The present invention is directed to small, low profile, antenna-transmitter systems that attach to exterior of the body and focus electromagnetic (EM) wave energy onto one or more precise regions inside the body. The antenna-transmitter system may also deliver energy to the surface of the body without focusing. The present invention is further directed to a method of focusing energy, such as electromagnetic radiation, onto a single nerve to effect selective neurostimulation, super- or sub-threshold, using a small, low profile, antenna-transmitter system that attaches to the body exterior and focuses electromagnetic wave energy onto the nerve.