Orthomode transducer and dual-polarized horn antenna in substrate integrated technology

A dual-polarized system fully implemented in substrate integrated technology is presented. It comprises an orthomode transducer (OMT) with planar excitation schemes for both orthogonal TE₁₀- and TE₀₁-modes and a dual-polarized horn antenna. The whole structure requires only two layers of substrate, and it is based on the extended substrate integrated waveguide (ESIW), which allows the propagation of TE_m0- and TE_0n-modes. A compact OMT design is proposed along with a procedure to optimize it. The matching and radiation characteristics of a dual-polarized horn antenna fed with this OMT are also studied. The complete structure was manufactured exhibiting an 8.6% bandwidth (13.9-15.15 GHz) where both modes are well matched (< -10 dB) and isolated (> 28 dB). The horn radiation patterns within the frequency range of operation are also similar for both polarizations. The proposed design demonstrates the feasibility of dual-polarized substrate integrated circuits (SICs). This opens the door to new substrate integrated devices as well as to the use of SICs in applications requiring polarization diversity at end-fire. All together, this combined design becomes a promising approach to tackle the increasing demand for capacity in modern communication systems.