• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.04a
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• pp.816-820
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• 2011

A method for increasing the difference of side-lobe level in spherical microphone array is presented. In array signal processing, it is known that narrow interval between sensors can increase the difference between main lobe and side-lobe of array response which eventually increase the source recognition capability. Recent commercial array being used, however, have shown certain limitation in using the number of sensors due to its costs and geometrical size of array. To overcome this problem, we have adapted MEMS sensors into spherical microphone array. To check out the improvement, two different types of spherical microphone array were designed. One array is composed with 32 regular instrument microphones and the other one is 85 MEMS sensors. Simulation and experiments were conducted on a sinusoidal noise source with two arrays. The time history data were analyzed with spherical harmonic decomposition and beamforming technique. 85 MEMS sensors array showed the improved side-lobe level suppression by more than 4 dB above the frequency content of 2 kHz compared to 32-sensor array.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.2
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• pp.364-372
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• 1994

Theoretical method for analyzing the radiation pattern of cross-type 5-patch rectangular microstrip antenna is presented. The equivalent circuit of the array antenna is represented by the conventional transmission line model and the radiation admittance derived from the equivalent circuit of the slitted parallel-plate waveguide filled with a dielectric. The calculated results for the radiation pattern are compared with the measured values.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.10a
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• pp.453-454
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• 2010

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.10a
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• pp.250-254
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• 2001

본 문에서는 Tschebyscheff 다항식 이론을 이용하여 상대적 전류 분포비가 1:2:2:1이 되도록 마이크로스트립 패치 어레이 안테나(MPAA) 설계 제작하였다. 지향성을 갖는 제안된 안테나는 작고 가벼우며 얇다. 또한 빔폭이 14。 인 어레이 안테나이고, 중심 주파수는 10.2553GHz이다. MPAA는 한 개의 마이크로스트립 패치 안테나(SMA:single microstrip antenna)특성과 비교 분석하였다. 그 결과 MPAA는 SMA보다 보다 좁은 복사 전력 빔폭과 큰 최대 복사 전력 이득을 획득했다. PIN 다이오드를 이용한 위상 변환기를 적용하면 전자적 빔스케닝이 가능하고, 소형 레이더 시스템에 적합하다.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.2
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• pp.39-46
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• 1990

In this paper, Rectangular microstrip patch array antenna. relative current of which is distributed to 1:2:2:1, is designed and fabricated by using Tschebyscheff's polynominal expression and is verified by theoretical analysis and experiment. Seeking for more accurate resonant frequency, an equivlent network, which is consisted including feed line and power distribution line, is analyzed by using the analysis method of transmission line mode. As a result of their comparison and examination, such as resonant frequency by fringing effects, by return loss, by experiment, it is conformed that errors are not barely and agreed with each other. is also agreed with a measured values.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.2
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• pp.415-421
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• 2005

The radiating or receiving characteristics of array elements (i.e., antennas) are changed from those of isolated elements due to mutual coupling effects and the array performance becomes different from those originally designed by assuming isolated elements. The effects of mutual coupling on the performance of a rectangular array with triangular grid geometry of dipoles above a ground plane are discussed with respect to element pattern. The concept of element gain function is used to examine the effects of mutual coupling on the array performance in terms of sidelobe level in the uniformly spaced and space-tapered rectangular arrays with triangular grid geometry of dipoles. It was shown that the sidelobe performance improved in the space-tapered array compared to the uniformly spaced array in the presence of mutual coupling effects. Computer simulation results are presented.

• The Journal of the Acoustical Society of Korea
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• v.28 no.8
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• pp.723-731
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• 2009

In this paper, we propose a novel sound field reconstruction algorithm using a three dimensional loudspeaker array for providing realistic sound field to multiple listeners. The proposed algorithm is based on minimization of the squared error between the original sound field and the reconstructed sound field by the loudspeaker array over a predefined three dimensional region of the space using a loudspeaker array surrounding the listening area. For evaluating the proposed algorithm, we constructed the three dimensional array composed of 40 loudspeakers and discuss the relevant experiment results.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.10a
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• pp.59-60
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• 2010

• The Journal of Korean Institute of Communications and Information Sciences
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• v.16 no.11
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• pp.1063-1070
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• 1991

A microstrip array antenna are designed to depend on the size of rectangular microstrip patch for the relative current destribution to be 1:2:2:1 or 1:1:2:2:1:1 using Tchebyscheff polynominals, and it consist of sharp beam pattern. Gain difference between the main lobe and sidelobe is calculated for theoritical values of 21.97 db or 29.54 db. The designed microstrip array antenna are measureed various characteristics, such as return loss, resonant frequency, radiation pattern, bandwidth, beamwidth, and agreed with each other and theoretical value. Also it is presented a process of phase variation of patch array antenna depend on relative current distribution for beam scanning.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.4 no.2
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• pp.34-40
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• 1993

A microstrip antenna for mobile system are designed at the resont frequency 0.88 GHz. The microstrip array antenna are designed to depend on the size of rectanular microstrip path for the relative current distribution to be 1:4.69:1 using Tchebyscheff polynominals. Gain difference between the main lobe and sidelobe is calculated for theoritical values of 20 dB. The designed microstrip array antenna are mesureed various characteristics, such as return loss, radiation pattern, V.S.W.R, bandwidth, and agreed with each other and theoretical value. Also it is presented a process of phase variation of patch array antenna depend on relative current distribution for beam scanning.