Fig. 8: Enhanced unidirectional transmission.
From: Unidirectional focusing for broadband Lamb guided wave based on mode conversion
a Schematic diagram of the enhanced unidirectionally-transmitted elastic meta-atoms (EUTEM). The geometric parameters w3 and h3 correspond to the width and depth of the mode reflectors, respectively, while the b1 and b2 represent the interval between adjacent grooves. b Transmission spectra of the reflector for S0-mode (blue short dashed line) and A0-mode (red solid line) Lamb waves. Inset: the corresponding transmittance. The schematic shows that the S0-mode Lamb waves can pass through the reflector while the A0-mode Lamb waves are reflected back. c Transmission spectra of the EUTEM for forward (red solid line) and backward (blue short dashed line) incident S0-mode Lamb waves. Inset denotes for the corresponding transmittance. The shaded area indicates frequency ranges with enhanced forward transmission. The black dash dotted line denotes the transmission spectrum without reflector for comparison. d Out-of-plane displacement field of the EUTEM for forward and backward-incident S0 mode at 330.5 kHz, corresponding to points A and B in (c), respectively.
