c-Axis zig-zag polarization inverted ScAlN multilayer for FBAR transformer rectifying antenna

Enegy harvesting from surrounding electromagnetic wave have attracted much attention in recent years. Low RF-DC conversion efficiency in the rectenna due to a weak power of electromagnetic wave is a problem. We here report the new type of polarization inverted FBAR transformer for RF amplification in the rectenna. c-Axis zig-zag polarization inverted 12 layer ScAlN was fabricated by glancing sputtering deposition. The 12 layer ScAlN HBAR clearly excites 12th-order shear mode of 1.4 dB at 612 MHz. c-Axis tilt angle of the layers was determined to be 40-45 degrees by an XRD pole figure. This new type of device is promising for high efficiency RF-DC conversion in the rectenna.