• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.11
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• pp.55-60
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• 2008

This paper proposed a dual-band RF switch using a Composite Right/Left Handed transmission line(CRLH TL) and PIN diode. RF switch is usually consist of $\lambda/4$ Right Handed transmission line(RH TL) and PIN diode. The dual band characteristics of RF switch was achieved by using CRLH transmission line instead of RH transmission line. CRLH Open-Stub was designed for resolve to reduction of isolation due to Package Inductance of PIN diode. The proposed RF switch was designed at GSM and DCS frequency-band. The measurement results showed a good agreement with theoretical result.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.4
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• pp.41-46
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• 2005

In this paper, a new method for suppressing microwelding on the RF MEMS (Radio Frequency Microelectromechanical System) direct contact switches is introduced. Two kinds of refractory metals, tungsten and molybdenum were coated onto the contact point of the switches and the effect of the coating was examined. The changes in insertion loss and isolation at the switch were measured by using network analyzer and power loss was evaluated by power measurement. The results revealed that while tungsten and molybdenum showed higher contact resistance than gold in low input power range, they enhanced the power handling capability and reliability of the switches in high input power region.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.4
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• pp.7-12
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• 2008

This paper presents a lateral resistive contact RF MEMS switch using comb drive. Our goal was to fabricate the RF MEMS switch with high reliability and good RF characteristics for front end module in wireless transceiver system. Therefore, comb drive is used for large contact force in order to achieve low insertion loss and small off-state capacitance in order to achieve high isolation. The single crystalline silicon is used for mechanical reliability. As a result, the developed switch showed insertion loss less than 0.44 dB at 2 GHz, isolation greater than 60 dB, and low actuation voltage at 26 V.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.13 no.5
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• pp.21-26
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• 2014

This paper proposes a frequency reconfigurable antenna which operates at not only LTE but also other currently serviced bands. The high band(1,710-2,170 MHz) performance was satisfied through PIFA structure, and the low band performance through the additional RF Switch by changing the state between SW1 and SW2. When the RF switch is SW1 state, the operation bandwidth is 782-907 MHz (GSM), and 738-861 MHz (LTE) at OFF state. The proposed antenna has a omni-directional radiation pattern and measured peak gains were 0.04-4.68 dBi at the SW1 state and 0.92-1.53 dBi at the SW2 state, respectively. Judging from the results, proposed reconfigurable antenna is expected to be applied to LTE-Advanced mobile terminals since the antenna shows an outstanding performance.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.3
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• pp.416-423
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• 2012

Using Ansoft HFSS(High Frequency Structure Simulator) and Serenade(circuit simulator), multilayer LPF and RF diode switch for GSM were designed. Diodes were transformed the inductor and capacitor in Tx and Rx for the simulation of equivalent circuit, respectively. In particular, the design of the simulation for multilayer RF diode switch was carried out with considering the variance of device and contraction percentage.

• Journal of Navigation and Port Research
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• v.28 no.5
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• pp.429-434
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• 2004

In this paper, we designed a reconfigurable slot antenna using sequentially voltage-applied RF MEMS switches. In order to obtain pull-in voltage and maximum stress of the MEMS switches, the switch structures in accordance with airgap height was analyzed by ANSYS simulation A actuation voltage of MEMS switches can be determined by switch geometry and airgap height between a movable plate and a bottom plate. The designed lengths of MEMS switches were 240 $\mu\textrm{m}$, 320 $\mu\textrm{m}$, 400 $\mu\textrm{m}$, respectively and the airgap was 6$\mu\textrm{m}$. The total size of the designed slot antenna was 10 mm x 10 mm and the slot length and width were 500 $\mu\textrm{m}$ and 200 $\mu\textrm{m}$, respectively. The length and size of the CPW feedline were 5 mm and 30-80-30 $\mu\textrm{m}$, respectively. and then the size of the CPW in the slot was 50-300-150 $\mu\textrm{m}$. The tuning of the resonant frequency of the proposed device is realized by varying the electrical length of the antenna, which is controlled by applying the DC bias voltages to the RF MEMS switches. The designed slot antenna has been simulated, fabricated and measured.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.75-77
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• 2018

최근 다양한 산업응용분야에서 가변커패시터의 필요성은 점점 증가하고 있다. 특히 고전력 RF플라즈마 시스템에서 임피던스 정합 회로에 사용되는 가변커패시터는 빠른 고전압 차단능력이 요구된다. 본 논문에서는 RF플라즈마 시스템의 임피던스 정합 회로에 활용되는 단방향 스위치를 사용한 전기적 가변 캐패시터 (Electrical Variable Capacitor, 이하 EVC) 회로의 전압 스트레스를 저감하는 방법에 대해서 제안한다. 제안된 방법은 13.56Mhz의 주파수와 1kW이상의 고전력 RF플라즈마 시스템에서 단방향 스위치의 전압 스트레스를 양방향스위치를 사용한 EVC 회로를 활용하여 저감한다. 본 논문에서 제안된 방법으로 전압 스트레스가 감소하여 EVC 회로를 고전력 초고속 RF플라즈마 시스템의 임피던스 정합 회로에 좀 더 효과적 으로 적용할 수 있게 된다. 시뮬레이션 및 실험을 통해 EVC 회로의 스위치에 걸리는 전압 스트레스가 40%이상 저감되는 것을 검증하였다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.6
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• pp.952-958
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• 2000

다양한 구조위 트랜스미션 라인과 힌지들을 갖는 고주파용 마이크로머신드 용량성 스위치들이 새롭게 디자인되었고 전기도금 기술, 저온 공정기술, 그리고 건식 식각기술들을 이용하여 제작되었다. 특히, 집적화된 용량성 스위치들이 높은 스위칭 on/off ratio와 on 캐패시턴스를 갖도록 하기 위하여 고유전율을 갖는 SrTiO3라는 상유전체를 절연체로 사용하였다. 제작된 스위치들은 8V의 구동전압, 0.08dB의 삽입손실, 42dB의 높은 isolation, 600의 on/off ratio, 그리고 50pF의 on 캐패시턴스의 특성들을 갖는다.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.378-378
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• 2013

칼코겐화물의 일부는 전류 등의 에너지 입력에 따라 결정구조가 비정질 및 결정 사이에서 가역적으로 변화하며 상변화에 따라 전기 저항이 바뀌는 특성을 가지고 있다. 이와 같은 칼코겐화물 상변화 재료의 장점을 이용하여 프로그래머블 스위치를 구현할 수 있다. 그러나 상변화 재료만을 이용하는 프로그래머블 스위치는 전기신호 누설의 문제점이 발생한다. 이러한 문제점을 해결하기 위해서 지난 연구에서는 문턱 스위칭 칼코겐화물을 포함하는 다층구조 스위치를 제안하였다. 본 연구에서는 프로그래머블 스위치의 구성물질로서 문턱 스위칭 특성을 보이는 GeTe 박막의 특성을 보고한다. RF magnetron sputtering 방식을 이용하여 GeTe 박막을 증착하고 온도에 따른 결정화 양상 및 표면 형상 변화를 관찰하였다. GeSbTe 박막의 경우 $100^{\circ}C$ 근방에서 결정화가 시작되었고, 온도가 증가할수록 결정화가 급격히 진행되었다. 반면 GeTe 박막에서는 온도 증가에 따른 결정화가 거의 일어나지 않았다. 이러한 결과로부터 GeTe 합금 박막은 프로그래머블 스위치의 구성요소로서 문턱 스위칭에 적합한 물질임을 확인할 수 있었다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.5
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• pp.1038-1043
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• 2003

A capacitive-coupled configuration MEMS switch is designed and fabricated, and its characteristics are measured. Low actuation voltage has been achieved by means of small distance between signal line and membrane. Minimum actuation voltage is about 11V. Isolation is around 40dB and insertion loss is about 0.2dB at 2GHz.