• Journal of Satellite, Information and Communications
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• v.4 no.2
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• pp.52-56
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• 2009

The design method of a four-port stripline circulator with a single ferrite disk is proposed using Green's function method. The four-port circulator gives the flexibility of the design of the communication system. Two cascaded three-port circulators has been used as a four-port circulator. However, if a four-port circulator with a single ferrite disk replace the present four-port circulator, then it will give less weight and volume and so has the advantage in satellite application.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.10
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• pp.1071-1077
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• 2002

In this paper, we have studied the dependence of insertion loss of the pressed microstrip PBG ring consisting of coupled two microstrip lines. When the distance decreases, two or three attenuation poles are created by the coupling between the lines. Thus the pressed PBG ring exhibits a wide stop band and sharp cutoff characteristics.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.7
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• pp.128-134
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• 2010

In this paper, a high-power 20-way stripline power divider with low insertion loss and low side lobe level is successfully designed, fabricated and measured as a feed network for an S-band linear array antenna having Dolph-Chebyshev current distribution which has a narrow beam width and very low side lobe level (SLL). The 20-way stripline power divider consists of an 8-way power divider, three 4-way power dividers and three ring hybrids. It utilizes a T-junction structure as a basic element for power dividing. Notches and modified input/output N-to-stripline transitions are used for improving insertion loss and return loss. The fabricated power divider shows insertion loss less than 0.3 ㏈ and rms phase mismatch less than 8o in the full bandwidth. A final 40-way power divider is synthesized by combining symmetrically two 20-way power dividers and is expected to have SLL over 40 dB, based on the measured results of the 20-way power divider.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.3
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• pp.280-288
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• 2009

In this paper, a high-power and low-loss stripline 10-way power divider is designed and fabricated fur the feed network of an S-band linear array antenna with Chebyshev current distribution which has a narrow beam width and low side lobe level(SLL) of 35 dB or more. The unit cell of the power divider is based on a T-junction power divider and the whole divider is comprised of the cascaded unit cells. The multi-stage impedance transformer and modified ring hybrid are used in designing the power divider for performance improvement. And the reflection loss and insertion loss are improved by modifying a connector structure for a coaxial-to-stripline transition.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.393-396
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• 2000

기존의 탄성표면파 듀플렉서 필터는 1/4 파장 정합선로를 이용한 격리회로를 이용하기 때문에 패키지 상에 스트립라인을 구성하는 제작상의 어려움이 있다 본 연구에서는 격리회로가 송신용, 수신용 필터와 함께 온칩상에 위치할 수 있는 새로운 형태의 탄성표면파 필터를 설계하였다. 그 과정으로 송수신 대역을 각각 담당하는 사다리형 필터를 설계하였고, 집중소자 즉, 인덕터와 캐패시터로 구성되는 탄성표면파 듀플렉서 필터의 격리회로를 구성하였으며, 우수한 성능을 가질 수 있도록 각각의 집중소자들의 값을 최적화하였다.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2000.11a
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• pp.420-423
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• 2000

본 논문은 IMT-2000 기지국용 이중편파 ASSAP(Air-Strip-Air-Patch)형 마이크로스트립 안테나를 설계하였다. 복사소자로는 급전선과 복사부와의 고립도가 좋은 개구 결합형 패치를 이용하였다. $\pm$45$^{\circ}$직교 슬롯을 이용하여 이중편파를 발생시키고 급전선으로는 광대역화를 위한 에어 스트립라인을 이용하였으며 안테나의 복사특성을 만족하기 위해 패치의 크기와 접지면의 크기를 조정하여 Ensemble로 시뮬레이션 하였다. 그 결과 설계 제작한 안테나는 두 개의 포트 모두 전대역에 걸쳐 1.5:1 이하의 VSWR과 -25dB이하의 격리 특성, 그리고 65$^{\circ}$$\pm$ 7$^{\circ}$의 수평범폭을 갖는다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.5C
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• pp.506-511
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• 2002

In this paper, waveguide-based power combiner using conventional slotline-to-microstrip transition was proposed at Ka-band. The proposed 2-way and 4-way power combiner consist of waveguide-to-slotline transition, two or four slotline-to-microstrip transitions, and impedance matching networks. Their structures were simulated and optimized by 3-D FEM simulation. The 2-way power combiner showed a very low back-to-back insertion loss of 1.0 dB and return loss better than 15 dB from 25.7 GHz to 29.8 GHz except the resonant frequency. The 2-way power combining approach was extended to 4-way power combining using slotline tee junction. The 4-way power combiner showed the similar performance to that of 2-way power combiner with 2 GHz smaller bandwidth.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.2 no.1
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• pp.22-29
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• 2003

A circuit model for the transition of stripline to dual slotline and a segmented method to analyze a notch antenna are presented. For the circuit model of the transition, the characteristic impedance, dispersions, and the shorted impedance of dual slotline are calculated and approximated with the closed-form expressions. The segmented analysis method allows to get readily an optimized results for the dual slotline-fed notch antenna. As a design example, a notch antenna is segmented into a 4'h order Marchand balun and a dual slot 134 notch antenna, and tested to show the validity of the proposed circuit model.

• Proceedings of the KAIS Fall Conference
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• 2012.05b
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• pp.712-715
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• 2012

본 논문에서는 EM 시뮬레이터를 이용하여 LTE2300 대역의 마이크로스트립 라인 대역여파기를 설계하고 시편을 제작하였다. 중심주파수 2300MHz, 대역폭 350MHz, 삽입손실 1.5dB, 감쇄는 1930MHz와 2690MHz에서 15dB 이상, 1000MHz에서 60dB 이상으로 설계하였다. 또한 반사손실은 15dB로 설계하였다. 구현은 유전율 9.8인 알루미나 유전체에서 하였으며, 전송선로와 접지는 silver paste를 사용하였다. EM 시뮬레이션을 통해 얻은 결과값과 이를 통해 실제 제작된 시편의 보정값을 얻어 data base화 하였으며, 좋은 재현성을 얻을 수 있음을 확인하였다. 특히 일반적으로 마이크로스트립 라인 필터의 제작에 적용되는 에칭 또는 포토리소그라피 대신 레이저를 이용하여 패턴을 구현하였으며, 이 또한 우수한 특성과 재현성을 보여주었다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.05a
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• pp.215-218
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• 2002

In this paper, we propose a microstrip line tunable phase shifter. If we vary the applied bias voltage, the relative dielectric constant of ferroelectrics also changes and we designed tunable phase shifter using Au/BSTO/MgO/Au structure. We also used a coupling structure to increase the amount of phase shift at certain frequency in a limited size and we could reduce the loss by reducing the line width.