Planar dual-polarized millimeter-wave shared-aperture array antenna with high band isolation

A planar millimeter-wave shared-aperture array antenna is proposed and designed in this paper.By composing the substrate integrated waveguide(SIW)and the stripline,the K-band antenna is embedded inside the Ka-band antenna to achieve a smaller size and a low profile by sharing an aperture.The Ka-band antenna radiates through the parallel slot pairs on the surface of the SIW cavities with horizontal polar‐ization,while the K-band antenna radiates through the butterfly-shaped slots with vertical polarization,which are also designed on the surface.Then the two array antennas can radiate by sharing a common ap‐erture with high isolation.To verify this idea,a proto‐type of an 8×8 shared-aperture array antenna has been designed with center frequencies of 19 and 30 GHz and fabricated using multilayer printed circuit board(PCB)technology.