Josephson arrays for compact, ultra-sensitive and wideband RF detectors

In the field of radio frequency detection, superconducting technology enables unmatched performance, combining wide bandwidth, high frequency, and high sensitivity, thereby meeting security and defense requirements. Indeed, superconducting detectors allow for the construction of non-resonant antennas, which are thus much smaller than the wavelengths being detected. They detect a single component of the magnetic field, enabling vector detection and direction finding. The vector aspect can be important not only for separately characterizing the three components of the detected wave, but also for co-located antenna configurations.

The main drawback of superconducting technology is its implementation, which requires cryogenic equipment to achieve the operating temperature of superconducting circuits. However, the detector’s low noise is intrinsically linked to low temperatures, and so-called “high-temperature critical” (HTc) superconducting technology offers a compromise between performance and system complexity, enabling integration into lightweight platforms.

We will briefly review the main characteristics of the superconducting state to highlight the conditions required for high-frequency magnetic detection in the presence of the Earth’s magnetic field. We will then provide some examples of existing implementations, and finally discuss architectures capable of addressing the problems typically encountered and pushing these limits further.