Abstract: A new and improved antenna-transmission line coupling system is provided wherein the electro-magnetic oscillations in the antenna are prevented from entering the circuitry which couples the antenna to its transmission line. The coupling structure (called coupler) includes an impedance matching transformer and a capacitor connected to the transformer and capacitively coupled with the antenna element. Various embodiments are provided for varying the capacitive coupling with the antenna element. Antenna elements having capacitor plates on their ends are disclosed; as well as an arrangement wherein a universal coupler having a broad band impedance matching transformer can be used with any number of antenna elements each tailored for a different commercial RF frequency band.

Abstract: A dual frequency band antennas system where the two frequency bands are not harmonically related includes first and second antenna sections. The first antenna section comprises a straight rod, with the length of the rod being at least one quarter wavelength at the center frequency of the lower of the two frequency bands. The second antenna section includes a straight portion terminated by a helical wire portion, with the total electrical length of the second antenna section being substantially equal to the length of the straight rod. A conductive antenna base is connected to at least one of the first and second antenna sections. A matching circuit coupled to the base is arranged to substantially cancel the reactive portion of the impedance of the connected antenna section for both frequency bands and to substantially equalize the resistive portion of the impedance of the connected antenna section to the resistive portion of the output impedance of the radio transceiver to which the antenna system is coupled.

Abstract: An antenna assembly, and associated method, for a radio, such as a portable radiotelephone, which is of minimal physical dimensions and which is operable over a wide range of frequencies. A length of wire is helically-shaped and includes at least a portion of a winding. A capacitive top-hat is positioned at an end portion of the wire. By increasing the number of windings of the wire, the height of the antenna assembly is reduced, but such reduction also reduces the size of the bandwidth of frequencies over which the antenna assembly is operable. Increase in the size of the surface area of the capacitive top-hat increases the size of the bandwidth over which the antenna assembly is operable. Selection of the top-hat size and the number of windings permits beth physical dimensions of the antenna assembly and the size of the bandwidth to be selected.

Abstract: A monopole antenna (1) is constructed with a ground plane disc (2), a top loaded antenna disc (3), and a length of coaxial cable (4) having an outer conductor (5) connected to the ground plane disc (2), an inner conductor (7) of the cable (4) being connected to the antenna disc (3), and a loading disc (6) between the ground plane disc (2) and the antenna disc (3), the loading disc (6) being connected to an outer conductor (5) of the cable (4).

Abstract: In an umbrella top-loaded monopole (UTLM) antenna, the charge distribution on top-load radials increases approximately linearly from the top of the antenna because the activated wires are separating from the tower and each other at the same time they are getting closer to ground. The UTLM antenna of the invention incorporates a top-load configuration in which top-load elements, whether they be radiating or receiving, are arranged in the shape of frames that originate at the top of the antenna and that extend away from the antenna towards the antenna's base where, at those points of the configuration furthest from the antenna tower and closest to ground at least two top-load elements converge to shield each other and hence reduce charge density. The top-load frames may be arranged contiguously such as in a rosette configuration. The self-shielding effect of the invention permits an antenna to operate at considerably higher voltage.

Abstract: The present invention concerns an antenna for portable radio devices including a helical antenna coupled at the base to a transmitter/receiver. The pitch of a conductive material helix constituting the helical antenna varies according to the height of the helix. It decreases from the base of the helical antenna towards its top.

Abstract: In the preferred embodiment of the invention, a broadband dipole antenna 10 for transmitting and receiving electromagnetic energy constructed of coaxially aligned radiating elements 14 and 16 is provided. Each of the radiating elements 14 and 16 has a charge collector 40 and 42 affixed to its free end, that function to collect charges forming a current sink for collecting the current generated by the radiating elements. Coupled with the radiating elements is an isolation choke 44 to isolate the radiating elements against electrical disturbances caused by the antenna support platform 130 and 138 effecting a match of the impedance between the radiating elements and the transmission lives. Another preferred embodiment is a monopole 86 equipped with a charge collector 96. The dipole 10 and monopole 86 are provided pairs of open-sleeves 28 and 26 and 92 and 94 to enhance the instantaneous bandwidth of the radiating elements.

Abstract: A miniature antenna with an elongated base portion and an essentially circular top loop that is perpendicular thereto. A U-shaped load is connected between the partially helical base portion and the top loop, and its first leg is connected essentially perpendicular to the elongated base portion while its second leg is connected essentially tangential to the top loop.

Abstract: A broadband off-center fed dipole antenna capable of resonating at multiple frequencies with a near integer relationship between fundamental and harmonic frequencies and with standing wave ratio of less than or equal to 1.5:1 at desired frequencies without the need of an antenna tuning device. One preferred embodiment of the antenna comprises a first radiating section having an inner line electrically coupled to a balun transformer and a trap and an outer line electrically connected to the trap and an insulator. A second radiating section is connected to the balun transformer and has another insulator secured to its other end.

Abstract: A low profile, dual purpose antenna for simultaneous UHF and LF use has two coplanar antenna elements, one of which is circular and the other of which is a concentric annulus separated from it by a dielectric, as well as a third, linear antenna element extending from the center of the circular element. The circular element serves both to assist in tuning the UHF section of the antenna and as a voltage probe for the electrostatic component of the LF signal. Integrated within the antenna housing is a high input impedance, low noise amplifier for bandwidth limiting the LF signals. A coaxial feeder cable serves to connect both UHF and LF sections of the antenna to external equipment. Entry for the coaxial feeder cable into the antenna housing is through a threaded collar, which also acts as a single point fixing of the antenna to the roof of a vehicle.

Abstract: A portable radio communication device has an antenna which can be extended for use and retracted for storage, and can transmit a signal at the same level of electric energy when the antenna is stored as when the antenna is extended. When the antenna is retracted and stored, the stored condition is detected by a detecting switch. In response to a detected signal from the detecting switch, a transmission output controller produces an increased transmission output control signal to increase the level of electric energy of the signal to be transmitted which is higher than a normal level of electric energy of signals transmitted from the antenna. When the increased transmission output control signal is generated, a power amplifier amplifies a signal to be transmitted which is supplied from a transmission signal generator, and supplies the amplified signal to the antenna. Therefore, even when the antenna is stored, it can radiate the signal at the same level of electric energy as when the antenna is extended.

Abstract: A broad band mobile telephone antenna comprises a first conductive circular plate and a second conductive circular plate. The first plate is located above and in parallel with the second plate. The diameter of the second plate is equal to or larger than that of the first plate. The second plate is used as a ground plate, is attached on a body of an automobile. A short-circuit rod, for matching an impedance between the first plate used as an antenna and a coaxial feeder cable for the antenna, is connected between the first and second plates. An upper end of a core rod is connected to the first plate at the substantial center thereof. A lower end of the core rod is extended toward an opening formed in the substantial center of the second plate. The opening is connected to a connector which is placed inside the automobile through an opening formed in the body. The connector connects the core rod and the coaxial cable which is connected to a transmitter/receiver of a mobile telephone system.

Abstract: An antenna for mobile communication of this invention comprises a first metal plate having a slit, a second metal plate opposed to the first metal plate and electrically connected to the first metal plate, two metal foils connected to the second metal plate, and a cable for supplying feed signals to the first metal plate and the second metal plate, the cable including a first conductor connected to the first metal plate via a capacitor and a second conductor connected to the second metal plate.

Abstract: Non-resonant, end fire antennae that operate over broad frequency bands, can be incorporated into arrays and have low RF cross-sections are constructed from a transmission line, usually a piece of coaxial cable that if it is not self supporting, is mounted on or in a lightweight structural material with an outer end with a sheath or stripline the shape of half of a notch. The other half of the notch is formed from a conductor electrically connected to the center conductor of the coaxial cable. The cable and conductor are variably spaced to transition the characteristic impedance of the cable to that of free space. The conductor and the sheath are terminated either with ground connections or by inductive loads.

Abstract: Resonant, end fire antennae that operate over broad frequency bands with a boosted gain at a preferred frequency, that can be incorporated into arrays, and that have low RF cross-sections are constructed from a transmission line, usually a piece of coaxial cable that if it is not self supporting, is mounted on or in a lightweight structural material with an outer end with a sheath or stripline the shape of half of a notch. The other half of the notch is formed from a conductor electrically connected to the center conductor of the coaxial cable. The cable and conductor are variably spaced to transition the characteristic impedance of the cable to that of free space. The transmission line and the conductor each have a quarter wavelength tuning stub connected thereto to boost the gain of the antenna at a predetermined frequency. The conductor and the sheath are terminated either with ground connections or by inductive loads.

Abstract: An extendable antenna which has a cylindrical antenna guide for slidably retracting a first antenna portion of the extendable antenna into the interior of a housing of a radio transceiver in which the antenna guide is provided at its one end with a cylindrical grounding connection member connected to a grounded portion of the radio transceiver and to be brought into contact with a first contact portion of the antenna when the first antenna portion is retracted into the interior of the housing. The grounding connection member is disposed to contact with the housing so as to face a water drain hole provided in the housing, whereby, when the first antenna portion with rain water attached thereto is retracted into the interior of the housing, the rain water introduced into the antenna guide is guided through the interior of the cylindrical grounding connection member and discharged through the water drain hole of the housing to the outside of the radio transceiver.

Abstract: A conductive layer is formed on one surface of an insulating substrate. Notches are formed in the conductive layer to be axially symmetric at equal angular intervals of 120.degree.. A feeding line of a notch antenna is formed on the other surface of the substrate. The feeding line has a C-shape and wide portions for adjusting the phases of excitation of the notches, and receives power at its one point. A ground plate is arranged to be parallel to the substrate. A feeding rod is connected to the conductive layer. The conductive layer and the ground plate are short-circuited by impedance matching pins. The matching pins are integrally formed with the ground plate. The notches and the feeding line constitute an notch antenna, and the feeding rod, the ground plate, the conductive layer, and the matching pins constitute a capacity loaded monopole antenna. To resonate these antennae at a plurality of resonant points, slits are formed in the conductive layer to be axially symmetric at equal angular intervals of 120.

Abstract: A radio antenna which takes the form of a flexible elongated transmission cable. This cable encloses a pair of conductors which are insulated from each other. The cable is encased in an electrically conductive sheath. The received signal is picked up by the sheath and transmitted through an impedance matching network and into the pair of conductors. The length of the sheath is correlated to a preselected fractional value of the wavelength of the received signal.

Abstract: A device is provided for use in a helical antenna having an antenna element wound about the periphery of a dielectric support post, the post being in the form of a tube or cylinder. The device has an electrically conductive member electrically connected to one end of said antenna element. The conductive member is of any appropriate shape or configuration and is operable to increase the loading on the antenna whereby standing waves on the antenna element are reduced and a more uniform electrical current is produced along the antenna element.

Abstract: A collapsible `bedspring` monopole antenna is configured to be effectively non-observable in its collapsed condition and, when deployed, remains sufficiently compact to ensure very low observability characteristics, while providing broadband coverage over a wide viewing aperture. The antenna is comprised of a conductor formed as a tapered helix. One end of the conductor is coupled to an antenna feed. The outer end of the helix is looped around on itself to form a circular loop. A plurality of substantially rectilinear `radials` are soldered to distributed locations around its circular loop, so as to extend outwardly and tangentially from the outer perimeter of the loop and provide `top hat` capacitive matching elements. To define the height of the deployed antenna and to electrically short out plural locations of the helix, a plurality of conductive straps are joined to respective spaced apart locations of the helix.

Abstract: A top loaded antenna comprises a spaced pair of top load plate and a ground plate. A matching element integrally formed with a feedline and a shortline is disposed between the top plate and the ground plate for coupling between the plates, eliminating the necessity of separately and individually coupling the feedline element and shortline element to the plates.

Abstract: Wideband antenna systems may provide continuous coverage over the VLF, HF, VHF, and UHF frequency ranges. Matching transformers, insertion resistors and damping elements are integral parts of these antenna systems.

Abstract: An FM wave antenna including a coaxial cable, a parallel conductor which are provided parallel to a metal conductor such as a vehicle body and an amplifier provided between the coaxial cable and the parallel conductor. The coaxial cable is made up of a central core and inductive outer sheath and one end of the inductive outer sheath is connected to the metal conductor, and one end of the parallel conductor is also connected to the metal conductor. The amplifier amplifies signals from the parallel conductor and inductive outer sheath of the coaxial cable and outputs amplified signals to the central core of the coaxial cable.

Abstract: A broadband omnidirectional antenna has a monopole element driven by an rf source at one end and a load at its other end consisting of insulated parallel conductors tuned to different resonant frequencies. The parallel conductors are equidistantly spaced so that transmission line coupling occurs between adjacent conductors. The parallel conductors progressively decrease in length the further away each conductor is supported from the driven element. The antenna elements can be fabricated from attached insulated wires or ribbon cable and thus the antenna can have low weight, little bulk and great flexibility.

Abstract: An antenna is provided which includes first and second helical elements which are separated by a dielectric spacer. The first helical element is fed a radio frequency driving signal and the remaining second element is coupled to ground. The first and second elements are coupled together in a fashion which results in a dramatic increase in antenna bandwidth in comparison to prior helical antennas.

Abstract: A broad-band, small-size radio-frequency antenna system includes a transmission line antenna feeding a monopole antenna, the antenna system exploiting the opposite narrow-band characteristics of the above antennas so as to complement each other and to produce an antenna system of broad-band monopole antenna characteristics.

Abstract: A tunable fiberglass whip antenna comprises an elongated fiberglass core having a conductive wire coiled around the core and serving as the antenna. The uppermost extremity of the wire is tightly coiled around an axial bore within the fiberglass. A metal insert, fixed within the fiberglass bore is in threaded engagement with a set screw accessible from the top of the antenna. By adjusting the longitudinal position of the set screw relative to the tightly wound wire at the end of the antenna, the inductive coupling between the coil and screw is varied to thereby change the effective length of the antenna.

Abstract: A portable antenna construction is provided for high frequency radio transmission and reception. A physically and electrically shortened center-fed dipole, the antenna includes a driven element assembly 62, a center insulator assembly 60, a center loading coil assembly 74, two end loading coil assemblies 70 and 72, two capacity hat assemblies 64 and 68, and a mast assembly 63, each such assembly constructed from parts allowing for easy assembly and disassembly. The antenna further includes a carrying case 78 of sufficient size to hold all disassembled parts, so that such disassembled parts can be easily transported. Center loading coil assembly 74 includes a center loading coil 76 having multiple tap points 77 for transmission line connection, thereby permitted impedance match at any frequency to which the antenna is tuned.

Abstract: Disclosed is a low profile wideband VHF antenna wherein impedance matching ver the required operating band is provided without the use of multiple circuit components, for tuning, switched into and out of the antenna by an assembly of switch contacts. The antenna is comprised of an end and preferably a bottom fed vertical radiating rod or monopole element whose upper end is terminated in a substantially flat circular top capacitance disc via a frequency sensitive inductance constructed of a ferrite core inductor whose .mu. characteristic varies approximately inversely with respect to frequency.

Abstract: What is disclosed is an antenna system for aircraft and one having particr utilization on a helicopter where there is a need, among other things, to eliminate insofar as possible rotor blade modulation of the signal radiated from on-board air-to-ground communication system in the 2 to 30 MHz band. The antenna comprises a current fed grounded loop-antenna having an electrical length which is relatively short with respect to the operating wavelength. The antenna conductor is mounted by means of insulators on the outside of the aircraft body, having one end connected to the transmitter while the other end is series connected to a lumped electrical inductance element whose opposite end is terminated in the metallic skin of the aircraft. The electrical inductance, moreover, is variable so as to resonate the antenna to the driving impedance of the transmitter.

Abstract: An impedance matching transformer and isolation inductance construction for a vertical-end fed radio antenna which enables simple manufacturing tecniques to obtain uniformity of impedance matching from one antenna to the next and which enables the use of a sintered magnetically permeable core of a length longer than three inches. The impedance matching transformer includes a two turn primary and insulating means accurately spacing these two turns. The core is made up of a plurality of relatively cylindrical formed short core elements from sintered magnetically permeable material in end to end relationship. Very thin plastic spacers are interposed between the adjacent ends of the core elements and between the sides of the elements and the housing to prevent chipping.

Abstract: A spring tunable antenna for mounting to the frame of a vehicle. The antenna includes a base adapted to be mounted on the vehicle, a flexible rod supported at its lower end in the base, and a low-resistance wire conductor wound helically around the rod. The conductor windings in the tip region of the rod are selectively movable, whereby the antenna may be tuned.

Abstract: A vertical antenna comprises a substantially vertical conductor supported on an insulating rod and wound tightly at the top to provide a top loading coil. A capacitive plate is conductively attached to the antenna conductor between the top loading coil, and a connecting adapter located at the lower end of the insulating rod and to which the antenna conductor is joined. An additional radiating coil is wound over the lower portion of the antenna, including the capacitive plate, while being insulated therefrom.

Abstract: A radio frequency antenna comprising a shaft fabricated from dielectric material, and first and second conducting means disposed on the exterior surface of the shaft, the conducting means including linear conductors located on opposite sides of one portion of the shaft and intertwined insulated coils on a second portion of the shaft connected to the respective linear conductors. Tuning members can be connected to the conducting means for selectively changing the resonant frequency of the antenna.

Abstract: A top-loaded, helically-wound vertical antenna is described having an upright non-conductive core with a conductive element extending from a base upward alongside the core terminating in a closed, tightly-wound loading coil at the top of the core. The loading coil has a main upper coil segment and a lower small coil section which are separated a desired distance so that they are electromagnetically and electrically connected in series but sufficiently spaced to prevent temporary overloading. Electrically isolated booster coils are mounted about the conductive elements at desired locations of the lead section in which the booster coils are not electrically connected to the conductive element or to each other for boosting the reception of r-f energy.

Abstract: A collapsible-helix antenna, continuously variable in length and self-resonant with a uniform resistance over an exceedingly wide frequency range, for example 2-32 mHz. The collapsible-helix is continuous in two sections: a fixed-length, shorted-out section wherein the turns of the helix are collapsed upon each other; and a variable-length section wherein the helix has an approximately constant pitch, and is a radiating element. Means are provided to drive turns of the helix from either section to the other, providing a helix with continuously variable physical and electrical length.

Abstract: The disclosure relates to an antenna system for C.B. radio use which is mounted upon a metallic base, such as the roof of an automobile, the antenna having the S-shape or Greek-key design configuration, the antenna being mounted at one end of the base through an insulating medium, the one end being coupled to a plate on the insulating medium which forms a capacitor with the insulating medium and the metallic base of fixed predetermined value. A variable capacitor is also formed between end extension of the plate and the free end of the antenna.

Abstract: A top termination for short monopoles is disclosed which reduces transmisn losses by placing the series inductor outside the top-capacitor-to-ground field while coupling the top capacitor to the monopole through said series inductor.BACKGROUND OF THE INVENTIONIn the field of transmission of radio waves by means of a monopole antenna it is well known that the optimum physical length of the monopole should be equal to a quarter wavelength to provide a purely resistive impedance at the antenna base without the use of compensating inductance or capacitance. At lower frequencies, however, wavelengths become sufficiently long so as to make monopole antennas having the ideal 1/4 wavelength dimension cumbersome and impractical. Accordingly, the antenna length has been reduced while a compensating inductance or capacitance or both have been added so that the electrical length of the shortened antenna approaches the electrical length of the idea 1/4 wavelength antenna.

Abstract: A broadband antenna in the form of a multiple element interlaced dipole array is mounted on a thin elongated strip of dielectric material which is mechanically flexible, light weight and electrically small. Each dipole has a first tapered radiator section with an inductive loading section electrically connected to one end of the tapered radiator section. A capacitive end-loading section is connected to the inductive loading section. Second tapered radiator sections are joined to one another by a second inductive loading section. The inductive loading sections increase the effective electrical length of the first and second tapered radiators, respectively. A UHF gap filling conductor is connected to each of the dipoles to suppress grating lobes at the high-frequency end of the frequency spectrum received by the antenna.

Abstract: The invention relates to an antenna structure comprising a number of parallel conductors having dimensions and spacings which are small against operating wavelength, and positioned perpendicular to a conducting ground plane; the upper ends of the conductors are terminated by metal plates acting as capacitors against the ground plane, and interconnected by inductive elements, the lower ends of some of said conductors are electrically connected to said ground plane, while another one of these conductors is connected to a power source to impress a voltage between the lower end of said other conductor and said ground plane.