Fractional Bandwidth up to 24% and Spurious Free SAW Filters on Bulk 15°YX-LiNbO Substrates Using Thickness-Modulated IDT Structures.

To cope with ubiquitous wireless connectivity and the increased and faster data delivery in 5G communication, surface acoustic wave (SAW) filters are progressively requiring wider bandwidths. Conventional bulk 15°YX-LiNbO substrates with a large coupling coefficient () are attractive for the low-cost mass production of wideband SAW filters, but these generally suffer from spurious responses, limiting their practical application. In this work, a novel and simple SAW configuration is proposed that uses thickness-modulated interdigital transducer (IDT) structures to overcome the limitations set by spurious responses.

Large-Range Spurious Mode Elimination for Wideband SAW Filters on LiNbO₃/SiO₂/Si Platform by LiNbO₃ Cut Angle Modulation.

A LiNbO3 (LN)/SiO2/Si multilayered structure was recently reported as a new platform for achieving wideband radio frequency (RF) filters. However, the in-band ripples in filters resulting from the spurious Rayleigh mode lead to deteriorated performance, and thus, a wide Rayleigh elimination window (REW) is highly desired for realizing spurious-free wideband surface acoustic wave (SAW) filters with a wide design space and good process tolerance. Here, we investigated the spurious mode suppression on the LN/SiO2/Si platform theoretically and experimentally through modulating the cut angle ( θ ) of LN.

Structure with thin SiO/SiN bilayer and Al electrodes for high-frequency, large-coupling, and low-cost surface acoustic wave devices.

With the development of fifth-generation wireless systems, the Internet of Things, and health services, surface acoustic wave (SAW)-based filters and sensors have attracted considerable interest. This study presents a new structure for high-frequency, large-coupling, and low-cost SAW devices that helps implement high-frequency and wideband filters and enhances the sensitivity of sensors. The structure is based on 15°Y-X LiNbO, thin SiO/SiN bilayer overlay, and Al electrodes.

Enhanced Performance of ZnO/SiO/AlO Surface Acoustic Wave Devices with Embedded Electrodes.

With the advent of the 5G era, surface acoustic wave (SAW) devices with a larger bandwidth and better temperature stability are strongly required, meanwhile the dimensions of devices are continuously scaling down. In this work, a new layout of ZnO/SiO/AlO SAW devices with embedded electrodes was developed, and with the help of the finite element method (FEM), the propagation characteristics were simulated. Through adopting embedded electrodes, a large electromechanical coupling coefficient () of 6.