Partially Etched Piezoelectric Film Filled with SiO2 Structure Applied to A1 Mode Resonators for Transverse Modes Suppression.

With the arrival of the Fifth Generation (5G) communication era, there has been an urgent demand for acoustic filters with a high frequency and ultrawide bandwidth used in radio-frequency (RF) front-ends filtering and signal processing. First-order antisymmetric (A1) lamb mode resonators based on LiNbO3 film have attracted wide attention due to their scalable, high operating frequency and large electromechanical coupling coefficients (K2), making them promising candidates for sub-6 GHz wideband filters. However, A1 mode resonators suffer from the occurrence of transverse modes, which should be addressed to make these devices suitable for applications. In this work, theoretical analysis is performed by finite element method (FEM), and the admittance characteristics of an A1 mode resonator and displacement of transverse modes near the resonant frequency (fr) are investigated. We propose a novel Dielectric-Embedded Piston Mode (DEPM) structure, achieved by partially etching a piezoelectric film filled with SiO2, which can almost suppress the transverse modes between the resonant frequency (fr) and anti-resonant frequency (fa) when applied on ZY-cut LiNbO3-based A1 mode resonators. This indicates that compared with Broadband Piston Mode (BPM), Filled-broadband Piston Mode (FPM) and standard structures, the DEPM structure is superior. Furthermore, the design parameters of the resonator are optimized by adjusting the width, depth and filled materials in the etched window of the DEPM structure to obtain a better suppression of transverse modes. The optimized A1 mode resonator using a DEPM structure exhibits a transverse-free response with a high fr of 3.22 GHz and a large K2 of ~30%, which promotes the application of A1 mode devices for use in 5G RF front-ends.

Characteristics of carotid atherosclerosis in elderly patients with type 2 diabetes at different disease course, and the intervention by statins in very elderly patients.

INTRODUCTION: Chronic complications of diabetes have become the leading cause of death in elderly patients with diabetes. Carotid atherosclerosis, one of the major complications, was evaluated and the effects of atorvastatin on carotid atherosclerosis in very elderly patients with type 2 diabetes were observed. MATERIALS AND METHODS: Patients were divided into three groups: (i) disease course <5 years; (ii) disease course 5-10 years; (iii) disease course >10 years, and carotid atherosclerosis was evaluated. The very elderly patients were treated with statins, and the effect was observed. RESULTS: Carotid intima-media thickness values, plaque instability and levels of homocysteine, cystatin, and C-reactive protein in diabetes patients were significantly higher than those in the healthy control group, whereas levels of C-peptide and estimated glomerular filtration rate in the patients were significantly lower. In patients with type 2 diabetes for >10 years, intima-media thickness values and plaque instability were obviously higher than those in patients with type 2 diabetes for <5 years, while levels of fasting C-peptide and estimated glomerular filtration rate were lower than those in patients with type 2 diabetes for <5 years. In the very elderly patients, after statins treatment, intima-media thickness values, levels of homocysteine and C-reactive protein were significantly reduced, as well as the number of unstable plaques. CONCLUSIONS: In the elderly patients with type 2 diabetes, carotid atherosclerosis-related factors increased obviously, and renal function declined obviously, which were closely related to the disease course. Atorvastatin significantly reduced homocysteine and C-reactive protein, and delayed and reversed the progress of carotid atherosclerosis in very elderly patients with type 2 diabetes.