• Journal of electromagnetic engineering and science
• /
• 제11권2호
• /
• pp.91-96
• /
• 2011

In this paper, we propose a microstrip bandpass filter using stepped-impedance coupled-line hairpin resonators. The stepped-impedance coupled-line hairpin resonator has extended harmonic suppression in comparison with a conventional hairpin resonator due to transmission zero and the movement of harmonic frequencies resulting from the stepped-impedance characteristic. A high-pass type impedance/admittance inverter is employed in order to improve the lower frequency skirt characteristics of the passband. A 4-pole bandpass filter is designed and fabricated at 1.8 GHz. The measured results show the excellent attenuation performance at the stopband which is greater than 30 dB up to 10 GHz.

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• 제53권7호
• /
• pp.395-400
• /
• 2004

In this paper, the four-pole elliptic function microstrip filter at 2.4GHz band with fractional bandwidth of 4% is realized using compact miniaturized hairpin resonators. The parallel algorithm FDTD method is used to analyze S-parameter of hairpin resonator filter more accurately, and to calculate the electric coupling and magnetic coupling among the hairpin resonators. Absorbing boundary conditions for mesh termination used Sulivan's simplified PML and the FDTD code was paralleled by MPI for IBM SP2 which had enhanced calculation speed. The experimental measurements are performed by HP8720D vector network analyzer. Measured results on fabricated hairpin type cross coupled bandpass filters show good agreements with theoretic results.

• Progress in Superconductivity
• /
• 제2권2호
• /
• pp.92-96
• /
• 2001

We have fabricated a modified hairpin-type YBa$_2$Cu$_3$O$_{7-{\delta}}$ (YBCO) 2-pole microstrip bandpass filter with the center frequency of 5.8 GHz. We designed a hairpin-type filter with interdigital-coupled inner poles to improve the filter performance. Compared to a typical hairpin-type filter of the same size, the center frequency, the bandwidth and the insertion loss appeared smaller by 14.5% ,29.6%, and 0.55 dB, respectively. The dimensions of the filter were 13.7mm ${\times}$3.3 mm. YBCO films deposited on r-cut sapphire buffered with a CeO$_2$thin layer were used fur making the filter.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• 제11권5호
• /
• pp.89-96
• /
• 2012

In this paper, a low phase noise oscillator is designed using an interdigital hairpin resonator for UTIS (Urban Traffic Information Systems). The interdigital hairpin resonator has several characteristics compared with a conventional hairpin resonator, which are 70% size reduction and improvement of harmonic characteristics. In addition, Q (Quality factor) of the interdigital hairpin resonator is about 132, which is suitable for the design of a low phase noise oscillator. The oscillator suggested in this paper shows the output power of 12 dBm and the phase noise characteristic of -100.8 dBc/Hz at 100 kHz offset frequency from the center frequency of 5.75 GHz. The phase noise is improved by about 12 dB compared with a conventional oscillator using an interdigital hairpin resonator.

• Journal of the Korean Institute of Telematics and Electronics D
• /
• 제36D권12호
• /
• pp.21-30
• /
• 1999

Several kinds of design method for the hairpin type band-pass filter have been reported. The conventional design methods have some restrictions in characteristic impedance of coupled line section, which provide complexities to designer. In this paper, the novel design formulas for the hairpin type band pass filter have been derived and proposed to resolve the problems of the reported design methods. By employing the equivalent circuit of the coupled line section and band pass filter design theory, the design procedures and formulas are derived. The hairpin type RX/TX band pass filters for the IMT-2000 service have been designed, fabricated with duplexer configuration, and then measured to show the validity of the proposed design method.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• 제25권8호
• /
• pp.1103-1112
• /
• 2001

The effect of pressure gradients on the hairpin structures in three different turbulent boundary layers (ZPG : Re(sub)$\theta$=910, FPG : Re(sub)$\theta$=575, APG : Re(sub)$\theta$=1290) has been examined with instantaneous velocity fields obtained in streamwise-wall-normal planes using PIV (particle image velocimetry) method. In the outer layer hairpin vortices occur in streamwise-aligned packets that propagate with small velocity dispersion. The signature pattern of the hairpin consists of a spanwise vortex core located above a region of strong second quadrant fluctuation (u<0 and v>0 : Q2 event) is clearly observed. The formation of packets explains the occurrence of multiple VITA events in turbulent burst. Noticeable differences are found in the average inclination angles of hairpin vortex packets which are 45$^{\circ}$, 35.7$^{\circ}$, and 51.9$^{\circ}$in the case of ZPG, FPG and APG, respectively. It is found that the large, time-varying, irregularly shaped zones with nearly constant streamwise momentum exist throughout the boundary layer. Within the interior of the envelope the spatial coherence between the velocity fields induced by the individual vortices leads to strongly retarded streamwise momentum, explaining the zones of uniform momentum. The formation of the uniform momentum zone is remarkably different with respect to the pressure gradients especially in the logarithmic layer.

• The Journal of the Korea institute of electronic communication sciences
• /
• 제9권10호
• /
• pp.1169-1174
• /
• 2014

In this paper, for improving the performance of selecting and the sensitivity of the L-Band microwave radiometer for remote sensing of soil-moisture, the harmonic-suppressed hairpin bandpass filter is described. As the harmonic frequencies of the SIR can be controlled by the ratio of the impedance and electrical length, SIRs are used in the hairpin BPF for suppressing harmonics. Manufactured harmonic-suppressed hairpin BPF has the SIRs of three types and its harmonic is suppressed under 35 [dB] until 5 times of the center frequency of 1390 [MHz].

• Computers and Concrete
• /
• 제14권2호
• /
• pp.109-125
• /
• 2014

The force transfer mechanism in positive moment continuity details for prestressed concrete girder bridges is investigated in this paper using a three-dimensional detailed finite element model. Positive moment reinforcement in the form of hairpin bars as recommended by the National Cooperative Highway Research Program Report No 519 is incorporated in the model. The cold construction joint that develops at the interface between girder ends and continuity diaphragms is also simulated via contact elements. The model is then subjected to the positive moment and corresponding shear forces that would develop over the service life of the bridge. The stress distribution in the continuity diaphragm and the axial force distribution in the hairpin bars are presented. It was found that due to the asymmetric configuration of the hairpin bars, asymmetric stress distribution develops at the continuity diaphragm, which can be exacerbated by other asymmetric factors such as skewed bridge configurations. It was also observed that when the joint is subjected to a positive moment, the tensile force is transferred from the girder end to the continuity diaphragm only through the hairpin bars due to the lack of contact between the both members at the construction joint. As a result, the stress distribution at girder ends was found to be concentrated around the hairpin bars influence area, rather than be resisted by the entire girder composite section. Finally, the results are used to develop an approach for estimating the cracking moment capacity at girder ends based on a proposed effective moment of inertia.

• Journal of Microbiology and Biotechnology
• /
• 제19권3호
• /
• pp.271-276
• /
• 2009

Functional gene studies in the cultivated white button mushroom Agaricus bisporus have been constrained by the absence of effective gene-silencing tools. Using two endogenous genes from A. bisporus, we have tested the utility of dsRNA hairpin constructs to mediate downregulation of specific genes. Hairpin constructs for genes encoding orotidine 5'-monophosphate decarboxylase (URA3) and carboxin resistance (CBX) were introduced into A. bisporus using Agrobacteriummediated transfection. Although predicted changes in phenotype were not observed in vitro, quantitative-PCR analyses indicated unambiguously that transcripts in several transformants were substantially reduced compared with the non-transformed controls. Interestingly, some hairpin transformants exhibited increased transcription of target genes. Our observations show that hairpin transgenic sequences can mediate downregulation of A. bisporus endogenous genes and that the technology has the potential to expedite functional genomics of the mushroom.

• Structural Engineering and Mechanics
• /
• 제58권1호
• /
• pp.39-58
• /
• 2016

Since the publication of ACI 318-02, the concrete capacity design (CCD) method has been used to determine the resistance of unreinforced concrete anchors. The regulation of steel-reinforced anchors was proposed in ACI 318-08. Until ACI 318-08, the shear resistance of concrete breakout for an unreinforced anchor during an earthquake was reduced to 75% of the static shear strength, but this reduction has been eliminated since ACI 318-11. In addition, the resistance of a hairpin-reinforced anchor was calculated using only the strength of the steel, and a regulation on the dynamic strength was not given for reinforced anchors. In this study, shaking table tests were performed to evaluate the dynamic shear strength of unreinforced and hairpin-reinforced cast-in-place (CIP) anchors during earthquakes. The anchors used in this study were 30 mm in diameter, with edge distances of 150 mm and embedment depths of 240 mm. The diameter of the hairpin steel was 10 mm. Shaking table tests were carried out on two specimens using the artificial earthquake, based on the United States Nuclear Regulatory Commission (US NRC)'s Regulatory Guide 1.60, and the Northridge earthquake. The experimental results were compared to the current ACI 318 and ETAG 001 design codes.