INVESTIGATION OF THE ENHANCED EFFICIENCIES OF SMALL SUPERCONDUCTING LOOP ANTENNA ELEMENTS

The fields backscattered from arrays of electrically small copper and YBCO superconducting loops are measured and compared with moment metho d predictions to confirm the gain enhancements and changes in Q factor s due to increasing the efficiencies of the antenna elements alone, wi thout the influence of feed and matching networks. Measurements on cop lanar and parallel loop arrays show only small increases in the backsc attered fields of the YBCO scatterers, with the largest increase in ef ficiency being for the single loop. The mutual resistance between elem ents reduces the benefit of adding more elements to a YBCO loop, to a greater extent than when copper elements are added to a copper loop.