• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.10 no.5
• /
• pp.79-86
• /
• 2011

In this paper, a S-band coaxial waveguide-based spatial combiner is proposed. The proposed combiner consists of coaxial waveguide, impedance transformer, and finline-to-microstrip transformer. The coaxial waveguide is used as the host of the combining circuits for higher output power and better uniformity by equally distributing the input power to each element. The finline-to-microstrip transformer is designed by using antipodal antenna, and obtained low reflection coefficient by applying the small reflection theorem. The measurement results show the coaxial waveguide combiner has a maximum combining efficiency of 95%.

• Journal of Advanced Navigation Technology
• /
• v.14 no.6
• /
• pp.909-915
• /
• 2010

In this paper, the unequal power divider based on CRLH (Composite Right/Left-Handed) transmission line with dual-band characteristic is proposed. They consist of dual-band branch line hybrid coupler, the connection between input and isolation port of hybrid coupler and ${\lambda}/4$ impedance transformer. When the transmission line between input and isolation port of hybrid coupler is asymmetrical connected, the divider is obtained the output results of the equal phase and unequal power dividing ratio. The simulation results of the divider represent the power ratio of 0 dB ~ 20 dB. To validate a function of divider, the hybrid coupler and transformer with 880 MHz and 1850 MHz is implemented. As a result, the proposed unequal divider obtains the power ratio of 3.2 dB ~ 8.8 dB at 880 MHz and 2.5 dB ~ 14.0 dB at 1850 MHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.14 no.10
• /
• pp.1052-1059
• /
• 2003

In this paper, we proposed the directional coupler using two layer microstrip substrate which is improved coupling and isolation. Also, we notified a design method. Modified re-entrant mode coupler is the structure added to the aperture on the ground plane in order to improving the coupling value. And, by adding to slits on the floating conductor, this structure has good performance in isolation, VSWR according to S$\sub$11/, and phase difference. As a result, proposed re-entrant mode microstrip directional coupler has about 1.5 dB more higher coupling and 20 dB more higher isolation than conventional coupler. And because this coupler has good performance in phase difference, it can be used multi-section coupler.

• Korean Journal of Optics and Photonics
• /
• v.10 no.6
• /
• pp.487-493
• /
• 1999

In this paper, we studied the characteristics of a soliton coupler using a bent nonlinear waveguide. The bent soliton coupler has very ,harp switching characteristic like the conventional soliton coupler due to the threshold effect of soliton emi,sion from the nonlinear waveguide. By using the bent structure, we can reduce the threshold power for the soliton emission. We consider the saturation effect of nonlinearity and the loss in the medium for more accurate and practical numerical analysis in wave propagation through the bent soliton coupler. The simulation results show that the consideration of the saturation effect and the ]os~ may be very important in the analyses and design of the nonlinear waveguide devices. The bent structure is useful for the emission of the spatial soliton with the low threshold power, when we consider the saturation and the loss effect. ffect.

• 한국정보통신설비학회:학술대회논문집
• /
• 2003.08a
• /
• pp.283-285
• /
• 2003

본 논문에서는 nonradiative dielectric(NRD) 도파로를 이용해 60GHz대에서의 $90^{\circ}$ 하이브리드 3dB 방향성 결합기를 설계하였다. 3dB 결합기의 설계 시 NRD 도파로의 기본 모드인 $LSM_{11}$ 모드를 여기 시키기 위한 변환기를 설계하였고 NRD 도파로의 특징인 밴딩에서의 모드 컨버젼 현상을 확인하고 이를 이용하여 $LSE_{11}$ 모드를 이용한 3dB 결합기를 설계하였다.

• Journal of the Korean Institute of Telematics and Electronics D
• /
• v.36D no.4
• /
• pp.8-17
• /
• 1999

In this paper, a proposal for improving the performance of IF in-phase combiner is presented in view of simple hardware design and good performance for space diversity application. By adding the stable normalization circuit to the phase detector, better performances are obtained even for a severe notch depth of 30 dB. To check the validity of this proposal, various results based upon numerical simulation and laboratory test are presented here in conjunction with 64-QAM digital radio relay system.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
• /
• 2003.11a
• /
• pp.318-321
• /
• 2003

마이크로스트립 구조의 방향성 결합기는 이방성 유전체로 인하여 지향성 특성이 저하된다. 즉 우, 기모드의 위상차에 의해 격리특성이 저하된다. 이러한 문제점을 개선하고자 결합선로간의 대칭형으로 입출력단에 위상 보상용 커패시터를 구현해주어 격리특성을 개선하였다. 보상용 캐패시터는 평면형으로 구현하여 제작의 편리하고, 우, 기모드 위상차를 줄여주어 높은 지향성 특성을 얻을 수 있었다. 부가적으로 결합선로의 길이를 약 10%를 줄 일수 있다. 제시된 방법의 타당성을 입증하기 위하여 12dB, 20dB와 30dB의 마이크로스트립 방향성 결합기를 제작하여 30dB의 높은 지향성 특성을 얻었다.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.14 no.3
• /
• pp.171-176
• /
• 2014

The polarization characteristics of ultracompact polarization-insensitive directional coupler (PIDC) based on double sandwiched rib-type waveguide are explored in detail by using longitudinal modal transmission-line theory (L-MTLT). To obtain the polarization-insensitive condition of ultracompact directional coupler, the coupling length and coupling efficiency as functions of the refractive index and thickness of sandwiched rib-type waveguide are analyzed for quasi-TE and quasi-TM modes. The numerical results show that the ultracompact polarization-insensitive coupler with hundreds of micrometer scales is realized by properly choosing structural and material parameters of double sandwiched layers. Furthermore, the influence of fundamental mode profile, which is distributed in lateral waveguide of coupler, on the coupler performance has been investigated.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.13 no.1
• /
• pp.101-105
• /
• 2002

In this paper, the coupling windows of the dielectric resonator filter have been analyzed. The coupling factor which has been used to characterize the coupling window is represented by closed form expressions. The deviation of the coupling factor as the size of coupling window has been compared between calculated by presented method and measured ones. There are very closed agreements. The presented method can be applied not only to design dielectric resonator but also to design varactor tuned dielectric resonator filter so as that the passband bandwidth is constant within tuned ranges.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2001.10a
• /
• pp.218-221
• /
• 2001

이 논문에서는 800MHz 대역에서의 interdigital 커패시터를 이용한 높은 지향성의 방향성 결합기를 설계하였다. 본 논문에서는 20dB 방향성 결합기 설계에 있어 interdigital 커패시터의 파라미터 W, G, Ge, Lo, Wt에 따른 결합도와 격리도의 변화를 분석하여 최적화 함으로써 30dB이상의 지향성을 얻도록 설계하는 것을 목적으로 하였다.