Optimized microwave delivery structures for quantum diamond microscopes

Magnetic field sensors and imagers employing nitrogen vacancy (NV) centers in diamond require strong, uniform microwave (MW) fields near 3 GHz. We present a new design for a planar waveguide structure fabricated on silicon carbide (SiC), which combines homogeneous microwave delivery with the heat-spreading benefits of SiC. We perform finite element simulations in COMSOL, we fabricate and test MW structures, and we compare experimental performance with simulation results. We demonstrate optimized MW power delivery and improved MW field uniformity. We implement these MW delivery structures in quantum diamond microscopes (QDMs) to improve magnetic imaging performance in fields ranging from Earth and planetary sciences to biology.