A miniaturized 45° linearly polarized planar substrate integrated waveguide cavity-backed antenna using L-shaped slot

In this paper, a 45° linearly polarized substrate integrated waveguide (SIW) cavity-backed antenna with reduced size is proposed. A L-shaped slot is etched on the top plate of the SIW cavity to realize both miniaturization and 45° polarization. Quarter-TE
₁₁₀
mode is excited in the cavity for the first time instead of conventional TE
₂
±o mode to obtain miniaturization, while 45° polarization is accomplished by adjusting the slot's two arms to equal length. A prototype, which has a size of 0.38λ
₀
× 0.38λ
₀
× 0.025λ
₀
, is fabricated to verify the design. The measured characteristic results match well with the simulated ones.