Tom Bruhns, K7ITM wrote:
"See the discussion in King, Mimno, and Wing`s "Transmission Lines,
Antennas. and Wave Guides"."

Ronold W.P. King did a fine job explaining "closed circuits as
antennas". It starts on page 224. The shielded loop is diagrammed on
page 234.

As Tom Bruhns says, the exterior of the loop is driven from the gap at
the midpoint in its shield.
The shielded wire loop is coupled by its proximity to the interior
surface of the shield. The outside of the loop is coupled by conduction
across the open circuit edges to the inside surface of the loop. The gap
is the drivepoint. The secret to noise immunity is symmetry and balance
in all aspects of the loop.

Best regards, Richard Harrison, KB5WZI