Figure 1
(a) Micrograph showing Device A used for the wireless actuation experiments. The four gold tabs marked ‘G’ are the ground terminals, whereas those marked RF-1 and RF-2 may interchangeably be used to apply and measure the input and output signals of the resonator, respectively. The plate-type piezoelectric element of the resonator measures 245 by 100 μm. Eight interdigitated electrodes are overlaid on this element with four connected to the RF-1 tab though thin connects on one side, whereas the remaining four are connected similarly to the RF-2 tab on the opposite side. (b) Schematic diagram depicting the working of the patch antenna in both 2D and 3D views. The antenna consists of two parallel conductors (the patch and the ground plane) separated by a suitable dielectric. Fringing fields at the ends of the patch allow the antenna to radiate and receive linearly polarized electromagnetic waves, with the highest directivity in the z axis (perpendicular to the patch surface). (c) A COMSOL multiphysics model similar to the dimensions and layering details of Device A was developed to show wireless actuation of the resonator. A y-polarized E-field is normal incident upon the resonator (solid black arrow). The (golden) interdigitated electrodes sit atop the piezoelectric layer followed by the ground plane, a layer of silicon oxide and silicon. The model is suspended at the center of a cuboid box of air (not shown) serving as the air domain. (d) The resulting displacement versus frequency curve from the COMSOL simulation shows that the piezoelectric resonator model (conforming to Device A) resonates at 121.7 MHz under wireless actuation. 3D, three dimensional; 2D, two dimensional.
