A Dual W-band High-Order Mode Substrate Integrated Waveguide Cavity-Backed Antenna for Radar Sensing and Communication Applications

This paper presents a dual W-band cavity-backed slot antenna using the substrate integrated waveguide (SIW) technique. Two high-order modes, TE
₃₁₀
/TE
₁₃₀
(superposition of TE
₃₁₀
and TE
₁₃₀
) at 78.7 GHz and TE
₃₂₀
at 89.7 GHz, are adopted to overcome the resolution and variation constraints of a standard printed circuit board (PCB) process. Fabricated with a Rogers RO4003C substrate, this antenna achieves 8 and 8.2-dBi gains at 77 and 90.5 GHz, respectively, and 10-dB impedance bandwidths of 76.5-79.5 GHz and 89.5-91 GHz. Moreover, the respective over-the-air (OTA) experiments with an FMCW signal at 77 GHz and a QPSK modulation signal at 91.5 GHz are conducted to demonstrate the feasibility of applying this antenna in millimeter-wave (mmWave) radar sensing and communication applications.