The fabrication of a cosine coil having unevenly distributed struts is detailed. Placing the struts in such a manner enables a standing wave at the desired frequency and, hence, only one resonance frequency is obtained. This study details the fabrication of a cosine coil tuned to the LJ-7 frequency (77.76 MHz) and then double-tuned to the H-1 frequency (200.1 MHz) when operated at 4.7 Tesla. Double-tuning is attained by placing an LC trap in series with a capacitor used to single-tune the coil. Also, a method is suggested by which a cosine coil can be broadbanded in the lower frequency range simply by replacing a fixed capacitor.
Hawk, Roger M.; Gullapalli, Rao P.; and Shungu, Dikoma P.
"Double Tuned Cosine Coil for NMR Imaging/Microscopy,"
Journal of the Arkansas Academy of Science: Vol. 45
, Article 12.
Available at: http://scholarworks.uark.edu/jaas/vol45/iss1/12