A novel Ka-band planar magic-T used as Wilkinson power divider

In this paper, The design of a novel magic-T with Pi-shaped microstrip line structure is proposed. The planar magic-T structure using a microstrip-to-slotline (MS-to-SL) transition is designed as a Wilkinson power divider in the Ka band, while the difference port (E) is terminated with 50 ohm precision loads. In conventional Wilkinson power divider, a chip resistor, R, is connected between the outputs of the two branches and provides the required isolation, which causes on the order of 0.3dB at the Ka-band [1]; while in this planar magic-T structure, the MS-to-SL transition provides good isolation between the outputs of the two branches. Simulation results show that the average in-band insertion loss is about 3.32 dB with return loss above 21 dB. A 41-dB isolation between ports E and H, and a 21-dB isolation between ports2 and 3 were observed.