P K Singhal, Kartik Mendiratta, Manav Gupta, S K Kundu,. 2020. “Attainment of Circular Polarization in Planar Patch & Conformal Patch Antenna Using Ring Slotted Ground Plane”. International Journal of Advanced Science and Technology 29 (3), 425 -39. http://sersc.org/journals/index.php/IJAST/article/view/3941.