A radio frequency coil comprises an annular conductor or parallel annular conductors (22, 22c, 22d) configured to support: (i) a uniform electrical current distribution generating a first B.sub.1 field (B.sub.1,uniform) at a first magnetic resonance frequency directed out of a plane of the annular conductor or conductors; and (ii) a sinusoidal electrical current distribution generating a second B.sub.1 field (B.sub.1,sine) at a second magnetic resonance frequency directed parallel with the plane of the annular conductor or conductors. A magnetic resonance scanner comprises: a magnet (10) generating a static magnetic field (B.sub.0); a magnetic field gradient system (14) configured to superimpose selected magnetic field gradients on the static magnetic field; and said radio frequency coil including said annular conductor or parallel annular conductors (22, 22c, 22d).