Showing papers on "Stub (electronics) published in 1997"

Optical receiver stub fitting

Abstract: A cable assembly for attachment to an entry port of an optical enclosure. The assembly includes a plug for an end of an optical cable in a sealed housing having a single rigid tube and a single sealed nut. Connectorized optical fibers or an optical ribbon extend from the plug into the equipment enclosure.

Wire antenna with stubs to optimize impedance for connecting to a circuit

Abstract: An antenna, used as a voltage and power source, is designed to operate with an arbitrary load, or front end. One or more stubs are added to one or more of the antenna elements. The stubs act as two conductor transmission line and are terminated either in a short-circuit or open-circuit. Where the transmission line is odd multiples of the guided wavelength in length, the short-circuit stubs act as lumped inductors and the open-circuit stubs act as lumped capacitors. The magnitude of these lumped capacitors and inductors (reactances) is affected by a stub length, a stub conductor width, and a stub spacing. Zero or more short-circuit stubs and zero or more open-circuit stubs are added to one or more of the antenna elements to change the reactive (imaginary) part of the antenna input impedance. In a preferred embodiment, the reactive part is changed to equal the negative magnitude of the reactive part of the front end input impedance.

Wire antenna with optimized impedance for connecting to a circuit

Abstract: An antenna used as a voltage and power source is designed to operate with arbitrary load, or front end. The antenna has one or more (number of) loading bars that are placed adjacent to the elements of the antenna at a spacing distance. The real part of the antenna input impedance is changed by adjusting the loading bar length, width, and/or spacing distance and/or the number of loading bars. These changes are implemented to reduce the real part of the antenna input impedance to make it small enough to develop an adequate voltage, Vp, to operated the front end and connected circuitry. In a preferred embodiment, the real part of the antenna input impedance is reduced to the point at which Vp no longer increases. One or more stubs is added to one or more of the antenna elements. The stubs act as two-conductor transmission line and is terminated either in a short-circuit or open-circuit. The short-circuit stubs act as a lumped inductor. The open-circuit stub acts as a lumped capacitor. The magnitude of these lumped capacitors and inductors (reactances) is affected by a stub length, a stub conductor width, and a stub spacing. Zero or more short-circuit stubs and zero or more open-circuit stubs are added to one or more of the antenna elements to change the reactive (imaginary) part of the antenna input impedance. In a preferred embodiment, the reactive part is changed to be equal to the negative magnitude of the reactive part of the front end input impedance. For a given real part of the antenna impedance, Ra, this approach maximizes both the DC voltage generated from the input and maximizes the power transferred between the antenna and the front end.

Aperture-coupled planar inverted-F antenna

Abstract: An aperture-coupled planar inverted-F antenna (PIFA) including a radiating patch formed on one side of a ground plane and separated therefrom by a first dielectric which may be air, foam or another suitable material. A shorting strip connects a side of the radiating patch to the ground plane at a point corresponding to a dominant mode null, such that the size of the radiating patch may be reduced by a factor of two. A microstrip feedline is arranged on an opposite side of the ground plane and separated therefrom by a second dielectric which may be part of a substrate formed of printed wiring board material. Signals are coupled between the microstrip feedline and the radiating patch via an aperture formed in the ground plane. The use of aperture coupling avoids the excessive cost associated with conventional TEM transmission line or coaxial feeds, while providing improved manufacturability and ease of integration relative to PIFAs with conventional feeds. Moreover, the aperture coupling provides improved tuning flexibility. For example, a portion of the microstrip feedline may be used as a tuning stub to provide impedance matching on the feedline.

Recessed fixture frame and method

Abstract: An improved recessed fixture frame and method for installing the recessed fixture frame in new, existing or rough-in construction is disclosed. The improved recessed fixture frame includes a frame band for supporting and surrounding a fixture housing and at least one mounting assembly connected to the frame band in such a manner that the frame band is capable of being adjusted between the ends of the mounting bars. The mounting assembly includes at least one hinged mounting stub operatively hingeably connected to at least one end of the mounting assembly. Each hinged mounting stub includes a fastening means for affixing the recessed fixture frame to a structural member in a first position. In the first position, the recessed fixture frame extends downwardly from the structural member. After the fixture frame has been wired-in, the fixture frame is rotated about ninety degrees (90°) about the hinged mounting stubs to a second position where the non-hinged mounting stub at the other end of the mounting assemblies are operatively connected to a second structural member.

High pressure casing patch

Abstract: A method of preparing a downhole casing tubular and a casing patch apparatus for connecting onto a stub casing in a wellbore are provided. The casing patch apparatus includes a tubular body having an opening large enough to pass over the stub. The casing patch also includes a seal assembly having at least one cantilevered fin mounted within the body. The fin has an initial inner diameter smaller than the outer diameter of the stub such that it is deflected as the body is advanced over the stub. The fin provides a metal-to-metal seal between the body and the stub. A gripping assembly holds the body to the stub.

Open- and short-circuit terminated series stubs in finite-width coplanar waveguide on silicon

Abstract: Open- and short-circuit terminated series stubs in finite-width coplanar waveguide (FCPW) fabricated on high-resistivity Si are experimentally characterized over the frequency range of 2-40 GHz. In coplanar waveguide (CPW), these stubs are typically placed in the center conductor, but in FCPW, the stubs may also be placed in the ground planes resulting in novel circuit elements with characteristics that make the stubs useful for matching circuits and filters. Equivalent circuit models for the stubs are presented, and it is shown that when the stub is in the ground plane the resonant frequency is equal, the inductance and resistance is halved, and the capacitance is double the values of the same stub in the center conductor. Furthermore, it is shown that by varying the stub position in the ground plane, higher Q stubs can be obtained.

Lightning supression system for tower mounted antenna systems

Abstract: A lightning suppression system comprising a directional coupler, a quarter-wavelength stub, a first cylindrical capacitor, a second cylindrical capacitor and a lightning suppression circuit. Each of the cylindrical capacitors has an inner conductor element, an outer conductive tube and a dielectric material. Direction coupler acts to block direct current and low frequency signals from passing therethrough. The quarter-wavelength stub comprises a helicoid and acts to reflect radio frequency signals back to the transmission line while allowing direct current and low frequency signals to flow therethrough. First cylindrical capacitor and second cylindrical capacitor combine to form a low pass filter which allows direct current and low frequency signals to flow through while blocking other signals. The lightning suppression circuit suppresses high voltage direct current and low frequency signals such as those produced by near lightning strikes.

Stub-tuned, proximity-fed, stacked patch antenna

Abstract: A reduced weight, low profile, stacked patch antenna includes an `active` antenna patch element, a `parasitic` antenna patch element, and a tuning stub portion of a microstrip feed, which resonate at respectively different frequencies. The tuning stub is located adjacent to the active patch element, so that electromagnetic field energy associated with the tuning stub is coupled to the active and parasitic patches of the stacked patch structure, thereby creating a distributed resonance characteristic, having an augmented bandwidth compared with that of a conventional patch antenna. Manufacture of the stacked patch antenna is facilitated by the use of both a proximity feed and the interleaving of layers of adhesive material among the respective components of the stacked structure.

Method of fabricating a true-time-delay continuous transverse stub array antenna

Abstract: Methods of fabricating air-dielectric true-time-delay, continuous transverse stub array antenna. The first method uses conventional machining or molding techniques to fabricate layers of plastic with desired microwave circuit features. The plastic layers are then metalized, assembled (aligned) and joined together, such as by using ultrasonic welding techniques. Readily available metalization and ultrasonic welding techniques exist that may be used. The second method uses sheets of metal, into which microwave circuit features are fabricated, such as by machining. The layers are then assembled (aligned) and joined together, using one of several available processes, such as an inert gas, furnace brazing technique, for example.

Planar antenna radiating structure having quasi-scan, frequency-independent driving-point impedance

Abstract: A planar antenna radiating structure comprising an array of continuous transverse stubs having a stepped configuration arranged in a ground plane of a parallel-plate waveguide. Control of the complex reflection coefficient of the aperture of the radiating structure over a range of operating frequencies and scan angles is accomplished using parallel-plate waveguide modes through a choice of stub length(s), stub height(s), inter-stub spacings, parallel-plate separation and the properties of dielectric media used for the parallel-plate waveguide and stubs.

Low-pass filter with directional coupler and cellular phone

Abstract: An integrated component providing the function of both a conventional directional coupler and a low-pass filter having two attenuation poles at a specified frequency band without changing the line length. Stub lines are connected to both ends of a main transmission line of a directional coupler. A frequency of the attenuation poles is adjustable by characteristic impedance, terminating conditions, and line length of the stub lines.

Method for attaching a rotor blade to an integrally bladed rotor

Abstract: A method for replacing a rotor blade on an integrally bladed rotor having a disk is provided, comprising the steps of: (a) removing a damaged rotor blade, leaving a stub portion of the rotor blade extending out from the disk, the stub portion of the rotor blade having a suction side and a pressure side; (b) providing a die, having a pressure side and a suction side, wherein each side includes a platform trough; (c) fastening the die to the rotor blade stub, with the pressure side of the die positioned on the pressure side of the stub, and the suction side of the die positioned on the suction side of the stub; (d) extruding a portion of the rotor blade stub into the platform troughs, thereby creating a platform; and (e) attaching a rotor blade to the platform.

Disk drive rotary actuator having arm with cross-member containing elastomeric damping member

Abstract: A magnetic recording disk drive uses a rotary actuator with an elastomeric damping member located on the actuator arm. The actuator head support arm has a pair of rails that extend from the actuator pivot to the distal end where the read/write heads are supported. A lateral cross-member extends between and interconnects the rails. The cross-member contains a recess, and elastomeric damping material is located in the recess. The recess is a cut completely through the cross-member so that the cross-member is formed as two stubs extending from respective rails with a gap between the stub ends. The damping material is located in the gap and damps vibration of the actuator arm.

A capacitively loaded half-wavelength tapped-stub resonator

Abstract: This paper examines a new resonator which is created by adding capacitive loading to a half-wavelength tapped-stub resonator. This capacitively loaded resonator has the property that both the Q and the resonant frequency can be set independently. This property is important because it allows this resonator to be used as either a tracking filter which maintains a constant bandwidth or as a filter which can vary its Q while maintaining a fixed resonant frequency. In this paper, equations are derived for choosing capacitance values that yield a desired resonant frequency and value of Q. Examples of using this resonator as both a fixed-frequency variable-Q filter and a constant-bandwidth tracking filter are provided. Theoretical results are verified by measurements.

A reduced branch-line coupler with eight stubs

Abstract: A branch-line coupler using eight stubs is proposed for size reduction. As for the stubs, a structure consisting of two sections of high and low impedance transmission lines is presented in order to connect a low impedance stub to a signal line. According to transmission line theory, no practical differences are found in the frequency characteristics between the normal hybrid and an experimental circuit, except for slight differences in higher frequency region over the center frequency. The experimental circuit was reduced to 25% in area, and showed good agreement with theory.

Grinder mixer assembly

Abstract: The grinder mixer assembly includes a drum assembly with end plates rotatably supported on stub shafts. These stub shafts are secured to arms of a yoke assembly. The spindle of a first hydraulic motor is secured to one of the stub shafts. The housing of the first motor is connected to a center portion of the drum by a key. The spindle of a second hydraulic motor is secured to the other stub shaft. The housing of the second motor is to a center portion of the drum by a key. The keys transmit torque from drive rings attached to each motor to driven rings attached to the drum mid way between the end plates of the drum.

Quantum wire switch and switching method

Abstract: A quantum wire switch and a switching method for switching charge carriers between a first output and a second output utilizing quantum interference of the charge carriers. A quantum switch includes a quantum wire extending from an input to a first output, a second quantum wire extending from the input to a second output, and a third quantum wire extending between the first and second outputs, the three quantum wires together defining a ring. A controllable-length quantum wire electron stub tuner is connected to the ring. As charge carriers propagate from the input around the ring the stub tuner is used to control the quantum interference of the charge carriers resulting in local maxima and minima at various points around the ring. Setting the stub to a first length results in a local maximum at the first output and a local minimum at the second output, and the charge carriers can propagate to the first output and not the second output. Setting the stub to a second length reverses the locations of the local maxima and minima, and the charge carriers propagate to the second output but not the first output. The invention can also include a second controllable-length stub attached to the ring to increase switching efficiency. A quantum switch according to the invention can also act as a simple binary NOT logic gate or a simple binary AND logic gate.

A reduced size helical antenna

Abstract: Conventional axial mode helix antennas offer wide bandwidth, high gain, and circular polarization. They are in widespread use at UHF frequencies. Their physical size, however, can become excessively large at lower frequencies. In this paper we present a new design of the helical antenna, termed the stub loaded helix (SLH), which offers a substantial size reduction over a conventional axial mode helix without sacrificing performance. For the same number of turns, a stub loaded helix offers a 4:1 reduction in overall size while maintaining comparable gain performance. The usable bandwidth ofthe stub loaded helix is less than the conventional helix design (25% versus 50%) due to reduced axial ratio performance of the stub loaded helix.

Phase tuning technique for a continuous transverse stub antenna array

Abstract: A continuous transverse stub antenna array (10) comprises phase tuning sections (11) disposed between adjacent stub elements (13). The antenna array (10) includes a sheet (12) of dielectric material having a plurality of transverse stub elements (13) extending from a first surface (14) thereof. A first metal layer (16) is disposed on the first surface (14) and side surfaces (15) of each of the stub elements (13), and a second metal layer (16) is disposed on a second surface (17) of the sheet of dielectric material that forms a ground plane (18) of the array (10). A plurality of tuning sections (11) are formed in the sheet (12) of dielectric material and are disposed between each of the stub elements (13) that extend laterally across the sheet (12) of dielectric material. The plurality of tuning sections (11) have a cross sectional shape in the form of an inverted T.

Increasing the bandwidth of a meander line antenna consisting of two strips

Abstract: Small antennas for handsets in personal communication systems are required. A meander line antenna (MLA) can be used in such systems. The input impedance of the MLA can be easily matched by use of impedance step-up and balance mode impedance loading. But increasing the bandwidth of an MLA through the use of a two-strip geometry has not been accomplished so far. A method for increasing the bandwidth of the 2-strip MLA is described. An equivalent circuit of the MLA is represented by use of the balance mode impedance as an open- or short-circuited shunt stub. On the basis of the equivalent circuit, a numerical analysis of the impedance characteristics of the 2-strip MLA is carried out. In the analysis, the contribution of the parameters of the 2-strip MLA towards increasing the bandwidth are discussed.

Method for sealing a stub tube in a nuclear reactor

Abstract: Methods for sealing cracks adjacent stub tube attachment welds in a reactor pressure vessel of a nuclear reactor are described. The reactor pressure vessel includes at least one stub tube through which a control rod housing extends. The control rod housing is attached to one end of the stub tube with an upper stub tube attachment weld. In one embodiment, a sidewall of a control rod drive housing is cut at a location below the upper stub tube attachment weld to form a weld passage in the control rod drive housing between the control rod drive housing and the stub tube. A weld is then formed in the weld passage so that it is in physical contact with both the stub tube and the control rod housing, and thus seals the control rod drive housing against the stub tube.

Waveguide stub-line tuning of RF cavities with heavy beam loading

Abstract: A method is proposed for using adjustable, waveguide stub-line tuners to match the load impedance of the cavity plus beam to the power source, without the need to detune the cavity. Adjustable stub-line tuners are shown to be able to completely match the resistive and reactive parts of the load impedance to a generator under all conditions of beam loading, ensuring optimum power transfer between generator and cavity. This technique may have advantages in high-current storage rings such as the SLC damping rings and the new PEP II storage rings. The coupled-bunch instability driven by the fundamental mode of the cavity is re-appraised in this coupling scheme in which the cavity is no longer detuned. The consequences of this matching scheme are also considered for the beam loading stability limit.

Analysis of stub loaded microstrip patch antennas

Abstract: Rectangular and circular patch antennas loaded with a microstrip stub were previously analyzed using the generalized Thevenin theorem. In the Thevenin theorem approach, the mutual coupling between the patch current and the surface current on the stub was not taken into account. Also, the Thevenin theorem approach neglects continuity of current at the patch-stub junction. The approach presented in this present paper includes the coupling between the patch and stub currents as well as continuity at the patch-stub junction. The input impedance for a stub loaded microstrip patch is calculated by the general planar dielectric dyadic Green's function approach in the spectral domain. Using the spectral domain dyadic Green's function with the electric field integral equation (EFIE), the problem is formulated by using entire domain basis functions to represent the surface current densities on the patch, the loading stub and the attachment mode at the junction. Galerkin's procedure is used to reduce the EFIE to a matrix equation, which is then solved to obtain the amplitudes of the surface currents. These surface currents are then used for calculating the input impedance of stub loaded rectangular and circular stub loaded rectangular and circular microstrip patches. Numerical results are compared with measured results and with previous results calculated by the Thevenin's theorem approach.

Method for sealing a stub tube in a nuclear reactor

Abstract: A method for sealing cracks adjacent stub tube attachment welds in a reactor pressure vessel of a nuclear reactor is described. The reactor pressure vessel includes at least one stub tube through which a control rod housing extends. The control rod housing is attached to one end of the stub tube with an upper stub tube attachment weld. A sidewall of a control rod drive housing is cut at a location below the upper stub tube attachment weld to separate an upper portion of the control rod housing from a lower portion of the control rod housing. The lower portion of the control rod drive housing is removed from the bottom head opening, and a replacement lower portion is positioned in the bottom head opening proximate to the remaining upper portion. The replacement lower portion then is secured to the reactor pressure vessel without securing the replacement lower portion to the remaining upper portion of the control rod drive housing.

Interferometric quantum wire switch

Abstract: A device topology is proposed and analyzed which is based upon quantum wire components. The device controls the conductance between an input line and a pair of output lines by varying the phase shift around a quantum wire ring connecting the external nodes. The phase shift is controlled using a simple electron stub tuner. Switching characteristics with efficiencies greater than 95% for certain geometries have been calculated.

Generating electrical energy from rotary movement of stub axles carrying rail vehicle wheels

Abstract: Electrical energy is produced by a generator with the same axis. The generator has a stator fixed to the vehicle frame and a rotor located on the stub axle with permanent magnets distributed around the periphery. Apart from the generation of electrical output energy, electrical energy for the measurement of the speed of at least one wheel is generated. The electrical output energy is generated exclusively via the induction between the rotor equipped with permanent magnets and the stator. The measurement energy for the speed measurement occurs by separate sensors that can be influenced by a constant magnetic field between the rotor and the sensors. An Independent claim is also provided for the electrical energy generating circuit.

Coplanar waveguide stub/filters on thin membranes and standard substrates

Abstract: Several coplanar waveguide series stubs and filter structures based on such stubs were designed and manufactured on standard semiinsulating GaAs substrates and thin GaAs membranes as well as on silicon based thin dielectric membranes. Coplanar waveguide circuits realized on thin membranes offer significant advantages over conventional coplanar or microstrip lines for monolithic or hybrid MIC applications.