• 자연과학논문집
• /
• 제17권1호
• /
• pp.39-50
• /
• 2006

서로 수직으로 편광된 이중모드 고체레이저에서는 두 개의 이완 진동수가 존재한다. 이런 이동 모드 고체레이저를 변조시켜 주면 혼돈 등의 복잡한 현상이 일어날 수 있다. 본 논문에서는 수직으로 편광된 이중 모드 고체레이저에 대해 빛과의 상호작용에서 비등방성을 고려하여 맥스웰-블로흐 방정식을 유도하고, 이를 사용하여 복잡한 비선형 동력학적인 현상을 설명하였다.

• 한국통신학회논문지
• /
• 제30권9A호
• /
• pp.788-794
• /
• 2005

In this paper, we focus on the potential of dual polarized antennas in mobile system. thus, this paper designs exact dual polarized channel with Spatial Channel Model (SCM) and investigates the performance for certain environment. Using proposed the channel model; we know estimates of the channel capacity as a function of cross polarization discrimination (XPD) and spatial fading correlation. It is important that the MIMO channel matrix consists of Kronecker product dividable spatial and polarized channel. Through the channel characteristics, we propose an algorithm for the adaptation of transmit antenna configuration to time varying propagation environments. The optimal active transmit antenna subset is determined with equal power allocated to the active transmit antennas, assuming no feedback information on types of the selected antennas. We first consider a heuristic decision strategy in which the optimal active transmit antenna subset and its system capacity are determined such that the transmission data rate is maximized among all possible types. This paper then proposes singular values decision procedure consisting of Kronecker product with spatial and polarize channel. This method of singular value decision, which the first channel environments is determined using singular values of spatial channel part which is made of environment parameters and distance between antennas. level of correlation. Then we will select antenna which have various polarization type. After spatial channel structure is decided, we contact polarization types which have considerable cases It is note that the proposed algorithms and analysis of dual polarized channel using SCM (Spatial Channel Model) optimize channel capacity and reduce the number of transmit antenna selection compare to heuristic method which has considerable 100 cases.

• Journal of electromagnetic engineering and science
• /
• 제19권1호
• /
• pp.37-41
• /
• 2019

A stack-ring configuration is proposed for designing a dual-band circularly polarized (CP) antenna. Each ring generates different resonant frequencies. A good CP performance at both resonant frequencies is achieved by adjusting the relative distance between the two rings. The two operating bands are separated with a small frequency ratio of 1.07. Measured results show that radiation patterns with good CP characteristics are obtained at the two resonant frequencies.

• 한국전자파학회:학술대회논문집
• /
• 한국전자파학회 2003년도 종합학술발표회 논문집 Vol.13 No.1
• /
• pp.418-422
• /
• 2003

In this paper a dual-band circularly polarized stacked microstrip antenna for Global Positioning System (GPS) service and Digital Multimedia Broadcasting (DMB) service is designed. By stacking two different corner-truncated square microstrip patches, dual-band, dual polarization characteristic is obtained. Experimental results show impedance bandwidth of 60 MHz (3.8%) and axial ratio bandwidth of 6 MHz (0.4%) in GPS and impedance bandwidth of 126 MHz (4.7%) and axial ratio bandwidth of 30MHz (1.1%) in DMB.

• 한국전자파학회:학술대회논문집
• /
• 한국전자파학회 2005년도 종합학술발표회 논문집 Vol.15 No.1
• /
• pp.231-234
• /
• 2005

In this paper, Dual-polarized Tx/Rx antenna for RFID reader is designed and fabricated to apply to RFID reader. Each feeding network of Tx/Rx is designed to improve the port-isolation and cross-polarization, and sequential rotation feeding scheme has been applied to increase of axial ratio bandwidth. Measured results show that 2.35dBi of antenna gain in 900MHz$\sim$928MHz, 150MHz of 3dB axial ratio bandwidth, -38dB$\sim$-40dB of port-isolation, and -30dB$\sim$-40dB of cross-polarization.

• 한국전자파학회:학술대회논문집
• /
• 한국전자파학회 2005년도 종합학술발표회 논문집 Vol.15 No.1
• /
• pp.235-240
• /
• 2005

This paper presents a dual band circularly polarized microstrip patch antenna. The antenna consists of two corner truncated patches implemented in one plane and single feed point. The input signal is directly excited to the patch 2 and the patch 1 is fed from patch 2 by coupling between two patches. The antenna is operated at 900 MHz and 2.45 GHz bands and has the right hand circularly polarized radiation pattern at all. The measured gains of the antenna are 2.95 dBic at 900 MHz band and 4.6 dBic at 2.45 GHz band.

• 전기학회논문지P
• /
• 제64권3호
• /
• pp.121-124
• /
• 2015

In this paper, we developed the compact Doppler radar using the compact dual-circularly polarized antenna for medical application. The operating frequency is 2.47 GHz for considering ISM band. In order to decrease the size of the entire system, we designed the compact antenna and located the circuit board at the back of the antenna. The simulation of the proposed antenna was performed by the finite difference time domain (FDTD) method. The total volume of the proposed system is $65{\times}45{\times}6mm^3$ including the antenna. From the experiment, the developed bio-radar could be used to support the device for medical applications.

• 방송과미디어
• /
• 제11권1호
• /
• pp.78-85
• /
• 2006

Cognitive radio is a paradigm for wireless communication in which either network of wireless node itself changes particular transmission or reception parameters to execute its tasks efficiently without interfering with the licensed users. This paper represents a performance of the cognitive radio technology on dual polarized MIMO system using six-port receiver. Six-port technology is well known direct conversion receiver. In this paper, a six-port phase discriminator based polarization signal separation is shown. That is, the SER(Symbol Error Rate) performance is improved using polarization separator and simple receiver architecture is proposed applying six-port receiver. The six-port technology has priority to adapt changeable frequency system and variable environments for cognitive radio. In general, dual polarized MIMO system has good capacity and quality using polarization separator [1].

• Journal of electromagnetic engineering and science
• /
• 제10권4호
• /
• pp.309-315
• /
• 2010

A dual-band dual-polarized microstrip antenna array for an advanced multi-function radio function concept (AMRFC) radar application operating at S and X-bands is proposed. Two stacked planar arrays with three different thin substrates (RT/Duroid 5880 substrates with $\varepsilon_r$=2.2 and three different thicknesses of 0.253 mm, 0.508 mm and 0.762 mm) are integrated to provide simultaneous operation at S band (3~3.3 GHz) and X band (9~11 GHz). To allow similar scan ranges for both bands, the S-band elements are selected as perforated patches to enable the placement of the X-band elements within them. Square patches are used as the radiating elements for the X-band. Good agreement exists between the simulated and the measured results. The measured impedance bandwidth (VSWR$\leq$2) of the prototype array reaches 9.5 % and 25 % for the S- and X-bands, respectively. The measured isolation between the two orthogonal polarizations for both bands is better than 15 dB. The measured cross-polarization level is ${\leq}-21$ dB for the S-band and ${\leq}-20$ dB for the X-band.

• 한국컴퓨터정보학회논문지
• /
• 제24권11호
• /
• pp.71-78
• /
• 2019

현재 상용화된 대부분의 3D 디스플레이는 왼쪽 눈과 오른쪽 눈의 입력영상을 다르게 만들어 입체감을 만드는 양안시차 방식을 적용하고 있다. 하지만 상용화된 3D 영상 출력 장치는 성능 부족에 의한 시청자의 불편 유발과 시청위치의 제약 등의 문제들이 있다. 본 논문에서는 기존 Dual-cell 구조 대비 시야각, Crosstalk 감소, 광투과도를 향상할 수 있는 Single-cell 구조의 편광안경식 입체영상 시스템을 개발하고, 투과도 실험과 시야각 평가를 통해 Single-cell 구조의 편광안경식 입체영상 시스템 특성분석과 Dual-cell 구조 대비 성능향상 효과 분석을 진행하였다. 분석 결과 Single-cell 구조가 Dual-cell 구조 대비 투과도 부분에서 약 25% 이상의 높은 성능을 보이며, 시야각 평가 중 입체 영상 특성품질의 주요지표인 3D crosstalk 지표는 약 37% 이상 향상되는 것을 확인할 수 있었다.