Showing papers on "Stub (electronics) published in 2009"
TL;DR: In this paper, a single-feed low-profile and easy to fabricate circularly polarized microstrip patch antenna has been developed for GPS applications, where four slots are etched near edges of the patch and a crossed slot etched in the center for generating circular polarization.
Abstract: A single-feed low-profile and easy to fabricate circularly polarized microstrip patch antenna has been developed for GPS applications. For dual frequency operation, four slots are etched near edges of the patch and a crossed slot etched in the center for generating circular polarization. In order to reducing the frequency ratio of two frequency bands of the antenna, the patch is loaded by four short circuit microstrip stubs. The paper reports several simulation results that confirm the desired characteristics of the antenna. Using stub loading, the frequency ratio of two bands of the antenna can be, even, reduced to 1.1.
152 citations
Patent•
28 May 2009TL;DR: In this paper, a voltage controlled oscillator having low phase noise and including a variable resonator including a varactor and a control voltage terminal is described. And a high Q value is realized for a fundamental wave frequency, where the oscillator is connected to an open-end stub having a length shorter than or equal to an odd multiple of one quarter of a wavelength of a harmonic signal plus one sixteenth of the wavelength of the harmonic signal.
Abstract: A voltage controlled oscillator having low phase noise and including: a variable resonator including a varactor and a control voltage terminal; and an open-end stub connected in parallel to the variable resonator, the open-end stub having a length shorter than or equal to an odd multiple of one quarter of a wavelength of a harmonic signal plus one sixteenth of the wavelength of the harmonic signal, and longer than or equal to an odd multiple of one quarter of the wavelength of the harmonic signal minus one sixteenth of the wavelength of the harmonic signal. In this structure, a high Q value is realized for a fundamental wave frequency. Fluctuation in a control voltage due to a harmonic signal is controlled.
149 citations
TL;DR: In this paper, the authors proposed a dual-band circular polarization (CP) antenna with ground plane embedded with an inverted-L slit, which is capable of generating a resonant mode for broadband impedance-bandwidth.
Abstract: Novel broadband monopole antenna designs with dual-band circular polarization (CP) are presented. The proposed antenna comprised of a ground plane embedded with an inverted-L slit, which is capable of generating a resonant mode for broadband impedance-bandwidth, and excites two orthogonal E vectors with equal amplitude and 90deg phase difference (PD) for radiating left-hand circular polarization (LHCP) at 2.5 GHz and right-hand circular polarization (RHCP) at 3.4 GHz. A bevel is cut in the rectangular radiator to increase the impedance-bandwidth. The measured result of the impedance-bandwidth is about 4.46 GHz from 2.12 to 6.58 GHz; the 3-dB axial ratio (AR) bandwidths are about 150 MHz at the lower band (2.5 GHz) and 230 MHz at the upper band (3.4 GHz). Furthermore, embedding an I-shaped slit in the rectangular radiator and adding an I-shaped stub in the ground plane, the impedance-bandwidth can be further increased to 6.30 GHz (2.17-8.47 GHz), and the 3-dB AR-bandwidth at the upper band is greatly enhanced from 230 to 900 MHz.
136 citations
TL;DR: In this paper, a generalized approach to design an electromagnetically coupled microstrip ring antenna for dual-band operation is presented, where a stub is attached to the inner edge of the side opposite to the feed arm to compensate for the losses in electrical length caused by widening.
Abstract: This paper presents a generalized approach to design an electromagnetically coupled microstrip ring antenna for dual-band operation. By widening two opposite sides of a square ring antenna, its fractional bandwidth at the primary resonance mode can be increased significantly so that it may be used for practical applications. By attaching a stub to the inner edge of the side opposite to the feed arm, some of the losses in electrical length caused by widening can be regained. More importantly, this addition also alters the current distribution on the antenna and directs radiations at the second resonant frequency towards boresight. It has also been observed that for the dual frequency configurations studied, the ratio of the resonant frequencies (center dot r(2)center dot center dot r(1)) can range between 1.55 and 2.01. This shows flexibility in designing dual frequency antennas with a desired pair of resonant frequencies.
83 citations
TL;DR: In this paper, the authors presented a direct synthesis procedure for efficient design of a class of ultra-wideband bandpass filters with composite series and shunt transmission-line stubs.
Abstract: This paper presents a direct synthesis procedure for efficient design of a class of ultra-wideband bandpass filters with composite series and shunt transmission-line stubs. The proposed single-stage bandpass prototype is formed by cascading two sets of series open-ended and shunt short-ended stubs through a multisection nonuniform transmission line. All the stubs are set with an identical electrical length, i.e., thetasc , at lower cutoff frequency fc and the middle connecting line is composed of stepped-impedance transmission line with i sections, and each section has an electrical length thetasc. The proposed filter topology aims to construct an ultra-wide bandpass filter with Chebyshev equal-ripple responses and (i + 3) in-band transmission poles. Based on the derivation of the transfer function, a synthesis approach is established and systematically described to design this type of filters according to the specifications such as lower/upper cutoff frequencies. Next, a multistage bandpass filter prototype is proposed and the synthesis design procedure is also presented. The implementation is achieved by using hybrid microstrip line and slotline sections. Compared with traditional stub filters, the proposed filters achieve higher order transmission zeros and thus provide higher selectivity. As design examples, two single-stage and one three-stage bandpass filters are designed and fabricated to confirm the theoretical predictions.
77 citations
TL;DR: Investigation reveals that the transmission valleys of the spectra could be divided into two categories, which is quite different from conventional Bragg reflectors.
Abstract: Plasmonic reflectors based on serial stub structure are studied in this paper. A general theory of periodic stub structure using transmission line model is developed. The transmission characteristics, e.g., periodicity and symmetry of the spectra, are closely related to the ratio of structure period to stub length. Investigation reveals that the transmission valleys of the spectra could be divided into two categories, which is quite different from conventional Bragg reflectors. Finite-Difference Time-Domain (FDTD) method is used in numerical analysis in this paper.
76 citations
07 Jun 2009
TL;DR: In this paper, a 60 GHz reflectarray with a single p-i-n diode was investigated. And the reflection phase was changed by 180° in accordance with the on/off state of the diode, which works as a single-bit phase shifter.
Abstract: A 60-GHz band electrically reconfigurable reflectarray has been investigated. Each reflecting element is printed on a dielectric substrate and has a rectangular microstrip patch and a stub loaded with a single p-i-n diode. The reflection phase is changed by 180° in accordance with the on/off state of the p-i-n diode; namely, the stub works as a single-bit phase shifter. A prototype consisting of 40 × 40 elements spaced at 0.7λ was fabricated, and the reflection coefficients of the elements and the radiation patterns while the beam steering was performed were measured. Good agreement was observed between the results of the simulations and experiments.
72 citations
TL;DR: In this article, the effects of preload and cooling phase on the residual strength and stiffness of concrete-filled steel tubular (CFT) stub columns which were heated and cooled down to room temperature under sustained axial load were investigated.
69 citations
TL;DR: In this article, a triple-mode hexagonal bandpass fllter with capacitive loading stubs is introduced, which adds an open capacitive stub to enlarge the equivalent self capacitance of the resonator, which declines its resonant frequencies.
Abstract: A novel triple-mode hexagonal bandpass fllter with capacitive loading stubs is introduced in this article. The technique, adding an open capacitive stub, is applied to enlarge the equivalent self- capacitance of the resonator, which declines its resonant frequencies. Three radial-line stubs in the center of top layer are used to implement this technique. One mode resonant frequency is varied with the radii of three radial-line stubs, while the other two modes are nearly not afiected. This fllter has a pair of transmission zeros which are close to the passband, thus it behaves with high selectivity. For method validation, a bandpass fllter operating at 2.4GHz is fabricated and measured. The experimental results are demonstrated and discussed.
64 citations
TL;DR: In this paper, a dual-band enhanced-bandwidth microstrip antenna with a frequency separation of f2=f1 = 1:33 was presented, where a rectangular patch was loaded with a stub at one of its radiating edges.
Abstract: A dual-band enhanced-bandwidth microstrip antenna is presented with a frequency separation of f2=f1 = 1:33. In order to achieve the dual-frequency operation, a rectangular patch is loaded with a stub at one of its radiating edges. To improve bandwidth at each band, two parasitic patches are coupled to the driven element.
58 citations
TL;DR: In this paper, a compact microstrip dual band transversal bandpass filter (DBTBPF) using short-circuited stub loaded half-wavelength resonator and stepped impedance resonator is proposed.
Abstract: A compact microstrip dual band transversal bandpass filter (DBTBPF) using short-circuited stub loaded half-wavelength resonator and stepped impedance resonator is proposed. Multiple transmission zeros are created to improve the selectivity of the DBTBPF. Furthermore, the bandwidths of the proposed filter can be regulated in a relatively wide range. Two 2.4/5.2 GHz DBTBPFs with 192 MHz and 120 MHz absolute equal bandwidths, respectively, are designed. The measured results agree well with the simulations.
TL;DR: In this paper, the authors presented a compact ultra-wideband bandpass filter (BPF) with a notch band in the performance by using an embedded open-circuited stub structure.
Abstract: In this letter, we present a compact ultra-wideband bandpass filter (BPF) with a notch band in the BPF performance by using an embedded open-circuited stub structure. The filter mainly consists of conventional stepped impedance resonator (SIR) as the multiple-mode resonator and two enhanced coupled input/output lines. The bandwidth can be analyzed by using the image-parameter method to obtain the proper dimension of the coupled lines and verified by using electromagnetic (EM) simulation. The embedded open-circuited stub structure in the SIR is used to produce a narrow notched band at 5.8 GHz, which its frequency position and bandwidth can be tuned by its physical parameters. The measured 3 dB fractional bandwidth of 113.8% and narrow notched band with 25 dB rejection is achieved. Good agreement between the EM simulation and measurement is obtained.
TL;DR: In this article, a finite element analysis based on ANSYS code was employed to simulate the deformation curves and predict the load-carrying capacities of high-strength steel stub columns.
TL;DR: In this paper, a modified printed ultra wideband (UWB) slot antenna with a square structure and a trapezoid tuning stub as well as a band-notch characteristic is presented by embedding two L-shaped slits at the edge of the open radiating slot.
Abstract: A novel modified printed ultra-wideband (UWB) slot antenna with a square structure and a trapezoid tuning stub as well as a band-notch characteristic is presented By embedding two L-shaped slits at the edge of the open radiating slot, a tunable notched band, for avoiding interference between the UWB and WLAN systems, is achieved Moreover, by optimising the dimensions of the polygon-like slot and tuning stub, the impedance bandwidth and matching of the antenna can be improved The realised slot antenna operates over 26-136 GHz for VSWR < 2 and has a rejected band of 49-585 GHz
TL;DR: In this article, a compact filter for ultra wideband (UWB) applications is proposed and developed through quasi-equal allocation of the first three resonant frequencies of a stub-loaded resonator together with strong input/output excitation.
Abstract: A compact filter for ultra-wideband (UWB) applications is proposed and developed through quasi-equal allocation of the first three resonant frequencies of a stub-loaded resonator together with strong input/output excitation. Measured results show low insertion loss and flat group delay in the entire passband as well as a wide stopband. The size for this single-layer UWB filter without feeding lines is only 9.5×5 mm (0.53 λg ×0.28 λg in which λg is the guided wavelength of 50 Ω microstrip at the centre frequency).
TL;DR: In this paper, a compact dual-band bandpass filter using short stub loaded resonators is presented, the proposed resonator possesses the advantage that its center frequency of the even mode can be flexibly controlled, whereas that of the odd mode is fixed.
Abstract: Compact dual-band bandpass filter using short stub loaded resonators is presented in this letter, the proposed resonator possesses the advantage that its center frequency of the even mode can be flexibly controlled, whereas that of the odd-mode is fixed. A dual-band filter using pseudo-interdigital SSLR is implemented with three transmission zeros. Meandering SSLR is proposed to obtain independently controlled bandwidth at each band. Two experimental examples of filters have been designed and fabricated, good agreements are shown between the simulation and the measurement. The bandpass filters have very smaller area in comparison of previous works. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 959–963, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24209
TL;DR: In this article, a new dual-band branch-line coupler scheme is proposed based on the unequal length branch line coupler structure and the center-tapped stub lines, which allows the possibility of the stubless dualband operation for some special cases, and the same phase relation can be obtained between the two output signals at the two frequency bands.
Abstract: A new dual-band branch-line coupler scheme is proposed based on the unequal length branch-line coupler structure and the center-tapped stub lines The unequal length structure reduces the size of the dual-band branch-line coupler using center tapped stubs Also, it offers the possibility of the stubless dual-band operation for some special cases, and the same phase relation can be obtained between the two output signals at the two frequency bands
Patent•
25 Nov 2009
TL;DR: A radiometric heating/sensing probe for radiating electromagnetic waves of a first frequency capable of heating tissue and detecting electromagnetic signals of a second frequency emitted by the tissue indicating tissue temperature was proposed in this article.
Abstract: A radiometric heating/sensing probe for radiating electromagnetic waves of a first frequency capable of heating tissue and detecting electromagnetic waves of a second frequency emitted by the tissue indicating tissue temperature. The probe includes a dual frequency antenna, a signal transmitting path to the antenna and a signal receiving path from the antenna to a radiometer. A diplexer connected between those paths inside the probe includes a quarter wave stub in the form of a shorted slab line-type transmission line in the signal transmitting path. The entire probe package is only about 0.4 in. long and 0.08 in. in diameter so that it can be used in many minimally invasive applications.
TL;DR: Gaussian process (GP) regression is proposed as a structured supervised learning alternative to neural networks for the modeling of CPW-fed slot antenna input characteristics, with results of an accuracy comparable to the target moment-method-based full-wave simulations.
Abstract: Gaussian process (GP) regression is proposed as a structured supervised learning alternative to neural networks for the modeling of CPW-fed slot antenna input characteristics. A Gaussian process is a stochastic process and entails the generalization of the Gaussian probability distribution to functions. Standard GP regression is applied to modeling S11 against frequency of a CPW-fed second- resonant slot dipole, while an approximate method for large datasets is applied to an ultrawideband (UWB) slot with U-shaped tuning stub | A challenging problem given the highly non-linear underlying function that maps tunable geometry variables and frequency to S11=input impedance. Predictions using large test data sets yielded results of an accuracy comparable to the target moment-method-based full-wave simulations, with normalized root mean squared errors of 0.50% for the slot dipole, and below 1.8% for the UWB antenna. The GP methodology has various inherent beneflts, including the need to learn only a handful of (hyper) parameters, and training errors that are efiectively zero for noise-free observations. GP regression would be eminently suitable for integration in antenna design algorithms as a fast substitute for computationally intensive full-wave analysis.
TL;DR: In this article, a dual-band bandpass filter (BPF) using inverted stepped impedance resonators has been proposed, where the conventional half-wavelength open-circuited stub single-frequency resonators are replaced with dualband simple two-section stepped impedance configurations.
Abstract: This paper presents a new dual-band bandpass filter (BPF) using inverted stepped impedance resonators. In the proposed filter configuration, the conventional half-wavelength open-circuited stub single-frequency resonators are replaced with dual-band simple two-section stepped impedance configurations. Simple equations to design the dual-band stepped impedance resonators are derived using transmission line analysis. The filter structure is investigated using a full wave electromagnetic (EM) simulator and then realized at 2.5 GHz and 3.55 GHz bands. Experiments have also been done to validate the design concept. The distinguished dual-band performance of the proposed design is verified by the simulation and measurement results.
TL;DR: An overview of design requirements and novel approaches for improved performance UHF radio frequency identification (RFID) tags is presented, and two matching techniques, an inductively coupled structure and a serial stub structure are discussed.
Abstract: An overview of design requirements and novel approaches for improved performance UHF radio frequency identification (RFID) tags is presented. Two matching techniques, an inductively coupled structure and a serial stub structure are discussed. Different miniaturized antenna topologies are proposed, focusing on low-profile, high efficiency and high directivity in very compact (less than 3 in times 3 in) configurations.
TL;DR: A compact multiband antenna is presented for wireless handheld devices that has simpler structure, smaller size, and higher mode independence.
Abstract: A compact multiband antenna is presented for wireless handheld devices. The proposed design uses two folded L-shaped strips connected by a short stub and fed from a common excitation. Compared to other available multiband antenna designs, the proposed design has simpler structure, smaller size, and higher mode independence.
TL;DR: In this article, a bandpass filter (BPF) based on a conductor-backed coplanar waveguide structure with tunable transmission zeros is proposed. But, the proposed UWB BPFs have the advantages of compact size, low insertion loss, good selectivity, and flat group delay.
Abstract: This work presents a novel ultra-wideband (UWB) bandpass filter (BPF) based on a conductor-backed coplanar waveguide structure with tunable transmission zeros. The symmetrical UWB BPF, which consists of the broadside-coupled transitions and the stub resonators in double-layer configuration, achieves a UWB bandwidth with transmission zeros. For characterizing this structure, the equivalent-circuit model is established to realize a four-pole response with two transmission zeros located close to the passband edges. To eliminate the interference of the coexisting wireless local area network (WLAN) within the UWB spectrum, two slotlines are symmetrically arranged on the ground plane of UWB BPF to generate the band-notched frequencies at 5.2 and 5.8 GHz simultaneously. The proposed UWB BPFs have the advantages of compact size, low insertion loss, good selectivity, and flat group delay. All results obtained from the equivalent-circuit model and the full-wave simulation are verified by measurements.
Patent•
29 Jul 2009TL;DR: In this article, the microstrip array antenna includes a dielectric substrate formed with a conductive ground plate at a back surface thereof, and strip conductors formed on a front surface of the dielectrics substrate.
Abstract: The microstrip array antenna includes a dielectric substrate formed with a conductive ground plate at a back surface thereof, and strip conductors formed on a front surface of the dielectric substrate. The strip conductors includes a linear main feeding strip line, and a plurality of array elements connected to the main feeding strip line, the array elements being disposed at least one of both sides of the main feeding strip line at a predetermined interval along a longitudinal direction of the main feeding strip line. Each of the array elements includes a sub-feeding strip line connected to the main feeding strip line, a rectangular radiating antenna element connected to a terminal end of the sub-feeding strip line, and a stub connected to the sub-feeding strip line. The stub is disposed between the main feeding strip line and the radiating antenna element.
TL;DR: In this article, a triple-stub tuning system has been implemented on Alcator C-Mod, where one stub acts as a pre-matching stub and the other two stubs use fast ferrite tuners (FFTs) to accomplish fast tuning.
01 Jun 2009
TL;DR: In this article, a modified Wilkinson power divider/combiner using one added stepped-impedance open-circuited radial stub on each branch is proposed for UWB applications.
Abstract: A modified Wilkinson power divider/combiner using one added stepped-impedance open-circuited radial stub on each branch is proposed for UWB applications. The stepped-impedance open stub is used to introduce multiple transmission poles through the whole UWB frequency spectrum. The simulation results of the proposed small size and low cost power divider have shown equal power split between the two output ports with good insertion loss and satisfactory isolation within the whole UWB frequency range. Also, it has been shown that the designed UWB power divider has good return loss of all ports.
Patent•
17 Nov 2009
TL;DR: In this paper, the authors present an approach and techniques that provide tuning elements in antenna devices to tune frequencies of the antenna devices, including composite right and left handed (CRLH) metamaterial (MTM) antenna devices.
Abstract: Apparatus and techniques that provide tuning elements in antenna devices to tune frequencies of the antenna devices, including composite right and left handed (CRLH) metamaterial (MTM) antenna devices Examples of the tuning elements for CRLH MTM antenna devices include feed line tuning elements, cell patch tuning elements, meandered stub tuning elements, via line tuning elements, and via pad tuning elements tuning elements that formed near corresponding antenna elements such as the feed line, cell patch, meander stub, via line and via pad, respectively
30 Oct 2009
TL;DR: In this paper, a novel miniaturized microstrip bandpass filter has been proposed by using coupled simplified composite right/left-handed zeroth-order resonators, which consists of microstrip transmisson line sections, high/low-impedance short-line elements and grounded stub.
Abstract: A novel miniaturized microstrip bandpass filter has been proposed by using coupled simplified composite right/left-handed zeroth-order resonators. The SCRLH ZOR consists of microstrip transmisson line sections, high/low-impedance short-line elements and grounded stub. Being one of the artificially metamaterials, the ZOR reonates when the phase constant equals to zero. Compared with the conventional half-wavelength resonator, the superiority of the ZOR mainly lies in its compact size. In addition, it is easy to tune the zeroth-order resonant frequency thanks to the simple structure and easy fabrication of the ZOR. In this paper, the performance and design of the ZOR is first studied in detail. Then the ZOR is exploited to devise a three-order Chebyshev coupled microstrip bandpass filter. Different coupling schemes are adopted including interdigital capacitor coupling for the interstages and aperture-backed dual-finger parallel-coupled line structures at the terminals, thus, the specified coupling strengths can be conveniently satisfied. Finally, a prototype device filter operative at S-band is provided to illustrate the proposed techniques. Salient feature of the size reduction of the novel filter is achieved (more than 70%) when compared to a conventional structure.
TL;DR: In this paper, a modified band-rejected circle-like slot antenna with a folded fork-shaped tuning stub is proposed for various UWB applications, where the forked-shaped strips are folded back and result in a pair of coupled lines on the tuning stub.
Abstract: A novel modified band-rejected circle-like slot antenna with a folded fork-shaped tuning stub, for various UWB applications, is proposed. To achieve band-rejected filtering property at the 5 GHz WLAN bands, the forked-shaped strips are folded back and result in a pair of coupled lines on the tuning stub. Moreover, by optimising the dimensions of the fork-shaped tuning stub, the total bandwidth of the antenna can be greatly improved up to 156%. Measured results show that the realised antenna operates over 2.2-18 GHz for VSWR < 2 and has the notched band from 5.1 to 6.2 GHz.
TL;DR: In this article, a new band-notch ultrawideband (UWB) printed monopole antenna is proposed, where the bandnotch characteristic is realized by introducing a microstrip feeder with a tuning stub.
Abstract: A new band-notch ultrawideband (UWB) printed monopole antenna is proposed, where the band-notch characteristic is realized by introducing a microstrip feeder with a tuning stub. The simulation results agree well with the measured ones, showing that the proposed antenna provides an operating band ranging from 2.9 to 11.6 GHz, a notched band from 5.0 to 5.9 GHz, and a good omni-directional far-field radiation in the H-plane. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1908–1911, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24507