Abstract: According to one embodiment of the invention, an end-fire cavity slot antenna array structure includes an upper skin formed from a composite material corresponding to a outer surface of an aircraft wing a lower skin formed from a composite material corresponding to a portion of an inner surface of the aircraft wing and a plurality of proximately positioned electrically conductive elements disposed between the upper and lower skins. Each electrically conductive element is formed from at least one sheet of composite material having an electrically conductive surface, and the sheet of composite material is configured such that the electrically conductive surface defines an inside surface of the electrically conductive element and any outside surfaces of the electrically conductive element that are in contact with an adjacent electrically conductive element.