• 전자공학회논문지D
• /
• 제34D권3호
• /
• pp.17-24
• /
• 1997

Broad-band RAM's (Radar absorbing materials) are designed by multi-layered lossy dielectrics. The depth, the relative permittivity and the loss tangent of each layer are optimized in order to meet the required reflective power over the specified frequency range using a genetic algorithm. The reflection coefficients are calculated by the continued fraction method. A new population model of the partial initialization method during iterations is applied for the multi-modal functions to enhance the performance of the genetic algorithm. The optimal RAN's are designed by setting the relative permittivity and the loss tangent of the dielectrics as a funtion of the frequency over 5~20GHz.

• 기술사
• /
• 제24권1호
• /
• pp.95-103
• /
• 1991

The communication transmission engineering plays the most important role in electrical communications engineering. Recently, it has been making remarkable progress as an infrastructure supporting informationaged society. Specially, the start of television conference and service of high speed digital transmission can be said it is announcing a raising curtain of high speed broad band age. Together with high speed broad band service needs a capacity as much as several or several hundred times of telephone with one circuit, various kinds of service forms are anticipated to emerge, it is anticipated to give a big impact to the way of future communications newtork. At present, telecommunication network is transforming telephone voice information by analog technology into a flexible higher system disposable of a variety of information such as pictures or data other than telephone by the introduction of digital technology. Consequently, the development of hereafter for the following respective technologies is desired.

• 기술사
• /
• 제24권2호
• /
• pp.127-136
• /
• 1991

The communication transmission engineering plays the most important role in electrical communications engineering. Recently, it has been making remarkable progress as an infrastructure supporting informationaged society. Specially, the start of television conference and service of high speed digital transmission can be said it is announcing a raising curtain of high speed broad band age. Together with high speed broad band service needs a capacity as much as several or several hundred times of telephone with one circuit, various kinds of service forms are anticipated to emerge, it is anticipated to give a big impact to the way of future communications network. At present, telecommunication network is transforming telephone voice information by analog technology into a flexible higher system disposable of a variety of information such as pictures or data other than telephone by the introduction of digital technology. Consequently, the development of the hereafter for the following respective technologies is desired.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 1997년도 춘계학술대회논문집; 경주코오롱호텔; 22-23 May 1997
• /
• pp.86-94
• /
• 1997

An investigation into the modal interaction of an autoparametric system under broad-band random excitation is made. The specific system examined is a spring-pendulum system with internal resonance, which is known to be a good model for a variety of engineering systems, including ship motions with nonlinear coupling between pitching and rolling motions. By means of the Gaussian closure method the dynamic moment equations explaining the random response of the system are reduced to a system of autonomous ordinanary differential equations of the first and second moments. In view of equilibrium solutions of this system and their stability we examine the system responses. The stabilizing effect of system damping is also examined.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2002년도 하계종합학술대회 논문집(1)
• /
• pp.455-458
• /
• 2002

Design methods are presented for an X-band traveling-wave slot array realized on a rectangular waveguide. An array of 21 longitudinal slots is realized on the broad wall of a rectangular waveguide. The squint of the antenna main beam is adjusted using the element spacing and the waveguide broad wall dimension. The excitation of the array is controlled by the slot offset from the waveguide center line Multiple I-plane steps are placed around last slot elements so that the second-order beam due to tile reflected wave Is minimized A waveguide-to-coaxial adapter Is designed for feeding the array antenna from a coaxial system. Results of the design show an outstanding performance of the antenna 17.1 dB gain. 36"beam 1111, and -21 dB maximum sidelobe level.evel.

• 한국전자파학회논문지
• /
• 제12권1호
• /
• pp.58-64
• /
• 2001

B-WLL 용 마이크로스트립 패치 안테나를 설계 및 제작하였다. 배열 안테나를 만들기 위해 안테나의 크기를 소형화하였다. 두 개의 기생 소자를 급전되는 메인 패치에 가깝게 위치시킴으로써 광대역 특성을 얻을 수 있었다. 설계, 제작된 안테나는 약 15%의 대역폭을 가졌다. 넓은 대역폭에 걸쳐 방사 패턴을 측정하였다.

• 전기학회논문지
• /
• 제68권1호
• /
• pp.83-89
• /
• 2019

In this paper, beam forming using moving least squares method (MLSM) is studied. In the previous research, the least squares method (LSM), one of the data interpolation methods, was used to determine the desired beam pattern and obtain a beam pattern that minimizes the square of the error with the desired beam pattern. However, LSM has a disadvantage in that the beam pattern can not be formed to satisfy the exact steering angle of the desired beam pattern and the peak sidelobe level (PSLL) condition. To overcome this drawback, MLSM is used for beam forming. In order to verify, the proposed method is applied in beam forming of Bezier platform array antenna which is one of conformal array antenna platform.

• 한국정보기술학회 영문논문지
• /
• 제9권2호
• /
• pp.99-105
• /
• 2019

In this paper, we describe the procedure of simulation design and measured results of a compact planar antenna for handset applications. The broad bandwidth covering the interested frequency band for mobile handset is achieved by introduction of an open ended L-shaped slot which is newly proposed and corresponds to the monopole slot. In order to minimize the impact on circuit part placement, the proposed antenna is placed on the ground plane edge of PCB with size of 60×65 mm². The measurement result for 10dB impedance bandwidths is 640 MHz (1.7~2.34 GHz), covering the required bandwidths for DCS (Digital Cellular System)-1800 (1710 ~ 1880 MHz) / IMT (International Mobile Telecommunication)-2000 (1885 ~ 2200 MHz) bands. In particular, we would like to emphasize the proposed antenna has an omnidirectional radiation pattern suitable for commercial wireless communication.

• 대한화학회지
• /
• 제19권5호
• /
• pp.317-324
• /
• 1975

$Na^+,\;Ca^{2+},\;Ni^{2+},\;Al^{3+}$ 이온이 포화된 montmorillonite상에 여러 溫度에서 일어난 $H_2O와\;D_2O$의 氣相吸着에 관하여 연구하였다. 吸着으로 인하여 생긴 OH의 IR 신축진동 band를 computer에 의하지 않고 4개의 Gauss 成分으로 나누었다. 물과 silanol OH기와의 共鳴理論은 $3625cm^{-1}와\;2680cm^{-1}$로 증명되었다. $3400cm^{-1}$와 2475cm 에서의 broad한 吸收는 吸着된 물과 水素結合을 일으키고 있는 silanol OH의 신축진동에 의한 것이었고 $3650cm^{-1}와\;2345cm^{-1}$ band는 吸着된 $H_2O와\;D_2O$에 의한 것이었다. 吸着水와 表面 OH사이의 水素結合은 精電氣的 相互作用에 의한 것임이 밝혀졌다.

• 한국식품과학회지
• /
• 제18권2호
• /
• pp.163-167
• /
• 1986

녹두의 발아중 수분 함량의 변화, 총 단백질과 가용성 단백질 함량의 변화, 그리고 전기영동에 의한 가용성 단백질의 변화 패턴을 조사하였다. 건조녹두의 수분함량은 12.7%이고 침지 후에는 60% 였으며 발아함에 따라서 점차 증가하여 90.7%까지 올라갔다. 녹두를 침지하므로써 급격히 총 단백질 함량과 가용성 단백질 함량이 감소하였고 발아 일수가 경과함에 따라서 점진적인 감소를 보였으며, 총 단백질과 가용성 단백질은 비슷한 감소 패턴을 보였다. 녹두의 가용성 단백질을 SDS로 처리하지 않고 전기영동 하였을때 2개의 넓은 band와 3개의 즘은 band를 얻을 수 있었고, 발아함에 따라서 2개의 넓은 band는 점차 희미해져 단백질이 분해되고 있음을 알 수 있었다. 그러나 다른 band의 단백질들은 비교적 분해되지 않고 남아 있었다. 녹두의 가용성 단백질을 SDS-PAGE로 관찰 하였을때 19개의 분명한 band를 얻을 수 있었고 발아함에 따라서 대부분의 단백질 band는 분해되어 희미해져 갔으나 상당한 부분이 발아 7일째까지 분해되지 않고 남아 있음을 알 수 있었다.