Rotating coupler for transmitting high frequency energy

A rotary coupler for coupling two relatively rotating circuits, said rotary coupler comprising:

• first means defining a free inner space which permits connection leads to pass therethrough;
• said rotary coupler having its rotational axis extending lengthwise through said iner space;
• and
• second means defining a resonant circuit disposed outside of said inner space and including folded resonant spaces, one of said folded resonant spaces being for energy transmission, and at least one of said folded resonant spaces being equal to between one-fourth and one-half, inclusive, of the principal wavelength to be transmitted via said rotary coupler.