CONTROL OF RADAR CROSS-SECTIONS OF ELECTRICALLY SMALL HIGH-TEMPERATURE SUPERCONDUCTING ANTENNA ELEMENTS USING A MAGNETIC-FIELD

The radar cross sections (RCS) of small circular loops made from YBCO high temperature superconductor are calculated as a function of applie d magnetic field strength. It is shown that the RCS is reduced as the magnetic field increases, and that the effect is more pronounced as ra diation resistance decreases. Two factors contributing to the RCS redu ctions are identified, firstly an increase in surface resistance with magnetic field, and secondly a detuning effect caused by a change in t he loop input reactance. It is suggested that antennas might be made f rom superconductor as a means of controlling their RCS, rather than fo r improved efficiency.