Patent ID: 7782159

Claim:
A rotary coupler comprising: a stator comprising a stator surface and a first electrically conducting track disposed on said stator surface for providing a single transmission line and having a first end and a second end spaced from the first end, said first track extending along a generally circular arc substantially around said stator surface; and a rotor comprising a rotor surface and a second electrically conducting track disposed on said rotor surface for providing a transmission line and having a first end and a second end spaced from the first end, said second track extending along a generally circular arc partially around said rotor surface, said second track having a length which is less than the length of the first track, wherein said rotor surface is spaced apart from and facing said stator surface; a passive RF measuring sensor based on one of resonators or delay lines; wherein the first end of said first track is configured to be connected to signal generating means and said second end of said first track is configured to be connected to ground through a resistor having a resistance substantially equal to the characteristic impedance of the transmission line provided by the first track; wherein said first track has a length substantially equal to an integer number of wavelengths of a signal produced by said signal generating means; and wherein the first end of said second track is configured to be connected to ground through said passive RF measuring sensor.