Fig. 5
From: A metasurface with bidirectional hyperbolic surface modes and position-sensing applications
IFCs of the first two bands. a, c The IFCs of the first bands for a = 1.4 mm and a = 0.4 mm, respectively. b, d The IFCs of the second bands for a = 1.4 mm and a = 0.4 mm, respectively. The gray discs located at the center are the light cones at 3.7 GHz for (a), (c) and at 10.8 GHz for (b), (d), respectively. Frequency values are marked in GHz, and the frequency increases from blue to orange
