Showing papers on "Stub (electronics) published in 2008"
TL;DR: In this paper, open-loop resonators loaded by shunt open stubs are proposed to design compact dual-band bandpass filters with improved out-of-band rejection characteristics.
Abstract: In this paper, open-loop resonators loaded by shunt open stubs are proposed to design compact dual-band bandpass filters with improved out-of-band rejection characteristics. The second passband of the dual-band filter is obtained by tuning higher resonant modes of the open-loop resonator by the stub length and position. A tapped-line input/output feed structure is used for external coupling. Required external coupling is obtained by adjusting the tapping position and dimension of the stub-loaded resonator. A lossless transmission line model is used to determine the resonance properties of the resonator and the external quality factor. Theoretical predictions are verified by the experimental results of three dual-band filters.
221 citations
TL;DR: In this article, a new wideband circularly polarized square slot antenna (CPSSA) with a coplanar waveguide (CPW) feed was proposed, which features two inverted-L grounded strips around two opposite corners of the slot and a widened tuning stub protruded into the slot from the signal strip of the CPW.
Abstract: This paper presents a new wideband circularly polarized square slot antenna (CPSSA) with a coplanar waveguide (CPW) feed. The proposed antenna features two inverted-L grounded strips around two opposite corners of the slot and a widened tuning stub protruded into the slot from the signal strip of the CPW. Broadside circular-polarization (CP) radiation can be easily obtained using a simple design procedure. For the optimized antenna prototype, the measured bandwidth with an axial ratio (AR) of less than 3 dB is larger than 25% and the measured VSWR les 2 impedance bandwidth is as large as 52%.
185 citations
TL;DR: It was found that metal-dielectric-metal plasmon waveguides with a stub structure, i.e. a branch of the waveguide with a finite length, can function as wavelength selective filters of a submicron size.
Abstract: We found that metal-dielectric-metal plasmon waveguides with a stub structure, i.e. a branch of the waveguide with a finite length, can function as wavelength selective filters of a submicron size. It was found that the transmission characteristics of such structures depend on the phase relationship between the plasmon wave passing through the stub and the one returning to the waveguide from the stub. We also propose structures with a lossless 90o bend in a plasmon waveguide, utilizing a stub structure. Furthermore, we present a functional stub structure, e.g., a 1:1 demultiplexer and a wavelength selective demultiplexer.
176 citations
TL;DR: In this paper, the authors used inner-welded longitudinal stiffeners to improve the structural performance of thin-walled hollow steel structural stub columns filled with concrete and found that adding steel fibres to concrete is the most effective method in enhancing the ductility capacity.
Abstract: It is generally expected that inner-welded longitudinal stiffeners can be used to improve the structural performance of thin-walled hollow steel structural stub columns filled with concrete. Thirty-six specimens, including 30 stiffened stub columns and six unstiffened ones, were tested to investigate the improvement of ductile behaviour of such stiffened composite stub columns with various methods. The involved methods include increasing stiffener height, increasing stiffener number on each tube face, using saw-shaped stiffeners, welding binding or anchor bars on stiffeners, and adding steel fibres to concrete. It has been found that adding steel fibres to concrete is the most effective method in enhancing the ductility capacity, while the construction cost and difficulty will not be increased significantly.
157 citations
TL;DR: In this article, a compact ultra wideband (UWB) bandpass filter with notched band has been proposed and implemented, where three pairs of tapered defected ground structures (DGS) are formed to assign their transmission zeros towards the out of band signal, thereby suppressing the spurious passband.
Abstract: A compact ultra-wideband (UWB) bandpass filter (BPF) with notched band has been proposed and implemented in this letter. H-shaped slot is studied and adopted to tighten the coupling of inter-digital capacitor in order to improve the BPF's performance. Three pairs of tapered defected ground structures (DGS) are formed to assign their transmission zeros towards the out of band signal, thereby suppressing the spurious passband. Combining these two structures we obtain a small sized UWB BPF. Meander line slot is developed to reject the undesired wireless local-area network (WLAN) radio signals. An experimental UWB filter with notched band was fabricated with 35% less length as compared to an embedded open-circuited stub. The measured BPF insertion loss is less than 1.0 dB throughout the pass band of 2.8 to 10.8 GHz, the variation of group delay less than 0.20 ns in this band except for the notched band, and a wide stopband bandwidth with 20 dB attenuation up to at least 20.0 GHz.
152 citations
TL;DR: In this article, a rectifying antenna (rectenna) using a compact circularly polarized (CP) patch antenna with RF-to-DC power conversion part at 2.45 GHz is introduced, in which the unbalanced slots structure is adopted for size reduction and 2nd harmonic rejection.
Abstract: A novel rectifying antenna (rectenna) using a compact circularly polarized (CP) patch antenna with RF-to-DC power conversion part at 2.45 GHz is introduced, in which the unbalanced slots structure is adopted for size reduction and 2nd harmonic rejection. To contribute a rectenna for RF power conversion, the back side of the CP antenna is the doubler rectifier circuit with 3rd order harmonic rejection radial stub for efficiency optimization and harmonic power re-radiation elimination. The adopted CP antenna built on low cost FR-4 substrate has measured bandwidth of 137 MHz (10 dB return loss) as well as 30 MHz CP bandwidth (3 dB axial ratio). By up to 3rd order harmonic rejection, the RF-to-DC conversion efficiency would reach 53% and 75% with 1 K Omega resistor load under ANSI/IEEE uncontrolled and controlled RF human exposure limit respectively.
148 citations
TL;DR: A novel structure in which a short optical fiber stub containing a weakly tilted Bragg grating is spliced to another slightly offset fiber, which presents an extremely high sensitivity for microbending and its frequency response has been tested to higher than 2 kHz so far.
Abstract: A novel structure in which a short optical fiber stub containing a weakly tilted Bragg grating is spliced to another slightly offset fiber. The total power reflected from this structure is independent of temperature and occurs in two well-defined wavelength bands, only one of which reflects a different amount of power as the fiber stub bends or vibrates. The smart sensing structure presents an extremely high sensitivity for microbending, and its frequency response has been tested to higher than 2 kHz so far in temperature-immune vibration measurements via cost-effective power detection.
135 citations
TL;DR: In this article, a broadband circularly-polarized (CP) square slot antenna fed by an asymmetric coplanar waveguide (CPW) from a corner of the slot is proposed.
Abstract: A novel broadband circularly-polarised (CP) square slot antenna fed by an asymmetric coplanar waveguide (CPW) from a corner of the slot is proposed. A CP bandwidth larger than 10% can be attained simply by using an inverted-L tuning stub protruded from the signal line of the CPW. With an additional pair of grounded strips implanted in the slot, the 3 dB axial-ratio bandwidth and the VSWR les 2 impedance bandwidth can be greatly raised to be as high as 30 and 35%, respectively.
115 citations
TL;DR: In this paper, a compact rat-race coupler is developed using shunt-stub-based artificial transmission lines (SSB ATLs), which can be implemented with a 3.9% circuit size reduction compared to the conventional one.
Abstract: In this letter, a compact rat-race coupler is developed using shunt-stub-based artificial transmission lines (SSB ATLs). A conventional quarter-wavelength microstrip can be equivalent to an SSB ATL realized by two series high-impedance microstrips with the high-impedance branch-type shunt stubs. The circuit configuration of the SSB ATL is beneficial to miniaturize the circuit size using the folding technique. By integrating six SSB ATLs, a compact rat-race coupler can be implemented with a 3.9% circuit size of the conventional one. The measured results of the developed rat-race coupler are in a good agreement with the simulated results by full-wave electromagnetic simulator.
104 citations
TL;DR: In this paper, a compact microstrip dual-band bandpass filter using novel E-type resonators is presented, which can be adjusted to a desired value in a relatively wide range.
Abstract: A compact microstrip dual band bandpass filter (BPF) using novel E-type resonators is presented in this letter. The E-type resonator is a short-circuited stub loaded hairpin resonator, two passband frequencies of which can be regulated by adjusting the characteristic impedance and electrical length of the hairpin and the stub. By combining pseudo-interdigital coupling structure, the coupling coefficients of two bands can be adjusted to a desired value in a relatively wide range. In addition, hook feed line is introduced to obtain desired external coupling degrees for two bands. Thus, controllable fractional bandwidths (FBWs) can be achieved. Two two-order 2.45/5.25 GHz dual band BPFs with 3 dB FBW 7%/7% and 5%/5%, respectively, are designed. The measured result agrees well with the simulation.
94 citations
TL;DR: In this paper, a novel ultra-wideband (UWB) circular slot antenna with a parasitic strip for immunity at 5.2/5.8 GHz is proposed, which has advantages of low cost, compact size and easy design.
Abstract: A novel ultra-wideband (UWB) circular slot antenna with a parasitic strip for immunity at 5.2/5.8 GHz is proposed. The antenna has an indented circular stub and an inverted C-shaped parasitic strip embedded inside the circular slot. The desired band-notched UWB operation can be obtained by choosing the size of the inverted C-shaped parasitic strip. The proposed antenna has advantages of low cost, compact size and easy design. Details of the proposed design and experimental results of the constructed antennas are presented.
TL;DR: A design of a multiresonant monopole antenna for a personal wireless communication handset using a bent tuning stub, a shorting strip line, a U-shaped slit and the addition of a narrow resonant slit to the main radiator is proposed.
Abstract: A design is proposed of a multiresonant monopole antenna for a personal wireless communication handset. Multiresonant operation is achieved through the use of a bent tuning stub, a shorting strip line, a U-shaped slit and the addition of a narrow resonant slit to the main radiator. The first resonant frequency is determined by the main radiator of the proposed antenna, and the second resonant frequency is controlled by the length of the bent tuning stub. The third resonant frequency is generated by adding a narrow resonant slit to the perimeter of the main radiator. The three resonant frequencies of the designed antenna can be independently controlled by tuning the length of the individual elements of the proposed antenna. The measurement shows the intended four wireless communication services: global system for mobile communication (GSM900), digital communication system (DCS1800), US-personal communication system (US-PCS), and satellite-digital multimedia broadcasting (S-DMB). The proposed antenna is small enough to be built into a practical wireless mobile handset. The parameters determining the antenna's multiresonant characteristics are analyzed, and experimental results of the constructed prototype are presented and discussed.
TL;DR: In this article, a stub-alternated microstrip line is proposed for multi-gigabit/second parallel links on a PCB, where the uniformly distributed stub structure eliminates the far-end crosstalk by increasing the mutual capacitance with little change in the mutual inductance.
Abstract: A stub-alternated microstrip line is proposed for multi-gigabit/second parallel links on a PCB. Without guard traces, the uniformly distributed stub structure eliminates the far-end crosstalk and crosstalk-induced jitter by increasing the mutual capacitance with little change in the mutual inductance. Coupling characteristics were measured and fitted with an empirical equation.
TL;DR: In this paper, the authors presented the calculations of transmission line loss factor by extracting from the Q-factor measurement of the quarterwavelength open stub resonators over the designed frequency and other resonant frequencies.
Abstract: This paper presents the calculations of transmission line loss factor by extracting from the Q-factor measurement of the quarterwavelength open stub resonators over the designed frequency and other resonant frequencies. A comparison of the loss factor of the design frequency with other resonant frequencies of each of the stub’s quarter-wave resonances is provided in this paper. The radiation and discontinuity losses are undesirably included in the unloaded Q-factor measurement and it shows that the unloaded Q-factor is not repeatable at different designed frequency. The implementation of the loss factor measurement by quarter-wavelength open stub resonators is becoming more and more important to be considered with the increase of using the electronic circuits operating at high frequencies. † This author is also with Department of Electronic Engineering, Tam Kang University, 151 Ying-chuan Road, Tamsui, Taipei County, Taiwan 25137, R.O.C.
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19 Dec 2008TL;DR: In this article, a photovoltaic structure is constructed by forming a stub, growing a nanowire from the stub, and conformally coating the nanowires with a semiconductor mask.
Abstract: A photovoltaic structure (105) of a photovoltaic cell (100), (200) and a method (300) of fabricating a photovoltaic structure (105), (100), (200) employ a nanowire (140) having a base connected to a stub (120) and an electrical isolation layer (130) surrounding the stub. The stub is a constituent of a substrate surface (112). The nanowire extends away from the substrate surface and is wider than the stub. The nanowire base overlies a part of the isolation layer that is adjacent to the stub. A semiconductor junction comprises the nanowire. The method (300) includes forming (320) the stub; growing (340) the nanowire from the stub; and conformally coating (360) the nanowire. A nanoparticle (150) is applied (322) to the substrate surface. The isolation layer is created (324) on and embedded in the substrate surface using the nanoparticle as a mask. A portion of the substrate surface underlying the nanoparticle forms the stub. The nanoparticle (150) catalyzes nanowire growth (340) on the stub. The stub is narrower than the nanoparticle.
TL;DR: In this paper, a planar dual composite right/left-handed transmission line (D-CRLH TL) using a defected ground structure (DGS) and stub with rectangular patch is presented.
Abstract: The planar dual composite right/left-handed transmission line (D-CRLH TL) using a defected ground structure (DGS) and stub with rectangular patch is presented. The required series parallel resonance tank and shunt series resonance tank for the D-CRLH TL are provided by DGS and stub with rectangular patch, respectively. Its equivalent circuit is provided to analyze D-CRLH TL. The characteristics such as dispersion relation and frequency response of D-CRLH TL are analyzed by circuit analysis, Bloch-Floquet theory, and full wave simulation. The measured results of dispersion curves and frequency behaviors have good agreements with theory. Finally, it is shown that compact multiband resonator using proposed D-CRLH TL can be realized.
TL;DR: Some new parameters in Vivaldi Notch antennas are debated over in this paper and can be availed for the bandwidth application amelioration.
Abstract: Some new parameters in Vivaldi Notch antennas are debated over in this paper. They can be availed for the bandwidth application amelioration. The aforementioned limiting factors comprise two parameters for the radial stub dislocation, one parameter for the stub opening angle, and one parameter for the stub’s offset angle. The aforementioned parameters are rectified by means of the optimization algorithm to accomplish a better frequency application. The results obtained in this article will eventually be collated with those of the other similar antennas. The best achieved bandwidth in this article is 17.1 GHz.
TL;DR: The results show that PSO is an efficient method for solving these kinds of problems and can be applied for the design of microwave circuits.
Abstract: This letter presents the concept of particle swarm optimization (PSO) technique applied to two sets of microwave circuits: microstrip coupler and single shunt stub matching circuit. The PSO technique that is applied to these two set of designs is tested and compared with simulation results. The results show that PSO is an efficient method for solving these kinds of problems and can be applied for the design of microwave circuits. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1333–1336, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23369
15 Jun 2008
TL;DR: This paper presents a UHF miniaturized patch antenna aimed at this application, fed by a balanced feed to avoid a cross-layered construction and matched with a stub.
Abstract: The growing interest in the Radio Frequency Identification (RFID) technology is giving rise to new applications, in particular for the identification of metallic objects. This interest has initiated the development of new designs for RFID tag antenna. This paper presents a UHF miniaturized patch antenna aimed at this application. The patch antenna is fed by a balanced feed to avoid a cross-layered construction and matched with a stub. Its miniaturization is achieved by inserting a u-shaped slot in the radiating patch.
TL;DR: In this paper, the authors demonstrate an evanescent field modality for terahertz frequency time-domain measurements, based on the interaction between a sample and the evanescence field extending above lithographically defined terrahertz waveguides, using freely positionable dielectric samples (GaAs) moved in close proximity to the waveguide.
Abstract: We demonstrate an evanescent field modality for terahertz frequency time-domain measurements, based on the interaction between a sample and the evanescent field extending above lithographically defined terahertz waveguides. We quantify this interaction using freely positionable dielectric samples (GaAs) moved in close proximity to the waveguide (a terahertz microstrip line), finding a reduction in the microstrip-propagating pulse amplitude and an increase in its time delay when the dielectric is brought into the microstrip evanescent field. We also show that the frequency response of resonant passive circuit elements (stub band-stop filters), integrated into the microstrip line, can be used to determine the terahertz frequency properties of scanned samples, opening the way for a terahertz subwavelength imaging modality, the resolution of which is limited by lithographic constraints, rather than by free-space diffraction.
TL;DR: In this paper, a novel and simple design of wideband coplanar waveguide (CPW)-fed bow-tie slot antennas with multiple band-stop characteristics featuring multi-network applications is presented.
Abstract: A novel and simple design of wideband coplanar waveguide (CPW)-fed bow-tie slot antennas with multiple band-stop characteristics featuring multi-network applications is presented. A frequency stop band can be created by embedding the slot with a pair of stubs, which causes the resultant magnetic fields almost counterbalance in the slot and to be non-responsive at the desire stop band. The effects of the dimensions of the stub on the stop band are also analysed. Dual band-stop characteristic is also accomplished by embedding two pairs of stubs in the slot. Details of the proposed designs and experimental results of the constructed prototypes are presented.
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22 Dec 2008TL;DR: A rotor for a gas turbine engine having a stub shaft and an axis of rotation, the rotor including a turbine hub clamped to a coaxial tie shaft with a tie shaft nut, the stub shaft comprising: a hollow stub shaft body extending rearwardly axially of the turbine; a forward portion of the stub-shaft body disposed radially outwardly of the tie-shank nut and removably mounted to a rearward portion of a turbine; and a rear-ward portion including an inner bearing race mounting surface as mentioned in this paper.
Abstract: A rotor for a gas turbine engine having a stub shaft and an axis of rotation, the rotor including a turbine hub clamped to a coaxial tie shaft with a tie shaft nut, the stub shaft comprising: a hollow stub shaft body extending rearwardly axially of the turbine; a forward portion of the stub shaft body disposed radially outwardly of the tie shaft nut and removably mounted to a rearward portion of the turbine; and a rearward portion of the stub shaft body including an inner bearing race mounting surface.
TL;DR: In this article, a circular loop antenna with self-biased magnetic film loading at 1.7 GHz was proposed, which achieved a tuning range of 50-400% of the antenna bandwidth.
Abstract: A circular loop antenna with self-biased magnetic film loading at 1.7 GHz is presented. The proposed circular loop antenna is realised by cascading a microstrip loop and a tuning stub. Self-biased NiCo-ferrite magnetic films were used to tune the working frequency of the loop antenna. Three different cases of antennas with films loading were designed and analysed. Antennas with self-biased magnetic films loading working at 1.7 GHz with a tuning range of 50–400% of the antenna bandwidth were achieved.
TL;DR: In this paper, a 135deg/45deg phase shifter hybrid was proposed for sub-millimeter-wave sideband separation mixer schemes at submillimeter wave frequencies, which consists of an increased height 90deg 6-arm branch guide coupler with a three stub loaded differential line 45deg shift at the output.
Abstract: We present a 135deg/45deg phase shifter hybrid intended to be used in subharmonic sideband separation mixer schemes at submillimeter-wave frequencies. The design consists of an increased height 90deg 6-arm branch guide coupler with a three stub loaded differential line 45deg phase shifter at the output. The device has been implemented at G-band in an E-plane WR-05 splitblock design with a center frequency of 170 GHz and 15 % bandwidth. Measured S-parameter are in good agreement with simulations showing an isolation and return loss better than 20 dB and an amplitude and phase imbalance within 0.4 dB and 2deg, respectively.
15 Jun 2008
TL;DR: In this paper, the authors presented the general fundamental equations for a miniaturized narrow bandpass DBR filter, where the miniaturization is achieved by loading the transmission lines with capacitors while increasing their characteristic impedance.
Abstract: This paper presents the general fundamental equations for a miniaturized narrow bandpass DBR filter, where the miniaturization is achieved by loading the transmission lines with capacitors while increasing their characteristic impedance. The derived fundamental equations show the interesting performances of this miniaturized filter when compared with a classical one. Not only high miniaturizing percentage, but also better out-of-band rejection could be achieved. Hybrid classical and miniaturized DBR prototypes with a 1 GHz center frequency, based on a microstrip technology, were fabricated and measured. The obtained results show miniaturization of 75% and better filter out-of-band rejection. The increase of the insertion loss is solved by distributing the capacitance along the stub length.
TL;DR: In this article, a broadband Koch fractal loop antenna configuration with a novel Coplanar Waveguide (CPW) feed is presented, which is achieved by a radial stub loaded CPW feed, which acts as a lumped matching circuit.
Abstract: A broadband Koch fractal loop antenna configuration with a novel Coplanar Waveguide (CPW) feed is presented. Impedance matching is achieved by a radial stub loaded CPW feed, which acts as a lumped matching circuit. Experimental results show that the antenna has 2:1 VSWR bandwidth of about 19% operating in the frequency range of 1.26 GHz-1.52 GHz and 3:1 VSWR bandwidth of 57% has been measured in the frequency range of 1.21 GHz-1.99 GHz. The antenna exhibits well-defined radiation patterns over the band.
TL;DR: In this article, a dual-band balun is presented based on the traditional Marchand balun configuration, which utilizes a pair of lambda4 coupled-line sections and a single lambda4 open-circuit stub.
Abstract: In this paper, a dual-band balun is presented. Based on the traditional Marchand balun configuration, this device utilizes a pair of lambda4 coupled-line sections and a single lambda4 open-circuit stub to achieve a dual-band balun-type function. An experimental prototype, operating at both 2.4- and 5.8-GHz bands, has been realized on a traditional printed circuit board using the broadside-coupled asymmetric coplanar stripline technique. Experimental measurements show good agreement with full-wave computer simulations, showing good potentials for dual-band/multiband RF front-end modules.
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13 Aug 2008TL;DR: In this paper, a short-circuit unit was used to electrically connect the first radiator to the ground surface to adjust the signal received by the second radiator, and a first stub extending from the other end of the first radiator was used for adjusting the received signal.
Abstract: There is provided a an antenna including: a first radiator having one end connected to a power feeding unit and receiving a signal within a first frequency band; a second radiator having one end connected to a ground surface and receiving a signal within a second frequency band; a first stub extending from the other end of the first radiator and finely adjusting the signal received by the first radiator; a second stub extending from the other end of the second radiator and finely adjusting the signal received by the second radiator; and a short-circuit unit electrically connecting the first radiator to the ground surface.
TL;DR: In this paper, a two-layer bandstop filter using a defected ground structure (DGS) resonator with a parasitic stub is proposed, which is composed of a H-slot DGS resonator located on two stacked layer and a stub placed on the bottom layer.
Abstract: A new design of a compact two-layer bandstop filter using a defected ground structure (DGS) resonator with a parasitic stub is proposed. The proposed filter is composed of a H-slot DGS resonator located on the two stacked layer and a stub placed on the bottom layer. The parasitic stub modelled as an additional capacitance increases the effective capacitance of the resonator and lowers the resonance frequency. In addition, the rejection bandwidth is decreased and the quality (Q)-factor is also improved owing to enhancement of the stored energy in the resonator.
05 Jul 2008
TL;DR: In this article, a UHF band RFID tag dipole antenna enclosed by a short-stub is proposed, which has a compact size (64.1 mm times 17.8 mm) and large inductive reactance.
Abstract: Radio frequency identification (RFID) systems have been rapidly developing in the ultra high frequency (UHF) band due to the advantage of long recognition distance. To reduce the production cost, a tag antenna should be directly matched to a tag IC including a charge capacitor which compensates the large conductive reactance of a tag IC. In addition, the power from an antenna can be maximally delivered to a tag IC when an antenna impedance is conjugately matched with that of tag IC. However, folded dipole antennas, slot antennas, and meander antennas, which are commonly used for RFID tags in UHF band, do not have enough large inductive reactance for conjugate matching to a tag IC. Thus, new type of RFID tag antenna having large inductive reactance is necessary. In this paper, a UHF band RFID tag dipole antenna enclosed by a short-stub is proposed. The proposed antenna has a compact size (64.1 mm times 17.8 mm) and large inductive reactance.