highest frequency bands and shorter than a quarter wavelength of the lowest frequency band. The antenna system includes a matching network at its base matching the antenna on three frequency bands related by, substantially, the progression 1, 2, 4, and with the matching network including a shunt inductor and an inductor and capacitor in series with the signal feedpoint.

Abstract: A method and preferred apparatus for introducing radio frequency isolation near the base of a conductive tower to prevent significant flow of RF current into the ground, thereby to produce an elevated vertical antenna. The invention further relates to a method and apparatus for introducing RF power into the upper portion of the isolated tower to cause said portion to radiate or receive at desired frequencies. Isolation and "excitation" are accomplished by the placement of tuned shortened quarter wave conductive sections along selected portions of the tower, the quarter wave sections used for antenna excitation being also used for impedance transformation to match a coaxial transmission line of nominal inmpedance.

Abstract: A loading coil connects between an antenna and ground and has an intermediate feed point. A conductive member opposes at least several turns of the loading coil and is disposed in distributed capacitive relationship therewith. The conductive member and coil are separated by a dielectric member. The conductive member is preferably movable with respect to the coil to change the resonant frequency of the antenna and may be a conductive ring or disk axially shiftable with respect to the coil or a vane pivotable with respect to such coil. In one embodiment, the conductive member is fixed and the dielectric member, having a dielectric constant different from air, is shiftable to change the distributed capacitance of the conductive member and coil and hence the resonant frequency of the antenna apparatus.

Abstract: A compact arrangement having concentric loading element and coupling element with the latter forming a bearing support for a revolvable member mounting the former.

Abstract: An antenna adapter for television which comprises an input connecting element to be inserted into a plug socket for domestic use, which element is connected to one end of a feeder intermediately with a fuse connected in series, the other end thereof being formed so as to be connectable to the input terminal of the antenna, and a circuit-changing switch or a variable resistance in the midpoint of the feeder for appropriately changing the impedance of the feeder.