Showing papers on "Feed line published in 1989"

Planar array antenna, comprising coplanar waveguide printed feed lines cooperating with apertures in a ground plane

Abstract: A planar antenna of the kind comprising feed lines disposed in a flat circuit and cooperating by hyperfrequency coupling with a metal ground plane plate pierced by apertures has the feed lines presenting a termination juxtaposed with each aperture. A lower ground plane plate is disposed at a distance of approximately a quarter wavelength from the apertured metal plate. The apertured metal plate comprises a metal coating deposited on a dielectric substrate. The feed line comprise central conductors disposed in channels which open into the apertures. The array of apertures, channels and conductors can be produced on the dielectric substate by single face printed circuit techniques. The antenna may be used for the reception of direct broadcasts from satellites.

Rigorous analysis of a circular patch antenna excited by a microstrip transmission line

Abstract: Boundary conditions are enforced on a portion of the microstrip feed line as well as the patch antenna. The integral equation for the unknown currents on the antenna and feed is solved by applying the Galerkin method of moments in the Fourier transform domain. The validity of the solution is tested by comparison of computed results with experimental data. The theoretical treatment proves to be applicable to the most common feeding arrangements, namely, the direct edge-feed and proximity coupling excitation. In the latter case, two-layer substrates having distinct dielectric constants are studied. The purpose of the study is to deduce, for a given overall substrate thickness, the smallest line-ground plane separation for which a match of the radiator to the feed line is still possible. The advantages of such a configuration are discussed. >

Communication system for transmitting data between a transmitting antenna utilizing strip-line transmission line and a receive antenna in relative movement to one another

Abstract: A communication system for transmitting data between a transmitting platform and a receiving platform moving relative to each other. A circular strip-line transmission line forms the transmitting antenna located on the transmitting platform and a short segment of strip-line, similar in width to the circular strip-line, forms the receive antenna located on the receiving platform. The strip-line transmission line has at least two feedpoints for inputting data and at least two termination points that are terminated with a resistor to ground. The receive antenna is mounted close to the transmitting antenna.

Frequency independent circular array

Abstract: A circular array includes a plurality of antenna elements which are spaced apart from each other and situated in a conical arrangement and in parallel rows circumferentially about the longitudinal axis of the conical arrangement. The circumferential spacing between the phase centers of adjacent antenna elements of any one row situated closer to the base of the conical arrangement is greater than that of adjacent antenna elements situated relatively closer to the apex of the conical arrangement. The respective operating frequencies of the antenna elements of any one row situated closer to the base of the conical arrangment is lower than the operating frequencies of the antenna elements of any other row situated relatively closer to the apex. The circuit array antenna further includes a plurality of feed lines, where each feed line is coupled to an antenna element of each row in progression. The circumferential spacing between the phase centers of adjacent antenna elements of the conical arrangement is maintained at a fixed value of the wavelength of the operating frequencies of the antenna elements.

Microstrip array antenna

Abstract: A planar microstrip array antenna with a beam tilt, which comprises a plurality of pairs of circularly polarized wave radiating elements, the orientation angles of the two radiating elements in each pair being different by a predetermined angle within the plane of the planar antenna The antenna further comprises a feed line for supplying electric power to the radiating elements The feed line is provided with a plurality of pairs of terminal feeding portions which diverge corresponding individually to the pairs of circularly polarized wave radiating elements The paired feeding portions are equal in electrical length Since the respective orientation angles of the paired radiating elements are different, a phase difference is produced between the radiating elements, thus providing a beam tilt Since no phase shift portion for producing a phase difference is formed between the paired terminal feeding portions, the configuration of the feed line is simple

Analysis and design of series-fed arrays of printed-dipoles proximity-coupled to a perpendicular microstripline

Abstract: An analysis of a printed dipole element and a generalized configuration of a series-fed array of such elements, electromagnetically coupled to a covered microstripline running perpendicularly under it in a substrate-superstrate configuration, is presented. The solution is based on the principle of reciprocity and is formulated using a rigorous method of moments and full-wave spectral-domain Green's functions for multilayer dielectric substrates. The dipole excitation is characterized by an equivalent impedance, and can be controlled by suitably selecting the offset of the dipole from the feed line. Mutual coupling between dipoles is included. Using the results of the element analysis, a series-fed array prototype has been successfully designed, built, and tested in a standing-wave configuration; the design details are described, and measured performances are evaluated using the results of the array analysis. Mutual coupling effects are found to be not detrimental for this configuration, but can be severe for other nonstanding-wave configurations. >

Loop antenna with transmission line feed

Abstract: A loop antenna includes a circuit board having a ground plane layer. A formed loop is located on one side of the circuit board and a transmission line is located on the opposite side of the circuit board. Capacitors interconnect the ends of the formed loop and the transmission line. The transmission line is a microstrip formed by the ground plane layer in a microstrip portion. The circuit board includes RF circuitry that is located on the side of the circuit board opposite to the transmission line so that the ground plane shields the circuitry from the transmission line.

Distributed planar array beam steering control with aircraft roll compensation

Abstract: A distributed parallel processing architecture (10) for electronically steerable multi-element RF array antennas provides real time rapid array updates with decreased hardware cost and complexity. The array is subdivided into plural sub-arrays (34) (each sub-array has more than one RF radiating element) and a phase shift interface electronics ("PIE") device (30) is provided for each sub-array. Parameters specific to the RF elements within the sub-arrays (34) are preloaded into the corresponding PIE (30). Pointing angle and rotational orientation parameters are broadcasted to the PIEs (30), which then calculate, in parallel and in a distributed processing manner, the phase shifts associated with the various elements in their corresponding sub-arrays. Linearization, phase compensation for various factors (e.g., operating frequency, measured characteristics of individual RF elements, feed line delay to individual elements, etc.), and the initial phase shift calculations themselves are thus performed on essentially an element-by-element basis without requiring individual calculation hardware for each element. Array spoiling in response to real time array rotational orientation is provided. Update rates of greater than 10KHz are attainable.

Double skirt omnidirectional dipole antenna

Abstract: An omindirectional antenna includes one or more dipole radiators. Each dipole radiator comprises a first and second cylindrical radiating element. Each radiating element includes an end plate for mounting the radiating element coaxially on a tubular mast. The cylindrical radiating elements, end plates and tubular mast are all DC connected. A feed line is provided which may extend through the center of the mast and exit at an opening for connection to a secondary feed line. The secondary feed line is connected to an end of one of the cylindrical radiating elements of each pair of elements for each dipole radiator. The feed line is connected to the end of the cylindrical radiating element opposite the end plate. The configuration of the dipole radiators is such that the radiator functions an an RF choke for the adjacent radiators. An additional single cylindrical element can be provided at the end of a plurality of dipole radiators to provide RF choking for the immediately adjacent dipole radiator. A plurality of main feed lines may be included to extend through the center of the mast with corresponding openings for connection to secondary feed lines.

Highly directive radio receiver employing relatively small antennas

Abstract: A radio receiver having a narrow effective beamwidth includes a receiver antenna, a receiver and a receiver transmission line interconnecting the two, and an interference cancellation system having an auxiliary antenna, a first directional coupler connected to the auxiliary antenna, a second directional coupler connected to the receiver transmission line, a synchronous detector connected to the first and second directional couplers, a signal controller and a subtractor connected to the signal controller and to the receiver transmission line. The receiver antenna is selected to exhibit an omni-directional antenna pattern, while the auxiliary antenna is selected to exhibit a null in its antenna pattern. The null is directed toward the desired signal such that any signals outside of a predetermined angle from the center of the null will be cancelled by the interference cancellation system, and the desired signal which is received within a predetermined angle from the center of the null will be substantially unaffected by the interference cancellation system.

Balanced antenna feed system

Abstract: A means for feeding or extracting radio frequency energy from an antenna element which uses coaxial transmission line, without upsetting the antenna elements physical or electrical symmetry, thus providing improved standing wave ratios and near theoretical radiation patterns. Because coaxial cable is inherently unbalanced, double reactance cancellation and resistance transformation are integrally provided by a feed loop shunted across the antenna element improving performance.

Microstrip structure having contact pad compensation

Abstract: A microstrip structure includes a microstrip transmission line having a characteristic impedance, a contact pad for interconnection of the transmission line to an external device, and a compensation line connected between the contact pad and one end of the microstrip transmission line. The contact pad has larger dimensions than the transmission line and thus introduces parasitic capacitance. The compensation line is a narrow line having high impedance and is selected such that its equivalent inductance resonates with the parasitic capacitance at the upper frequency of the range of frequencies over which the transmission line is intended to be operated, thereby matching the contact pad to the transmission line.

Frequency agile transmitter antenna combiner

Abstract: A frequency agile transmitter antenna combiner is disclosed that allows combining multiple transmitter outputs onto a single antenna feed where the transmitters are operated at multiple frequencies. According to the invention, a method is disclosed and an apparatus is described for receiving a plurality of RF signal inputs where each input may contain any of a predetermined set of frequencies. The input frequency is then coupled to a frequency splitter that couples the input frequency to a dedicated combiner that tends to isolate the RF inputs from each other. The signal is then coupled to a combiner output, and ultimately to a single antenna feed line.

Multilayer and parasitic configurations

Abstract: Microstrip antennas composed of multiple conducting patches or feed lines electromagnetically coupled to the resonant, radiating patch offer several ad vantages over the traditional single patch connected to a feed line or feed probe. These advantages include increased bandwidth or multiple frequency operation, dual polarisation, and control of input impedance. However, the antennas are often more complicated to fabricate or they may require more surface area, so that the designer may be required to sacrifice one desirable feature in order to obtain another one. Most of the structures in this chapter have been modelled by using either the cavity model or moment methods, and the segmentation method has also been applied to some of the configurations. In general, the analysis techniques provide a good qualitative model for the antennas, thus providing the designer with the insights needed to develop a functional antenna. Many of the existing analyses also have shown good quantitative agreement for the cases appearing in the literature, but the ranges of validity are not generally known, and the computed results may not be sufficiently accurate for many practical values of substrate permittivity and thickness or for variations in patch geometry. Nonetheless, multiple-layer microstrip antennas and antennas utilising parasitic coupling to the feed or to other resonant patches offer distinct advantages for many systems applications, and are likely to be used in antenna systems that require the specialised features available from these antennas.

Microwave plane antenna with two arrays which have beams aligned in the same direction

Abstract: A microwave plane antenna including rows comprising pairs of parallel conductive line antenna elements configured as a pair of out-of-phase square waves and a signal feed circuit of strip lines arranged as a corporate feed network. The respective conducting paths which run from a main feed inlet end of the circuit to each signal receiving end of the respective elements being varied in length, so that the main beam direction can be set in a plane including that of the antenna and normal to lengthwise axis of the antenna elements for a remarkable increase in the reception gain.

Experimental investigation of slot type dual spiral antenna fed by a microstrip line

Abstract: The fundamental radiation characteristics of the slot-type dual spiral in the presence of a plane reflector are described The testing frequencies used are in the 12-GHz range It is demonstrated that a single slot-type dual spiral antenna can be fed by a microstrip transmission line, whose tail section is used for impedance matching of the antenna and the transmission line An array consisting of eight slot-type dual spirals can also be fed by a microstrip transmission line, in the presence of a plane conducting reflector The unidirectional radiation pattern, axial ratio, and return loss are discussed on the basis of experimental data >

Broadband transmission line coupled antenna

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.

Antenna for mounting on a non-conductive surface, such as a window of a vehicle

Abstract: A communications antenna for mounting on a non-conductive surface, such as a window (20), of a vehicle, in which signals are passed between a transmission line (10) and the radiator element (21) of the antenna via a capacitive element (C3) comprising two conductive coupling elements (16, 17) disposed on opposite surfaces (18, 19) of the window (20). The transmission line (10) is coupled to the conductive coupling member (16) on the interior surface of the window (20) by a tuned circuit (L1 C1) and a further capacitative element (C2) which match the impedance of the transmission line (10) and maximises the transmission of signals between the antenna and the transmission line.

Omnidirectional antenna, particularly for the transmission of radio or television signals in the decimetric-wave range, and radiation system formed by an arrangement of these antennas

Abstract: This antenna, in particular intended for the transmission of radio or television signals in the decimetric-wave range, comprises: - a vertical, central support tube (100), - a plurality of identical radiating arrays (200), preferably three in number, uniformly distributed around the central tube and each formed from a vertical bifilar line (210, 210') supporting, coupling and supplying in a symmetrical manner, a plurality of horizontal dipoles (220, 220') uniformly distributed along this bifilar line, and - an equipower, equiphase power distribution system, preferably housed entirely inside the central support tube, identically and simultaneously supplying the three radiating arrays from a single coaxial supply line. The antenna lacks a reflector, this significantly reducing its weight and its wind resistance relative to conventional panel antennas generally used in this range. Advantageously, these antennas are superimposed and enclosed in a sealed, essentially cylindrical, self-supporting and superimposable radome. This antenna achieves an omnidirectional pattern at 0.9 dB between 460 and 860 MHz, and can radiate 5 to 7 kW per antenna element.

Microwave adjustment device for a transition between a hollow waveguide and a plane transmission line

Abstract: A microwave adjustment device for a transition between a hollow waveguide (11) and a plane transmission line (10), the device comprising: an intermediate coaxial waveguide (12) comprising a core (20) whose first end opens out into the hollow waveguide and terminates in an antenna (23) and whose second end passes through the substrate on which the plane transmission line is deposited; a curved metal tape (26) having a first end fixed to the second end of the core (20); and a screw (27) fixed to the second end of a tape (26) in order to adjust the gap between the second end and the transmission line (18). The invention is applicable to microwave beam telecommunications.

Hot-line working device

Abstract: PURPOSE: To easily and efficiently perform hot-line work by installing a drive/ control power source device for a manipulator on a car body at a lower part, and installing a power feed line to be capable of following expansion of an elevation device. CONSTITUTION: A power source device 23 for driving and controlling of manipulators 6, 7 is installed on a car body 1, and a power feed line 26 is freely supplied/rewinded by a winding device 27 to be capable of following expansion/contraction of an elevation device 3, so power feed from a lower part to an upper part is enabled. In addition, the power source device 23 for control and the power feed line 26 are set to float from grounding bodies such as the car body and the elevation device 3 by insulation such as an insulator 24. Efficient work can thus be executed using the high-output electric motor- driven manipulators 6, 7 of excellent actuation responsiveness and controllability. Since insulation of the electric manipulators 6, 7 used in hot-line work to the ground is complete, ground fault accidents will not occur even when a metal exposed part of the manipulator 6, 7 gets in contact with a hot line, thereby safety work can be performed.

Broadband 3 DB 90 deg. coupler for microwaves - comprises four quarter-wave line lengths making ring connected via half-wave lines to ports

Abstract: The coupler is a doubly symmetric tour-port supplying a signal line at a first port and having second and third ports having a 90deg. phase difference. The fourth port is decoupled and carries no output power. The four-port consists of quarter lambda -long lengths of line (5-8) forming a ring with alternate wave impedances (71 and 72) connected to the four connection points via. a half lambda - long piece of line with a wave impedance differing from the feed line or several cascaded half lambda - long line pieces (9-16) with wave impedances of which at least one differs from the wave impedance of the feed line to which the ports (1-4) are connected. The individual line lengths or all of them can be replaced by lumped elements. ADVANTAGE - Marked ports. High decoupling. Realised as microstrip.

Slot type stacked spiral antenna

Abstract: PURPOSE: To realize an antenna in a low attitude and to reduce the loss of a feed line by exciting a pair of spiral slot parts by a triplate line. CONSTITUTION: When spiral slot parts 5a and 5b are excited with a coupling slot part 5c between them by a feed line 3 of a triplate line 3, circularly polarized waves are radiated from spiral slot parts 5a and 5b by magnetic currents flowing to respective slots. Since spiral slot parts 5a and 5b are wound in the same direction, electric field vectors in circularly polarized waves are rotated in the same direction, and the synthesized radiation field polarized wave is a circularly polarized wave. Thus, a directivity symmetrical with respect to the center axis of radiation is obtained, and the antenna in a low attitude is realized, and the loss of the feed line is reduced. COPYRIGHT: (C)1991,JPO&Japio

A transmission line model of cable to antenna coupling inside a screened room

Abstract: A coupled-transmission-line model that evaluates the coupling of emissions from a cable to an antenna when both are located within a screened room is presented. The cable is positioned over a conducting bench in the room. The model developed is valid over the frequency range 10 kHz to 30 MHz. Its parameters can be found quickly and can be easily adjusted to account for changes in height, length, location across the bench, and radius of the cable. A method for evaluating the coupling parameters of the model is given. It involves the use of conformal transformations and image techniques. >

Power stabilizer and isolation/coupler network

Abstract: The invention is directed to a directional coupler for coupling together a radar frequency transmitter to a combined transmitting and receiving antenna, a power absorber and a receiver. A tunable stub is employed to reflect a selected amount of transmitted energy to the local oscillator (LO) of the receiver for mixing with the incoming received signal. The coupler can be constructed from any known type RF transmission line suitable for passing or coupling signals of radar frequencies. A significant amount of the transmitter power is absorbed in a power absorbing RF load allowing only a small amount to be transmitted from the antenna and a still smaller amount fed back as LO to the receiver. The invention works equally as well on a disk type antenna and a phased array antenna.

Dielectric loaded array antenna

Abstract: PURPOSE:To reduce the array density of unit antennas constituting an array antenna and to reduce power loss in the unit antennas and in constitution for executing feed to respective unit antennas by increasing the aperture efficiency of respective unit antennas. CONSTITUTION:The array antenna 1 is arranged on a wiring substrate 2 consisting of an electric insulating material. With providing dielectrics 5 on patches 4, the aperture efficiency and the gain are made to increase in the antenna 1. Thus, the arrangement density of the patches 4 on the wiring substrate 2 can be reduced, and the loss of consumption power in a feed line with respect to the patches 4 can be reduced, whereby whole efficiency can be improved.

The TFTR ICRF antenna‐power feed and phase control of two mutually coupled antenna elements

Abstract: A transmission line model for the TFTR ICRF antenna is presented. The antenna is considered as being composed of mutually coupled transmission lines. Expressions for the input impedance of such a structure are given. Details of the considerations in setting up the antenna feed structure are presented. The requirement of dual feed drive coupled with the desire for phase and amplitude control place restrictions on the operating circuit.

Influence of microwave scattering by power transmission lines on digital radio communications

Abstract: A method for evaluating power transmission line interference with microwave radio communication circuits due to microwave scattering is presented and used to predict digital radio transmission performance degradation. Numerical results show that the effects of power line screening on highly efficient digital radio systems are more serious than on analog (FM) radio systems since power lines cause quadrature distortion and intersymbol interference as well as average level reduction. An experimental result using a communication satellite beacon shows that conductors within the first Fresnel zone cause the interference. >

Power supply system for dc electric car

Abstract: PURPOSE:To aim at simplifying the arrangement of a power feed system by using, as a DC breaker, a semiconductor switch in a DC-DC semiconductor converter for dropping a high voltage of a main power feed line to an electric car voltage which is then fed to an auxiliary power feed line. CONSTITUTION:A voltage from power stations 1, 2 to a main power feed line 7 is increased much greater than an electric car voltage of an electric car power feed line 4, and DC-DC semiconductor converters 81 through 84 which are changeable both forward and reverse directions are connected between the main power feed line and an auxiliary power feed line 3 for supplying power to the electric car power feed line 4 so that the power feed voltage is dropped to the electric car voltage for supply power. Further, the semiconductor sections of the DC-DC semiconductor converters 81 through 84 are used as DC breakers so that emergency current is inputted through a terminal N so as to energize semiconductor switches to cut off the connection to the main power feed line 7 when an electric car 61, 62, 63 enters into a regenerative braking operation upon a grounding accident. Thus, it is possible to aim at reducing the cost of the overall arrangement, and to increase the intervals of power stations so as to decrease the number of the power stations.