scispace - formally typeset
Search or ask a question

Showing papers on "Coaxial antenna published in 1984"


Journal ArticleDOI
TL;DR: In this paper, two types of modified dipole antennas, Zigzag and Meander-line, were analyzed and the shortening ratios were calculated and the radiation patterns were similar to the radiation pattern of a conventional half-wave linear dipole antenna.
Abstract: Two types of modified dipole antennas, zigzag and meander-line types, are analyzed and the shortening ratios are calculated. A zigzag dipole antenna with a wire length of 0.58 wavelengths has a shortening ratio of 24 percent with a resonant resistance of 46 \Omega . A meander-line dipole antenna with a wire length of 0.70 wavelengths has a shortening ratio of 30 percent with a resonant resistance of 43 \Omega . It is found that the radiation patterns of these two types of antennas are similar to the radiation pattern of a conventional half-wave linear dipole antenna.

125 citations


Journal ArticleDOI
TL;DR: In this paper, the cavity-model theory was applied to a 5 cm circular-disk microstrip antenna with an air gap between the substrate and the ground plane, and a simple formula for the resonant frequencies was obtained.
Abstract: The circular-disk microstrip antenna with an air gap between the substrate and the ground plane is analyzed using the cavity-model theory. A simple formula for the resonant frequencies is obtained. The internal fields, the radiation fields, the effective loss tangent, and the input impedance are derived when the antenna is provided with a coaxial feed. The theory predicts that the air gap does not alter the relative field patterns significantly but it provides a simple parameter by which the resonant frequencies of the antenna can be tuned. Measurements have been performed on a 5 cm circular-disk microstrip antenna with an air gap and good agreement between theory and experiment is obtained.

121 citations


Book
01 Jan 1984

82 citations


Patent
Takashi Oda1, Koji Yamasaki1
19 Mar 1984
TL;DR: An antenna having an antenna aperture area and an antenna reactance comprises a first antenna element defining a first aperture area, a first reactance and a second antenna element connected in parallel to the first antenna to put a miniature radio receiver into operation in a desired frequency band as discussed by the authors.
Abstract: An antenna having an antenna aperture area and an antenna reactance comprises a first antenna element (31) defining a first aperture area and a first reactance and a second antenna element (32) connected in parallel to the first antenna element to put a miniature radio receiver into operation in a desired frequency band. The second antenna element has a second aperture area and a second reactance greater than the first aperture area and reactance, respectively, so that the antenna aperture area and reactance are substantially determined by the second aperture area and the first reactance, respectively. The first and the second aperture areas may be coplanar. Alternatively, the aperture areas may be orthogonal to each other.

63 citations



Journal ArticleDOI
TL;DR: In this paper, an ultra-high frequency (UHF) fan-dipole is optimized for wideband operation near the first resonance in order that the antenna could be used in a planar array of half-wavelength spaced elements operating over a conducting ground plane.
Abstract: An ultrahigh frequency (UHF) fan-dipole is optimized for wide-band operation near the first resonance in order that the antenna could be used in a planar array of half-wavelength spaced elements operating over a conducting ground plane. The resultant voltage standing-wave ratio (VSWR) of the optimized dipole (with a 50 \Omega coax input) is less than 2:1 over a 37 percent bandwidth.

47 citations


Patent
Carl P Tresselt1
08 Nov 1984
TL;DR: In this article, an array antenna system incorporating a plurality of antenna elements each having two quarter wave patches or monopoles for radiating microwave energy in a forward and reverse direction was described.
Abstract: An array antenna system has been described incorporating a plurality of antenna elements each having two quarter wave patches or monopoles for radiating microwave energy in a forward and reverse direction, a first and second beam forming network coupled to a coupler for each antenna element, wherein microwave energy coupled to the antenna element from one beam forming network couples lagging phase to one of the two quarter wave patches and from the second beam forming network couples lagging phase to the other quarter wave patch. The invention overcomes the problem of antenna utilization by providing two autonomous beam patterns with independent control or for overcoming the problem of antenna pattern performance by providing a second pattern which may be combined with the first pattern to provide, for example, an improved front-to-back ratio.

38 citations


Journal ArticleDOI
TL;DR: Inagaki modes represent a new modal formalism for problems of radiation and scattering from arbitrary discrete and continuous structures that can be generalized to be orthogonal over any sector of the sphere at infinity, as well as the source region itself.
Abstract: Inagaki modes represent a new modal formalism for problems of radiation and scattering from arbitrary discrete and continuous structures. These modes can be generalized to be orthogonal over any sector of the sphere at infinity, as well as the source region itself. Theory and application of these modes to problems of pattern synthesis and array optimization, including constraints, are presented. Examples are given for a line source, an array of printed dipoles, and a dipole array in free space.

33 citations


Patent
07 Mar 1984
TL;DR: An antenna arrangement for use in a bore hole to receive radar signals and produce electrical signals from which the incidence direction of the radar signals can be determined includes a cross coil arrangement with two coils having elongated sides mounted adjacent the outer surface of a cylindrical insulative probe body as mentioned in this paper.
Abstract: An antenna arrangement for use in a bore hole to receive radar signals and produce electrical signals from which the incidence direction of the radar signals can be determined includes a cross coil arrangement with two coils having elongated sides mounted adjacent the outer surface of a cylindrical insulative probe body. In one embodiment, one cross coil assembly is used in conjunction with an omnidirectional antenna and an evaluation circuit. In another embodiment two axially aligned cross coil assemblies are connected to also be usable as an omnidirectional antenna.

31 citations


Journal ArticleDOI
TL;DR: In this article, the uniform transmission line model is applied to determine the resonant frequency of a coaxial probe fed rectangular patch antenna tuned by a number of passive metallic posts suitably placed within the antenna's boundary.
Abstract: The uniform transmission-line model is applied to determine the resonant frequency of a coaxial probe fed rectangular patch antenna tuned by a number of passive metallic posts suitably placed within the antenna's boundary. An approximate expression is given for the resonant frequency as a function of the post location and number, and of the other characteristic parameters of the antenna. Theoretical results are compared with available measured values.

30 citations


Patent
01 Feb 1984
TL;DR: In this article, a cylindrical cavity-backed multipole antenna system for high frequency applications is described, which comprises a plurality N of planar radiation elements disposed on a dielectric disc mounted on the top surface of a conductive cylinrical cavity and equally spaced about its axis.
Abstract: A cylindrical cavity-backed multipole antenna system for high frequency applications is disclosed. The antenna system comprises a plurality N of planar radiation elements disposed on a dielectric disc mounted on the top surface of a conductive cylindrical cavity and equally spaced about its axis. A network circuit is adapted to introduce, for the system sum signal, progressive phase shifts of 360°/N to signals associated with adjacent elements and, for the difference signal, progressive phase shifts of 720°/N. The antenna system may be used to both transmit and receive electromagnetic radiation. The antenna sum and difference patterns are substantially symmetric in space about the antenna boresight.


Patent
13 Oct 1984
TL;DR: In this article, a loop antenna at a side where a high frequency pickup opposes to a chain circumferential ridge and connecting a capacitor in series with the antenna is used to provide the resonance characteristic and to attain the reception with high sensitivity.
Abstract: PURPOSE: To provide the resonance characteristic and to attain the reception with high sensitivity by providing a loop antenna at a side where a high frequency pickup opposes to a chain circumferential ridge and connecting a capacitor in series with the antenna. CONSTITUTION: An outer conductor of a coaxial cable 52 is grounded and a signal detected by the loop antenna 42 is sent to a receiver 54 by the cable 52. The receiver 54 has an impedance matching circuit 56, an amplifier circuit 58 and a selection output circuit section 60. The circuit 56 includes a band-pass filter 62 and a discharge tube 64, a detection voltage of a capacitor 44 obtained from the antenna 42 is fed to the input side of the filter 62 and an output of the filter 62 connects to a parallel circuit comprising an electrostatic breakdown protecting discharge tube 64 and a capacitor C 3 . The impedance matching for the antenna 42 is attained by the filter 62 and its output signal is amplifier by a high frequency amplifier circuit 58. The circuit 58 includes 2-stage connection transistors Q 1 , Q 2 and its output is fed to a selection output circuit 60, from which a sound output is obtained. COPYRIGHT: (C)1987,JPO&Japio

Journal ArticleDOI
TL;DR: In this article, a microstrip array with mutual coupled rectangular patch radiators is described, and experimental results are presented for both linearly and circularly polarised antennas which demonstrate the usefulness of this special antenna configuration.
Abstract: A microstrip array with mutual coupled rectangular patch radiators is described. By the avoidance of a corporate feeding network, advantages in the antenna performance and design are realisable. Experimental results are presented for both linearly and circularly polarised antennas which demonstrate the usefulness of this special antenna configuration.

Patent
26 Sep 1984
TL;DR: In this article, an antenna switchable between the VHF and UHF frequency bands is proposed. But the antenna is not suitable for the use in a helicopter. But it can be mounted on an airplane.
Abstract: This invention concerns an antenna switchable between the VHF and UHF frequency bands. This antenna incorporates a capacitive element, disposed at a specified distance from a reflecting surface mounted on the body of the vehicle. For VHF, tuning is obtained by a fixed self-inductance in parallel and a variable self-inductance in series with the capacitive element. The latter comprises various sections which can be short-circuited by switches. For UHF, the variable self-inductance is totally short-circuited and the fixed self-inductance is disconnected by a switch; then, plates form, with the reflecting surface and the capacitative element, a "manchette" antenna. This switchable antenna can in particular be mounted on an airplane.

Patent
02 Aug 1984
TL;DR: In this paper, a multi-arm spiral antenna for wideband transmission and reception of both right-hand and left-hand circularly polarized electromagnetic energy is described, where each antenna arm includes a series of cells wherein the impedance of the antenna arm monotonically decreases over a first portion of the cell length and increases over a second portion of cell length to provide the signal reflection necessary for mode conversion without introducing abrupt impedance transitions.
Abstract: Disclosed is a multiarm spiral antenna for wideband transmission and reception of both right-hand and left-hand circularly polarized electromagnetic energy. Each antenna arm includes a series of cells wherein the impedance of the antenna arm monotonically decreases over a first portion of the cell length and monotonically increases over a second portion of the cell length to thereby provide the signal reflection necessary for mode conversion (operation in both polarization senses) without introducing abrupt impedance transitions. Various cell geometry that can be employed is described.

Journal ArticleDOI
R. Clapp1
TL;DR: In this article, the R-2R concept was modified to allow a full circle of array elements to be mapped onto a full-circle of beam ports, resulting in 360 degrees of simultaneous antenna beams, which can be used both for transmission and reception.
Abstract: The R.2R lens is a remarkable microwave device that provides perfect focusing, giving multiple simultaneous antenna beams from a circular or cylindrical array. However, the perfect focusing of the R-2R brings with it a serious limitation on angular coverage as a result of the angular doubling that enters when the array elements in the antenna are connected to the launcher elements on the lens periphery. We have now found a way to modify the R-2R concept so that a full circle of array elements can be mapped onto a full circle of beam ports. The new mapping makes use of hybrid junctions and either four or six physical lenses. The interconnections result in 360\deg of simultaneous antenna beams, each of which can be used both for transmission and for reception.

Patent
10 Jan 1984
TL;DR: In this paper, a dipole ring array comprising eight elements surrounding the navigation array was used to produce good circular polarization in the far field, which is achieved with a high gain to the sides with minimum losses.
Abstract: A NAVSTAR satellite has a navigation antenna array beamed toward the earth. A communications antenna array for communicating with other satellites requires a pattern null near the axis and high gain to the sides with minimum losses. This is achieved with a dipole ring array comprising eight elements surrounding the navigation array. The ring has a diameter of 1.1 wavelength, and is fed with equal amplitudes and a third mode phase progression, which produces good circular polarization in the far field. For a different sized dipole ring, there will still be an optimum phase distribution which will give good circularly polarized patterns.

Patent
Takashi Oda1, Koji Yamasaki1
16 Mar 1984
TL;DR: An antenna having an antenna aperture area and an antenna reactance comprises a first antenna element defining a first aperture area, a first reactance and a second antenna element connected in parallel to the first antenna elements to put a miniature radio receiver into operation in a desired frequency band.
Abstract: An antenna having an antenna aperture area and an antenna reactance comprises a first antenna element (31) defining a first aperture area and a first reactance and a second antenna element (32) connected in parallel to the first antenna element to put a miniature radio receiver into operation in a desired frequency band. The second antenna element (32) has a second aperture area and a second reactance greater than the first aperture area and reactance, respectively, so thatthe antenna aperture area and reactance are substantially determined by the second aperture area and the first reactance, respectively. The first and the second aperture areas may be coplanar. Alternatively, the aperture areas may be orthogonal to each other. With this improved antenna a higher gain is accomplished, while the resultant inductance of the antenna is reduced. Moreover, the frequency band of the antenna is wider (Figure 4).

Journal ArticleDOI
TL;DR: In this article, the JET antenna was conceived as a "limiter antenna", completely recessed in a lateral frame which has the dual purpose of protecting the conductors and limiting the plasma radius, and the coupling of this antenna was calculated in slab geometry, using a variational formulation which finds the selfconsistent currents in the antenna elements.
Abstract: The JET antenna has been conceived as a 'limiter antenna', completely recessed in a lateral frame which has the dual purpose of protecting the conductors and limiting the plasma radius. The coupling of this antenna is calculated in slab geometry, using a variational formulation which finds the self-consistent currents in the antenna elements. Full account is taken of the modes excited inside the limiter frame and of their coupling to waves in the inhomogeneous plasma. This yields the antenna impedance as a function of frequency and the field structure inside the plasma, including power fluxes and dispersion, as a function of penetration.

Patent
27 Sep 1984
TL;DR: In this article, a dielectric trough waveguide antenna composed of a metallic guide having a metal substrate covering the bottom of the guide and a plurality of metal radiators placed periodically on the dielectrics at the interface was proposed for millimeter wave applications.
Abstract: A dielectric trough waveguide antenna composed of a metallic guide having a dielectric substrate covering the bottom of the guide and a plurality metal radiators placed periodically on the dielectric at the dielectric-air interface provides a low loss antenna suitable for millimeter wave applications.

Patent
04 Jul 1984
TL;DR: In this paper, the radiation pattern of the antenna to be tested is expressed by an integral transform of a unidimensional function which is solved by computing means, and the antenna is illuminated by a transmit antenna having wavefronts in the shape of circular cylinders.
Abstract: Method and equipment are disclosed for picking up the radiation pattern of an antenna to be tested from measurements in near-field. The antenna to be tested is illuminated by a transmit antenna having wavefronts in the shape of circular cylinders. The radiation pattern of the antenna to be tested then is expressed by an integral transform of a unidimensional function which is solved by computing means.

Patent
Robert E. Myer1
25 Jun 1984
TL;DR: In this article, the authors proposed a method to make one telescopic section into a center-fed, high frequency antenna and using its coaxial cable feed line for coupling mechanical extension and retraction forces to that section.
Abstract: A plural band telescopic antenna, including an added band much higher than the frequencies of the AM/FM band, is realized by making one telescopic section into a center-fed, high frequency antenna and using its coaxial cable feed line for also coupling mechanical extension and retraction forces to that section.

Patent
31 Jul 1984
TL;DR: An antenna device for a direction finder includes a substantially grounded conductive base plate, a plurality of web-shaped antenna elements mounted in spaced relation on the base plate and having central portions extending in crisscross relation and insulated from each other.
Abstract: An antenna device for a direction finder includes a substantially grounded conductive base plate, a plurality of web-shaped antenna elements mounted in spaced relation on the base plate and having central portions extending in crisscross relation and insulated from each other, an electronic switching circuit for alternately grounding ends of the antenna elements and picking up reception outputs from opposite ends of the antenna elements at a constant period with the antenna elements being switched out of phase at an angle corresponding to the angle at which the antenna elements extend across each other, and a circuit for combining outputs from the antenna elements. According to another embodiment, the antenna elements comprise the web-shaped antenna elements and a vertical antenna element disposed substantially centrally in the web-shaped antenna elements.

Patent
21 Aug 1984
TL;DR: In this article, a circularly polarized microwave radio antenna which is constructed so that its phase center can be very easily and very accurately positioned with respect to a marker point over which the antenna is placed is disclosed.
Abstract: A circularly polarized microwave radio antenna which is constructed so that its phase center can be very easily and very accurately positioned with respect to a marker point over which the antenna is placed is disclosed. The antenna includes a ground plane, antenna elements in a common plane parallel thereto and supported by a perpendicular center post, separate feed lines for each element and a combining network all positioned symmetrically about an axial bore in the center post so that the phase center of the antenna is on the axis of the center post at the intersection with the upper surface of the ground plane. A graduated rod may be positioned in the bore to align the antenna with the marker point. The antenna is especially useful in microwave radio interferometry systems for measuring relative position vectors between survey marks on the ground using radio frequency signals transmitted from earth orbiting satellites but may be used in any application where accurate positioning of an antenna's phase center relative to a reference point is desired or required. The antenna can be easily reproduced with substantially identical electrical and mechanical characteristics.

Journal ArticleDOI
TL;DR: A flush-mounting antenna is described which could be used, in lieu of present antennas, to provide direction finding and steerable directional pattern capability in airborne beacon transponder systems.
Abstract: A flush-mounting antenna is described which could be used, in lieu of present antennas, to provide direction finding and steerable directional pattern capability in airborne beacon transponder systems. The antenna is comparable in size to the existing, omni-directional antennas presently used for air-traffic control and military identification, friend or foe (IFF) functions. The design and performance of an experimental model of the antenna are discussed.


Patent
02 Oct 1984
TL;DR: In this paper, a phase-shift control for a phased array antenna is described, where the antenna modules are arranged in rows and columns and a central computing means for calculating from the beam direction to be determined and the frequency of the energy emitted.
Abstract: In a phase-shift control for a phased array antenna the antenna modules are arranged in rows and columns. The phase shift control is provided with central computing means for calculating from the beam direction to be determined and the frequency of the energy emitted, the terms in the mathematical expression for the phase setting for the separate phase shifters in the antenna modules, which terms are the same for all phase shifters, and a computing chip present in each antenna module for deter­ mining the desired phase setting from the terms determined by the central computing means and the position of the separate phase shifters in the array.

Patent
01 May 1984
TL;DR: The field component diversity antenna and receiver arrangement as discussed by the authors comprises at least a first pair of parallel spaced, straight, vertical elemental antenna elements disposed substantially parallel to the electric field component of a transmitted signal to receive the transmitted signal in a multipath fading environment.
Abstract: The field component diversity antenna and receiver arrangement comprises at least a first pair of parallel spaced, straight, vertical elemental antenna elements disposed substantially parallel to the electric field component of a transmitted signal to receive the transmitted signal in a multipath fading environment where the electric field and magnetic field components are uncorrelated and a 180° hybrid circuit coupled to the first pair of spaced antenna elements to provide a first output signal proportional to the electric field components and a second output signal proportional to the magnetic field component. The spaced elemental antenna elements may be monopole elements or dipole elements. The pair of antenna element may be connected together by a straight conductor to enhance the magnetic field component. The first and second output signals may be combined by known diversity combining arrangement to achieve a diversity advantage.

Patent
02 Mar 1984
TL;DR: In this article, the authors describe an antenna which may be collapsed and stored in a compact configuration and readily released from storage to assume a deployed operative state, where the antenna is a wire member comprised of a straight section and an integral transverse helical spring section.
Abstract: The present disclosure describes an antenna which may be collapsed and stored in a compact configuration and readily released from storage to assume a deployed operative state. More specifically, the antenna is a wire member comprised of a straight section and an integral transverse helical spring section. The antenna lends itself to storage about the axis of a right circular cylinder while permitting full deployment parallel to the longitudinal axis of the latter. This arrangement permits the storage of potential energies of torsion and bending respectively in the helical spring and straight portions of the antenna, and permits continuous motion in these planes to effect antenna erection and deployment.