Dual-Polarized SIW-Based Scalable Antenna Array and 2-D Monopulse Beamforming Applications

This letter presents an SIW-based dual-polarized 2-D monopulse scalable antenna array in the millimeter-wave (MMW) scenario. To obtain similar radiation characteristics for dual polarization over a wide bandwidth, a symmetric magnetoelectric dipole cavity-backed antenna is designed. A <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\mathbf{T}{{\mathbf{E}}_{140}}$</tex-math></inline-formula> mode feeding cavity is utilized to make the array scalable. The cascades of magic tees enable this dual-polarized array to achieve sum-difference beamforming in two dimensions. To validate our idea, a 4 × 4 antenna prototype was manufactured and tested. The measured overlapped bandwidth for eight ports reaches 23.02% [(33.45 to 42.15) GHz]. The gains of the sum, difference, and bi-difference beams reach 19.4 dBi, 16.1 dBi, and 13.4 dBi, and their null depths are greater than 31 dB.