Asimplified integral equation for a dielectric-coated antenna composed of arbitrarily connected straight-wire segments is formulated in a Hallen-type form. The derived integral equation contains only a single integral for numerical procedures. The current distribution obtained for a short helical antenna coated with dielectric material agrees with that for previously published results. As an application of the integral equation, a rectangular spiral antenna is analyzed to show the effects of dielectric coating on the radiation fields.