Fig. 2.

Propagation of surface EM waves and field confinements on two ultrathin corrugated metal strips (W = d, t = 0.0036d, a = 0.4d, and d = 5 mm) with different groove depths (h = 0.8d and h = 0.7d). The operating frequency is 12 GHz (λ = 25 mm). An electric monopole pointing to the y direction with unit current is used for excitation at the left edge. (A and B) Simulated amplitudes of electric fields (|E|) on the two corrugated metal strips (A: h = 0.8d; B: h = 0.7d) over a length of 400 mm (16λ). (C and D) Field distributions on the cross-sections of the two corrugated metal strips (C: h = 0.8d; D: h = 0.7d) located 300 mm (12λ) away from the source (the dashed line in A and B). The black lines indicate the cross-sections of the two strips. The CSP modes are tightly confined to the corrugated strips with strong field enhancements. (E and F) Electric field distributions along the vertical cut (E) and horizontal cut (F), shown by the orthogonal dashed lines in C and D. The fields near the deeply corrugated strip (h = 0.8d) are much stronger and decay exponentially faster compared with those of the shallowly corrugated strip (h = 0.7d) along the two orthogonal directions.