The magic tee is a four-port device. Since its collinear ports are perfectly matched, it is also referred to as a matched hybrid tee. When two equal-amplitude, in-phase signals are fed into the collinear ports, the resultant output signal appears at the H-plane port only. On the other hand, when two equal-amplitude, 180˚ out-of-phase signals are fed into the collinear ports, the resultant output signal appears at the E-plane port only. Alternatively, signals fed into the H-plane port are split into two equal-amplitude, in-phase signals at the collinear ports and signals fed into the E-plane port are split into two equal-amplitude, 180° out-of-phase signals. The H-plane and E-plane ports are isolated. Because of this feature, the magic tees are widely used in monopulse radar antenna systems and many other systems where phase and port isolation are critical. When either the H-plane or E-plane port is terminated, these magic tees are used as in-phase or out-of-phase power splitters or combiners. Furthermore, the magic tees can be used to construct multi-way power combiners or dividers.