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.

This paper reviews applications of acoustic wave devices in mobile communication. After a general and historical introduction to bulk acoustic wave (BAW) and surface acoustic wave (SAW) devices, a review is given on the architectures where acoustic wave devices are applied driving the requirements on the SAW and BAW components. Following this, we discuss the progress in technology important materials. Next, an overview on the modeling and characterization of SAW and BAW at high power levels is given. Finally an overview of packaging technologies and an outlook to future developments is provided. Finally, an outlook to future developments is provided.

In this paper, we study information-theoretic limits for simultaneous wireless information and power transfer (SWIPT) systems employing practical nonlinear radio frequency (RF) energy harvesting (EH) receivers (Rxs). In particular, we consider a SWIPT system with one transmitter that broadcasts a common signal to an information decoding (ID) Rx and multiple EH Rxs. Owing to the nonlinearity of the EH Rxs’ circuitry, the efficiency of wireless power transfer depends on the waveform of the transmitted signal. We aim to answer the following fundamental question: What is the optimal input distribution of the transmit signal waveform that maximizes the information transfer rate at the ID Rx conditioned on individual minimum required direct-current (DC) powers to be harvested at the EH Rxs? Specifically, we study the conditional capacity problem of a SWIPT system impaired by additive white Gaussian noise subject to average-power (AP) and peakpower (PP) constraints at the transmitter and nonlinear EH constraints at the EH Rxs. To this end, we develop a novel nonlinear EH model that captures the saturation of the harvested DC power by taking into account not only the forward current of the rectifying diode but also the reverse breakdown current. Then, we derive a novel semiclosed-form expression for the harvested DC power, which simplifies to closed form for low input RF powers. The derived analytical expressions are shown to closely match circuit simulation results. We solve the conditional capacity problem for real-and complex-valued signalling and prove that the optimal input distribution that maximizes the rate-energy (R-E) region is unique and discrete with a finite number of mass points. Furthermore, we show that, for the considered nonlinear EH model and a given AP constraint, the boundary of the R-E region saturates for high PP constraints due to the saturation of the harvested DC power for high input RF powers. In addition, we devise a suboptimal input distribution whose R-E tradeoff performance is close to optimal. All theoretical findings are verified by numerical evaluations.

This paper presents a novel quarter-mode packaged bandpass filter with four transmission zeros (TZs) in substrate-integrated waveguide (SIW) technology. The filter has an insertion loss of 2.85 dB at 30 GHz and fractional bandwidth of 20%. The design methodology of the TZs was first demonstrated to increase the attenuations of the filter stopband. The quarter-mode SIW resonators were analyzed with high-mode suppression by properly setting their feed points. The packaged filter was consistent between the simulation and measurement results and offers the advantages of compact configuration and easy integration with other devices. Mode suppressions of up to 110 GHz were also provided. The proposed concept is attractive for designing miniaturized and high-performance-packaged filters for 3-D millimeter-wave transceiver systems.

Recent advances in silicon semiconductor technology with transit and maximum oscillation frequencies above 300 GHz have enabled the integration of complex transceiver front ends operating in the millimeter-wave (mmW) regime for a variety of applications. Among these, the most prominent frequency ranges (and their associated applications) are currently the 60-GHz short-range communication frequency band [1]-[2] and E-band wireless back-haul solutions [3]-[4], as well as the 76-81-GHz band for automotive radar sensor realizations [5]-[6].

Nonlinearity can give rise to intermodulation distortions in Surface Acoustic Wave (SAW) devices operating at high input power levels. To understand such undesired effects, a FEM simulation model in combination with a perturbation theory [2] is applied to find out the role of different materials and higher order nonlinear tensor data for the nonlinearities in such acoustic devices. At high power, the SAW devices containing metal, piezoelectric substrate and temperature compensating (TC) layers are subject to complicated geometrical, material and other nonlinearities. In this work, third order nonlinearities in TC-SAW devices are investigated. The materials used are LiNbO3-rot128YX as the substrate and Copper electrodes covered with a SiO2 film as the TC layer. An effective nonlinearity constant for a given system is determined by comparison of nonlinear P-matrix simulations to IMD3 measurements of test filters in a first step. By employing these constants from different systems, i.e. different metallization ratios, in nonlinear periodic P-matrix simulations a direct comparison to nonlinear periodic FEM-simulations yields scaling factors for the materials used. Thus, the contribution of the different materials to the nonlinear behavior of TC-SAW devices is obtained and the role of metal electrodes, substrate and temperature compensating film are discussed in detail.