A radio frequency (RF) coil comprising a plurality of electrically
uninterrupted conductive legs, each leg having a first end and a second
end, and at least one continuous conductor electrically connected to the
first ends of the legs. Frequency tuning of the coil is achieved by
translating, along the legs, an electrically continuous tuning band that
includes a capacitor closed about the axis of the coil in proximity to
the conductive legs. Maintaining electrical symmetry of the coil results
in tuning ranges of at least 30 percent of the nominal value of the
resonant frequency.