From Microwave Acoustic Filters to Millimeter-Wave Operation and New Applications

Abstract

This paper reviews the latest developments in microwave acoustic wave devices. After an introduction and brief history of bulk acoustic wave (BAW) and surface acoustic wave (SAW) devices, a review is given for guided SAWs and XBARs -two new technologies, which are promising for future 5G applications. Following this, we discuss recent simulation techniques, such as 3D finite element method (3D FEM) and simulation of nonlinearities, as well as filter synthesis. Next, a review on tunable and reconfigurable acoustics is given. Finally, we present the latest developments in microwave acoustics for millimeter-wave (mm-wave) operation as well as BAW oscillators.INDEX TERMS Bulk acoustic wave (BAW) devices, filter, filter-synthesis, front-end, high power, MTT 70th Anniversary Special Issue, multiplexer, nonlinearity, resonator, surface acoustic wave (SAW) devices.

Application of an overlay for spurious suppression of multi-layered surface acoustic wave resonators with double busbar configuration

“…With the rapid advance of mobile communication technologies, surface and bulk acoustic wave (SAW/BAW) filters have taken over the RF filter market due to their compact footprint and high-quality factor (Q). [1][2][3] SAW resonators are still in the mainstream of commercial products because of their low cost, simple structure, and mature fabrication technology. The increasingly crowded spectrum and more miniaturized RF front-end modules require SAW resonators with much higher Q factor and temperature stability.…”

Investigation of spurious mode suppression in 3.8 GHz shear-horizontal mode surface acoustic wave resonators based on LiNbO3/SiO2/Si multilayer structure

“…For * Author to whom any correspondence should be addressed. hand-held applications, it is known that acoustic filters have outperformed any other filtering technology due to their ability to offer a small form factor, high selectivity, steep roll-off and low cost at the same time [3,4]. Conventionally, LiNbO 3 (LN) and LiTaO 3 (LT) bulk crystal substrates are considered as viable solutions to realize wideband RF acoustic filters due to their ability to support highly piezoelectric shear-horizontal (SH) surface acoustic waves (SAWs) with a large electromechanical coupling factor (k t 2 ).…”

Use of periodic 2D pillar array for performance enhancement of AlN-based SMR BAW resonators

“…Now, RF bulk acoustic wave (BAW) resonators employing AlN thin films [1][2][3][4][5][6] are widely used and indispensable in the RF frontend of mobile communication terminals. [7][8][9] RF BAW resonators employ acoustic resonance of piezoelectric thin membranes, and they should be isolated acoustically from surroundings necessary for their physical support. This isolation is realized by two methods.…”