A radiating element having a transition from a waveguide to a dipole radiator. The radiating element utilizes the electric field of electromagnetic waves propagating in the waveguide to excite a section of a microstrip transmission line that is collinear with the waveguide's propagation direction. A waveguide septum guides the electric field of the electromagnetic waves into the transmission line and provides impedance matching. The transmission line can be formed on a first side of a dielectric substrate having a ground plane on a second side of the substrate. A first dipole leg is formed by making a ninety degree turn in the transmission line. A second dipole leg is extended from the ground plane and turned opposite from the first dipole leg. The transmission line includes a transformer having stepped or gradual changes in width of the transmission line leading to the dipole to provide additional impedance matching.