Signal transmission device

A signal transmission device comprising:

• a first body made of electromagnetic shielding material and fixed to a rotary shaft which passes through the first body, said first body revolving together with the rotary shaft around an axis of the rotary shaft;
• a second body made of electromagnetic shielding material and stationarily disposed around the rotary shaft;
• first conductive elements each of which being substantially concentrically formed on a first substrate in a manner that peak magnitude points of traveling wave component of transmission signal generated on the elements are positioned out of alignment with each other between at least neighboring elements in radial direction of the concentrically formed elements, said first element being disposed in one of the first body and the second body;
• second conductive elements each of which being formed on a second substrate and having a first width long enough to cover the concentrically formed first element in the radial direction and a second width in a direction perpendicular to the radial direction, said second element being disposed in the other one of the first body and the second body;
• a third ring-shaped conductive element formed on a third substrate disposed in the first body:
• and
• a fourth ring-shaped conductive element formed on a fourth substrate disposed in the second body the third element and the fourth element being opposite to each other when the first body and the second body are coupled to each other.

A signal transmission device comprising:

• a first body made of electromagnetic shielding material and fixed to a rotary shaft which passes through the first body, said first body revolving together with the rotary shaft around an axis of the rotary shaft;
• a second body made of electromagnetic shielding material and stationarily disposed around the rotary shaft;
• a first conductive element disposed in the first body;
• a second conductive element disposed in the second body;
• a first balun unit for converting impedance of a signal to be transmitted and supplying the converted signal to multiple signal-input points of one of the first conductive element and second conductive element;
• and
• a second balun unit for receiving signal from multiple signal-output points of the other one of the first element and the second element, converting impedance of the received signal to produce a signal.