• Journal of electromagnetic engineering and science
• /
• v.2 no.1
• /
• pp.28-33
• /
• 2002

The LHCP circularly polarized antenna operating at DBS band is developed by employing the sequential-rotation technique in which each subarray is comprised the three truncated-corner patch square element. Antenna designed with sequentially-related technique whose M=3, p=2 has the effect of improved axial-ratio bandwidth, cross-polarization etc. And it is proved that the degradation of radiation pattern can be reduced significantly by minimizing the radiation loss of feeding line structure. Antenna designed shows extremely low side lobe level of below - 25 dB in the diagonal plane and cross-polarization level of below -20 dB in the all plane. And these performances comply with the array antenna specification for DBS.

• Journal of Electrical Engineering and Technology
• /
• v.10 no.1
• /
• pp.320-324
• /
• 2015

Mutual coupling between antenna elements of a linear microstrip patch antenna array positioned along the H-plane including the effect of edge reflections is investigated. Simple formulas are presented for the estimation of the grounded dielectric substrate size with minimum mutual coupling. The substrate sizes calculated by these formulas are in good agreement with those obtained by the full-wave simulation and experimental measurement. The substrate size with minimum mutual coupling is a function of the effective dielectric constant for surface waves and the distance between the antenna centers. The substrate size with minimum mutual coupling decreases as the effective dielectric constant for surface waves on a finite grounded dielectric substrate increases.

• The Bulletin of The Korean Astronomical Society
• /
• v.41 no.2
• /
• pp.59.2-59.2
• /
• 2016

As an enhancement to increase mapping speed of the current ALMA TP array, development of a focal plane array system working at ultra wide frequency range of 275-500 GHz with GPU-based software spectrometers has been carried out since 2015. Major progresses on such component development as wideband DSB mixers, a profiled corrugated horn, receiver optics, LO system and GPU-based spectrometer are reviewed with brief introduction to implication of ALMA 2030 for technical implementation.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.1 no.2
• /
• pp.27-31
• /
• 2000

Thermal imaging system is implemented for the measurement and the analysis of the thermal distribution of the target objects. The main Part of the system is thermal camera in which a focal plane array typed sensor is introduced The sensor detects mid-range infrared spectrum or target objects and then it output generic video signal which should be processed to form a thermal image frame. A digital signal processor(DSP) in the system inputs analog to digital converted data. performs algorithms to improve the thermal images and then outputs the corrected frame data to frame buffers for NTSC encoding and for digital outputs.. To enhance the quality of the thermal images, two point correction method is applied. Figures indicate that the corrected thermal images are much improved.

• The Bulletin of The Korean Astronomical Society
• /
• v.39 no.2
• /
• pp.116.2-116.2
• /
• 2014

As Korean engineering contribution to ALMA enhancement, development of focal plane arrays(FPAs) for the total power array in ALMA compact array has been projected mainly to increase mapping speed in interferometric multi-pointing observation(mosaicking). To tackle engineering issues expected in order to be compatible with the existing ALMA receivers, we plan to develop a prototype 300-500 GHz heterodyne FPA system including a software spectrometer using GPU clusters for ASTE(Atacama Submillimeter Telescope Experiment) telescope by 2017.

• Proceedings of the IEEK Conference
• /
• 2008.06a
• /
• pp.355-356
• /
• 2008

Effect of the pin radius on the radiation characteristics of a patch antenna with a pin array inserted between a patch and ground plane is investigated. As the pin radius increases, the resonant frequency increases and the radiation intensity in the horizontal plane decreases. However, the radiation intensity in the horizontal plane increases for the pin radius larger than a certain value.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 1997.10a
• /
• pp.158-163
• /
• 1997

In this paper the tool geometry of the PSS test were optimized in order to assure the reliability of the test. Considering many factors for optimization of the tool geometry, computer-simulation technique using three-dimensional finite element method(FEM) was used. Three design variables -the punch length, punch crown and punch corner radius- are chosen to be optimized according to the Taguchi's experiment technique with the L9 orthogonal array. The optimum condition to ensure the plane strain mode over the overall area of the specimen was clarified. Moreover the simulation results are confirmed by experiment.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.6 no.3
• /
• pp.113-121
• /
• 2003

In this paper, the transmit antenna for the space feeder used for the phased array antennas is investigated. The multi-aperture horn antenna is proposed as the transmit antenna and the characteristics are verified with the Matlab coding, HFSS of Ansoft Corp., and MWS of CST Corp., The E-plane and H-plane beam patterns of the multi-aperture horn antenna are nearly symmetrical and the sidelobe level of the I-plane beam pattern is lower than that the of general pyramidal horn antenna. The fabricated multi-aperture horn antenna is measured using the near-field measurement system. The measured results show good agreement with the simulated ones.

• Journal of the Korean Society for Industrial and Applied Mathematics
• /
• v.8 no.2
• /
• pp.1-5
• /
• 2004

A multiplicative plane partition is a two-dimensional array of positive integers larger than 1 that are nonincreasing both from left to right and top to bottom and whose multiple is a given number n. For a natural number n, let $f_2(n)$ be the number of multiplicative plane partitions of n. In this paper, we prove $f_2(n)\;{\leq}\;n^2$ and a table of them up to $10^5$ is provided.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2002.11a
• /
• pp.383.2-383
• /
• 2002

In this paper, an experimental technique using a reference accelerometer has been developed to measure the in-plane vibration intensity of a beam. It has the advantages of shortening measurement time and reducing accelerometer phase error comparing with the cross spectral Intensity measurement technique using an accelerometer array. The distribution of the in-plane vibration Intensity over the beam has been measured. (omitted)