Showing papers on "Feed line published in 1981"

Multi-band single-feed microstrip antenna system

Abstract: A multi-band microstrip antenna comprising a plurality of separate radiat elements which operate at widely separated frequencies from a single common input point. The common input point is fed at all the desired frequencies from a single transmission feed line. A variety of combinations of microstrip elements can be used. The individual radiating elements are each made to look substantially like an open circuit to all other frequencies but the respective frequency at which they are to operate by respective feed point location and dimensioning of the transmission lines from the common input point to the feed points of the separate elements.

Wideband quasi-log-periodic microstrip antenna

Abstract: The paper describes a new design method for a wideband array of log-periodically scaled microstrip resonator antennas. The radiating elements are series-fed by a simple coplanar microstrip network. This network consists of an open-circuited feed line with a branch line connected to each radiating element. Both a network and a radiating model for the complete structure are explained. These models predict with good accuracy the input impedance and the radiation pattern as a function of frequency. The results for a 5-element S-band antenna are presented as an illustrative example. This antenna combines a good impedance match (VSWR ? 2.6) with a reasonable power gain in broadside direction (> 5.5 dB) over a 22% bandwidth. This means a tenfold increase in the bandwidth in comparison with a single microstrip resonator antenna.

Coupled multilayer microstrip antenna

Abstract: A coupled multilayer microstrip antenna having an upper and a lower microip element tuned to the same frequency, and separated from each other by a dielectric substrate. The pair of elements is located over a suitable ground plane and separated from the ground plane by a second dielectric substrate. The upper element is the driven element which is directly coupled to the feed line while the lower element is parasitically coupled to upper element. The lower element cancels the image field as seen by the upper element providing enhanced radiation at angles closer to the ground plane.

Transmission-Line Transformers

Abstract: The radio-frequency transformers described in this paper consist of matched transmission lines of equal length and characteristic impedance. The lines are connected according to rules given in the text. These transformers exhibit a very broad frequency response which can be readily estimated; two methods of analysis are presented. The computations agree well with the test results.

Patch antenna having tuning means for improved performance

Abstract: A patch antenna employing a matching stub for improved performance. The patch antenna comprises a conductive patch disposed closely over a ground plane, having a shorting pin shorting the conductive patch to the ground plane at a central point and a coaxial feed line attached to the conductive patch at a point between the shorting pin and the edge of the patch for conducting electromagnetic energy to or from the conductive patch. The matching stub comprises a conductive member extending at least partially between the ground plane and the conductive patch at a point located on the opposite side of the shorting pin from the feed line. Performance is further improved by leaving only a small portion of the inner conductor of the coaxial feed line uncovered by the outer conductor.

Analysis of Miniature Electric Field Probes with Resistive Transmission Lines

Abstract: The miniature dipole probe is a useful tool for measuring the electric field at high radio and microwave frequencies. A common design for the probe consists of an electrically short dipole antenna with a diode across its terminals; a resistive, parallel-wire transmission line transmits the detected signal from the diode to the monitoring instrumentation. The high resistance per unit length of the transmission line reduces the direct reception of the incident field by the line and also reduces the scattering of the incident field by the line. In addition, the resistive transmission line serves as a low-pass filter in the detection process. In this paper, the effect of the resistive transmission line on the operation of the miniature field probe is analyzed. Specifically, the reception of the incident signal by the transmission line is compared with that of the dipole. The scattering of the incident signal by the transmission line is studied by means of the scattering cross section, and the limitation imposed on the measurement of amplitude-modulated signals by the low-pass filtering by the resistive line is examined. The results of the theoretical analyses are presented as simple formulas which are useful in the design and optimization of the probe. The theoretical results are shown to be in good agreement with measurements.

Broadband RF isolator

Abstract: A broadband RF isolator system for connection between RF devices such as inear antennas is disclosed. In accordance with this invention, two or more antennas are spaced several wavelengths apart, connected to coaxial feeds and choked at their adjacent ends to establish the electrical length. In one embodiment of the invention, the isolator is formed by placing a second line adjacent the coaxial line connected to the upper antenna. The addition of this second line forms a balanced transmission line having a given characteristic impedance. The second line is terminated at one end by a resistor having a resistance equal to the value of the characteristic impedance. In a second embodiment the second line is replaced by a coaxial sleeve which is also terminated at one end with a resistor having a resistance value equal to the characteristic impedance. In four additional embodiments, which are essentially variations of the second basic embodiment, coaxial sleeves are also utilized to form the isolation system.

Circularly Polarized Linear Array Antenna Using a Dielectric Image Line

Abstract: A new circularly polarized antenna using a dielectric image line is proposed. This antenna is composed of a slotted conductive plane and a rectangular dielectric rod. This paper describes the design of and experimental results achieved with the circularly polarized array antenna fed by a dielectric image line. The fundemental characteristics of the image line are also presented. Since this line's losses are far lower than the microstrip line losses in the millimeter wavebands, antenna feed line losses expect to be also very low. Bandwidth within the 2-dB axial ratio was more than 7 percent, and the angle range within the same ratio was more than +-7.8 degrees at 29.5 GHz. This antenna is far superior to the microstrip line feed array antenna in the millimeter wavebands.

Arrangement for cooling a super conducting field winding and a damper shield of the rotor of an electric machine

Abstract: A cooling arrangement for a superconducting field winding of an electric machine, especially a turbo-generator, has a coolant space which contains a cryogenic coolant fed into it via a feed line, for cooling the field winding, and a coolant supply chamber which contains liquid coolant for cooling a damper shield. So that no separate feed and discharge lines are required for cooling the damper shield independently of the cooling of the field winding, the coolant supply chamber is connected directly to the coolant feed line via a radial connecting line, and the flow cross sections of the connecting line and of the section of the coolant feed line between the connecting head and the connecting point of the connecting line are made large.

Remote load current sensor

Abstract: Antenna arrays with more than one radiating element often require a calibration or adaptive technique to monitor the individual antenna currents and provide some form of correction. This invention is directed to a system of directional couplers and transmission lines usually placed between the transmitter and element matching network that develops a signal which is proportional to the actual antenna element radiating current. This includes mismatches and mutual impedance effects. A knowledge of the matching network is required. The system can be used in any guided transmission line system (i.e., waveguide, coax, stripline, microstrip, etc.)

Device for successively applying various coating fluids

Abstract: According to the invention, in a device for electrostatically atomising surface coating agents and the like with an atomiser bell which rotates at a high speed of revolution and whose inner surface is fed with surface coating agent, the supply of surface coating agent takes place by means of a double pipe which projects centrally into the bell and forms a feed line and a return line and whose outlet opening can be closed off.

Diesel engine fuel filter - has feed and injection pump connections and return flow connection, with non-return valve opening towards tank

Abstract: The fuel filter (1) is intended for a compression ignition engine and has connections (2-4) for a feed line (6) with feed pump (7) from the fuel tank (5), a feed line (9) to the injection pump (8), and for a return line (10) to the tank. The return line connection (2) contains a non-return valve which allows flow in the direction of the tank only. This valve may consist of a spring-loaded ball. The connection may contain the valve in a central bore leading to the filter and have radial bores leading to the return line, an overflow line (18) from the injection pump, and a leak line (17a) from the injectors respectively.

Constant current electronic intruder detection system

Abstract: An electronic detection system for detecting intruders employs a transmisn line as a sensing element. In one embodiment the transmission line is a modified surface-wave transmission line, for example, a Goubau line which is positioned about the perimeter of the area to be protected. An intruder in the field of the line causes an RF reflection back toward the source, which reflection may be detected by Doppler range-gating techniques. In other embodiments of the invention, the transmission line is an insulated, twisted wire pair or a deformable transmission line. In some instances, the transmission line may be replaced with an active or passive pressure line.

Wide band directional coupler

Abstract: A directional coupler for sampling energy traversing a CATV system of the type wherein wide band television signals are extracted from a coaxial transmission line situated at points located at varying distances from the line amplifier The coupler (10) includes a voltage sensing transformer (25) in shunt with the center (14) and outer (15) conductors of the cable (13) and a current sensing transformer (26) in series with the center conductor (14) The transformers are wound to provide the coupler with a relatively low tap value Windings in the shunt transformer (25) are used to internally boost the impedance at the input to the series transformer (26) to maximize return losses and directivity

Tunnel-concreting device with pivotable and disengageable end piece

Abstract: For a device for lining the clearance space behind a casing provided with filling openings in tunnel or gallery construction, the filling medium, in particular concrete, being forced through the filling opening by means of a pump via a pipe line, and an end piece which can pivot parallel to the casing axis being attached to the end of the pipe line, the end piece is realized by a concrete feed line provided with an articulated pipe joint and pivotably coupled to the pipe line. This concrete feed line is rigidly connected at the end to a telescoping supporting arm rotatable parallel to the casing axis. A tight and low-wear concrete line from the pipe line to the nozzle is realized with this configuration.

Bird-proof feed-horn windows for microwave radio system antennas

Abstract: Window units constructed from multiple dielectric plates offer means for combating bird damage to antenna feed horns on microwave radio systems. The need for such devices on Australian systems is increasing as routes are extended into the drier regions of the country. Measurements show that the antenna electrical characteristics are not appreciably altered by the new window units.

Ventriloqual jamming using a towed transmission line

Abstract: A radar jamming signal generated by equipment carried by a target aircraft, is launched onto the leading end of a towed single wire transmission line so as to travel the length of the line as a nonradiating surface wave. A drogue radiator is attached to the trailing end of the line for radiating the jamming signal transversely of the towed line so as to be received by and cause jamming of tracking and/or fire control radar. The length of the single wire transmission line is selected so that the trailing radiator causes the jamming signal to emanate from a position sufficiently behind the aircraft so as to be outside the destructive radius of weapon fire directed at the apparent source of the jamming signal by fire control radar. A ventriloqual-like deception of the radar is thus achieved. A wave launcher couples the jamming signal to the leading end of the transmission line and for this purpose includes an electrically conducted horn-shaped structure, a tunable coaxial feed end at the constricted end of the horn structure, an inner transition conductor connecting the inner conductor of the coaxial feed to a leading end of the single wire transmission line, and a plurality of annular dielectric lenses and dielectric guides cooperatively shaped and fitted to the horn structure in a manner that effectively matches the bounded electromagnetic transmission wave characteristics of the coaxial feed cable with the surface wave transmission characteristics of the single wire transmission line.

Improvements in or relating to line interface circuits

Abstract: A line interface circuit for a telephone exchange comprises a transmission bridge 10, and loop detector 14 and ring current generator 20 and -V. The ring current generator is arranged to produce a ringing voltage which is offset relative to the voltage of the line current feed for the associated telephone line.

Fountain construction with lighting means

Abstract: A fountain construction dispenses water in a pond or the like for aesthetic purposes. A feed line is located beneath the water surface, and a vertically extending feed pipe delivers water from the feed line to a dispensing nozzle at the upper end of the feed pipe. A pump having a connection with the feed line delivers the water under pressure. The feed line and associated feed pipe are shaped so that a lamp supporting bracket can be located at the juncture thereof. A lamp supported on the bracket emits a light beam axially relative to the feed pipe and nozzle whereby a particularly pleasing aesthetic effect is realized with minimum detraction from the beauty of the pond or the like resulting from the presence of the hardware in the pond.

Characteristic Impedances of Four-Conductor Transmission Line

Abstract: A general formula for calculation of the characteristic impedance of four conductor transmission line in a rectangular shield is derived. A number of coupled and single strip transmission lines are considered by simplifying the general formula. Numerical results for a line in a square shield are presented graphically.

Short circuit protection circuit for telephone exchange - has peak current sensitive cut-out transistor permitting A.C. path for call signal

Abstract: Feed lines (AC3 and AC3') connect a subscriber station (TSt-2) with the current and call signal supply circuit which includes transformer coupling (Tr2 and Tr2') for introducing the ringing alternating current supply, two series-connected transistors (Tra1 and Tra2) and a current sensor resistor (R1). A current sensor unit (A) controls a translator (Tra3) which at a predetermined max. current supplied by the central battery (G1) to render the transistors (Tra1 and Tra2) non-conductive. When a short circuit occurs in the subscriber feed line or at the current which condition is held in a bistable stage is part of the current sensor unit (A). However, on application of an external signal (u) the blockage can be removed and the line condition tested. It is possible to make the current sensor (A) generate repeated pulses (u) at selected time intervals so as to make the line operative within a reasonably short time after the short circuit is removed. The diodes (D1, D2, D3, D4) which bridge the blocking transistors allows the ringing current to pass the supply circuit at its self-limiting strength. PS.

Positional correction drive circuit - is for self-aligning microwave antenna, and compensates for in-the-wave transfer guides induced secondary error signals

Abstract: The circuit is capable of eliminating the effect of internally generated non-relevant wave-modes. A collector cone (6) provides the transition to a hollow conduit feed line (8) which couples to the mode coupling circuit (9) which splits the H-21 wave into phase components (13a,13b). A 90 degrees - 3dB hybrid amplifies the signals and feeds them into a switch (21) which permits either the left or the right circular polarised wave to be passed to the compensation amplifier (36) from which is derived the differential error correction voltage (38). However, on the component lines (13a,13b) are also present interference signals (Sa,SB), and these must be made ineffective. This is done by means of the polarisation gate (10) which separates the fundamental applied to unit (22) which receivees the useful signal, and the aforementioned both wanted and unwanted higher order wave signals which are passed to an amplifier (26) and the two outputs to quad phase shift/attenuator members (29,30) and further phase correction members (31,32). After eliminating the left or right circular component in a termination resistance (34) the remaining signal is applied to the compensator unit (36) where the unwanted components cancel each other.

Multiple RF channels bi-directional UHF amplifiers one radiating RF transmission line

Abstract: This paper describes the design parameters of a six (6) channel UHF radio communication system consisting of a single, 12 mile radiating RF transmission line network and 45 bi-directional RF amplifiers. The amplifiers will boost the UHF RF channels, in both directions, and provide the necessary transmit-receive RF isolation to permit the use of standard 5 MHz RF separation between Transmit and Receive UHF RF frequencies. The UHF RF channels will be used for hand held portable radio communications, for point-to-point data circuits (computer terminals) and for alarms on critical devices (fans, conveyor belts, elevators, etc.). This system is presently being installed and tested in an underground coal mine that is 650 feet below the surface. The design parameters were based on previous tests of a prototype system (two bi-directional RF amplifiers and 5000 feet of radiating RF transmission line) in the same coal mine.

Optical submarine cable repeater

Abstract: PURPOSE:To ensure assured and effective repair for an optical submarine system, by providing a coupling part which is detachable to a repeater box with a watertight structure and connecting the electric signals via this coupling part between a transmission line and a feed line. CONSTITUTION:A repeater box 4 can be divided at the part shown by arrows 9, and the transmission of information and the connection of electric power in the inside of a repeater can be performed by respective connectors 16 and 18. The divided repeater boxes 3 and 5 are connected together mechanically to ensure the transmission of the tension of an optical submarine cable 2 that is applied to the box 4 and to secure an watertight structure in the box 4. The optical signal transmitted through an optical fiber 6 is converted into an electric signal through a photoelectric converter 10 and then amplified by electric signal amplification processor 11 and 13. This amplified signal is converted again into an optical signal through an electrooptic converter 14 to be transmitted through an optical fiber 7. At the same time, the electric power is fed via an electric power feed line 8.

Current conduction in coaxial cable braids at radio frequencies

Abstract: Results of braiding-factor measurements on two coaxial cables, one with a wire braid and the other with a tape braid, are reported here. The investigations, performed in an attempt to understand more clearly the mechanism of current conduction in the braided outer conductors of cables at radio frequencies, establish the existence of two different levels for the braiding factor at the higher and lower radio frequencies, respectively. The determinations of quantitative values for these levels are extremely dependent on the tolerances of braid dimensions. In the transition region between the two frequency limits braiding factors are found to be anomalous.

Phase compensation system for branched aerial connections - uses different lengths for branches giving double compensation for different frequencies

Abstract: The phase compensation system for branched aerials for, e.g. t.v. signal transmission, reduces echoes. Where four aerial elements are connected at a junction to a feed line, one pair of the transmission lines connecting them are a quarter wavelength longer than the other pair and they are connected by a transformer with a transmission ratio of 1:4. Where a multiple branch connection is used, the portions of the oscillations from the branch connection points transmitted and then reflected back again are compensated according to their phase position. The two phase compensations for different operating frequencies are applied so that the band width is increased, or for a given band width, the reflection is decreased by applying two phase compensations for only one operating frequency. (DS).

A Coaxial Wavewide Commutator Feed for a Scanning Circular Phased Array Antenna

Abstract: A coaxial waveguide amplitude commutation feed system has been developed for application to the scanning circular array antenna problem. A dominant TEM mode and a pair of orthogonal TE/sub 11/ modes suitably excited at the input of a coaxial waveguide feed are employed to generate a simply commutatable low-sidelobe discrete amplitude distribution at the peripheral output ports of the coaxial circular array feed. The major advantages of the coaxial commutator feed compared to other circular array feed types are the broad bandwidth and small insertion loss simultaneously achieved with a simple feed geometry. The design and measured performance capability of a 30-percent RF bandwidth low-sidelobe coaxial commutator feed are described in detail.

Radiation characteristics of array of crescent slots fed through radial waveguide

Abstract: An array of annular slots fed through a radial waveguide does not produce axial radiation when excited through a simple coaxial line. One method of producing axial radiation is to make the excitation cos φ dependent. An alternative method of producing axial radiation is presented, where instead of changing the excitation the slot shape is changed, thereby keeping the excitation simple.