Embedded Graded Index Lens for Mitigating the Phase Error of an SIW Horn Lens Antenna

A graded index lens embedded in the body of a substrate-integrated waveguide horn antenna is designed using transformation optics to mitigate the phase error at the antenna aperture. A conformal transformation is established in the design procedure, which leads to an all-dielectric inhomogeneous medium that can be realized by perforating a Rogers RO4350B substrate. Compared to the conventional horn antenna with the optimum length, the proposed lens antenna is 30% shorter and enhances the directivity by a value of 2.5 dB at 40 GHz.