Abstract: A VHF-UHF waveguide non-metal and metal detector is disclosed having a waveguide antenna system of aluminum tubing with 4 aperture/slits at critical angles including dielectric centers in conjunction with a waveguide collector system of 2 sets of conical collectors mounted on a main unit containing a waveguide diaphragm and waveguide receiver case including receiver antenna wires with no metal contact.

Abstract: The present invention relates to a high-frequency switching circuit, and provides a high-frequency switching circuit capable of withstanding high output power, achieving highly efficient isolation, and reducing an insertion loss using inexpensive pin diodes. A switching control voltage or ground voltage developed at one power supply is applied to a control terminal. A diode resonant circuit includes a diode that applies a signal to an output terminal through an anode thereof and a signal to an input terminal through a cathode thereof, and has a resonant circuit, which attains a parallel resonance owing to a parasitic capacitance formed when the diode is off in the frequency band of the high-frequency signal, interposed between the anode and cathode of the diode. A first bias circuit separates a switching control current stemming from the switching control voltage applied to the control terminal from the high-frequency signal and supplies the switching control current to the anode of the diode.

Abstract: A ring antenna (10) for resonant circuits for identifying metallic containers has an annular core (11) having at least one core surface (11a') corresponding to at least one surface of the container and made from ferrite. The core may be U-shaped, having a base portion and a first and second arm portions, or L-shaped, having a base portion and a first arm portion (11a). The antenna (10) also has a copper wire coil (12) wound around a first portion of the core; and an aluminum shield (13) affixed to the at least one core surface (11b') and separating the core from the surface of the container. Further, a interrogation system for identifying metallic containers includes the ring antenna (10) coupled to a resonant circuit (86) included in a transponder or a reader.

Abstract: A transmission line antenna (10) comprises first and second ends (14 & 16). Each end has a mounting portion defining a mounting height and an overlapping portion (18 & 20) defining an overlapping width. The overlapping portions are formed by bringing the ends around the ring and past each other, and are electrically connected together. The antenna is interconnected to a circuit board having a circuit impedance, and the mounting height and overlapping width are configured such that the antenna impedance matches the circuit impedance.

Abstract: A loop antenna for a circularly polarized wave can operate in a wide frequency range and can be simply constructed. A radiating power fed to a feeding point via a coaxial line and a feeder conductor is transmitted through an I-shape conductor to a C-type loop element disposed in spaced facing relation to a ground plane. By the action of a cutoff part formed on the C-type loop element, the C-type loop element radiates a circularly polarized wave. An angle of between 35.degree. and 45.degree. formed by the I-shape conductor and the cutoff part.

Abstract: A small, high Q loop antenna configured on a printed circuit board as a planar structure receives a radio signal and shields its interior planar area against interfering electric field energy while concentrating therein radio signal magnetic flux. A magnetic pickup loop, coplanar to the antenna loop and magnetically coupled thereto, receives the radio signal power by virtue of its magnetic coupling to the loop antenna. The magnetic pickup loop couples to a receiving device and delivers the radio signal thereto. Illustrated embodiments include loop antennas tunable to a desired resonant frequency.

Abstract: An electronic article surveillance system capable of reliable operation at high frequencies such as about 8 MHz, has an arrangement of transmitter and receiver antennas each lying in a flat, horizontal plane in substantial alignment with each other, with the receiver antenna positioned at the floor of a passageway at an interrogation zone and the transmitter antenna positioned overhead. Each antenna takes the form of a pair of parallel-connected, coplanar loops with the transmitter-connected loops being positioned such that electrical current flows around each loop in parallel in the same direction (a ++ configuration) and in the receiver antenna electrical current flows around each loop in parallel in mutually opposite directions (a +- configuration). The antennas are approximately of the same size and overall configuration, and they are positioned in substantial alignment so that the currents induced in the receiver antenna by the field from the transmitter antenna will effectively cancel.

Abstract: An antenna is disclosed with a first Z-shaped strip resonant element disposed in a first plane. The first strip resonant element has first and second identical sized and shaped, parallel, longitudinal strip segments. The first strip resonant element also has a third segment which connects diagonally opposite ends of the first and second strip segments. The antenna also has a second Z-shaped strip resonant element disposed in a second plane that is parallel to the first plane. The second strip resonant element has fourth and fifth identical sized and shaped, parallel longitudinal strip segments. The second strip resonant element also has a sixth segment, having identical dimensions and an identical shape as the third segment, which connects diagonally opposite ends of the fourth and fifth segments. The second Z-shaped strip resonant element is disposed in the second plane so that the sixth segment overlies said third segment and so that said first, second, fourth and fifth segments overlie a rectangle.

Abstract: An efficient electrically small loop antenna includes a radiation device, an impedance matching network, and a connector that interfaces to associated electronic circuitry. The radiation device includes a conductive planar base element extending in a base plane and a conductive loop connected to the planar base element. The loop connects to the base element so that the electrical current for the antenna flows through both the conductive loop and the planar base element. The impedance matching network matches the radiation device to the associated electronic circuitry. The matching network is integrated into the planar base and is connected to both the conductive loop and the base element so that the electric current supplied to the antenna is conducted through both the base element and the conductive loop.

Abstract: An antenna orientation device which includes a base, an antenna structure with a first bearing surface, and a support for positioning the structure in relation to the base. The support includes a body coupled to the base and having a stem. The support also includes a resilient non-metallic bearing member carried on the stem which has a second bearing surface. The support also includes a fastener connected to the body for clamping the first and second bearing surfaces in rotary bearing relation. The bearing member is elastically deformed to provide retaining force sufficient to hold the structure against earth's gravitational pull in any one of a range of rotational positions about a substantially non-vertical axis. Each position within the range is selectable by rotating the structure by hand. This support can provide a rotational range of at least 45 degrees. The fastener may be configured as an adjustable screw to provide a way to vary retaining force.

Abstract: An RF control system characterized by the use of remotely located low profile radio frequency antennas which are concealed in conventionally appearing valve boxes or similar housings. The system includes a central control station, including a central RF transmitter, and a plurality of remote station, each including an RF receiver and antenna. A preferred remote station includes a valve box or similar housing of the type intended to be at least partially buried in the earth. The housing has a peripheral wall defining an access opening and a removable cover for bridging the opening. A directional discontinuity ring radiator (DDRR) antenna is physically mounted in the valve box housing on the interior side of the cover and is connected to a receiver, preferably also physically mounted on the cover.

Abstract: A versatile antenna system that, can help improve and produce a new line of TVS, radios, pagers, cordless, radio telephone and other communications gear. In its basics, the antenna is smaller in its wavelength, competitive in value. Some additional features described can make this antenna flexible and provide fast tuning, that can be more stable, with consideration to price, than an analog controlled device. The antenna can be utilized in a number of commercial applications and with the additional features described, it can have a number of advantages over the conventional telescoping antennas used for short wave, communications, TV or other uses.

Abstract: The present invention provides a method (400) and antenna (100) for providing an omnidirectional pattern. The antenna (100) is smaller than prior art omnidirectional antennas with the same bandwidth. The smaller size is made possible by the use of at least one capacitive element (104) at a discontinuity in the loop (102). The pattern is balanced and therefore the omnidirectionality is maintained by the current maximum (110 and 112) that are created by the capacitive element (104).

Abstract: A small loop antenna employs circuits for increasing the power output and bandwidth of such antennas by employing coaxial cable or wide antenna elements on which the coaxial cable may be mounted or use microstrip, both for the purpose of reducing the inductance and resistance of the antenna structure in a fixed ratio so that the reduced terminating resistance increases the level of signal output. This method applies to both receiving and transmitting antennas for cases where the terminating resistance is much larger than the radiation resistance plus the antenna and tuner loss resistances.

Abstract: A wristband for a wrist-mountable type electronic device comprises two wristband segments each including an outer layer member, an inner layer member and an antenna strip made of an electrically conductive member sandwiched between these members. The outer layer member is made of an ornamental material such as leather, while the inner layer member is made of urethane. The inner layer member includes extended portions which extend beyond the edges of the electrically conductive member to cover laterally the side edges of the outer layer member. The inner layer member also has a recess formed at its outer surface continuously extending along the longitudinal direction of the wristband. According to the present invention, the appearance of the wristband is improved, and the feel of the wristband is enhanced when it is mounted. Further, durability of the wristband is also improved.

Abstract: The present invention introduces an RFID system that comprises a two-dimensional antenna configuration having a dipole in combination with a loop antenna or a second dipole with their dipole axes at approximately a 90.degree. angle to one another. The pattern of two dipole antennas combined with the pattern of a single loop antenna, allows the sequential combination of the patterns to represent a nearly spherical antenna pattern in three dimensions, while the antennas reside in a two-dimensional plane. The presence of multiple antennas also allows for a method to switch among the multiple antennas to find the antenna or combination of antennas that create(s) the strongest RF communication link thereby enabling more efficient transmitted power or more directional reception coverage. Improving efficiency can be further improved by taking this concept one step further by adding multiple antennas into the interrogator unit.

Abstract: An antenna assembly providing selectable omnidirectional or directional reception of radio transmissions in a frequency band in accordance with the invention includes an electrically conductive reflector (432) defining a cavity (702) having a bottom (708), an opening (714) and a surface (704 and 706) extending from the bottom to the opening and an electrical output (763); an electrically conductive loop (431) coupled to ground and having an electrical outlet (766) for coupling to an RF amplifier (407), the loop being positioned between the bottom opening of the cavity; a RF switch (406) having an input (760) and first and second outputs (762 and 764), the RF switch having a first switching state electrically connecting the input to the first output and a second switching state electrically connecting the input to the second output, the first switch output being electrically coupled to ground and the second switch output being electrically coupled to the output of the electrically conductive loop; and wherein

Abstract: A short-distance communication antenna can satisfactorily transmit and receive an information signal within a regulation range of the radio law. Also, the short-distance communication antenna provided on a card reader/writer enables the card reader/writer to communicate with a non-contacting information card without being limited by the direction of the non-contacting information card upon reception. This short-distance communication antenna includes a plurality of magnetic poles disposed on a magnetic member and to and from which a magnetic flux is transmitted and received, and a coil for transmitting or transmitting and receiving the information signal mounted on at least one of the magnetic poles. Further, the short-distance communication antenna includes a housing having an aperture to and from which a magnetic flux is transmitted and received, and a coil for transmitting or transmitting and receiving the information signal mounted on said housing.

Abstract: A high frequency wave glass antenna for automobile in which a line shape or a strip shape antenna conductor is provided on a glass plate of a window of an automobile in an approximately circular, an approximately elliptic or an approximately polygonal form having an opening portion, a first end of two ends on both sides in the vicinity of the opening portion of the antenna conductor is connected to an electricity feeding portion and a second end thereof is connected to a grounding conductor, and which provides the electricity feeding portion and the grounding conductor that are proximate to each other, or the grounding conductor having a predetermined area.

Abstract: A vehicular radio reception antenna is concealed within a body trim piece such as a spoiler or a luggage rack. A supporting body panel is utilized as a ground plane and a conductive loop is concealed within the trim piece. A transmission line connects two opposite sides of the resulting slot. Capacitors are used to connect the conducting loop to the sheet metal ground plane in order to form a dual slot/monopole antenna for receiving both FM and AM signals.

Abstract: Antenna structure for use with a timepiece (100) adapted to be worn on the wrist and including a microreceiver (117,118), said antenna structure comprising an antenna (81) comprising at least one coil (85,86,87) and being capable of capturing an electromagnetic field bearing radio diffused messages for receipt and transformation by said microreceiver (117,118) into data perceptible to a user of said timepiece, conductive leads (82,83) for connecting said antenna (81) to said microreceiver (117,118), and a non-conductive support structure (84) comprising a first portion (90) onto which antenna (81) is mounted. The support structure (84) further comprises a second portion unitary (91) with and projecting from said first portion (90) and onto which said conductive leads (82,83) are mounted.

Abstract: A modified loop and nondirectional antenna system and receiver used in conjunction with a magnetic compass and 2 level vials for a point direction used to detect underground parasitic antennas or reflectors by supression and reception of receiver. The detector is directed at very deep propagated radio waves, several hundred feet deep or less.

Abstract: A thin IC card which is highly reliable, simple in construction and structure, to which a function section relating to main information processing can be easily attached, and which has improved portability, and a method for producing it are disclosed.

Abstract: A preferred embodiment of an antenna for radiating and collecting electromagnetic radiation includes a substantially planar conductive member having a first side and a second side. A strip conductor is positioned to the first side of the conductive member and substantially parallel thereto. A dielectric material is sandwiched between the strip conductor and the conductive member. A length of wire for radiating and collecting microwave electromagnetic radiation has a first end and a second end and lies substantially in a plane which is positioned to the second side of the conductive member and substantially parallel thereto. The length of wire is spaced apart a distance from the conductive member. A feed probe wire couples the first end of the length of wire to the strip conductor. The feed probe wire extends through the conductive member and through the dielectric material. A shorting wire couples the second end of the length of wire to the conductive member.

Abstract: A high frequency wave glass antenna for an automobile in which a line shape or a strip shape antenna conductor is provided on a glass plate of a window of an automobile in an approximately circular, an approximately elliptic or an approximately polygonal form having an opening portion, a first end of two ends on both sides in the vicinity of the opening portion of the antenna conductor is connected to an electricity feeding portion and a second end thereof is connected to a grounding conductor, and which provides the electricity feeding portion and the grounding conductor that are proximate to each other, or the grounding conductor having a predetermined area. An insular conductor is provided in a range wherein the insular conductor is capacitively coupled with a portion or a total of a preamplifier circuit.

Abstract: A wire antenna for circularly polarized wave has a loop conductor that is composed of an outer element 3a of one turn and an inner element 3b of three-fourths turn. The antenna has an overall length of approximately 7/4 wave length and is a 7/4 turn loop of a rectangular shape with opposite ends separated. Feeding terminals 2a and 2b as feeding points are positioned at one turn point of the loop conductor.

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: An efficient electrically small loop antenna includes a radiation device, an impedance matching network, and a connector that interfaces to associated electronic circuitry. The radiation device includes a conductive planar base element extending in a base plane and a conductive loop connected to the planar base element. The loop connects to the base element so that the electrical current for the antenna flows through both the conductive loop and the planar base element. The impedance matching network matches the radiation device to the associated electronic circuitry. The matching network is integrated into the planar base and is connected to both the conductive loop and the base element so that the electric current supplied to the antenna is conducted through both the base element and the conductive loop.

Abstract: A method and apparatus for rapidly determining the resonance of a loop antenna (7). In order to set the loop antenna (7) to the desired operating frequency, the antenna is used with an amplifier (15). In view of the high Q provided by the loop, it is used at the output of the amplifier (15) to create a tank circuit. The loop is adjusted to create the proper amount of phase shift driving the amplifier (15) into oscillation. The antenna is then tuned to allow the amplifier (15) to oscillate at a desired frequency. This frequency is monitored on a frequency counter. When the desired frequency is attained, the loop antenna is properly adjusted and can be connected to a transmitter. The invention allows quick and easy adjustment of the loop antenna without having to apply RF energy to the antenna or make VSWR calculations.

Abstract: A low profile antenna system comprises a frame having front and side surfaces for enclosing a printed circuit board supporting a receiver, the front surface of the frame including a first conductive plate, an isolated portion thereof, which couples to the printed circuit board and forms a first portion of a loop antenna. A conductor is coupled to the printed circuit board and forms a second portion of the loop antenna. A second conductive plate is coupled to the frame and forms a rear surface of the frame to completely enclose the printed circuit board. The second conductive plate is capacitively coupled to the conductor thereby enhancing the sensitivity of the loop antenna.

Abstract: An antenna module suitable for a reduction in size and weight of equipment and improved in manufacturability. The antenna module includes a ground element formed from a planar conductor, an antenna element formed from a planar conductor and arranged in parallel to the ground element, and a loop element formed from a tubular conductor and arranged between the ground element and the antenna element in predetermined positional relationship with both elements so as to be connected with the antenna element. The loop element has a first hollow portion passing therethrough in a given direction. The antenna module further includes an element support formed from an insulator and arranged so as to fill a space between the ground element and the antenna element and substantially fully cover an outer surface of the loop element. The element support is formed with a second hollow portion passing therethrough in the same direction as that of the first hollow portion of the loop element.

Abstract: An antenna for a portable radiotelephone which is configured in consideration of the nature of the electromagnetic wave and of the antenna-user relation in order to improve antenna performance in terms of received gain and directivity. Specifically, this is a multi-directional antenna configuration, including two or more planes of antenna oriented in different directions, for receiving electromagnetic waves in various angles or directions. The invention deals with at least two different cases in order to achieve satisfactory reception by a portable radiotelephone: when an antenna is relatively close to the user or a virtual ground, it should be provided normal to the user, and on the other hand, at another angle or parallel to the user when relatively far from the user or virtual ground.

Abstract: An arm-attached band type radio apparatus capable of providing a stable antenna gain without being affected by the band size has an arm attaching band that is formed into a loop by way of a buckle 31 having an metallic electrode plate 32, first and second conductor plates 5L, 5R, shaped so as to form a slot antenna, to form a loop-like slot antenna. The distal end side of conductor plate 5L has an overlap capacitance changing portion 15 so that, when the connecting position of the band changes according to the thickness of the wearer's arm, the overlap capacitance between first conductor plate 5L and metallic electrode 32, is changed. The magnitude of the capacitance change corresponds to a change in the inductance of the antenna to compensate for a shift in the resonance frequency. The overlap capacitance can be changed by controlling the overlap area or the effective dielectric constant of the material separating conductor plate 5L from metallic electrode 32.

Abstract: An inventory management system which includes a transponder, an interrogation transceiver and control devices utilized therewith. The control devices operate to minimize the power consumption of the transponder while permitting selected, coded operation of the inventory management system. The interrogation transceiver provides linkage to the transponder by means of a modulated radio frequency (RF) carrier during system operation. A transmit/receive switch is also included in the invention to prevent harmful coupling between the transponder receiver and the transponder transmitter. This could occur during data exchanges between the transponder and the interrogation receiver.

Abstract: An EAS system in which a transmitter alternately drives first and second antennas with the same coded message signal in its entirety. The antennas, in turn, transmit first and second signals each containing the coded message signal into respective first and second partially overlapping parts of an interrogation zone. Also disclosed is an antenna structure comprised of a plurality of loops extending one after the other and successive ones of which are of opposite phase. One of the loops circumscribes an area which is smaller than each of the other loops to realize reduced coupling to adjacent structures.

Abstract: A microwave intrusion detection system having a transceiver positioned to one side of a substantially conductive member and an antenna positioned on the other side of the conductive member. The antenna shares the conductive member with the transceiver by utilizing the conductive member as a reflective surface. A transmission line is included which has a strip conductor positioned to the one side of the conductive member and a dielectric material therebetween. An antenna has a substantially planar conductive member, a strip conductor positioned to one side of the conductive member, and a dielectric material sandwiched therebetween. A length of wire lies in a plane which is positioned to a second side of the conductive member and is spaced apart a distance from the conductive member. A feed probe wire couples one end of the length of wire to the strip conductor and extends through the conductive member and through the dielectric material.

Abstract: The invention relates to an apparatus which is desiged for underground use in order to facilitate a two-way communication. The apparatus is operated within the frequency band 0.1-2 MHz, in order to make the electromagnetic waves propagate advantageously by utilizing the metal structures installed in the underground facilities and the bedrock itself. According to the invention, the transmitter/receiver unit is provided with an analog to digital converter (5) and respectively a digital to analog converter (20) in order to transmit the intermediate signal coded in digital form in between the two units of the apparatus.

Abstract: An antenna circuit for a non-contact IC card exchanges signals with an external device utilizing electromagnetic waves. The antenna circuit includes a coil and a capacitor connected to form a resonant circuit. The coil includes a main coil having a spiral conductive pattern disposed on a peripheral portion of a substrate and a plurality of adjusting patterns, each electrically connecting a portion of the conductive pattern corresponding to a desired number of turns of the main coil to an end of the main coil. The plurality of adjusting patterns are disconnected from the main coil, except for one adjusting pattern, to obtain a coil of desired inductance.

Abstract: A modified folded dipole antenna (20) comprises a central feeder (23), first and second portions (38 and 40) coupled to the feeder. The first and second portions have first and second folded ends (42 and 44). The folded ends are in close proximity to each other and are electromagnetically coupled to each other. Thus, a modified folded dipole antenna is formed which receives and/or transmits radio signals in at orthogonal orientations.

Abstract: A novel antenna system disposed around a conveyor belt for the interrogation of objects passing through the antenna which overcomes centralized dead zone problems is disclosed. A frame antenna which is disposed around the conveyor belt achieves the interrogation and a separate reading antenna, which is disposed hingedly from the top of the frame antenna performs the reception.

Abstract: An antenna for reception of signals in a plurality of frequency bands employed in portable and vehicular communications is constructed of a dielectric layer disposed on a metallic plate which serves as a ground plane. Microstrip antenna elements in the form of a planar radiator encircled by a loop radiator are disposed upon the dielectric layer. A rod radiator oriented normally to the plate extends through the patch radiator and the dielectric layer, and is surrounded by a dielectric cylinder which insulates the rod radiator from the planar radiator and the plate. The planar radiator may be configured as a patch radiator, a spiral radiator, or a crossed dipole radiator. Also, one or more additional layers of patch radiator elements may stacked upon the patch radiator to provide a stacked microstrip radiator. Terminals are positioned about the planar radiator for extracting orthogonal components of a circularly polarized electromagnetic signal.

Abstract: An antenna system maximizes a gain associated an antenna loop by expanding a free end away from a fixed end of the loop in response to first and second portions of the antenna loop resiliently engaging first and second interior sides of a housing to maintain the position of the antenna loop and increase the effective area of the antenna loop.

Abstract: An electromechanical assembly for use in a portable communications device including an antenna loop and a coil spring coupled to the antenna loop for making electrical contact with one terminal of a battery and for supplying a bias for physically holding the battery substantially immobile, wherein the coil spring and the antenna loop are formed of a continuous piece of material.

Abstract: An antenna system comprises at least first and second antennas circumscribing a common center thereof at respective different distances from the common center, and circuitry for exciting the first antenna at a greater level than the second antenna, the excitation of the first and second antennas by such exciting circuitry being of respective opposite phasing. The excitation circuitry is operative to provide first fields adjacent the antenna system to a predetermined distance therefrom which are essentially controlled by the excitation of the first antenna and to provide for second fields beyond the predetermined distance which are of lesser strength than the first fields and are determined by both of the first and second antennas.

Abstract: A low cost, high efficiency, end fed half wave folded dipole radio frequency antenna. The antenna includes an improved balun including a conductive tubular base secured to a conventional coaxial cable connector, a conductive tube telescoped relative to the base with a slot between the base and tube having an area corresponding to the extent the tube and base are telescoped together and two wires within the tube connected to the coaxial connector and each having an insulating sleeve. A folded wire loop antenna is connected to the wires and extends away from the balun. The loop may include coils to improve the gain of the antenna. A tubular insulating housing encapsulates the antenna.

Abstract: An antenna (10) capable of receiving signals of various frequencies includes a series of superconducting antenna segments and decouplers disposed between each adjacent pair of antenna segments for selectively decoupling at least one antenna segment from the antenna (10) in response to the frequency of the signal received.

Abstract: Glide-slope aerial system intended to function in a relatively restricted space, for example the radome space of an aircraft, comprising one or more half-loop aerials which are supported by the electrically conducting ground plane of the radome space. Each aerial (10) is mounted on a separate base plate (11) whose dimensions are chosen in a manner such that the base plate is resonant at the frequency at which the respective aerial operates. The base plate is positioned in the radome space in a manner such that the base plate extends at least essentially parallel to the ground plane (14), the distance between the base plate and the ground plane being approximately equal to or less 1/4 of the wavelength at which the respective aerial functions.

Abstract: A flexible antenna which operates to control both the reactance as well as the resistance of the antenna. A motorized pulley system attached between two supports is utilized to control the effectrive length of the wire as well as the height of the antenna above ground. The antenna includes a flat base portion suspended between the supports and leg portions extending from the base to the apex of the triangle close to the ground. The total length of the antenna as well as the height of the base portion above the ground is dependent upon the particular frequency which is to be transmitted or received.

Abstract: A small antenna for portable radios and the like in which two planar conductive boards are disposed in parallel relationship at a spaced interval which is small when compared with received radio wavelengths. A dielectric frame is disposed between the two planar conductive boards keeping them at the preselected spaced interval. Arbitrary feeding points are selected along the edges of the two conductive boards and at least one conductor is positioned at an arbitrary selected feeding point to short-circuit the two conductive boards. In some cases a plurality of arbitrary feeding points may be selected along the edges of the two conductive boards and a plurality of conductors positioned at the plurality of arbitary selected feeding points which short-circuits the conductive boards. The positions of the plurality of conductors which short-circuit the conductive boards may be automatically changed at will to provide the most desirable condition responsive to the direction of the radio waves.

Abstract: Disclosed is a loop type antenna, fed by a coaxial line, comprising:a symmetrical, plane, loop-shaped radiating element enclosed on itself, connected to the core of the coaxial feed line at one point of the loop;a reflector plane extending in parallel to the plane of the loop and at a distance from it; and,a symmetrizer element in the shape of a metallic plate, placed between the loop and the reflector and extending in parallel to the plane of the loop and to that of the reflector plane, with a general shape substantially corresponding to the shape of that portion of the loop which is connected to the core of the coaxial line, this plate being connected to the ground of the coaxial feed line. The disclosure also concerns an array antenna comprising an ordered grouping of several antennas, excited simultaneously, said loop and said plate of each antenna extending over a common reflector plane.