• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.16 no.4
• /
• pp.335-341
• /
• 1991

We derive the radiation field equation at the naar field region to analyse EMI by the rectangular horn antenna. The EMI loadk current calculated from the load current induced on the transmission line being close to the rectangular horn antenna using the field theory and the transmission line theory. We find the conditions minimizing the EMI from the load current transfer function of distance, frequency and impedances at sending and receiving end. The smaller sending end impedance, the larger EMI load current and the larger sending impedance, the smaller EMI load current.

• Publications of The Korean Astronomical Society
• /
• v.8 no.1
• /
• pp.1-15
• /
• 1993

We made a pyramidal horn antenna system for 21cm cosmic radio wave. The antenna system has a rectangular waveguide with $TE_{10}$ mode and a copper probe to detect the electromagnetic wave in waveguide. The parameters of the probe are obtained by experiments using two waveguides. Pyramidal horn antenna is designed to get a gain of 20dB. The size of the aperture of this horn is $94cm{\times}74cm$. The beam width of half power is about $14.7^{\circ}$ for the frequency of 1.4GHz. The horn is made of aluminum plate with a thickness of 2mm. The signal from horn and waveguide is amplified in a receiver system and is converted into DC in the detecter. The intensity of the signal is recorded on a chart recorder. We observed the sun using this simple radio telescope and obtained the brightness temperature of $2.2{\times}10^5K$, which indicates that the sun is quiet at 21cm.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2007.06a
• /
• pp.569-571
• /
• 2007

In this paper, hem antenna composed of rectangular hern, circular polarizer and straight-type mode convertor is designed and fabricated. The circular polarizer is designed as a dielectric type having broadband characteristic, and it is inserted into the rectangular hem with $45^{\circ}$ inclination. The straight-type mode convertor has a terrace-type structure in order to convert the TEM mode signal of coaxial cable to the TE mode of rectangular waveguide, and this structure minimizes conversion loss. Fabricated hem antenna operates at $30.085\sim30.885GHz$ and has VSWR < 1.5, Axial ratio < 1.0dB and antenna gain of $6.7\sim7.0dBi$ in the band.

• Journal of Korean Neurosurgical Society
• /
• v.59 no.3
• /
• pp.322-324
• /
• 2016

To introduce a new device for catheter placement of an external ventricular drain (EVD) of cerebrospinal fluid (CSF). This device was composed of three portions, T-shaped main body, rectangular pillar having a central hole to insert a catheter and an arm pointing the tragus. The main body has a role to direct a ventricular catheter toward the right or left inner canthus and has a shallow longitudinal opening to connect the rectangular pillar. The arm pointing the tragus is controlled by back and forth movement and turn of the pillar attached to the main body. Between April 2012 and December 2014, 57 emergency EVDs were performed in 52 patients using this device in the operating room. Catheter tip located in the frontal horn in 52 (91.2%), 3rd ventricle in 2 (3.5%) and in the wall of the frontal horn of the lateral ventricle in 3 EVDs (5.2%). Small hemorrhage along to catheter tract occurred in 1 EVD. CSF was well drained through the all EVD catheters. The accuracy of the catheter position and direction using this device were 91% and 100%, respectively. This device for EVD guides to provide an accurate position of catheter tip safely and easily.

• Conservation Science in Museum
• /
• v.25
• /
• pp.51-62
• /
• 2021

The Belt with Rhinoceros-Horn Ornaments(known as a seodae in Korean) from the family of Princess Deokon's descendants housed in the National Hangeul Museum underwent emergency treatment for a special exhibition in 2019 upon the request of the National Hangeul Museum. Priority was given to the restoration of the original form of the severely damaged belt and the repair of its detached horn ornaments. Prior to the conservation treatment, researchers conducted a theoretical study of the belt with rhinoceros-horn adornments to learn the names of its structural components and the changes in form that the type experienced by period, thereby establishing a plan for conservation treatment and setting a direction. Among the belts worn by officials from the Joseon dynasty, rhinoceros-horn ornaments were attached to those of officials of the first rank and were considered the most precious behind the king's belt with its jade ornaments. The rhinoceros horn adorning the belt is classified into three categories according to quality. This belt has horn adornments of the highest quality, falling under the "grape design" category with dark brown dots concentrated in the center. The belt has a rectangular shape and lacks a buckle, reflecting a popular form from the nineteenth century. The structure of the belt was identified over the process of conservation treatment, offering information about its method of production. In addition, comparison of the relic with belts with rhinoceros-horn ornaments depicted in Joseon-period portraits of officials allowed the identification of changes in formal features and the detailed structures of belts with rhinoceros-horn ornaments by period. It confirmed that the belt subject to conservation treatment shows the features of belts with rhinoceros-horn ornaments produced in the nineteenth and twentieth centuries.

• Journal of IKEEE
• /
• v.15 no.4
• /
• pp.299-304
• /
• 2011

In this paper, the circular polarized horn antenna composed of circular polarizer and impedance transformer is designed, and fabricated. For the circular polarizer, two types of the polarizer are designed and the electrical performance of them is compared; rectangular waveguide polarizer with $45^{\circ}$-inclined dielectric slab and oval shaped one. Straight type mode converter has a stepped impedance structure and plays a role of converting waveguide TE mode into coaxial TEM mode, and the proposed antenna is designed to directly connect with active components using the feed-through in the input port of the mode converter. Fabricated antenna has the wideband performance, VSWR<1.5 and Axial ratio < 1.0dB, ranging from 30.085 to 30.885 GHz, and the antenna gain is 6.7~7.0 dBi.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.24 no.5
• /
• pp.502-507
• /
• 2013

In this paper, a circular dual mode horn with modified aperture is proposed to improve a E/H-plane radiation pattern symmetry of a conventional oversized circular dual mode horn. The proposed antenna consists of a feeding section, a mode generation section and a phase matching section which has aperture shape transition from circle to ellipse or rectangle to improve a E/H-plane radiation pattern symmetry. To compare the performances between the proposed antenna and the convenional circular dual mode horn, the conventional circular dual mode horn and the proposed circular dual mode horn with rectangular aperture are fabricated and researched at 15 GHz. The measured results show that the conventional circular dual mode horn has 3.394 dB difference while the proposed antenna has only 0.539 dB difference between E and H-plane radiation patterns within the -11 dB beamwidth($53^{\circ}$) which is required beamwidth of the feed horn for the maximum aperture efficiency where f/d ratio of reflector antenna is 1.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
• /
• 2002.11a
• /
• pp.306-310
• /
• 2002

본 논문에서는 기존의 혼 안테나에 Dielectric rod를 삽입하는 구조를 사용하였다. 입력구조는 Rectangular Waveguide Feed에 Cone을 접목시키는 형태로 구현되었으며 기존의 E-Plane taper구조보다 특성이 양호하며 소형화를 구현해냈다. 제작된 안테나의 중심주파수는 37GHz이며 정재파비 특성 또한 양호하다. 여러 Feeding 구조 중 Bandwidth를 좀더 확장할 수 있는 구조에 초점을 맞추어 대역폭은 13%이상을 구현했으며 시뮬레이션 툴은 Ansoft HFSS V7.0으로 최적화한 후 제작 및 측정하였다. 또한 사용된 Dielectric rod의 제질은 Teflon(ETFE, $\varepsilon$$_{r}$=2.03)을 사용하였다.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.11 no.1
• /
• pp.52-60
• /
• 2002

The purpose of this research is to study the vibration and acoustic pressure radiation from a thin isotropic flat plate stiffened by a rectangular array of beams, and excited by a time harmonic point force. These constructions on aircraft and ship structures are often subjected to fiequency dependent pressure fluctuations and forces. Forces from the these excitations induce structural vibrations in a wide range of fiequencies, which may cause such things as acoustic fatigue and internal cabin noise in the aircraft. It is thus important that the response characteristics and vibration modes of such periodic structures be horn. From this theoretical model, the sound pressure levels(SPL) in a semi-infinite fluid(water) bounded by the plate with the variation in the locations of an external time harmonic point farce on the plate can be calculated efficiently using three numerical tools such as the Gauss-jordan method the LU decomposition method md the IMSL numerical package.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.45 no.1
• /
• pp.91-96
• /
• 2008

In this paper, a monopulse fled for three mode $2{\times}2$ array feed horn antenna was designed. Gain of single feed was 8.25dB. Increasing property of gain and rectangular waveguide and reflection of free space is decreased because it has structure extending to electric plane at connected part from transformation to free space. When fled port1 and port2 is placed vertically and thickness of aperture hem is reduced, isolation is satisfied with property of lower -25dB. Also, at higher frequency, it is confirmed that isolation is improved. Combination of electric field occurs less influence because port1 and port3 is placed horizontally and distribution of electric field is connected to parallel. However, because of combination of electric field, it is more improved from 2dB to 6dB than isolation of port1 and port2. Direct combination occult less effect at port1 and port4 than effect of port2 and port3, it is lower -35dB.