Ultra-Wideband Printed Slot Antenna With Graded Index Superstrate | Semantic Scholar
Investigation on the aspect ratio of conducting superstrates in deciding its function as a gain enhancer/suppressor for wideband slot antenna | SpringerLink
Figure 11 from Wideband bow-tie slot antenna with tuning stubs | Semantic Scholar
Characteristics of a Wide-band, High Gain, Eight-element Slot Antenna for PCS, IMT-2000 and WLL-band | Microwave Journal
Design of ultra wideband trapezoidal shape slot antenna with circular polarization - ScienceDirect