Automatic direction finder sense antenna

An antenna system for an aircraft having composite structures, comprising:

• an airframe having a composite exterior surface;
• a first metallized conductor on the exterior surface of said composite structure having formed therein an opened area which is rectangular in shape;
• a second metallized conductor on the exterior surface of said composite structure composed of a different material than said first metallized conductor and being shaped with a defined circumference within the opened area in the first metallized conductor and generally conformal with the exterior surface of said composite structure, said defined circumference of said second metallized conductor being smaller than the circumference of the opened area in the first metallized conductor, and said second metallized conductor being shaped and positioned so that a gap of generally uniform width exists between a peripheral edge of the second metallized conductor and the opened area of the first metallized conductor sufficient to allow lightning energy to be discharged thereacross;
• an automatic direction finder receiver electrically connected to said first and second metallized conductors capable of detecting changes in capacitance of said first and second metallized conductors;
• and
• a primary loop antenna attached to the aircraft and electrically connected to said automatic direction finder receiver.

A method for making a conformal sense antenna on the exterior surface of a composite aircraft structure, comprising the steps of:

• placing a first metallized conductor on the exterior surface of the composite aircraft structure;
• removing a first portion from the first metallized conductor so as to form an outer conductor with an open area;
• placing a second metallized conductor composed of a different material than said first metallized conductor in said open area such that a gap is present between said first and second metallized conductor;
• and
• connecting said first metallized conductor and said second metallized conductor to ADF radio equipment.