• 제어로봇시스템학회:학술대회논문집
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• 1991.10b
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• pp.1737-1741
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• 1991

The authors proposed a new two-dimensional(2D) positioning system by use of M-array and correlation technique which is suitable for noisy environment in '88KACC and its revised versions in '89KACC and '90KACC. This system uses the property of M-array that the autocorrelation function of the M-array has a sharp peak at its origin. In this paper, a new mark pattern is developed, instead of M-array, with which the two-dimensional positioning system becomes robust to rotation error of TV camera. The property of the rotation-free pattern is checked under various conditions, and it is shown that, by use of this rotation-free pattern, the positioning system can be used not only in a noisy environment but also in a roughly aligned set up of the TV camera.

• Journal of the Korea Society of Computer and Information
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• v.8 no.1
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• pp.90-96
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• 2003

In this paper, arranged the isotropic point source of N number with the structure which is identical with the receive area. And against the array structure which has the radiation pattern which is identical with the receive area it researched. The arranged the element space flees grating lobe and in order to set the characteristic of optimum with half-wave equally space it selects. After inducing the array factor of each array structure, it calculated a radiation pattern. As a result of, the radiation pattern of the each Planar array antenna with structure of the receive area was similar and the possibility of getting an beam characteristic it was.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.735-741
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• 2003

A simplified view of array design and application process was introduced. Array design is critical to achieve a successful phased array measurements. A planar microphone array is designed to produce optimum performance and also to fit economic requirement in integrating data acquisition system. Certain performance characteristics are of primary concern when designing arrays. These characteristics include array resolution, spatial aliasing and array sidelobe suppression. Every array has its directional pattern that shows such characteristics. Assuming that a monopole source is located in center, beam-patterns have been simulated varying measurement conditions such as number of sensors. array aperture size, distance between array and source, frequency of interest and so on. Sensor correction was conducted on very channel using magnitudes and phased of FRF with respect to a reference microphone channel. Then with a spiral type array, measurements have been made with two point sources of same frequency in order to investigate array resolving abilities. It is observed that higher frequency source achieves better resolution than lower one does.

• The Journal of the Acoustical Society of Korea
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• v.16 no.1
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• pp.47-53
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• 1997

This paper concerns an efficient approach to forming a beam pattern of a microphone array to deal with broadband signals such as speech in a teleconference. A numerical method is proposed to find updated location of sidelobes for equalizaing the sidelobes via perturbation of array parameters such as array weight or microphone spacing. Thus the microphone array is optimized in a Dolph-Chebyshev sense such that directional or background noises incident in an array visual range are eliminated efficiently. It is shown that perturbation of microphone spacing yields an optimum pattern more appropriate for dealing with broadband signals than that of array weight. Also, a novel method is proposed to find a beam pattern which is robust with respect to sidelobe in a scanning situation. Computer simulation results are presented.

• The Journal of the Acoustical Society of Korea
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• v.40 no.1
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• pp.10-17
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• 2021

The cymbal transducer is a miniaturized version of the Class V flextensional transducer. It has low resonant frequency and high output pressure characteristics compared with its size. However, since it has high quality factor and low energy conversion efficiency as well, it is often used as an array rather than single. When used as an array, a big change in the frequency characteristics occurs in comparison with that of the single transducer due to the interaction between constituent transducers. In this study, we designed a pattern of cymbal array with a view to having broadband characteristics. Three transducers having different center frequencies were designed first. The designed cymbal transducers were used to construct all possible patterns of a 3 × 3 planar array. After analyzing frequency characteristics of these patterns, based on the results, we derived the most effective pattern to achieve a higher fractional bandwidth. The derived array pattern showed an improvement of the fractional bandwidth by 24.9 % in comparison with the reference model.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.9 no.5
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• pp.458-464
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• 2016

This paper proposes the compensation method which decreases the radiation pattern distortion caused by the mutual coupling in an array antenna. If the element distance of an array antenna decreases, the radiation pattern could be distorted by the strong mutual coupling, which changes the magnitude and phase of input signals and causes an unwanted radiation pattern. To remove the pattern distortion, compensated input signals are inserted in an array antenna. The magnitude and phase of input signals are determined by Particle Swarm Optimization (PSO) algorithm. A $4{\times}1$ dipole array antenna with omnidirectional elements is used to confirm the validity of the algorithm, where each element is placed in 0.2 wavelength to evoke the strong coupling. After input signals are optimized by PSO, it is found that the compensated radiation results in the same as the ideal case.

• Journal of the Korean Institute of Telematics and Electronics
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• v.19 no.6
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• pp.80-83
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• 1982

A quarter-wavelength open circuited microstripline slot array is realized at X-band froquency. The optimal feeding point is experimentally determined. The input impedance of the slot array for various frequencies and its radiation pattern are measured. The bandwidth of the slot array is increased by using the 4$\times$4 elements which are slightly different in length and feeding network which is suggested in this papers.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.10a
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• pp.104-107
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• 2007

An aspheric microlens array to improve the properties of multi optical probes was designed and fabricated. To generate multi optical probes with good qualities, a microlens array with the minimum spherical aberration was designed by ray tracing. Using the reflow process, a master pattern of aspheric microlens array was made and finally with the ultraviolet-imprinting (UV-imprinting) method, the aspheric microlens array was replicated. The reflow condition was optimized to realize the master pattern of the microlens array with the designed aspheric shape. The intensity distribution of the optical probes at the focal plane showed a diffraction-limited shape.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.3 no.2
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• pp.31-38
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• 2010

It is difficult to design accurately the bandgap of metamaterial depending on metamaterial pattern and array configuration. In this paper, we propose a design method for the wanted bandgap frequency using any metamaterial pattern in 2 dimensional array. Metamaterial structure is consisted of periodic array. Therefore the calculation area in FDTD(finite difference time domain) method can be reduced by applying the periodic boundary condition to 2-D metamaterial array. The method for design and calculation the L and C values by using 2-D is also considered. So it can be designed more accurately and rapidly. For example, we designed metamaterial square pattern array in 5 GHz, and compared with the 1-D metamaterial pattern using analysis method in microstrip line. As a result, we found that the accuracy of this proposed method can be incresed to 14.7%.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.5
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• pp.46-53
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• 2011

The effect of a finite substrate on the radiation characteristics of a linear 7-element array antenna positioned along the E-plane is investigated. Active reflection coefficients and average active element patterns are simulated for various substrate sizes. The E-plane radiation pattern of a fully excited array for various scan angles is correlated with the active reflection coefficient and average acitive element pattern. The effect of E-plane substrate size on the radiation characteristics of a linear array along the E-plane is larger than that of H-plane substarte size.