• Title, Summary, Keyword: RF 수신코일

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Design and Implementation of Microstrip Quadrature Coupler and High Power Transmitting/Receiving Switch Using Dynamic Loading Technique for 1-Tesal MRI System (동적 부하 기술을 이용한 1-Tesla 자기공명 영상 시스템용 마이크로 스트립 quadrature coupler 및 고출력 송수신 스위치의 설계 및 제작)

  • 류웅환;이미영;이흥규;이황수;김정호
    • Journal of the Korean Institute of Telematics and Electronics D
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    • v.36D no.3
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    • pp.1-11
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    • 1999
  • It is now common practice to utilize the quadrature RF coils to improve the signal-to-noise ratio (SNR) in the Magnetic Resonance Imaging (MRI) System. In addition, to make such an available SNR improvement, it is mandatory to use a well-designed quadrature coupler, which facilitates a perfect 3-dB coupling and quadrature-phase shift. However, the four ports matching condition has to be well considered during the RF excitation and the signal detection period. This work investigates the effects of such a mismatching condition (especially, due to patient) from the analysis, simulation, and real implementation and firstly proposes dynamic loading technique for a quadrature coupler and transmitting/receiving switch module to minimize a patient mismatching and enhance a system reliability. Also, we designed and implemented the quadrature coupler and transmitting/receiving switch module using microstrip. As a result, the SNR of our MRI system using the microstrip quadrature coupler and transmitting/receiving switch module with dynamic load increases 3 dB compared with the old one using USA quadrature switch. Also, the power capability of quadrature coupler and transmitting/receiving switch module is 5-kw peak power. Considering power loss and reduction of size, we used a RT/duroid 6010 substrate with high permittivity and for simulation we use Compact Software.

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