Abstract: An apparatus and method is provided to shield contactless portable electronic consumer devices such as radio frequency identification devices (RFID), tokens, mini-cards, key fobs, cellular phones, smartcards, etc. from wireless interrogation. In one embodiment, a contactless portable consumer device which includes a first antenna is shielded from unauthorized wireless interrogation with a radio frequency (RF) shield. The RF shield includes electrically conductive, non-ferromagnetic material and is configured to prevent unauthorized data transfer between a second antenna external to the portable consumer device and the first antenna.

Abstract: A method for selectively removing metal from a metallized substrate (e.g., a metallized polymer film) and the formation of devices thereby are provided. Th method involves selectively exposing the metallized surface to a demetallizing (i.e., an oxidizing) chemical solution. The metallized layer can be selectively exposed to the demetallizing solution using a flexographic printing process wherein printing rollers are used to transfer the demetallizing solution to the metallized surface. An identification device including, for example, a holographic, retro-reflective, or other metallized material and a radio-frequency transponder are also provided. The radio-frequency transponder includes an RF chip and an antenna in electrical communication with the chip. The identification device including the holographic image allows both electronic identification through the reading or identification data stored in the chip and optical identification via the holographic image.

Abstract: An inductive antenna device intervenes in communication between an RFID tag including an RFID chip and a tag antenna and an RFID access device for accessing the RFID tag. The inductive antenna device includes an access-device-side antenna that is electromagnetically coupled with the antenna of the RFID access device, and a tag-side antenna that is electromagnetically coupled with the tag antenna. The RFID chip and tag antenna in the RFID tag are in an electromagnetically shielded space. The inductive antenna device is attached to the RFID tag or the inductive antenna device is brought in a predetermined position to make communication possible between the RFID tag and RFID access device. An authorized access to the RFID tag is thereby permitted with easy operation with unlimited number of access times, and an illegal leak of the tag information is prevented with a low cost configuration.

Abstract: The invention relates to a multiple phase shifter for protecting individuals against electromagnetic waves. The invention comprises several phase shift modules which each comprise two identical or homothetic flat loops which are electrically connected by means of two inter-loop connection elements at a first opening in each of the loops and which are electrically insulated from one another with the exception of the inter-loop connection elements. Each module is electrically connected to another module by means of two inter-module connection elements and is essentially identical or homothetic to the other modules. The inter-module connection elements connect one of the loops of one module at a second opening in the loop to one of the loops of another module at a second opening in said loop. The modules are electrically insulated from one another with the exception of the inter-module connection elements.

Abstract: An information processing apparatus for use in a transmitting or receiving operation by a non-contact type IC card function and a reader/writer function includes a loop antenna having a feeding element having a first number of turns winded in a predetermined form, and a non-feeding element provided inside or outside of the feeding element and having a second number of turns winded in the form.

Abstract: Devices and methods are provided to enhance magnetic field communication. One aspect of the present subject matter relates to a method for transmitting and receiving signals using an antenna element electrically connected to a driver and an amplifier. According to various embodiments of the method, a first signal is transmitted from the antenna element and a second signal that was induced in the antenna element is received. Transmitting the first signal includes driving the first signal through the antenna element using the driver, and monitoring the first signal through an input impedance of the amplifier. Receiving the second signal includes reducing the input impedance of the amplifier, and receiving the second signal at the amplifier through the reduced input impedance. Various embodiments shield the antenna element from electric and electromagnetic fields. Other aspects are provided herein.

Abstract: Disclosed are deactivatable RFID labels and tags in individual and web form, and methods of making same. When it is desired to deactivate the label or tag, the tag or label is subjected to tearing. One arrangement involves providing the label or tag with a tear strip by which the RFID transponder in the label or tag is destroyed, and in another arrangement a tag can be torn along a weakening line to destroy the RFID transponder.

Abstract: A medical device and system is provided with a device housing and with a radio frequency detection device. The radio frequency detection device is functionally connected to an antenna for detecting a radio frequency identification element. The radio frequency detection device has a transmitter and an at least partly electrically conductive shield, which encloses at least the transmitter such that a field generated by the transmitter is effectively shielded towards the outside and the antenna is arranged within the housing and outside the shield.

Abstract: A circuit board has a first face and a second face opposite to the first face. A low noise amplifier is mounted on the second face. A pole-type antenna module is extending vertically along a central axis thereof A shield cover is attached to the second face of the circuit board so as to cover the low noise amplifier. The circuit board is formed with a through hole connecting the first face and the second face. The pole-type antenna module is inserted into the through hole so that a lower part thereof is accommodated in the shield cover and an upper part thereof is protruded from the first face of the circuit board.

Abstract: The invention provides protection to wireless portable transponders from unauthorized interrogation by employing a mechanism for disabling reception by or from the antenna of the transponder. Transponders include RFID tags that are attached to items that a persons may purchase or carry. Such transponders generally have an ability for receiving and storing electronic and other information, commonly in binary form using memories as in electronic circuits, etc. The invention is designed to provide privacy of electronic information. The tags can be protected from receiving or providing unauthorized or unwanted information. The invention provides the mechanism that permit the owner to decide when reception/interrogation of personal or other information is not desired by employing the provided mechanical disable control.

Abstract: An arrangement for providing protection to wireless portable transponders (including resonant tags such as RFID tags) from unauthorized interrogation by employing a mechanical arrangement for disabling reception by or from the antenna of the transponder. The tags can be protected from receiving or providing unauthorized or unwanted information. Contemplated are mechanical arrangements that permit the owner to decide when reception/interrogation of personal or other information is not desired by employing the provided mechanical disable control arrangement. Also broadly contemplated herein is the altering interrogation characteristics of RFID tags to such an extent that they may still be read at a close range instead of the original range, and this result of this altering is visible to the user.

Abstract: The antenna includes a base and a plurality of antenna feeds carried by the base for respective different rotational polarizations. A plurality of inner elongate convex coupler elements are carried by the base and connected to respective ones of the antenna feeds for respective different rotational polarizations, and a plurality of outer elongate convex resonant elements are carried by the base and extend outwardly therefrom a distance greater than the plurality of inner elongate convex coupler elements. The plurality of outer elongate convex resonant elements may be tuned to different resonant frequencies to thereby support the different rotational polarizations. Thus, a small circularly polarized antenna with a hemispherical pattern for high frequency (HF) or satellite applications is achieved.

Abstract: Methods, systems, and apparatuses for a radio frequency identification (RFID) tag tester/programmer and marker are described. A surface is in contact with a web of RFID tags. The surface has a first portion and a second portion. The first portion of the surface is grounded to ground tags of the web that are in contact with the first portion. A radio frequency (RF) source transmits a RF signal to interact with a tag adjacent to the second portion of the surface. The RF signal may be a signal for testing the tag and/or a signal for programming the tag.

Abstract: A plurality of small loop antenna cells 61, 62 and 63 are magnetically coupled to an antenna coil 8 of a non-contact type data carrier 3. In the plurality of small loop antenna cells, the directions of the magnetic moments of the signals transmitted to the non-contact type data carrier 3 are opposite to each other, the sum of the magnetic moments generated from all the small loop antenna cells 61 to 63 is zero and a conductor forming a short ring pattern 67 is provided collectively for the plurality of small loop antenna cells. Thus, imbalance caused between the small loop antenna cells 61 to 63 can be compensated for by the short ring pattern 67.

Abstract: The reader or transmitter and/or receiver (22) includes a sheathed antenna formed of two groups of turns or coils (6, 8, 9; 16, 17). The first group of turns or coils forms a sheathed antenna. The second group includes two coils (16, 17) arranged between the central coil (6) and respectively the two end coils (8, 9) of the first group. The second group of coils is powered in phase quadrature relative to the first group of coils, the set of coils being arranged so as to obtain a magnetic field (H) whose amplitude (A) is approximately constant along the central axis (24) of the antenna inside the overall inner volume of the latter.

Abstract: To provide a loop antenna capable of attenuating the distant electric field with the attenuation of the magnetic flux in the vicinity of an electromagnetic wave restrained, and a contactless IC card read/write apparatus. A loop antenna 10 has an electromagnetic wave shield 1 over at least one side of the loop antenna, the electromagnetic wave shield 1 comprising a plurality of electric conductors 2, a ground contact 3 for grounding the plurality of electric conductors and a lead wire 4 for connecting the plurality of electric conductors 2 to the ground contact 3. The plurality of electric conductors 2 are electrically connected via the lead wire 4 to the ground contact 3 and the plurality of electric conductors 2 are arranged so that the paths of the respective electric conductors 2 from any of their given points to the ground contact 3 via the lead wire 4 are determined uniformly.

Abstract: A system for minimizing the effect of null zones in an interrogation zone of a marker detection system. The system includes a reference antenna system configured to produce a first reference electromagnetic field during a first time period. The antenna system also includes a phase canceling antenna system configured to produce a second electromagnetic field substantially in phase with the reference electromagnetic field during the first time period and a third electromagnetic field substantially out of phase with the reference electromagnetic field during the first time period. The phasing of the first field or the second and third fields may be continuously switched while the phase of the other is held constant. A method of spatially shifting null zones in an interrogation zone of a marker detection system is also provided.

Abstract: An antenna (10) having an emitter element which is positioned in front of a conductive reflector (13) and has a three-dimensional cast part. The cast part is implemented as conductive and has a closed peripheral structure (11) having alternating constrictions and bulges. The peripheral structure (11) spans an imaginary surface (14) which is intersected by at least two planes of symmetry (15.1, 15.3) of the cast part. At least two fastening elements (12.1, 12.2) are provided, which extend essentially perpendicular to the imaginary surface (14) and support the peripheral structure (11) at two points which lie on one of the planes of symmetry (15.1; 15.3). At the lower ends (16), the fastening elements (12.1, 12.2) are connected to the reflector (13), the fastening elements (12.1, 12.2) also being used for electrical excitation of the emitter element.

Abstract: A dual band antenna system that combines into a single integrated device an H-field shielded loop antenna and an E-field antenna. The system includes an unshielded section bounded on each end by first and second shielded sections, respectively. Input frequency filters are electrically connected to the first shielded section to selectively pass one of a first radio frequency signal or a second radio frequency signal through the first shielded section. Output frequency filters electrically connected to the unshielded section for switching between two paths of transmission and associated modes of operation: (i) a first mode (operating as an H-field antenna) in which an H-field transmission pattern is generated in the first and second shielded sections; and (ii) a second mode (operating as an E-field antenna) wherein an E-field is radiated via the E-field antenna.

Abstract: The invention relates to a terminal for communication with data supports which function in a non-contact manner, comprising a transreceiver circuit with two resonant circuits with antenna and condenser for the emitting of two radio frequency fields of different carrier frequencies, whereby the common antenna (A) for both resonant circuits comprises a winding.

Abstract: In an antenna for communicating an electromagnetic wave, a first converger converges the electromagnetic wave. A second converger faces the first converger and includes a conductor plate having a through hole, into which a magnetic flux of the converged electromagnetic wave is converged. The through hole is formed at a center portion of the conductor plate so as to have a size which is sufficiently smaller than a wavelength of the electromagnetic wave. The conductor plate is formed with a cutout extending from a part of the through hole to an outer periphery of the conductor plate. A converter faces the through hole of the conductor plate to convert the converged magnetic flux into voltage.

Abstract: There is provided an antenna apparatus in which a non-detection region is made minimum within the regulatory limit of radio wave radiation, and satisfactory communication is enabled over a wide range. Four substantially square antennas are adjacently arranged on the same plane to constitute an antenna assembly, which is arranged to be opposite to a similar antenna assembly. Reverse phase currents flow to the first antenna and the third antenna, and similarly, reverse phase currents flow to the second antenna and the fourth antenna. The second and the fourth antennas are subjected to phase inversion for every data communication between a pattern 1 in which same phase currents flow to the second antenna and the third antenna and a pattern 2 in which same phase currents flow to the first antenna and the second antenna. A predetermined phase difference is provided between the first and the second antenna assemblies.

Abstract: A direction-finding antenna that conforms to flat and semi-flat surfaces is disclosed. It has a low profile in comparison to most existing direction-finding antennas and its surfaces are shaped so that reduced radar reflections and reduced radar cross sections of the antenna assembly are achieved. The antenna assembly has direction-finding characteristics that are essentially equivalent to traditional antennas that have high profiles and that are mounted high and away from external surfaces of platforms for unobstructed views of arriving electromagnetic energy and away from reflected electromagnetic waves and reradiators.

Abstract: A passive, non-multiplexed, two-axis antenna for sensing time-varying magnetic fields of a particular carrier frequency at a second point in space as produced by a electromagnetic field generator located at a first point in space. The antenna has a particular sensitive plane and produces a single output signal having amplitude proportionally related to the magnitude of the incident magnetic field's vector projection onto the antenna's sensitive plane. If the phase of the magnetic field is known, then the antenna's signal is processed to obtain the incident magnetic field's vector components. The antenna enables the realization of two- or three-axis magnetic field receivers with reduced signal processing complexity, cost and power requirements.

Abstract: An artificial magnetic conductor is resonant at multiple resonance frequencies. The artificial magnetic conductor is characterized by an effective media model which includes a first layer and a second layer. Each layer has a layer tensor permittivity and a layer tensor permeability having non-zero elements on the main tensor diagonal only.

Abstract: Antennas with steerable antenna patterns and techniques for using such antennas are described. In accordance with the invention, antenna patterns with one or more NULLs are used. Through the use of digital control signals the antenna pattern is steered so that a source of signal interference, e.g., a multipath signal, will be located in a NULL. In this manner the received signal's S/N ratio can be maximized thereby facilitating demodulation. The techniques of the invention can be applied to television, computer devices, mobile devices and a wide range of other systems. Digital commands to control an antenna may include multiple information fields, e.g., a direction field, a channel field, a gain field and a polarity field. Antennas incapable of supporting the specified fields disregard information in fields which are not supported. Information in each supported field is decoded and used to adjust the corresponding antenna characteristic.

Abstract: A shielded magnetic-field antenna has at least one turn of a metallic element and metallic tubular shielding positioned around the element. The turn (3a) is produced in a printed circuit on a card made of insulating material (4a). The shielding has two open rings (5a, 6a) each produced in a printed circuit and disposed respectively on a bottom card (9a) and a top card (10a) made of insulating material. The cards are assembled by gripping the turn between the top and bottom cards. A plurality of metallic vias (7a, 8a) connect side edges of the two rings. The vias extend through the cards, and are positioned around the turn.

Abstract: In one aspect, the invention encompasses a system for electronic identification of a plurality of units. The system comprises transponders which are connected with respective individual units, and which comprise antennas. The system further comprises an interrogator configured to read the transponders. The interrogator includes an interrogator antenna. At least one of the interrogator antenna or the transponder antennas comprise a coil of conductive material which has a first planar portion within a first plane and a second planar portion within a second plane, with the first and second planes intersecting. In another aspect, the invention comprises a method for electronic identification of a plurality of passing animal bodies, wherein the individual animal bodies have respective transponders associated therewith. An interrogator having an antenna associated therewith is provided.

Abstract: In an antenna 1a for reader/writer of an interrogator in a non-contact data carrier system comprising the interrogator and a transponder, the antenna for reader/writer of the interrogator comprises a transmitting antenna 2 for transmitting a signal to the transponder and a receiving antenna 3 for receiving a signal from the transponder, and the receiving antenna 3 is a loop coil located at a position where magnetic fields of opposite polarities are induced in the receiving antenna 3 by magnetic coupling between the receiving antenna 3 and the transmitting antenna 2 and where the magnetic fields of opposite polarities cancel out each other. Preferably, the transmitting antenna 2 is comprised of at least two loop coils 2a, 2b for generating magnetic fields of opposite polarities to each other.

Abstract: An antenna (28) for use in a wireless communication module (10) includes a shield plate (40), an antenna loop element (42), and a transmission line element (44). The wireless communication module (10) also includes a receiver (37) having a circuit board (30). The shield plate (40) is located on a first side (32) of the circuit board (30); and the antenna loop element (42) and the transmission line element (44) are located on an opposite side (34) of the circuit board (30). The shield plate (40) is electrically connected to a first loop end (50) of the antenna loop element (42). A capacitor (64) interconnects a second loop end (52) of the antenna loop element (42) to a first transmission line end (58) of the transmission line element (44). A second transmission line end (60) is electrically open.

Abstract: An improved loop antenna (10) comprises first (12) and second (16) conductive loops. Each of the first and second conductive loops has a discontinuity (14, 18). The first and second conductive loops (12, 16) are arranged substantially concentrically to form a capacitive coupling such that the tuned frequency of the loop antenna (10) has improved protection from external capacitance effects.

Abstract: An antenna system for use in detecting an information tag in an interrogation zone comprising a first coil for generating a first field in an interrogation zone, a second coil that is larger than said first coil and positioned proximate the first coil for generating a second field that opposes the first field, and a nonferrous conductive plate positioned proximate the first and second coils and being shaped so that its periphery is approximately at least as large as the periphery of the second coil.

Abstract: A sheet antenna apparatus capable of favorably receiving vertically polarized electromagnetic waves is provided which includes an antenna element 11 comprising a main antenna portion 15 having a vertical segment 19, a pair of upper and lower lateral segments 20 and 21 respectively extending laterally from opposite ends of the vertical segment 19 and a pair of feeder segments 22 respectively extending inwardly from the terminating ends of the lateral segments 20 and 21, and a parasitic antenna element comprising an inner loop portion 16 and an outer loop portion 17 which form a double loop and are disposed as adjoining to one of the lateral segments 20 and 21. The vertical segment 19 of the antenna element 11 substantially coincides with the direction of vertically polarized electromagnetic waves and hence receives vertically polarized electromagnetic waves favorably.

Abstract: An RF identification system having an interrogator operable to send RF interrogations to a transponder and to receive RF responses from the transponder. The interrogator is in electrical communication with a closed slot antenna. The closed slot antenna is formed by an an outer visual magnetic loop and an inner visual magnetic loop such that the antenna has a superior magnetic field when compared to a balanced double loop antenna with an equal area and a superior far-field noise suppression when compared to the single loop antenna. The antenna receives said RF responses from the transponder and provides said RF responses to said interrogator. Other devices, systems and methods are also disclosed.

Abstract: A sealed, modular downhole antenna for measuring electrical characteristics of wellbore fluids and formations. An antenna includes a thin-walled curved metal tube, which houses coil of a length of conductive wire. The wire may be insulated by an insulating coating, as well as a filler that resides in the tube. The tube includes a coupling gap, to facilitate coupling electromagnetic energy through the tube, to and from the conductive wire. The tube also has a wall opening, for ends of the wire to attach to an adapter-connector. The adapter-connector includes suitable features for modular connection to an electrical cable, electrical connectors, or other electrical equipment. Features of the invention may be provided to ensure that such connection is resistive to the high pressures that are often encountered downhole. In this respect, the tube may be also coated with a sealant layer, to hermetically seal the tube, coupling gap, and junction between the adapter-connector and the tube.

Abstract: An antenna system comprises a stack of elements that include a GPS patch antenna on a groundplane with an associated low-noise amplifier (LNA), a first Faraday shield of flat ribbon cable covering a first ferrite rod magnetic field antenna, a second ferrite rod magnetic field antenna separated from and orthogonal to the first ferrite rod magnetic field antenna, a second Faraday shield of flat ribbon cable covering the second ferrite rod magnetic field antenna and having a LNA for each of the ferrite rod magnetic field antennas. A third Faraday shield is positioned between the first and second ferrite rod magnetic field antennas. All the Faraday shields are connected to ground such that there are no loops that may act as shorted turns to avoid desensitizing the ferrite rod magnetic field antennas.

Abstract: A broadband, high-efficiency loop radiator is characterized by a coaxial loop one wavelength in circumference with a continuous center conductor fed through a coaxial T feed and a discontinuity of the outer shield next to the feed point of 50 ohms input impedance. Radiation occurs as a result of this transmission line discontinuity resulting in a reflected wave back down the shield. The one wavelength dimension of the loop generates two in phase electric dipoles spaced one diameter apart resulting in a bidirectional radiation pattern of 3 dBil and a 30% operational bandwidth due to the frequency compensation of the open stub. The open stub loop antenna acts as a low loss parallel tuned circuit appearing across a generator and the series impedance of the loop antenna resulting in increased bandwidth.

Abstract: By associating an open conductive shield with a radiating loop, it is possible to limit transmission of the electric field for the benefit of transmission of a magnetic field alone. It is shown in particular in the nuclear magnetic resonance imaging field that the antenna becomes less sensitive to the dielectric behavior of the zone in which the emitted field is radiated.

Abstract: An electronic article surveillance system is provided that comprises a core-wound drive coil which produces an AC magnetic interrogation field, and a detection coil provided on one side with at least one element of a screening material, which detection coil detects an AC magnetic response field generated by a magnetically active tag or marker which is subjected to the interrogation field when the tag or marker comes in proximity with the detection coil. The screening material may take the form of an open-ended electrically conductive box having an insulating gap along its length, or a laminate consisting of a plurality of metal foils interleaved with an electrically insulating material. The invention provides well-defined flux control for the detection coil which preventsinterference from unwanted external magnetic fields.

Abstract: A radiator useful for radiating pulses with a duration of about 10 ms is disclosed. Such pulses occupy the frequency band from zero to a few hundred Hertz. For a given time variation of an electromagnetic signal, the energy radiated in the far field is proportional to (Is).sup.2, where I is the current amplitude in the antenna and s is the length of the radiator. Typical antenna designs cannot be used at very low frequencies with large relative bandwidths. However, the large current radiator disclosed, herein, is small, has antenna currents in the order of 10.sup.8 A, and requires a drive voltage of about 1 volt and drive current of 10.sup.4 A. This large current radiator is designed with a small antenna length s by using a design wherein the antenna current is n times larger than the drive current. This is accomplished by winding electrically conductive means n times around a shield so that the n forward loop wires are all on one side of the shield, and cover a surface area sxW.

Abstract: An antenna system for a communication receiver (100) which has an internal antenna (200) and which is coupled to a portable computer (104) to deliver received data messages thereto comprises a resonant loop antenna (16) magnetically coupled to the internal antenna (200) of the communication receiver (100), and a resonant wireframe shield (18, 40) which is coupled to the resonant loop antenna (16) and oriented perpendicular thereto. The resonant wireframe shield (18, 40) shields the communication receiver (100) from an electrical interference signal generated by the portable computer (104).

Abstract: A concentrator adapted to concentrate signals for reception by a receiver, said concentrator comprising a conductive portion juxtaposed with said receiver, said concentrator being aligned so as to receive said signals and cause further signals to impinge on said receiver and thereby enhance reception of said signals by said receiver. Also disclosed is a shield for substantially eliminating magnetic field radiation from within a predetermined area, the field being diverted from the area via a conductive strip.

Abstract: The transmitting and/or receiving antenna of an electronic article surveillance system utilizes a paired-lead loop configuration. One lead forms the active loop.The other lead forms a passive loop, which parallels and is mutually coupled to the active loop, but not conductively connected to it. This other lead is resistively loaded.The passive loop of the receiving antenna can also be used to conduct signals between the receiver circuitry and the alarm reporting devices associated with the receiver.

Abstract: A magnetic antenna system particularly useable in electronic article surveillance systems for detecting the presence of a resonant tag utilizes multiple loop shielded transmitting and receiving antennas. The antennas employ shield structures that are designed to minimize the electric field response and to provide a balanced magnetic field response. The magnetic field responses of different ones of the loops in each of the antennas are different and the loops are oriented so that more responsive loops of the transmitting antenna are positioned opposite less responsive loops of the receiving antenna and vice versa in order to reduce the coupling between antennas without reducing the sensitivity of the receiving antenna to a tag signal.

Abstract: A multiple loop antenna particularly suitable for use with an electronic article surveillance security system for detecting the presence of a resonant tag employs first and second shielded twisted loops lying in a common plane and having portions thereof interleaved with each other. The loops are electrically coupled to each other and to a common transmitter or receiver. The loops may be fabricated from coaxial cable to achieve the shielding function at low cost while providing design flexibility.

Abstract: A multiple loop antenna particularly suitable for use with an electronic article surveillance security system for detecting the presence of a resonant tag employs first and second shielded twisted loops lying in a common plane and having portions thereof interleaves with each other. The loops are electrically coupled to each other and to a common transmitter or receiver. The loops may be fabricated from coaxial cable to achieve the shielding function at low cost while providing design flexibility.

Abstract: The present invention provides an automobile antenna system capable of receiving radio waves without need of an externally projecting part such as a pole type antenna externally exposed from the vehicle body, the automobile antenna system including a high-frequency pick-up disposed on the marginal portion of an engine hood or trunk lid on the vehicle body such that the length of the pick-up is parallel to the longitudinal axis of the engine marginal edge of the engine hood or trunk lid, whereby surface high-frequency currents induced on the vehicle body by radio waves and concentrically flowing on the marginal portion of the engine hood or trunk lid can be detected by the pick-up.

Abstract: An automobile antenna system for receiving various broadcast and communication waves without pole antennas projected from an automobile body. The system comprises a high-frequency pickup arranged along the length of a trunk hinge on the vehicle body to detect high-frequency surface currents which are induced on the vehicle body by broadcast waves and which are concentrated onto the trunk hinge.

Abstract: An automobile antenna system which requires no pole antenna or the like projecting outwardly from the automobile body includes a high-frequency pickup, for example, comprising a loop antenna, which is incorporated within a portion of the vehicle body. The high-frequency pickup is secured to the rear window frame and the longitudinal side of the loop antenna which is partially exposed through the casing of the high-frequency pickup is disposed in the vicinity of an edge-moulding mounting retainer. The loop antenna picks up high-frequency surface currents which are caused by broadcast waves and which concentratively flow in the edge-moulding mounting retainer.

Abstract: A compact transmitting and receiving antenna has dual feeds permitting magnetic and electric dipole radiation. The antenna includes a loop antenna disposed within a loop shield and a mast. The loop shield is insulated from ground and a feed is provided to it and the mast to excite these as an electric monopole. The shield becomes part of the monopole antenna and provides the benefits of top-loading. An isolation transformer permits the simultaneous transmission of monopole and dipole radiation. The transformer converts an unbalanced coaxial feed line to the balanced loop antenna and isolates the monopole feed voltage from the loop antenna feed. To eliminate the affect of the monopole feed on the loop feed, and vice versa, the components on the high side of the monopole feed (the loop shield and mast) are driven in common mode (voltage) by the monopole feed, and will not couple the loop antenna feed through the transformer windings.