A Guide to Active Antennas Based on Superconducting Quantum Arrays

We describe how to use correctly an active electrically small antenna (ESA) based on superconducting quantum array (SQA) to ensure a highly linear voltage output of the antenna. An interface to the antenna ought to realize strongly mismatched loading of the active ESA. To provide the optimal conjugation of the antenna with the load device such as a low-impedance superconductor analog-to-digital converter, several measures are formulated, including the assignment of the proper SQA design configuration and the implementation of a broadband superconducting impedance transformer in the interface waveguide line. A directional diagram of the SQA-based ESA has been obtained through a three-dimensional full-wave numerical simulation.