• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2002.02a
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• pp.135-137
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• 2002

In the favor of adjusting microwave signal, Hairpin type Filter, which delay microwave signal enough to several nanosecond, is a key component. One of the main advantage in using Hairpin type Filter is a conveniency for equipping with Delay Module, and because of having a wide bandwidth, Hairpin type Filter can be designed to satisfy the most applications. In this work, we attempted to estimate the delay time in a superconductive hairpin type filter A software to synthesize even and odd order equiripple hairpin type filter has been developed. This software arbitrarily locate its transfer zeros making symmetric of asymmetric amplitude response and equalizing group delay. Borland C++ compiler has been used. The program was designed to run under MS-DOS, Window 98, Window 2000. The program optimizes the position of the transfer function zeros in order to fulfill the group delay specification masks. We designed and fabricated a hairpin type HTS 2-pole microstrip bandpass filter to operate at 5.8Ghz. The fabrication method was pulsed laser deposition and YBCO films were deposited on sapphire substrates with a Ce$O_{2}$ thin layer as a buffer layer. We also developed a new style hairpin type filter by using interdigitide inner-pole. Compared to the same size regular hairpin type filters, our filters had a lower center frequency.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.5
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• pp.437-443
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• 2004

Aperture has been employed on the ground plane in the hairpin resonator. Aperture has been fabricated by etching the part of the ground effected coupling coefficient and then quality factor of hairpin resonator has been increased. When the hairpin oscillator using aperture has been compared with the conventional hairpin oscillator using microstrip, it has been improved the phase noise about 19 ㏈c @100 ㎑. As a result of PBG connecting to the output of the employing aperture hairpin oscillator, the second and third harmonics are suppressed. In this paper, oscillator has been designed and fabricated in operating 5.8 ㎓ band. The output power has been obtained 0,67 ㏈m and the second harmonic has been suppressed about -53,67 ㏈c.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.9A
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• pp.1434-1441
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• 1999

This paper presents an equivalent circuit of the hairpin line filter for accurate analysis and design. Its validity was verified by computer simulations and filter design experiments. Though the various design equations for a hairpin line filter have been proposed, there has not been a practically simplified equivalent circuit because it is hard to effectively represent interconnection effects between non-adjacent elements. In this paper, all the open ports of the hairpin line filter circuit are changed to the short ports using circuit duality, and the resulting circuits are transformed to graph model. The further simplified circuit model is obtained from boundary conditions, and then the final equivalent circuit of the hairpin line filter is derived in a dual structure of the filter.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2000.11a
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• pp.424-428
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• 2000

In this paper, a MIC(Microwave Integrated Circuit) bandpass filter for wireless LAN(local area network) band is designed using hairpin resonators. The coupling between the hairpin resonators in the filter can be implemented with Y-Tpye coupling or X-Tpye coupling instead of conventional coupling in order to reduce the filter size. The filter with miniaturized hairpin resonator using parallel coupling is smaller in size by 50% more than that of a general hairpin filter

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.8
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• pp.99-103
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• 2004

Aperture has been employed on the ground plane in the Hairpin resonator. Aperture made by etching the part of the ground effected coupling coefficient and then quality factor of Hairpin resonator has been increased. When the hair pin oscillator using aperture has been compared with the conventional hair pin oscillator using microstrip, it has been improved the phase noise about 19dBc ＠100KHz. Oscillation frequency of the hair pin oscillator using aperture has been 5.83GHz band and output power is -4.33dBm.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.1
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• pp.20-26
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• 2003

This paper presents hairpin-comb bandpass filter using ground aperture. Hairpin-comb resonator maintains the weak coupling though the space between two resonators is very small. This has the good merit that the entire filter size is small for narrowband bandpass filter. The coupling between two hairpin-comb resonators so very weak that can't be applicable to general microstrip. We compensate the coupling by using ground aperture. It makes the hairpin-comb filter possible that can be applicable to general microstrip. Also it has the good merit which adjusts the bandwidth by changing the size of aperture without changing the space. In this paper, we fabricate the bandpass filter, which has 1.78 GHz center frequency and 62 MHz (3.5%) fractional bandwidth.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.4
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• pp.589-594
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• 2002

The filter of hairpin type can be designed small but has a demerit which a design method is complex. This paper suggests the method that a hairpin line filter is designed with applying a transmission line method and J inverter circuit, accurately calculated the J value and the b parameter. It is considered about the line have no the mutual coupling element with next line to each other. is calculated a length of electric coupling line about coupling element in each inverter stage from the J value and the b parameter. In order to show the validity of the proposed design method, band pass filter of small hairpin line is designed at center frequency 2.6 GHz, with Serenade 8.0 software tool and the simulation characteristics are compared with design results.

• Journal of Korean Society for Quality Management
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• v.51 no.2
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• pp.283-296
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• 2023

Purpose: The purpose of this study is to actually implement and verify whether welding defects can be detected in real time by utilizing deep learning AI solutions in the welding process of electric vehicle hairpin winding motors. Methods: AI's function and technological elements using synthetic neural network were applied to existing electric vehicle hairpin winding motor laser welding process by making special hardware for detecting electric vehicle hairpin motor laser welding defect. Results: As a result of the test applied to the welding process of the electric vehicle hairpin winding motor, it was confirmed that defects in the welding part were detected in real time. The accuracy of detection of welds was achieved at 0.99 based on mAP@95, and the accuracy of detection of defective parts was 1.18 based on FB-Score 1.5, which fell short of the target, so it will be supplemented by introducing additional lighting and camera settings and enhancement techniques in the future. Conclusion: This study is significant in that it improves the welding quality of hairpin winding motors of electric vehicles by applying domestic artificial intelligence solutions to laser welding operations of hairpin winding motors of electric vehicles. Defects of a manufacturing line can be corrected immediately through automatic welding inspection after laser welding of an electric vehicle hairpin winding motor, thus reducing waste throughput caused by welding failure in the final stage, reducing input costs and increasing product production.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.7
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• pp.834-841
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• 2004

Experimental study on the three-dimensional topology of hairpin packet structures in turbulent boundary layers were carried out. Two different Reynolds number based on momentum thickness, Re$\sub$$\theta$/=514 and 934 were generated in a blowing type wind tunnel under the condition of zero pressure gradient. Simultaneous measurements of velocity fields at a wall-normal plane and wall-parallel plane by a plane PIV and a Stereo-PIV systems. The two Nd:Yag laser systems and three CCD cameras were synchronized to obtain instantaneous velocity fields at the same time. To avoid optical noise at the crossing line by the two laser light sheets, a new optical arrangement using polarization was applied. The obtained velocity fields show the existence of hairpin packet structure vividly and the idealized hairpin vortex signature is confirmed by experiment. Two counter-rotating vortex pair which reflects the cutting plane of hairpin legs are found both side of a strong streaky structure when the wall-normal plane cuts the hairpin head.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.610-615
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• 2003

This experiment has been carried out to find the structure of turbulent boundary layer with instantaneous velocity fields obtained in stream-wall-normal planes using a stereo-PIV (Particle Image Velocimetry) method. And it has been measured perpendicular plane and horizontal plane with hairpin vortex structure by Reynolds number change and made third dimension shape for section of horizontal plane through stereo-PIV. In the outer layer hairpin vortices occur in streamwise-aligned packets that propagate with small velocity dispersion. A streaky structure is composed of counter-rotating vortex. According as y+ increases, streaky structure's interval space decrease, and it shows that hairpin shape of prior research is vertified. The objective of the present research is to gain a better understanding of coherent structures in the outer of wall turbulence by experimentally examining coherent structures.