Planar Shared-Aperture Array Antenna With a High Isolation for Millimeter-Wave Low Earth Orbit Satellite Communication System

A planar dual-band shared-aperture array antenna for the
${K}$
-/
Ka
-band low Earth orbit (LEO) satellite communication is presented in this article. Substrate integrated coaxial line (SICL)-fed bow-tie transverse slots and substrate integrated waveguide (SIW)-fed slot pairs are employed to provide
${K}$
-band horizontal polarization and
Ka
-band vertical polarization, respectively. The
${K}$
-band and
Ka
-band radiating elements share a common metallic-via-array, which can effectively improve the port-to-port isolation. Furthermore, the port-to-port isolations in both bands can be also improved by introducing the high-pass characteristic of SIW and out-of-phase cancellation between two current paths. For the sake of achieving low-profile height and compact size, the
${K}$
-band feeding network is subtly buried between
Ka
-band shielding cavities. As a proof-of-concept example, a shared-aperture dual-polarized array antenna operating at
${K}$
-/
Ka
-band is designed and fabricated for verification by using a multilayer printed circuit board (PCB) technology. The measured results show a good concordance with the simulated one, indicating that the proposed antenna has the advantages of wideband, high isolations, low profile, and easy planar integration, which can be adopted for the millimeter-wave (mm-Wave) LEO satellite communication system.