K-Band Planar Magic-T Using LTCC Technology

This letter presents the design of magic-T using low-temperature co-fired ceramic (LTCC) technology by microstrip-slotline transitions and aperture-coupled structures. The magic-T is designed to work at the center frequency of 21 GHz with the bandwidth of 8 GHz. The size of the circuit is only 6 mm × 6 mm due to LTCC multilayer structures. Measured data and numerical simulations show good amplitude and phase characteristics, and high isolation is also achieved.