Maximum power of a miniature superconducting radiator

Two factors limiting the maximum radiating power of a miniature (0.1 x 0.1 x 0.1 m) niobium superconducting radiating element for use in antenna arrays are evaluated: (1) the maximum admissible reactive power, and (2) the need for thermal compensation in the cryostat. It is shown that these factors impose significant limits on the radiating power. A radiating power of the order of several kW is found to be achievable at frequencies above 60 MHz.