Figure 4: Theoretical explanation of effective impedance boundary-induced directivity control.

(a–c) Simulated intensity patterns of a plane wave passing decorated sample at 5,800 Hz, 8,600 Hz and 15,000 Hz, respectively. (d) Tailor factor changing with frequency and kx. The red dashed line represents the resonance frequency of the HR and the green dashed line represents the situation in which ky equals zero. (e) Tailor factor changing with the period of HR and kx at f=8,000 Hz. The green dashed line represents the situation in which ky equals zero.