Split spiral broadband double channel NMR detector facilitated by LTCC technology

In the field of nuclear magnetic resonance (NMR), planar spiral detector coils have been exploited for their ease of fabrication with a high tolerance for accommodating flat samples and for the ability to be integrated with microfluidic systems. Additionally, recent studies demonstrated the feasibility of designing such micro planar spirals for broadband operation1,2. Here we explore a novel embodiment of the planar spiral with a third contact added at an intermediary position of the spiral track, which thereby acts as a double-channel NMR detector. The spiral geometry was optimized through simulation so that the inner loop and the full loop correspond to two frequency bands of interest. With the combined microfluidic and NMR devices fabricated for the first time in low-temperature co-fired ceramic (LTCC) technology, we demonstrate untuned broadband operation by presenting 1D NMR spectra of 4 isotopes from 125 MHz to 500 MHz, as well as 2D
HSQC measurements. The design is easy to use and shows high robustness, demonstrating potential for NMR studies of flow systems with multiple nuclei.