Electronic devices having antenna grounding rings

An electronic device comprising:

• an antenna having an antenna resonating element extending around an axis;
• a first substrate having a ground trace that forms part of an antenna ground for the antenna;
• a conductive interconnect structure coupled to the ground trace;
• and
• a second substrate having ring-shaped conductive traces concentrically extending around the axis and partially overlapping the antenna resonating element, wherein the ring-shaped conductive traces are coupled to the conductive interconnect structures, configured to receive an antenna current from the antenna resonating element via near-field capacitive coupling, and configured to short the antenna current to the ground trace on the first substrate via the conductive interconnect structure.

A wristwatch having a first face and a second face opposite the first face, the wristwatch comprising:

• a display at the first face;
• a housing wall at the second face
• an antenna resonating element configured to transmit radio-frequency signals at a first frequency through the housing wall;
• coil structures configured to receive wireless power through the housing wall at a second frequency that is less than the first frequency;
• a circuit board having a ground trace, wherein an axis extends through a lateral surface of the circuit board, the coil structures and the antenna resonating element laterally extending around the axis;
• and
• antenna grounding ring structures laterally extending around the axis, wherein the antenna grounding ring structures are configured to exhibit a first impedance in a radial direction towards the axis at the first frequency and a second impedance in the radial direction towards the axis at the second frequency, the second impedance being greater than the first impedance.