The present invention provides a composition for treating pain. The method accepts a pair of 2n-phase shift keying modulated signals via Ix and Qx electrical signal paths, where n>1. PR may generate a phase matched signal having substantially the same phase as that of the input signal. , no more than about 75 watts per inch of cured coating width. Field strength values and optionally calculated temperature distributions are provided for assisting the user in the planning of the thermotherapy.