The derivation process of a pair of H-type integral equations is reviewed for a system composed of curved wires and slots. The integral equations are characterized by two kernels Π and Π#, each being expressed in closed form. The integral equations are applied to a two-arm slot spiral antenna fed by two wires. Each feed wire is not in contact with the edge of the slot. The magnetic current distribution on the slot spiral, the radiation pattern, and the axial ratio are presented. The 3-dB axial ratio bandwidth is calculated to be 18%.