Showing papers on "Stub (electronics) published in 2003"

Broadband CPW-fed square slot antennas with a widened tuning stub

Abstract: By using a coplanar waveguide (CPW) feed with a widened tuning stub, a square slot antenna for broadband operation is presented. Experimental results show that the impedance matching for the proposed antenna strongly depends on the location of the tuning stub in the square slot, and the impedance bandwidth is mainly determined by the width and length of the tuning stub. By properly choosing the location and the size of the tuning stub, a wide impedance bandwidth of 60% can be obtained, which is about 1.9 times that of a conventional CPW-fed square slot antenna with a simple tuning stub. Details of the experimental results are presented and discussed.

Transmission and dispersion relations of perfect and defect-containing waveguide structures in phononic band gap materials

Abstract: By using a combination of finite difference time domain (FDTD) and plane wave expansion (PWE) methods, we study the propagation of acoustic waves through waveguide structures in phononic band gap crystals composed of solid constituents. We investigate transmission through perfect linear waveguides, waveguides containing a resonant cavity, or waveguides coupled with a side branch resonator such as a cavity or a stub. A linear guide can support one or several modes falling in the absolute band gap of the phononic crystal. It can be made monomode over a large frequency range of the band gap by varying the width of the guide. The transmission through a guide containing a cavity can be made very selective and reduced to narrow peaks associated with some of the eigenmodes of the cavity. The effect of a side branch resonator is to induce zeros of transmission in the spectrum of the perfect guide that appear as narrow dips with frequencies depending upon the shape of the resonator and its coupling with the guide. We find perfect correspondences between the peaks in the transmission spectrum of a waveguide containing a cavity and the dips in the transmission of a cavity side coupled waveguide. Finally, when a gap exists in the spectrum of the perfect guide, a stub can also permit selective transmission of frequency in this gap. The results are discussed in relation with the symmetry of the modes associated with a linear guide or with a cavity.

Compact microstrip bandpass filter with two transmission zeros using a stub-tapped half-wavelength line resonator

Abstract: A compact microstrip bandpass filter is developed using a half-wavelength (/spl lambda//2) transmission line resonator with a pair of tap-connected open-ended stubs. Such paired stubs with total length of about /spl lambda//2 constructs an equivalent line resonator. Together with two separated /spl lambda//4 line resonators, the three transmission poles can be achieved inside the passband. Meanwhile, two stub lengths are adjusted slightly longer and shorter than /spl lambda//4 to realize the two transmission zeros at both low and high rejection bands. Further, the long tapped-stub is kept wider than its short counterpart to improve the low rejection behavior. A filter sample is designed and fabricated to provide an experimental verification on the proposed filter.

Oscillator module incorporating looped-stub resonator

Abstract: A transmission line configured as a looped-stub resonator is disclosed, which can be used as a frequency selective element for an oscillator, such as a VCO of a phase locked loop. The transmission line is a fraction of an electrical wavelength, and can be embedded to provide an inner resonant layer of an overall layered structure. The transmission line is formed into a loop or multiple loops and may be terminated with a capacitor, short circuit, or open circuit. In the embedded case, dielectric insulating material can be used to surround the transmission line on top and bottom surfaces as layers. In addition, electrically conducting material layers can be used to surround the dielectric insulating material.

MEMS switchable interdigital coplanar filter

Abstract: This paper presents a tunable interdigital coplanar filter with tapped-line feedings. Microelectromechanical systems capacitors are used as a high contrast capacitive switch between a quarter-wavelength resonator and an open-ended stub to perform the frequency shift. A two-pole tunable filter with a 13% relative bandwidth has been designed, fabricated, and measured. The center frequency can be switched from 18.5 to 21.05 GHz with low return losses (less than 15 dB) and low insertion losses (3.5 dB).

High-power photonic millimetre wave generation at 100 GHz using matching-circuit-integrated uni-travelling-carrier photodiodes

Abstract: The design and characterisation of a millimetre wave uni-travelling-carrier photodiode with a monolithically integrated matching (impedance transform) circuit utilising a coplanar-waveguide short stub are presented. The device with the matching circuit shows about 50% higher efficiency at 100 GHz than the one without it. The frequency response was characterised through time-domain measurement by means of an electro-optic sampling technique. The 1 dB down bandwidth of the device is as wide as 40 GHz, and the frequency response characteristics are in good agreement with circuit model calculations. The maximum saturation output power is 20.8 mW at 100 GHz for a bias voltage of -3 V, which is the highest output power ever generated directly from a photodiode in the W-band.

A novel bi-directional amplifier with applications in active Van Atta retrodirective arrays

Abstract: A novel two-port bi-directional amplifier, which may simultaneously amplify the waves coming from both ports, is proposed and demonstrated in this paper Using this amplifier, a two-element active Van Atta retrodirective array is implemented and compared to a four-element passive array The bi-directional amplifier is constructed by two identical one-port reflection-type amplifiers and a 3-dB 90/spl deg/ hybrid The reflection-type amplifier is designed using an FET with a single-power-supply configuration A quarter-wavelength microstrip radial stub is connected to the device's source terminal to narrow down the negative-resistance frequency range so as to avoid oscillation at undesired frequencies The fabricated bi-directional amplifier provides the transmission gain over the frequency band from 576 to 688 GHz, with a peak value of 91 dB at 604 GHz Printed Yagi antennas with four directors are adopted to build both the active and passive Van Atta arrays The 3-dB back-scattering beamwidth of the active array is measured as wide as 74/spl deg/ Finally, it is observed from the measurements that, although only half of the antenna elements are used, the active Van Atta array produces a back-scattering field level 45 dB, on average, higher than the passive one does This verifies the performance of the bi-directional amplifier

A Single-Feed, Multi-Band, Virtual Two-Antenna Assembly Having the Radiating Element of One Planar Inverted-F Antenna (PIFA) Contained Within the Radiating Element of Another PIFA

Abstract: A unitary assembly provides two virtual planar inverted-F antennas (PIFAs) within a physical volume that is occupied by one of the PIFAs. The virtual two-antenna assembly includes a single RF feed, and provides multiple frequency response in the AMPS, PCS, GSM, DCS and GPS frequency bands. A composite radiating element is supported above a ground plane. A C-shaped slot divides the composite radiating element into an outer radiating element and an inner radiating element. Two metal stubs within a slot-discontinuity of the C-shaped slot physically and electrically connect the outer radiating element to the inner radiating element. An RF feed post connects to the outer radiating element, and both of the inner and outer radiating elements are shorted to the ground plane. One metal stub provides virtual RF feed to the inner radiating element, the other metal stub provides a matching and/or tuning function to the inner radiating element, and the two metal stubs provide a matching and/or tuning function to the outer radiating element. The outer radiating element includes an L-shaped slot, and the inner radiating element includes a linear slot. Reactive loading plates extend from the composite radiating element toward the ground plane.

Resonance stub effect in a transition from a through via hole to a stripline in multilayer PCBs

Abstract: We present results of study of the resonance stub effect occurring in a transition from a through via hole to a stripline in a multilayer printed circuit board (PCB). This effect for via structures including ground vias is estimated by numerical simulations and measurements in the frequency band up to 20 GHz. Ways to alleviate problems in the design of interconnections embedded in multilayer PCBs due to the resonance stub effect and possible applications of the effect in microwave filtering are traced.

Low conversion-loss fourth subharmonic mixers incorporating CMRC for millimeter-wave applications

Abstract: Low conversion-loss millimeter-wave fourth subharmonic (SH) mixer designs are proposed in this paper. A millimeter-wave (35 GHz) fourth SH mixer with four open/shorted stubs is designed and measured. The conversion loss is less than 15 dB within a 2.4-GHz bandwidth. The minimum loss is 11.5 dB at the center frequency. By replacing two of the shunt stubs with a dual-frequency in-line stub consisting of newly developed compact microstrip resonating cells (CMRCs), the performance of the SH mixer is improved significantly. At 35 GHz, the conversion loss of this new fourth SH mixer is as low as 6.1 dB with a 3-dB bandwidth of 6 GHz. The conversion loss in the whole Ka-band (26.5-40 GHz) is less than 16 dB. The proposed fourth SH mixer incorporating with CMRCs provides a low-cost high-performance solution for RF subsystem design.

Novel subharmonically pumped mixer incorporating dual-band stub and in-line SCMRC

Abstract: A subharmonically pumped (SHP) mixer with very low conversion loss is proposed. The mixer employed the newly developed spiral compact microstrip resonant cell (SCMRC) and compact dual-band stub (DBS). Incorporating the in-line SCMRC and DBS into a second SHP mixer, we can provide proper terminations for the IF, RF, and local-oscillator (LO) signal simultaneously in addition to all major unwanted mixing products, leading to a unique low conversion-loss design. Our SHP mixer with a measured 3.9-dB single-sideband (SSB) down-conversion loss at 11.6-GHz RF signal outperforms typical designs of 8-12 dB, and represents a state-of-the-art performance for a planar X-band harmonic mixer. With a broad-band operation, our mixer shows an SSB down-conversion loss of less than 8.2 dB from 9 to 12.8 GHz. Moreover, the measured LO-RF isolation is better than 45 dB for LO frequency ranges of 4-5.8 GHz. Large-signal two-tone measurements reveal an excellent linear response of the working prototype, showing 7.5 dBm and 52 dB for the 1- dB power compression point and spurious-free dynamic range, respectively.

Reversible fiber optic stub fiber connector

Abstract: A fiber optic stub fiber connector for reversibly and nondestructively terminating an inserted field fiber having a buffer over at least a portion thereof. The connector includes a housing and a ferrule including a stub fiber disposed within and extending from a bore through the ferrule. The ferrule is generally at least partially disposed within and supported by the housing. The connector further includes a reversible actuator for reversibly and nondestructively terminating the inserted field fiber to the stub fiber. The reversible actuator includes a buffer clamp for engaging with the buffer to simultaneously provide reversible and nondestructive strain relief to the terminated field fiber.

Antenna with shorted active and passive planar loops and method of making the same

Abstract: The present invention provides an internal antenna for wireless devices comprising a ground plane and a planar loop antenna. The shorted loop antenna is provided with a gap and operates at a quarter wavelength. The compact single feed dual or multi band internal antenna is realized either through composite assembly of an active outer and inner radiating elements or by a selective combination of an active outer radiating element and a parasitic inner radiating element. The inner radiating element of the proposed invention is completely encompassed within the outer radiating element. The resonant tuning of the internal antenna is accomplished by means of the matching stub and capacitive loading plates with the matching stubs being entirely internal to the outer radiating element.

Method of making an optical fiber by laser cleaving

Abstract: A field-installable connector includes a connector housing and a ferrule having front and rear opposed faces and at least one fiber bore defined longitudinally therethrough. A laser processed stub optical fiber is disposed within the one fiber bore of the ferrule and extends a predetermined distance beyond the rear face of the ferrule. An alignment feature is operable for self-centering the stub optical fiber and a field optical fiber to perform a mechanical splice using a camming means. A method of laser processing a stub optical fiber includes rotating the stub optical fiber and sweeping a laser beam directed at a desired angle back and forth across a surface of the optical fiber. An oscillating motion of the laser is driven by an intermittent sinusoidal signal that results in two deposits of energy onto the stub optical fiber followed by a cooling period before subsequent deposits of energy occur.

System for terminating optical fibers in a fiber optic connector

Abstract: A fiber optic connector assembly includes an outer housing (16) having an interior cavity (18). A termination module (20) is insertable into the cavity and includes a ferrule (24) for terminating a distal end of at least one optical fiber stub. A base (26) is attached to the ferrule and includes a channel for splicing a proximal end of the optical fiber stub to a fiber end of a fiber optic cable. A cover (34, 36) is positionable onto the base for holding the fiber stub and fiber end in the channel. A clamp (38) is provided for holding the cover onto the base. A latch (38c) is provided between the clamp and the outer housing for holding the termination module in the cavity of the housing.

Permanent magnet rotor construction wherein relative movement between components is prevented

Abstract: A rotor construction may comprise a rotor with a centrally located permanent magnet section having aligned magnet segments and having a central hole throughout its length. A thin rod of magnetic steel is located in this central hole to support the permanent magnets from within. At each end of the rod are located threaded sections for attachment to supporting end stubs. A high strength steel sleeve is interference fit over both the magnets and the end stubs to provide a mechanical link from stub to stub. The guide rod insures that the end stubs and central magnet are concentric during initial processing, prevents relative motion between the rotor components and provides support for the magnet once the sleeve is installed.

A method to enhance the bandwidth of microstrip antennas using a modified E-shaped patch

Abstract: In this paper, a patch antenna with a slot and a tuning stub, or called a modified E-shaped patch (MESP), has been studied. Simulation has shown that the tuning stub has introduced a new resonant frequency, resulting in a bandwidth of 380 MHz, or 6.8% relative to the central frequency of 5.58 GHz. The experimental result shows 400 MHz, or 7.2%. While the bandwidth of a common rectangular patch of the same size on the same substrate, which is 220 MHz, or 3.96%, by simulation, and 254 MHz, or 4.6% by experiment.

Variable inclination continuous transverse stub array

Abstract: An antenna array employing continuous transverse stubs as radiating elements is disclosed. In an exemplary embodiment, the array includes an upper conductive plate structure comprising a set of continuous transverse stubs, and a lower conductive plate structure disposed in a spaced relationship relative to the upper plate structure. A rotation apparatus provides rotation between the upper plate structure and the lower plate structure.

Tuned radio frequency coaxial connector

Abstract: A tuned RF coaxial connector for mating a coaxial transmission line includes a cylindrical outer conductor, a coupling mechanism for mating the coaxial transmission line to the substantially cylindrical outer conductor, and an inner conductor extending coaxially within cylindrical outer conductor. One end of the cylindrical outer conductor interfits with the coaxial transmission line and another end of the cylindrical outer conductor interfits with an electrical device. The connector has an open circuit inner stub where the inner conductor of the transmission line couples to the inner conductor of the connector, or an open circuit outer stub where the outer conductor of the transmission line couples to the outer body of the connector, or both. Without the need for precise fitting of the conductors of the coaxial transmission line and the connector, the invention facilitates field installation of cables and connectors while reducing implementation cost.

Design and analysis of UWB band pass filter

Abstract: To realize a band pass filter (BPF) in ultra-wide band (UWB) communications, a device using a ring resonator with a stub is investigated A new proposal is made to control the frequency of the attenuation poles using both the ring and the stub impedance A five stage wide-band BPF is fabricated in this manner Its center frequency and bandwidth are calculated based on the ring resonator model The circuit conditions for obtaining two attenuation poles at either side of the pass band are given, together with a method for controlling them

Analysis and characterization of traveling-wave electrode in electroabsorption modulator for radio-on-fiber application

Abstract: Comparing with a lumped electroabsorption modulator (EAM), we show the merits of a long EAM with traveling-wave electrode with high radio-frequency (RF) gain that could be used in high-frequency analog application. By terminating the RF output port with the characteristic impedance of 30 /spl Omega/, the device exhibited a large enhancement of 6 dB above 10 GHz in the electrical-to-optical response and a wide fractional bandwidth as estimated from simulation. In addition, an input impedance matching circuit of stub embedded on the device chip was found to be very effective for improving RF characteristics in the narrow band of frequency.

Trailer sub-frame assembly

Abstract: A sub-frame assembly for use with a vehicle having wheels such as a trailer is provided The sub-frame assembly comprises two or more frame members, one or more cross members, and two or more stub torsion axle assemblies Each of the stub torsion axle assemblies have a torsion arm, a spindle extending from the torsion arm for mounting one of the wheels, and a distal end extending from the stub torsion axle assembly for mounting to the frame assembly The frame assembly may further comprise one or more shim plates for reception between the cross member and the distal end of the stub torsion axle assembly for allowing adjustment of the toe angle of the wheel assembly In addition, the stub torsion axle assembly may be rotatably mounted to the cross member whereby the camber angle of the wheel assembly may be adjusted

Compact-size coplanar waveguide bandpass filter

Abstract: A compact-size coplanar waveguide (CPW) bandpass filter (BPF) is proposed. In this study, we use the bended stub with novel folded skill to improve the three parallel coupled-lines structure of BPF for N = 1. It gets the sharp transition band (TB) and reduces the dimension of the circuit by 66.67% at 2.45 GHz. Its center frequency can be shifted easily by adjusting the interfaces of SS and S'S' simultaneously. It is very useful for applications in the wireless communication systems.

Antenna with printed compensating capacitor

Abstract: An antenna on a printed circuit board (PCB) with a compensating capacitor. The antenna has a radiator disposed over a first surface of the PCB. Wherein the radiator includes a signal feeding section and a tuning section coupled together at a joint. The tuning section includes a bending portion. Also and, a ground layer with or without a protuding portion is disposed on a second surface of the PCB, wherein the bending portion of the tuning section is overlapping with the ground layer to form the compensating capacitor. In addition, the radiator can also have a short circuit stub section, electrically coupled to the ground layer.

High power variable slide RF tuner

Abstract: A high power slide tuning capacitor (200) integrated into a circuit board adapted to function at RF and microwave frequencies. The capacitor (200) is comprised of a dielectric substrate (26) with a cavity (28) cut into a side of the substrate (26); a ground plane (24) mounted on a bottom surface of the dielectric substrate (26); a microstrip patch (22) mounted on a top surface of the dielectric substrate (26) and positioned above the cavity (28); and a movable dielectric stub (30) which engages the cavity (28) such that a variable length of the stub (30) is positioned beneath the microstrip patch (22). The microstrip patch (22) can be coupled to a desired circuit trace (20), effectively forming a shunt capacitor to ground.

Dual-band circularly polarized dielectric resonator antenna

Abstract: By choosing adequate shorted section of an annular slot, CP operation of the slot-coupled DRA has been implemented. From the results obtained, by changing the slot radius, a DR element can meet wide frequency band selections. And, using a pair of concentric C-shaped slots to excite dual-band CP operation has also been successfully implemented. The experimental results show good CP radiation characteristics for the two operating bands of the proposed design. Finally, it should be noted that the frequency ratio of the two operating modes shown here is /spl sim/1.67. By varying the two concentric C-shaped slots radius and fine-adjusting the shorted section flared angle and tuning stub length, different frequency ratios of the proposed dual-band CP operation are expected to be achieved.

The OSPF Not-So-Stubby Area (NSSA) Option

Abstract: This memo documents an optional type of Open Shortest Path First (OSPF) area that is somewhat humorously referred to as a "not-so- stubby" area (or NSSA). NSSAs are similar to the existing OSPF stub area configuration option but have the additional capability of importing AS external routes in a limited fashion.

Process control instrument intrinsic safety barrier

Abstract: A process control instrument includes a circuit board having a control circuit for generating or receiving a high frequency signal. An antenna includes an electrical conductor. An intrinsic safety circuit couples the control circuit to the antenna and comprises a microstrip transmission line on the circuit board electrically connecting the control circuit to the electrical conductor. A safety stub has a first end electrically connected to the transmission line proximate the electrical conductor and a second end connected to a ground of the control circuit.

Wideband dielectric resonator antenna excited by cavity-backed circular aperture with microstrip tuning fork

Abstract: A wideband dielectric resonator antenna excited by a circular aperture is investigated experimentally The aperture is coupled by a microstrip feedline with a microstrip fork-like tuning stub A backing cavity is placed beneath the stub to block undesirable backside radiation The return loss, field pattern, and antenna gain of the proposed configuration were measured, and the results are compared with those without the backing cavity