Showing papers on "Stub (electronics) published in 2001"

Wide-band low-loss high-isolation microstrip periodic-stub diplexer for multiple-frequency applications

Abstract: This paper introduces a three-port microstrip multifrequency diplexer used in a phased-array transceiver system that employs band-stop filters with open-circuited stubs for band selection and separation. The diplexer is designed to take 10, 12, 19, and 21 GHz into port 1 and to separate 10 and 19 GHz to port 2 and 12 and 21 GHz to part 3 with minimal dispersion. The insertion loss for each frequency varies from 0.4 to 3.4 db and the return loss is better than 10 dB. The isolation between channels at the four frequencies is greater than 50 dB. Each passband created between adjacent stopbands has a bandwidth over 1 GHz. The microstrip diplexer is designed using periodic stubs that collectively have the advantages of low insertion loss, high isolation and rejection, wide-band performance on each channel, and easy fabrication. This type of diplexer has many applications in multifrequency transceivers for communication systems.

Adjustable length antenna system for RF transponders

Abstract: The present invention provides an RF tag having an antenna that can be selectively tuned to achieve optimal performance. The RF tag comprises an RF transponder integrated circuit and an antenna connected to the RF transponder integrated circuit. The antenna includes components such as tuning stubs and loading bars that are physically alterable to selectively vary the performance characteristics of the antenna. The tuning stub and loading bar may each further comprising a variably selectable length having elements that may be removed by punching, cutting, etching, laser trimming or other process. The antenna may further comprise a leadframe or a flexible substrate.

Control of Attenuation Pole Frequency of a Dual-Mode Microstrip Ring Resonator

Abstract: A novel method is proposed to control the attenuation pole frequency of a dual-mode circular microstrip ring resonator bandpass filter, keeping the bandwidth constant. In this paper, the coupling between the dual modes is provided as the total effect of stub perturbation at the end of symmetry plane, and the angle be- tween input/output ports. By making a various combinations of these two parameters, it is possible to control the attenuation pole frequency. An additional small coupling induced by excitation ca- pacitance is also considered. Filters are simulated using the calcu- lated coupling constant, and then the attenuation pole frequencies and bandwidth of the simulated filters are verified by experiment. Theoretical expressions are further devised to calculate the atten- uation pole frequencies.

Control of attenuation pole frequency of a dual-mode microstrip ring resonator bandpass filter

Abstract: A novel method is proposed to control the attenuation pole frequency of a dual-mode circular microstrip ring resonator bandpass filter, keeping the bandwidth constant. In this paper, the coupling between the dual modes is provided as the total effect of stub perturbation at the end of symmetry plane, and the angle between input/output ports. By making a various combinations of these two parameters, it is possible to control the attenuation pole frequency. An additional small coupling induced by excitation capacitance is also considered. Filters are simulated using the calculated coupling constant, and then the attenuation pole frequencies and bandwidth of the simulated filters are verified by experiment. Theoretical expressions are further devised to calculate the attenuation pole frequencies.

Low-loss analog and digital micromachined impedance tuners at the Ka-band

Abstract: Presents new types of analog and digital micromachined impedance tuners. Analog impedance tuners using resonant unit cells realized by tunable micromachined capacitors showed a wide tuning range equivalent to almost two quadrants of the Smith chart with a maximum voltage standing-wave ratio (VSWR) of 21.2 at the Ka-band. Frequency variability is also provided through the use of J-inverters with tunable capacitors. Also presented is a digital micromachined tuner, where the short-circuited shunt stubs are loaded with microelectromechanical system (MEMS) capacitive switches. The electrical length of the stub and the overall impedance of the tuner are thus controlled according to the switching states of the MEMS capacitors. The digital tuner presented impedance ranges suitable for load impedances of the RF power transistors and showed a high maximum VSWR of 32.3. Compared with the state-of-the art tuners using field-effect transistors, micromachined tuners of this paper show superior VSWR ranges as well as wide impedance ranges. Micromachined tuners are very promising for low-loss tuning of the monolithic circuits as well as for accurate noise and power characterization.

2 and 4-bit DC-18 GHz microstrip MEMS distributed phase shifters

Abstract: Two and four-bit wideband distributed microstrip phase shifters have been developed on a 21 mil (533 /spl mu/m) silicon substrate for DC-18 GHz operation. Presented here is the first demonstration of microstrip distributed MEMS transmission line (DMTL) designs, periodically loaded by MEMS varactors in series with a fixed value microstrip radial stub. The two-bit design results in a reflection coefficient less than -10 dB,an average insertion loss of -2.8 dB, and a maximum phase shift of 262/spl deg/ at 16 GHz. The four-bit design results in a reflection coefficient less than -9 dB, an average insertion loss of -3.0 dB, and a maximum phase shift of 333/spl deg/ at 16 GHz.

Apparatus and method for enhancing low-frequency operation of mobile communication antennas

Abstract: The operation of a mobile communication apparatus is enhanced particularly in the lower frequency portion of its bandwidth by connecting an electrically-conductive reflector (30) to the electrically-conductive ground of the printed wired board (PWB) (4) containing the communication circuitry such that the reflector (30) effectively enlarges the ground of the PWB to load the antenna (10) in the lower portion of its radio frequency band. Another embodiment of the reflector may include stub reflectors integrally formed on the PWB, or connected thereto, preferably at the end of the PWB opposite to that connected to the antenna. The antenna may be an internal or an external antenna.

Compact, low insertion loss, sharp rejection wideband bandpass filters using dual-mode ring resonators with tuning stubs

Abstract: Novel wideband bandpass filters using dual-mode ring resonators with orthogonal direct-connected feed lines and tuning stubs are developed. The tuning stubs act as series resonators and provide sharp rejections for the filters. Also, a perturbation stub in each ring influences the fields of the ring resonators and generates a dual mode to extend the stop bands of the filters. The simulated and measured results agree well. This novel bandpass filter has advantages of compact size, low insertion loss, and sharp rejection.

Stub shaft conveyor roller

Abstract: A conveyor roller includes a generally cylindrical roller tube and a pair of stub shafts rotatably mounted in each end thereof. At least one of the stub shafts is mounted for axial movement between an extended position and a retracted position. When in the extended position, the stub shafts on each end of the conveyor engage respective mounting holes in the conveyor frame. To insert the conveyor roller in the conveyor frame, the movable stub shaft is moved to a retracted position while the roller is lowered into the conveyor frame. When the stub shaft aligns with the mounting holes in the conveyor frame, the stub shaft is urged back to the extended position by a biasing member to engage the mounting hole in the conveyor frame.

LiNbO3 resonant-type optical modulator with double-stub structure

Abstract: A resonant-type LiNbO/sub 3/ optical modulator with symmetric stubs and modulating electrodes was investigated. Modulation efficiency was enhanced by the resonance of the modulating electrode. The enhancement factor of the fabricated modulator was 3.41 at 10 GHz.

Multiband microwave antenna

Abstract: Microwave antennas with a dielectric substrate (1) and at least one resonant conductor track structure (31 to 39) are described, which are particularly suitable for mobile dual-band and multiband telecommunication devices such as mobile and cellular telephones, as well as for devices which communicate in accordance with the Bluetooth standard. In addition, attuning of the resonance frequencies of various operating modes to a concrete constructional situation is possible thanks to various line segments (34, 35) and tuning stub lines (41, 42) without the necessity of changing the fundamental antenna design. Finally, the antennas may be soldered together with other components onto a printed circuit board in a conventional surface mounting process.

Rebar stanchion horizontal lifeline fall arrest system

Abstract: A horizontal lifeline support system for use with a rebar stub or stud extending from a building structure. The system includes a stanchion having an elongated body, the body having a top end and a bottom end, the bottom end having an aperture therein, the aperture being adapted for accepting the rebar stud or stub on the building structure, and at least one guy member, the guy member having a pair of opposite ends, one of the ends of the guy member being connected to the top end of the stanchion and the opposite end having a clamp attaching the second end of the guy member to the building structure.

Broadband surge protector with stub DC injection

Abstract: A surge protector includes a coaxial through-section having a through inner conductor and a through outer conductor, a stub having a stub inner conductor, a stub outer conductor, a first end and a second end. The stub is coupled to the coaxial through-section, wherein the stub inner conductor is conductively coupled to the through inner conductor at the first end of the stub, and the stub outer conductor is conductively coupled to the through outer conductor at the first end of the stub. The stub inner conductor is substantially hollow and having at least one helical aperture disposed therein. A charge elimination device conductively coupled between the stub inner conductor and a grounding device, and a radio frequency short circuit bypass is electrically coupled between the stub inner conductor and the stub outer conductor. A DC injection port is also conductively coupled between the stub inner conductor and the stub outer conductor.

Method and apparatus for impedance matching in an amplifier using lumped and distributed inductance

Abstract: An impedance matching circuit (140) includes a capacitive element (C1, 220), having a capacitance C, coupled in parallel with an output node (215) of the matching circuit, and an inductor (L1, 225) coupled in series with a transmission line (T1, 230) between the input node and the output node. The transmission line has a length that, in combination with the inductor, provides impedance substantially equal to the input impedance of the transmission circuit (150) at a frequency of interest. In one embodiment, the inductor is connected to an output (195) of an amplifier (180), and the transmission line is connected to the inductor and to the output (215). The capacitive element is connected to the transmission line such that the length of the transmission line between the inductor and the capacitive element provides the desired inductance.

Tunability of acoustic spectral gaps and transmission in periodically stubbed waveguides

Abstract: A theoretical investigation is made of acoustic wave propagation in a periodically stubbed waveguide. In general the waveguide segments and stubs are made of different materials. The acoustic wave in such a system has twoindependent polarizations: out-of-plane and in-plane modes. The band structure and transmission spectrum is studied for diverse geometries using a simple and efficient version of the transfer-matrix method. For the same material between the waveguide and symmetric stubs the width of some gaps can change, upon varying the stub length or width, by more than one order of magnitude. A further modulation can be achieved for different material between the stubs and the main waveguide or if the stubs are asymmetric. The gaps in the band structure of an infinitely long system correspond to those in the transmission spectrum of the same system but with finite number n of units. For n finite (i) there exist pseudogaps that gradually turn into complete gaps with increasing n and (ii) the introduction of defects gives rise to states in the gaps and leads to transmission resonances.

Digital receiving system for dense environment of aircraft

Abstract: The capacity of a Mode-S ADS-B surveillance radar system is increased by sectorizing the radar system by the use of a directional array of Mode-S, quarter wavelength, single element, stub antennas. The ensemble of signals from the array of Mode-S antenna elements is processed electronically. The signal processing/receiver architecture increases the capacity of the Mode-S ADS-B system to be capable of effectively functioning within a highly congested airspace.

Coaxial continuous transverse stub (CTS) array

Abstract: A new coaxial continuous transverse stub (CTS) array is proposed, designed, constructed, and tested. It is an omni-directional low cost antenna array which provides good impedance matching characteristics and good tolerance to manufacturing errors. It can be simply fed by a coaxial connector and is particularly suitable for millimeter wave personal communication systems (PCS). It is shown that this type of radiating element provides high percentage of radiation, and for the simulated design of single- and multiple-element arrays, S/sub 11/ was below -10 dB across a 6 GHz frequency span at the Ka band. A three-element prototype coaxial CTS antenna array was designed, constructed, and tested in the X-band. Experimental results were in good agreement with the simulated performance. Potential application of this new antenna array in multiband operation is also described.

Method of forming a structure for electronic devices contact locations

Abstract: Probes for electronic devices are described. The probe is formed by ball bonding a plurality of wires to contact locations on a fan out substrate surface. The wires are cut off leaving stubs. A patterned polymer sheet having electrical conductor patterns therein is disposed over the stubs which extend through holes in the sheet. The ends of the wires are flattened to remit the polymer sheet in place. The wire is connected to an electrical conductor on the polymer sheet which is converted to a contact pad on the polymer sheet. A second wire is ball bonded to the pad on the polymer sheet and cut to leave a second stub. The polymer sheet is laser cut so that each second stub is free to move independently of the other second studs. The ends of the second stubs are disposed against contact locations of an electronic device, such as an FC chip, to test the electronic device.

Linearly polarised radial stub fed high performance wideband slot antenna

Abstract: A wideband printed slot antenna fed by a radial stub operating over the mobile communication bands PCN (1.716-1.880 GHz) and UMTS (1.9-2.0 GHz and 2.1-2.2 GHz) is presented. The impedance bandwidth of the antenna achieved for a VSMR/spl les/2 is 34% and the radiation patterns remain stable over the entire frequency band of operation (1.7-2.4 GHz) with cross-polarisation levels of less than -20 dB. Simulated and measured radiation pattern and return loss results are presented.

Directional coupler and directional coupling method

Abstract: Input port 101 is connected to output port 102 via open-circuited stub 107 , first transmission line 105 and open-circuited stub 108 . Coupling port 103 is connected to isolation port 104 via second transmission line 106 in electromagnetic coupling with first transmission line 105 . Open-circuited stubs 107 and 108 have a stub length corresponding to ¼ wavelength in desired stop frequency. It is thereby possible to provide a directional coupler and directional coupling method enabling the miniaturization and harmonic spurious suppression effect with a low loss and with excellence even in microwave/millimeter wave band.

Harmonic rejection load pull tuner

Abstract: The present invention discloses a harmonic rejection load pull tuner. The tuner of the invention has a large-band tuner having an input and an output, and a transmission line having a longitudinal axis. The transmission line has an input connected to the output of a DUT and an output connected to the input of the large-band tuner. In parallel with the transmission line is at least one stu b, the at least one stub having a length adapted to reflect out an nth order harmonic of a base frequency, where n is an integer greater than 1. The tuner of the prese nt invention can be used to perform input or output characterisation (or both) of a DUT, by selectively reflecting out at least one harmonic frequency of the ba se frequency. Consequently, the characterisation of the DUT is improved, since the effects of the harmonics are considerably reduced. The present invention als o concerns a method for performing input or output characterisation.

Design for openings in cold-formed steel channel stub columns

Abstract: This paper is concerned with the ultimate load capacity of perforated cold-formed steel channel stub columns. A design equation has been developed to determine the ultimate load capacity of perforated channel short columns containing either single or multiple openings of square, circular and manufacturer's opening shape. The equation is based on extensive parametric studies carried out using finite element modelling on plain and lipped channel sections containing openings. A wide range of parameters such as plate slenderness, opening shapes and sizes have been considered in the study. Web plate slenderness and opening area ratio are the two main variables used to derive the design equations. The accuracy of the proposed design equation is established by comparison with a number of experimental and finite element results reported by other researchers.

New class of microstrip miniaturised filter using triangular stub

Abstract: A new class of compact microstrip filter loaded with a low-characteristic impedance triangular stub is introduced. The respective filter upper stopband selectivity is improved. Without the presence of cross-coupling between non-adjacent resonators, one transmission zero is observed. Frequency tuning can easily be achieved by adjusting the reactance of the stub.

Design of a low-cost 2-D beam-steering antenna using ferroelectric material and CTS technology

Abstract: The design of a new low-cost antenna array with two-dimensional beam-scanning capability is presented in this paper. The design procedure is based on the continuous transverse stub (CTS) technology and the use of ferroelectric material. With the application of a low-loss ferroelectric material barium strontium titanium oxide with 40% oxide III, beam-scan capability from -60/spl deg/ to 60/spl deg/ was achieved. The tradeoffs in selecting the ferroelectric material and between losses and bias voltage in the CTS design were also examined. Furthermore, it was found necessary to adjust the dimensions of the radiating stubs, as well as the connecting sections of the feed waveguide so as to eliminate reflections between the stubs and, hence, maintain the desirable radiation pattern. It is shown that the use of an average height for the feed waveguide will result in deterioration in the radiation pattern.

New phase shifters and phased antenna array designs based on ferroelectric materials and CTS technologies

Abstract: As the search continues for low-cost and high-performance components for the front-end devices for wireless communications systems, some focus has been placed on exploring new and innovative designs based on ferroelectric technology. In this paper, we present new phase-shifter designs and an integrated phased-array antenna system based on the use of multilayer ferroelectric materials and the continuous transverse stub (CTS) technologies. Simulation results show that with the appropriate selection of the materials properties and the dimensions of the multilayer dielectric system, insertion losses may be reduced by as much as a factor of 100. These results also show that while only a slight reduction (15%) in the maximum achievable tunability was observed, it was possible to achieve significant improvement in impedance-matching characteristics. A procedure to enhance the radiation efficiency from an integrated ferroelectric/CTS phased antenna array design is described and specific array designs are discussed.

ALiquid Impedance Matching System for Ion Cyclotron Heating

Abstract: Ion cyclotron heating has been established as one of the heating schemes in nuclear fusion research and its use in steady state plasma heating in various devices is being considered. The optimal technology for steady state ion cyclotron range of frequency heating has not been firmly established. This article reports on the liquid stub tuner which was newly developed in research and development activities on the large helical device. It demonstrated high performance in real use in experiments. Two different impedance-matching systems based on the liquid stub tuner are studied: one is a triple liquid stub tuner system and the other is a single stub tuner system with a liquid phase shifter. The characteristics of the two systems are compared from the points of view of how wide a frequency range is covered, and how great the reduction of the voltage in the transmission line is.

Design for openings in equal-angle cold-formed steel stub columns

Abstract: This paper is concerned with the ultimate load capacity of non-perforated and perforated equal-angle cold-formed steel stub columns. An experimental study has been undertaken to investigate the behavior of such members and several column specimens were tested to failure under axial or eccentric loading. The experimental results were used to establish the accuracy of a finite element model proposed in this study and the modeling was used to carry out a parametric study. The study covers parameters such as plate slenderness ratio of the cross-section, perforation shape, size and number. A simplified design formula is proposed to determine the ultimate load-carrying capacity using the data obtained from the parametric study. The accuracy of the proposed formula is established by comparison with the experimental and finite element values.

Method and apparatus for measuring harmonic load-pull for frequency multiplication

Abstract: A method for measuring harmonic load-pull including supplying a fundamental frequency signal to a frequency multiplication device under test and obtaining a target even-order multiplied frequency signal. The fundamental load impedance and an even-harmonic load impedance are independently controlled with a load mechanical tuner having an open-ended stub that is one-quarter wavelength long at the fundamental frequency and satisfies a short-circuit condition with respect to the fundamental signal. A fundamental source impedance and an even-harmonic source impedance of an input signal applied to the device under test are independently controlled with a source mechanical tuner having a short-circuit stub that is one-quarter wavelength long at the fundamental frequency and satisfies a short-circuit condition with respect to even-harmonics.

Stub-tuned photonic crystal waveguide

Abstract: A photonic crystal waveguide apparatus has a photonic crystal having a waveguide which is capable of transmitting light having a frequency within a bandgap of the photonic crystal, and a resonant stub connected to the waveguide to control light in the waveguide. The resonant stub has a resonator region and a connecting channel which connects the resonator region to the waveguide. The resonant stub controls light transmission characteristics of the waveguide by creating a transmission zero in the transmission band of the waveguide. A tuner for tuning the resonant stub may also be provided to control the transmission zero to provide an active optical apparatus such as an on/off switch or a modulator.

Switch assembly with a multi-pole switch for combining amplified RF signals to a single RF signal

Abstract: A switch assembly has a housing and a plurality of controllable switches. The housing has a plurality of input ports and an output port and the plurality of individually controllable switches is arranged within the housing. Each switch has an open position and a closed position and is coupled to one of a plurality of input ports of the housing and a common summing junction within the housing. Each input port receives a coherent radio frequency (RF) signal. The output port is coupled to the common summing junction and outputs a sum signal that includes at least one of the RF signals received at the common summing junction when a switch is in the closed position. The switch assembly may further include impedance matching lines that transform a reference impedance value to a higher value prior to switching and an impedance transformation line that provides for the reference impedance value at a distal end of the impedance transformation line. The impedance transformation lines may be located outside the housing, inside the housing or inside and outside the housing. Further, the switch assembly may include at least one matching stub associated with the output port.