An Empirical Expression to Predict the Resonant Frequencies of Archimedean Spirals.

This work presents an empirical formula to accurately determine the frequencies of the fundamental and higher order resonances of an Archimedean spiral in a uniform dielectric medium in the absence of a ground plane. The formula is based on method-of-moments simulations which have been experimentally validated. This empirical formula is widely applicable to a broad range of spirals from thin-ring to disk-shaped (ratio of inner to outer radii 0 to 1), with 10 or more turns.

Development of a ¹³C-optimized 1.5-mm high temperature superconducting NMR probe.

We report a 1.5-mm NMR probe based on high temperature superconductors operating at 14.1T optimized for (13)C detection.

Design, construction, and validation of a 1-mm triple-resonance high-temperature-superconducting probe for NMR.

We report a 600-MHz 1-mm triple-resonance high-temperature-superconducting (HTS) probe for nuclear magnetic resonance spectroscopy. The probe has a real sample volume of about 7.5 microl, an active volume of 6.