Xu, Kai; Shi, Jin: 'High-efficiency circular dense dielectric patch antenna with frequency selectivity', Electronics Letters, 2018, 54, (14), p. 861-862, DOI: 10.1049/el.2018.1302
IET Digital Library, https://digital-library.theiet.org/;jsessionid=6ip4h6fegf43f.x-iet-live-01content/journals/10.1049/el.2018.1302