SMALL ANTENNAS USING HIGH-TC SUPERCONDUCTORS

This paper describes superconductive small antennas composed of helica l coil elements and quarter-wave matching circuits. We obtained a high efficiency of 70% by using a 500 MHz band one-element antenna with la mbda/40 element. We also realized a unidirectional radiation pattern a nd a higher radiation efficiency than an equivalent Cu antenna by usin g a 900 MHz band two-element superdirective antenna with a lambda/20 e lement and a lambda/11 element spacing. We confirm that the use of sup erconductors and the present design principle are very effective for r ealizing of highly efficient small antennas.