摘要 |
Reception and transmission of radio frequency signals is performed between the rotary portion and the stationary portion via an electromagnetically coupled portion in which a microstrip formed along substantial one lap of the circumference having a length equivalent to an odd multiple of substantially 1/2 of the electrical wave length of the transmitted radio frequency signal is electromagnetically coupled with a microstrip having a length equivalent to an add multiple of substantially 1/4 of the electrical wave length of the radio frequency signal.
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