• International journal of advanced smart convergence
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• v.6 no.2
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• pp.59-64
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• 2017

There are three sorts of voices of female vocalists: soprano, mezzo-soprano, and contralto according to the transliteration. Among them, the soprano has the highest vocal range. Since the voice is generated through the human vocal tract based on the voice generation model, it is greatly influenced by the vocal tract. The structure of vocal organs differs from person to person, and the formants characteristic of vocalization differ accordingly. The formant characteristic refers to a characteristic in which a specific frequency band appears distinctly due to resonance occurring in each vocal tract in the vocal process. Formant characteristics include personality that occurs in the throat, jaw, lips, and teeth, as well as phonological properties of phonemes. The first formant is the throat, the second formant is the jaw, the third formant and the fourth formant are caused by the resonance phenomenon in the lips and the teeth. Among them, pronunciation is influenced not only by phonological information but also by jaws, lips and teeth. When the mouth is small or the jaw is stiff when pronouncing, pronunciation becomes unclear. Therefore, the higher the accuracy of the pronunciation characteristics, the more clearly the formant characteristics appear in the grammar spectrum. However, many soprano singers can not open their mouths because their jaws, lips, teeth, and facial muscles are rigid to maintain high tones when singing, which makes the pronunciation unclear and thus the formant characteristics become unclear. In this paper, in order to confirm the accuracy of the pronunciation characteristics of soprano singers, the experimental group was selected as the soprano singers A, B, C, D, E of Korea and analyzed the grammar spectrum and conducted the MOS test for pronunciation recognition. As a result, soprano singer B showed a clear recognition from F1 to F5 and MOS test result showed the highest recognition rate with 4.6 points. Soprano singers A, C, and D appear from F1 to F3, but it was difficult to find formants above 2kHz. Finally, the soprano singer E had difficulty in finding the formant as a whole, and MOS test showed the lowest recognition rate at 2.1 points. Therefore, we confirmed that the soprano singer B, which exhibits the most distinct formant characteristics in the grammar spectrum, has the best pronunciation accuracy.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.1
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• pp.12-20
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• 2004

In this paper, the detection of 1 g and 10 g averaged SAR on human head caused by PCS/IMT-2000 handhold phones is analyzed and discussed. Planar structured Single-Semi-disc MPA and double-Semi-disc MPA is designed and resonance characteristics with variety of design parameters are analyzed. As a result, 2.0 ㎓ center frequency, at the bandwidth of single-semi-disc MPA and double-semi-disc MPA are 15.5 ％ and 31 ％, respectively. And monopole antenna with W4 length is designed and compared with double-semi-disc MPA in SARs. The SARs caused by double-semi-disc MPA on folder type handset are 0.811 W/kg and 0.507 W/kg and are about 32.7 ％ lower than monopole-1.206 W/kg and 0.7552 W/kg. While the radiation pattern of the monopole antenna is symmetrical, that of planar structured antenna is asymmetrical and SAR caused by double-semi-disc MPA is less than SAR by the monopole antenna.

• Journal of IKEEE
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• v.23 no.1
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• pp.14-21
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• 2019

In this paper, we implemented an on-board miniaturization antenna operating 2.4 GHz using MZR(Mu Zero Resonator). It is must be operating under the constraint that the size of the small terminal PCB should be $78{\times}38{\times}0.8mm^3$ and the size of the system should be $63{\times}38{\times}0.8mm^3$ and the size of the radiating part should be $15{\times}38{\times}0.8mm^3$. The feeding structure uses a CPW structure for stable feeding and a feeding point at the upper left of the system board. A magnetic field coupling structure is used for coupling the feeding part and the antenna. The resonance frequency of the MZR is determined by the series inductance and capacitance of the cell, so the gap between the cells, the length of the cell, the length of the interdigital capacitor, and the spacing between the radiation part and the ground plane are analyzed. The antenna was designed and fabricated using the results. The total size of the antenna including the feed structure is $20.8{\times}9.0{\times}0.8mm^3$, and the electrical length is $0.1664{\lambda}_0{\times}0.072{\lambda}_0{\times}0.0064{\lambda}_0$. The measurement result for 10 dB bandwidth, gain and directivity are 440 MHz(18.3%), 0.4405 dB, and 2.722 dB respectively. It is confirmed that the radiation pattern has omnidirectional characteristics and it can be applied to ultra small terminal antenna.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.5
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• pp.775-782
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• 2022

In this paper, a novel small-diameter cylindrical post capacitor inserted into an evanescent-mode rectangular waveguide (EMRWG) is proposed for easier tuning. In order to feed the EMRWG, the proposed structure uses a single ridge rectangular waveguide with the same width and height as the waveguide at the input and output ends. The inserted post capacitor are made up a circular groove formed in the center of the lower part of the broad wall of the EMRWG, and a concentric cylindrical post inserted into the upper part. First, the equivalent circuit model for the proposed structure is presented. When the EMRWG and the single ridge waveguide are combined, the joint susceptance and the turns ratio of the ideal transformer are calculated by two simulations using HFSS (3d fullwave simulator, Ansoft Co.) respectively. The susceptance and resonance characteristics of the inserted post were analyzed by using the obtained parameters and the characteristics of the EMRWG. A 2-post filter with a center frequency of 4.5 GHz and a bandwidth of 170 MHz was designed using a WR-90 waveguide, and the simulation results by using the HFSS and CST, equivalent circuit model were in good agreement.