Showing papers on "Stub (electronics) published in 1996"

L-resonator bandstop filters

Abstract: A design procedure is presented for narrow bandstop filters using TEM transmission line L resonators, which are intermediate of the gap- and parallel-coupled resonators typically used. In this configuration, parallel coupling occurs over a portion of the resonator length, with the remaining resonator length forming a stub. The grounded end of the resonator may be in either the coupled or stub portion of the resonator.

Bus configuration and input/output buffer

Abstract: A system for signal transmission has at least one bus for the signal transmission and a reflection-prevention resistance provided on a stub connected to the bus for preventing reflection of signals at an intersection between the bus and the stub The system includes termination resistances, and a switch unit for coupling the bus to termination voltage via the termination resistances in a first mode and for disconnecting the bus from the termination voltage in a second mode

L-resonator bandstop filters

Abstract: A design procedure is presented for TEM narrow bandstop filters using L resonators, which are intermediate of the gap- and parallel-coupled resonators typically used, having parallel coupling only over a portion of the resonator length and a grounded end in either the coupled or stub portion of the resonator.

Power leakage, characteristic impedance, and leakage-transition behavior of finite-length stub sections of leaky printed transmission lines

Abstract: Power leakage and leakage transition phenomena in finite-length stub sections are studied for slot- as well as strip-type leaky transmission lines. A three-dimensional (3-D) method of moments is used for the rigorous analysis of the stub sections. The results reveal several important characteristics of power leakage in printed circuits that are not obtainable from the two-dimensional (2-D) analyses of ideal infinite-length lines. A new definition of the characteristic impedance for a leaky printed transmission line is proposed, which is shown to correctly model the impedance behavior of the finite-length sections. It is noted that the standard definitions of characteristic impedance, commonly used for nonleaky transmission lines, may not apply to practical circuits when leakage exists. Further, the leakage transition behavior in the finite-length sections, operated around a "mode-transition" region, is explained from the 3-D analysis results. Leakage analyses of ideal infinite-length lines can not model such transition excitation in finite-length circuits.

W-band InGaAs/InP PIN diode monolithic integrated switches

Abstract: The design, fabrication, and experimental characteristics of InGaAs PIN diodes are presented for InP-based W-band monolithic integrated switches The diodes with 10 /spl mu/m-diameter were used and showed a breakdown voltage of 17 V, a turn-on voltage of 036 V, and a switching cutoff frequency of 63 THz The monolithic integrated switches employed microstrip transmission lines and backside via holes for low-inductance signal grounding A radial stub-based design was used for on-chip biasing, and the high-frequency characteristics of the switches were verified by on-wafer W-band testing The SPST PIN monolithic switch demonstrated 25 dB isolation, 13 dB insertion loss, and 08 dB reflection loss at 83 GHz

Sealing cable penetration for shielded cables

Abstract: The RF-proof cable penetration having a seal (9) for shielded cables, having a tubular threaded stub (7) which is to be inserted into a bore, and a locking nut (10) which is to be tightened onto the threaded stub, and having an annular clamping disk (8) which is forced, by a pinch seal (9) which is to be pressed on by the locking nut (10), against an annular shoulder on the threaded stub (7), is equipped according to the invention with a shielding sleeve (4) which has at least one radially projecting shoulder (6) at the front of the inner end. Furthermore, a stamping sleeve (5) is present which is to be pushed over the shielding sleeve (4) on the outside of the cable shield (3). In order to ensure a certain axial displaceability of the cable during mounting, the preassembled cable, provided with shielding sleeve (4) and mounted stamping sleeve (5), can be displaced axially relative to the threaded stub (7) owing to the fact that an annular shoulder has a continuous axial recess (12) in the interior of the threaded stub (7). By contrast with known EMC-capable cable threaded unions, the invention has the advantage that during the process of working the cable "fraying" of the shielding braid (3) is impossible on the cable, and parts of the shielding braid cannot break off, because co-rotation of the cable during tightening is prevented by latching the shielding sleeve (4) in the interior of the threaded stub (7). The time for mounting the cable can be substantially reduced.

CAD-oriented fullwave equivalent circuit models for waveguide components and circuits

Abstract: New multimode equivalent circuit models for single and cascaded E-plane and H-plane step discontinuities in rectangular waveguides are presented. The computer-aided design (CAD)-oriented equivalent circuit models enable rigorous and efficient fullwave analysis of waveguide components and circuits entirely by circuit simulation. The method has been implemented on the microwave circuit simulator Libra and applied to waveguide structures containing single and cascaded irises and stub discontinuities. Comparisons of circuit simulation results for single and cascaded inductive irises as well as a single and three E-plane stubs with the standard mode-matching method show perfect agreement. Results of a Ka-band bandpass filter analysis are in good agreement with a mode-matching solution that includes the correct edge condition.

Characterization of buried microstrip lines for constructing high-density microwave integrated circuits

Abstract: This paper describes the characterization of a guided wave structure, buried microstrip line (BMSL), which is considered to be promising for constructing high-density microwave and millimeter-wave integrated circuits because of its high isolation characteristics. The BMSL includes a dielectric medium surrounded by ground conductor walls and a strip conductor on the top of the dielectric. The BMSL structure is characterized by the two methods, the rectangular boundary division (RBD) method and the finite-difference time-domain (FDTD) method. The RBD method is employed to obtain basic parameters of the BMSL such as characteristic impedances and coupling coefficients over a wide range of line sizes taking advantages of its high calculation efficiency. On the other hand, the FDTD method has been used for more detailed characterization such as the frequency performances of stub matching circuits. The FDTD method is also used to confirm the validity of the quasi-TEM wave approximation which the RBD is based on. The analysis results reveal that the BMSL structure possesses much lower coupling coefficients than a conventional microstrip line does, from -15 dB to -100 dB depending on their burial depths.

Reflective wave compensation on high speed processor cards

Abstract: Packaged signal routing circuits (e.g. on printed circuit cards or boards), route pulse signals with very short rise times from a lossy driver to multiple devices. In these routing circuits, a complex network of conductors branches from a common junction adjacent the driver output into multiple (in the disclosed embodiment, three) conduction paths of unequal length. In accordance with the invention, the internal impedance of the driver is matched to the aggregate charateristic impedance of the branch paths, and a lossless compensating circuit is attached to a shortest branch path. The compensating circuit is designed to transfer signal reflections of predetermined form to the branching junction at the driver via the shortest branch. Without the compensating circuit, reflections presented to the branching junction from the shortest branch are dissimilar to reflections presented to that junction from other branch paths. Consequently, re-reflections return from the junction to the branches, causing distortions in signals sensed at the devices. However, with the compensating circuit connected in the shortest branch, reflections presented from that branch to the junction appear in a form matching reflections presented by the other branches; and the reflections from all branches then cancel at the driver junction. Consequently, signals sensed at the devices have considerably reduced distortions due to the absence of re-reflections. In a preferred embodiment, the compensating circuit consists of a printed circuit trace of predetermined length (representing a transmission line stub with predetermined phase delay characteristics) in series with a point capacitor (or several point capacitors) having predetermined capacitance (determining the shape of the compensating reflections). The compensating circuit, which extends beyond the end of the shortest branch, connects between the end of that branch and reference potential (e.g. ground). The end of the shortest branch is also attached to a device required to sense signals appearing at that point. A new method and polarized bridge device are disclosed for use in analyzing such networks in particular (and for analyzing transmission line effects in general). This method and device permit precise observation and comparison of reflections produced in branches of a network emanating from a common junction, and accurate determination of compensation suitable for modifying such reflections.

Correlation of Structural Analysis and Test Results for the McDonnell Douglas Stitched/RFI All-Composite Wing Stub Box

Abstract: The analytical and experimental results of an all-composite wing stub box are presented in this report. The wing stub box, which is representative of an inboard portion of a commercial transport high-aspect-ratio wing, was fabricated from stitched graphite-epoxy material with a Resin Film Infusion manufacturing process. The wing stub box was designed and constructed by the McDonnell Douglas Aerospace Company as part of the NASA Advanced Composites Technology program. The test article contained metallic load-introduction structures on the inboard and outboard ends of the graphite-epoxy wing stub box. The root end of the inboard load introduction structure was attached to a vertical reaction structure, and an upward load was applied to the outermost tip of the outboard load introduction structure to induce bending of the wing stub box. A finite element model was created in which the center portion of the wing-stub-box upper cover panel was modeled with a refined mesh. The refined mesh was required to represent properly the geometrically nonlinear structural behavior of the upper cover panel and to predict accurately the strains in the stringer webs of the stiffened upper cover panel. The analytical and experimental results for deflections and strains are in good agreement.

Characteristics of single-polarized phased array of tapered slot antennas

Abstract: Numerical and experimental studies are beginning to reveal some of the important design parameters of wide-band tapered slot antenna arrays. Results from several studies are presented to illustrate the problems encountered in antenna design and to provide guidance in developing successful designs. Parameter studies suggest that the stripline stub and slotline cavity have a large impact on performance at the upper and lower ends of the frequency band and that the antenna flare can be altered to impact in-band SWR. Some impedance anomalies that limit wide-band scanning are identified and some corrective actions are suggested.

Sealing element for a hydraulic screw connection comprising a hollow screw and an annular stub

Abstract: A sealing element for a hydraulic screw connection, comprising a hollow screw and an annular stub, for securing a rigid or flexible line connected or connectable to the annular stub and to a hydraulic component, wherein the annular stub is fixed in a pressure medium-tight fashion, via its plane end faces, between a head of the hollow screw and the component and swiveled into an arbitrary angular position relative to the component about the center line of the hollow screw. Two sealing element regions disposed in sealing seams located between the head of the hollow screw and the annular stub and between the component and the annular stub, are joined via a substantially cylindrical portion, and this cylindrical portion. This portion extends in the seam concentric with the largely cylindrical wall of the hollow screw. It has at least one radial opening.

Connector for blast initiation system

Abstract: A connector device (10, 214) for transferring a nonelectric blast initiation signal from a donor line (26, 224) to an acceptor line, e.g., an input stub (24, 217) has donor line retaining means (20a, 20b, 229) for disposing a donor line (26, 224) in signal transfer relation to the input stub (24, 217). An anvil member (27, 130, 226) is provided to support input stub (24, 217) at the point where it is in signal transfer relation with the donor line (26), preferably in conforming contact with the donor line (26). In a particular embodiment, the connector device has a body portion (10a) on which is retained a detonator cap (22). Cap (22) detonates upon receipt of a detonation signal from an input stub (24), optionally after a delay period if delay elements are incorporated into the cap 22. The connector device (10) has retainer spring clips (20a, 20b) for retaining the donor line (26) in signal transfer relation to the input stub (24). An output line retaining member (16) holds the output line (28) in signal transfer relation to the detonator cap (22).

Switchable bus driver termination resistance

Abstract: A system for signal transmission has at least one bus (10) for the signal transmission and a reflection-prevention resistance (Rs) provided on a stub (11) connected to the bus (10) for preventing reflection of signals at an intersection between the bus (10) and the stub (11). The system includes termination resistances (Rt), and a switch unit for coupling the bus (10) to termination voltage (Vtt) via the termination resistances (Rt) in a first mode and for disconnecting the bus (10) from the termination voltage (Vtt) in a second mode.

Bypass device in an amplifier unit

Abstract: A bypass device in a low noise amplifier unit for amplifying communication signals in the microwave frequency range. The device includes a printed circuit board with transmission lines (1, 2), an amplifier (A), a transmission line bypass segment (3) extending in parallel to the amplifier, and switching means for activating said bypass segment in case the amplifier becomes inoperable. The amplifier is connected between two transmission line stub segments (4, 5). The switching means include solid state components (Z1, Z2, Z3, Z4) having a controllable impedance, either very low or very high, these components being connected to ground at selected points (3a, 3b, 4a, 4b) in the bypass segment (3) and in the stub segments (4, 5) so as to activate the bypass segment when all of said solid state component are in a state of very high impedance and to effectively cut off the bypass segment when all of said solid state components are controlled to a state of very low impedance, in which case the communication signals pass through the amplifier.

Turbine engine rotor disk

Abstract: A turbine engine rotor assembly disk is provided which includes a forward web, an aft web, a plurality of first stub shafts, and a plurality of second stub shafts. The first and second stub shafts have axial ends and web ends. The stub shafts are attached to the respective forward or aft web, at the web end. The first and second stub shafts are equal in number, similarly spaced around the axial centerline, and attached to one another by fasteners.

Band pass filter

Abstract: PURPOSE: To surely eliminate the undesired signal bands and also to easily reduce the element size of a high frequency band filter. CONSTITUTION: A stub type resonator 2 is connected in series to the output line of a band pass filter main body 1 which defines high frequency bands as its pass bands. The spurious signals which are produced in the bands excluding those of the main body 1 are eliminated by the resonator 2. This resonator 2 is required to have a coaxial line having its tip opened in a T shape against the line itself and also to have a microstrip line constitution. In this constitution, a pattern is formed on a printed board or an electrode is formed on a ceramic substrate where the main body 1 is mounted. Then the pattern or the electrode is unified with the main body 1.

Off-chip 400 Mbps signal transmission: noise reduction using non-resonant lengths and other techniques

Abstract: A 400 Mbps single-ended off-chip link including an open-drain driver and quasi-differential receiver has been designed, simulated, and measured. In this work, the design choices, in particular as related to noise tolerance, are discussed. To reduce the reflections inherent in signal propagation at a 400 Mbps rate, both the data and clock interconnects are restricted to non-resonant lengths. To further improve impedance matching, a daisy-chain termination is evaluated in which the net termination occurs after rather than before, the package pin. Other methods of reducing reflection noise are discussed, such as providing resistor terminations on an SCM or MCM package in order to reduce stub lengths. Measurements indicate good agreement with simulation; when the link is implemented with the noise-reducing features described the measured noise and jitter is sufficiently low for reliable operation at 400 Mbps.

Transmission line filter having a switching function

Abstract: A strip line filter has a switching function for being operated without connecting a separate switch to a front end and a back end of the filter for preventing transmission electric power from being lost by a receiving unit, to thereby make the size of the transmitting and receiving system smaller. The strip line filter has a switching function in a transmission line filter, comprising: an inputting unit resonator and an outputting unit resonator, with the inputting unit resonator having a first open stub and a second open stub with the first open stub connected to ground through at least one capacitor; and the outputting unit resonator has a third open stub and a fourth open stub with the third open stub connected to ground through at least one capacitor, and being positioned within a distance of about one wavelength of a pass band frequency from the inputting unit resonator.

DC polarization device for high power, low intermodulation RF-systems

Abstract: The invention concerns DC-polarization devices for radio-frequency transmission systems of high power and low intermodulation, comprising a station (A) originating the RF signal, a station (B) receiving said RF signal from A, and a source D of direct current DC to be fed to B, and connected in a knot N to the line AB, the branches AN and DN comprising a short circuit stub (STU2) respectively an open circuit stub (STU1). Typically the normalised impedance (Z'op) of stub (STU2) is substantially equal to the normalise admittance (Yos) of stub (STU1), and the distance of the free heads of the near ends of the two stubs is the lowest possible.

DC bias device for high power, low intermodulation RF-systems

Abstract: A DC bias device for radio-frequency transmission systems of high power and low intermodulation connected between an originating station and a receiving station for an RF signal fed along a transmission line. Direct current is supplied from a source to the transmission line along a branch joined to the transmission line at a junction formed between the originating station and the receiving station. An open-circuit stub is formed along the transmission line between the transmitting station and the junction. A short-circuit stub is formed along the DC-supply branch between the source and the junction to the transmission line. The impedance (Zop) of the open-circuit stub, and the distance of the free heads of the near ends of the two stubs preferably is as low as possible.

Power distribution arrangement esp for powering loads in aircraft

Abstract: An arrangement for power distribution in an aeroplane uses a multi-wire power cable whereby in the length of the cable is located at least one distributor to which a group of loads is connected by a stub cable. A correlation unit (11 to 13) is assigned to each load group (8 to 10) connected on one side by the stub cable (5 to 7) with all the wires (1) of the power cable and on the other side with the individual loads. A central power controller (27) processes fault information through a control bus (33) and works with the correlators so that based on the fault information, the affected load is automatically reconnected to an intact power-carrying wire. The fault information is delivered by a status unit (44).

Optoelectronic tuning of microwave stub line

Abstract: The authors report a new optoelectronic technique for tuneable microwave matching. It is based on the illumination of a DC biased microstrip resonator on a silicon substrate. The matched frequency is tuned e.g. between 5 and 7 GHz, with a return loss over 45 dB, by varying the optical power and the DC bias.

Microwave semiconductor device

Abstract: PROBLEM TO BE SOLVED: To simplify assembling and manufacturing by selecting each characteristic impedance and electric length of stub lines of microstrip lines formed respectively on two boards to be prescribed values respectively so as to provide a high frequency band characteristic. SOLUTION: A ground conductor 3 is inserted between 1st and 2nd dielectric boards 1, 2 to form microstrip lines 6, 7 and a characteristic impedance and an electric length of a sub line of the microstrip line formed on one board and a stub line formed on the other board, a characteristic impedance and an electric length of a slot line are selected to be prescribed values. Thus, reflection depending on the characteristic impedance of the microstrip lines 6, 7 and reflection depending on the characteristic impedance of a slot, line 17 are cancelled at frequencies fH, fL at two points upper and lower than a center frequency and other than the center frequency to obtain a characteristic of the device is obtained and matching is taken even at upper limit frequency fH and a lower limit frequency fL of the desired frequency band. COPYRIGHT: (C)1997,JPO

Microwave and millimeter wave oscillator

Abstract: PROBLEM TO BE SOLVED: To provide a microwave/millimeter wave oscillator with which a phase noise is suppressed to a low level and an oscillation frequency can be highly stabilized by connecting a dielectric resonator to both a connection line and an output circuit. SOLUTION: A resonance circuit 4 at a gate has a connection line 8 and a dielectric resonator 9 is mounted so as to be connected to the connection line 8 and to be connected to an output circuit 6 as well. The gate on a GaAs substrate 12 is used as an active oscillator 1 and a varactor 3, and the resonance circuit 4 is formed by providing a short stub 2 for serial feedback, varactor 3 and connection line 8. Besides, a monolythic semiconductor integrated circuit having the output circuit 6 provided with an output matching circuit 5 using the short stub is formed. A dielectric resonance circuit 9 is composed of the ceramic of BaO 3 and arranged at a proximate position without being overlapped with the connection line 8 and the transmission line of the output circuit 6. Namely, rough connection more becomes the low phase noise. As the position of the dielectric resonator 9, the position of a simple transmission line on the following stage of the output matching circuit 5 is satisfactory. COPYRIGHT: (C)1997,JPO

Rainwater collecting and cleaning device

Abstract: of EP0753631Rainwater collection installation consisting of a concrete cylinder (10) with an internal, flexible, liner (5) which is attached to, and suspended from, an insert (2) which contains inlet stub (23), overflow stub (24) and extraction pipe (25).

Rotary apparatus with gap-controlling

Abstract: A rotary apparatus, such as a pneumatic motor, is disclosed. The rotary apparatus comprises an end plate having a race cavity, a main rotor with a stub shaft extending from one end, and a bearing, which includes an outer race seated in the race cavity and an inner race having a central bore. The stub shaft is fitted into the central bore with a frictional fit. In a preferred embodiment, the threaded shank of a screw is threaded into a threaded socket in the stub shaft so as to draw the stub shaft into the central bore with a washer bearing against the screw head, against the stub shaft, and against the inner race, whereby a controlled gap is provided between an outer surface of the main rotor and an inner surface of the end plate. In an alternative embodiment, a threaded-nut is threaded onto a threaded stud extending from the stub shaft so as to draw the stub shaft into the central bore with a washer bearing against the threaded nut, against the stub shaft, and against the inner race, whereby the controlled gap is provided. Also, a related method for assembling the rotary apparatus is disclosed, in a preferred mode for assembling the preferred embodiment and in an alternative mode for assembling the alternative embodiment.

Experimental evaluation of basic circuit components using buried microstrip lines for constructing high-density microwave integrated circuits

Abstract: The buried microstrip line (BMSL) is a promising transmission line structure for realizing low crosstalk characteristics. The measured crosstalk characteristics of model BMSL's have shown good agreement with the estimated ones based on the rectangular boundary division method and the finite-difference time-domain (FDTD) method, indicating that these calculation methods are appropriate for estimating the performance of BMSL's. These results also confirm our expectation that BMSL's have extremely low crosstalk characteristics such as -100 dB in real circuits at high microwave frequencies. The basic circuit components to construct high-density microwave circuits using BMSL's, couplers, stub matching circuits, and gap-coupled resonance filter circuits, were fabricated and experimentally evaluated.