Ha, D. T., T. Q. Ve, D. N. Dung, B. S. Tung, N. T. Hien, V. T. H. Hanh, B. X. Khuyen, and V. D. Lam. “Broadband Polarization Conversion Based on Small-Size Metamaterial in the GHz Band”. Vietnam Journal of Science and Technology, vol. 59, no. 5, Oct. 2021, pp. 580-8, doi:10.15625/2525-2518/59/5/15842.