A planar magic-T based on folded substrate integrated waveguide

In this paper, a novel planar magic-T using H-plane folded substrate integrated waveguide (FSIW) and E-plane substrate integrated waveguide (SIW) power dividers without narrowband slotline-to-SIW transition is proposed. Due to the symmetrical field in the FSIW, two equal in-phase outputs are achieved. The signal applied to the difference SIW port, is split by the middle metal ground into two out-of-phase signals. And a novel way to excite folded substrate integrated waveguide (FSIW) is utilized in order to obtain a broader bandwidth in the proposed magic-T. If the edge of the middle metal layer is designed properly, the bandwidth will be further extended. From 6.65GHz to 9.73GHz (fractional bandwidth 37.6%), the return loss is below -15dB and the amplitude and phase imbalances are less than 0.1dB and 1°, respectively. The measured results are in good agreement with the simulated results.