Abstract: An H-plane waveguide probe includes a microstrip formed on a dielectric substrate with a loop conductor generally configured in the shape of waveguide on one side and adapted to capture an incoming H-plane signal. A transition conductor formed on an opposing side of the substrate with a first leg and a second leg, connected together by a bend portion. The first leg of the transition conductor is generally parallel to the H-plane for coupling microwave energy from the waveguide to the microstrip. The second leg of the transition conductor is parallel to the E-field and is used to change the direction of the captured microwave energy along the H-plane direction to the E-plane direction. In order to optimize power transfer, the impedance of the loop conductor is selected to be about the same as the waveguide. The transition conductor is used to convert the E-field energy to a 50&OHgr; impedance, for example, for connection to an external microwave circuit.