Broadband Metamaterial Termination for Planar Superconducting Transmission Line Circuits

About this technology

Overview

NASA scientists at Goddard Space Flight Center have developed a broadband metamaterial termination for planar superconducting transmission line circuits. This technology was created as part of a collaborative effort with researchers on the Cosmology Large Angular Scale Surveyor (CLASS) microwave telescope array. Key improvements included adding an adiabatic absorber at the magic tee and vialess crossovers, which significantly reduces reflectance and sensitivity to fabrication variations. These changes ensured better impedance matching across the system, enhancing the fidelity and performance of the microwave circuits. The redesign aimed to address the limitations of earlier narrowband, resonant-tuned terminations that were highly sensitive to manufacturing tolerances, particularly at cryogenic temperatures. These traditional designs required strict control over surface resistance to meet transmission line impedance targets, which proved challenging and resulted in poor device yield at lower temperatures. This approach also provides better adaptability for high-performance microwave circuits used in astrophysical sensors and superconducting applications, where precision and reliability are paramount.