Shi Jianhua,Hu Hongbing,Gu Huidong,Li Haiquan,Wang Hongwei,Wu Lin,Jin Haobo
申请号：
US201615231571
公开号：
US2017093364(A1)
申请日:
2016.08.08
申请国别(地区):
美国
年份:
2017
代理人:
摘要：
Impedance matching circuits and methods for radio frequency (RF) transmission coil are disclosed. An example impedance matching circuit includes a coil matching circuit, a RF power detection circuit, and a spectrometer. The spectrometer outputs an output voltage reversely applied on a varactor diode of the coil matching circuit. An impedance of the coil matching circuit is changed based on the output voltage. The spectrometer outputs a RF transmission signal to the RF power detection circuit, receives a power of a RF reflected signal corresponded to the output voltages. The spectrometer receives powers of different RF reflected signals corresponded to different output voltages, and assigns an output voltage corresponded to a minimum power of the RF reflected signals as an impedance matching voltage, where an equivalent impedance of the coil matching circuit and the RF transmission coil matches with an impedance of RF transmission lines.
