On the design and performance of electrically small printed thick film YBa/sub 2/Cu/sub 3/O/sub 7/spl minus/x/ antennas

Strip material and substrate losses, that occur at the radiating element and the feeding-matching network of electrically small printed YBa/sub 2/Cu/sub 3/O/sub 7/spl minus/x/ (HTS) antenna systems, can substantially degrade their performance and, therefore, have to be considered in optimum efficiency and SNR designs. Identification and numerical estimation of such loss mechanisms, and assessment of the overall efficiency of the antenna system, which is of particular importance in design, is facilitated by fundamental microwave network analysis and the method of moments (MM). Four efficient designs, incorporating different feeding-matching configurations, are experimentally tested, and their performance is compared with the theoretical predictions. Superior gain can be demonstrated over similar supercooled Cu and Ag antennas. The applicability of low frequency efficiency measurement methods for highly efficient HTS antenna systems is outlined and extended for improved accuracy.<>