Mason Equivalent Circuit Model Research Articles

Two-Dimensional Equivalent Circuit Model of Ultrasonic Wireless Power Transmission

In this article, piezoelectric ceramic is a core device of an ultrasonic wireless power transmission (UWPT) system. The most commonly used piezoelectric ceramic in research and applications of UWPT has a ring-like shape. The piezoelectric ceramic rings usually work in the presence of significant radial and axial vibrations as long as they are not extremely thin. However, in most studies related to the UWPT, only the axial vibration mode is considered. The Mason equivalent circuit model of axial vibration is widely used and the effect of radial vibration on the whole system is ignored. In this article, first, a method to analyze the piezoelectric ceramic ring considering the radial-axial coupled vibration is proposed. Second, the analytical expressions of the constitutive equations of the piezoelectric ceramic ring are derived. Third, a new form of analytical equations is constructed, and a novel two-dimensional equivalent circuit of the UWPT system considering the radial-axial coupled vibration of the piezoelectric ceramic ring is proposed. Fourth, the input and output characteristics of the proposed model and the conventional Mason equivalent circuit model are simulated using MATLAB. Last, the simulation results are compared and verified by experiments. The results demonstrate that the proposed model can describe the system resonance more accurately and comprehensively than the conventional Mason model. As a whole, this study increases the accuracy of the equivalent circuit model of the UWPT system and has important theoretical significance for UWPT research.

High-order mode bulk acoustic wave resonators based on polarity-inverted SiAlN/AlN multilayered films for high-frequency operation

AlN film bulk acoustic wave (BAW) resonators operating at above 5 GHz for next generation mobile communications present some problems, such as the very thin thickness of the piezoelectric film and electrode films. These cause degradations of the power handling capability, electromechanical coupling factor, and Q value in film BAW resonators. Polarity-inverted multilayered AlN film BAW resonators can operate in high-order mode resonance. Therefore, an n-layer polarity-inverted film BAW resonator has n-times thicker piezoelectric film thickness than a standard BAW resonator with a monolayer piezoelectric film operating at same frequency. However, fabrication methods for polarity-inverted multilayered AlN films have not been established. This paper examines the effect of Si doping on AlN films on the crystal orientation, polarity direction, and electromechanical coupling factor (kt2). Furthermore, we fabricated and evaluated two- to eight-layer polarity-inverted SiAlN/AlN film high-overtone bulk acoustic wave resonators (HBARs). The polarity of the SixAl1−xN films inverted around x = 0.024–0.13. The crystal orientation and kt2 of the SixAl1-xN films were degraded with increasing Si concentration x. The eight-layer polarity-inverted SiAlN/AlN film HBAR resonated in the eighth mode. Moreover, the experimental longitudinal wave insertion loss exhibited a similar trend to the theoretical curve calculated by a Mason's equivalent circuit model considering the polarity inverted structure. The eight-layer polarity-inverted HBARs had approximately eight-times thicker piezoelectric film thickness than the monolayer AlN film HBAR. The insertion loss improved with increasing the number of polarity-inverted layers.

Design and Optimization of a Micron-Scale Magnetoelectric Antenna Based on Acoustic Excitation.

The development of antenna miniaturization technology is limited by the principle of electromagnetic radiation. In this paper, the structure size of the antenna is reduced by nearly two orders of magnitude by using Acoustic excitation instead of electromagnetic radiation. For this magnetoelectric (ME) antenna, the design, simulation and experiment were introduced. Firstly, the basic design theory of magnetoelectric antennas has been refined on a Maxwell’s equations basis, and the structure of the ME antenna is designed by using the Mason equivalent circuit model. The influence mechanism of structure on antenna performance is studied by model simulation. In order to verify the correctness of the proposed design scheme, an antenna sample operating at 2.45 GHz was fabricated and tested. The gain measured is −15.59 dB, which is better than the latest research that has been reported so far. Therefore, the ME antenna is expected to provide an effective new scheme for antenna miniaturization technology.

Bandwidth-enhanced magnetoelectric antenna based on composite bulk acoustic resonators

A bulk acoustic wave (BAW) driven magnetoelectric (ME) antenna has narrow operating bandwidth due to its high Q factor, and an effective mechanism for bandwidth enhancement is yet to be explored. This article presents a bandwidth-enhanced magnetoelectric (BWE-ME) antenna made of a Mo/AlN/FeGa sandwich stack, which is composed of three different resonant regions. These resonant regions in the discrete device can be equated as a parallel connection of dual high-overtone bulk acoustic resonators (HBARs) and single film bulk acoustic resonators (FBARs) with tiny frequency shift among the three resonators resulting in bandwidth broadening of the BWE-ME antenna. The resonant mode and return loss curves (S11) are simulated in a two-dimensional finite element method and fitted with the Mason equivalent circuit model. The frequency domain analysis shows that the magnetic flux density bandwidth generated by the multi-resonant mode interaction is 18 MHz, which matches the bandwidth of the measured reference gain S21 curve of the BWE-ME antenna, and the far-field radiated power characterization also shows the corresponding effective bandwidth distributed. The fabricated microelectromechanical systems antenna achieves a fractional bandwidth of 2.7% while maintaining the advantage of small size (0.49 mm2). Discrete composite BAW resonators that effectively combine the multi-resonant regions of HBARs and FBARs have the potential to realize compact and broadband BAW-ME antennas in the future.

Research in Nonlinearity of Surface Acoustic Wave Devices.

Surface acoustic wave (SAW) devices are one of the indispensable components in the radio frequency (RF) front-end of mobile phones. With the development of mobile communication technology, the requirements for linear specification of devices are more and more strict. Nonlinear distortions of SAW devices have a serious influence on the application of mobile RF modules. To satisfy the strict requirement of linearity of communication system, it is necessary to understand the generation mechanism of nonlinearity and study the accurate modeling, appropriate measurement methods, and nonlinear response elimination technology. In this paper, we summarize the research progress on the nonlinearity of SAW devices in recent years from four aspects: the generation mechanism, simulation methods, measurement system, and suppression technology. The nonlinear harmonics with the nonlinear Mason equivalent circuit model are simulated. Furthermore, harmonics and intermodulation signals of SAW filters are tested by the authors. Thanks to these research studies, it is of great significance to the development of future RF front-end modules with high linear SAW devices.

Equivalent circuit analysis of a shear-shear mode resonance LiNbO3/Metglas bilayer composites with giant magnetoelectric response

Previous papers have reported equivalent circuit analysis and circuit models of longitudinal or transverse type magnetoelectric (ME) composites. In this paper, a hybrid Mason's equivalent circuit model is developed for shear piezomagnetic/shear piezoelectric (S-S) mode resonance bilayer composites structure. A high-quality factor (Q-factor) LiNbO3/Metglas shear mode ME structure is then investigated by theoretical modeling of both piezomagnetic and piezoelectric layers. A hybrid shear mode equivalent circuit is presented by introducing the concept of Mason's equivalent circuit model for the piezomagnetic layer. The modeling results reveal the potential of S-S model ME composites with high Q- factor to achieve an exceptional high ME coefficient, e.g., the bilayer structure at resonance of RF frequency (>MHz) exhibits a ME coefficient of 175,000 V/cmOe.

Frequency-switchable polarity-inverted BAW resonators based on PZT/PTO epitaxial films using difference in coercive field

Electrical frequency switching in bulk acoustic wave resonators based on lead zirconate titanate (PZT)/PbTiO3 epitaxial bilayer films is demonstrated and analyzed. In general, the coercive field of PbTiO3 is higher than that of PZT. Independent polarity inversion of the PZT layers is achieved by applying an intermediate electric field between the coercive fields of PZT and PbTiO3 to the bilayer films. The resonant frequency is switched between the fundamental mode resonance (0.56 GHz) and second mode resonance (1.58 GHz) by applying a negative or a positive electric field to the resonators. The second mode operation can be achieved in the absence of an external electric field. A theoretical model simulated by Mason's equivalent circuit model including the effect of the polarity-inverted structure agreed well with the experimental results. The electromechanical coupling coefficients kt2 of both the PZT layer and the PbTiO3 layer of the polarity-inverted bilayer were estimated to be 17.6% (kt = 0.42) by comparing the experimental results with the theoretical simulations.

Optimization of a VOC Sensor with a Bilayered Diaphragm Using FBAR as Strain Sensing Elements.

Film bulk acoustic resonators (FBARs) are widely applied in mass bio-sensing and pressure sensors, owing to their extreme sensitivity and integration ability, and ability to miniaturize circuits. A volatile organic compound (VOC) sensor with a polymer-coated diaphragm, using FBARs as a strain sensing element is proposed and optimized. This vapor sensor is based on organic vapor-induced changes of mechanical deformation of the micro-diaphragm. The four FBARs are located at the edge of the bi-layer diaphragm comprising silicon nitride and silicon oxide for strain extraction. In this work, the strain distribution of the FBAR area under vapor loads is obtained using the finite element analysis (FEA) and the response frequency changes of the FBARs under vapor loads are obtained based on both the first-principle methods to deduce the elastic coefficient variation of aluminum nitride film in FBARs under the bending stresses and the Mason equivalent circuit model of the sensor using ADS software. Finally, optimizations are performed on both the bilayered diaphragm structure and sensing film. The diaphragm with a 0.7 μm silicon nitride layer and a 0.5 μm silicon oxide layer are considered to be the optimized design. The optimal coverage area of the sensing film for the diaphragm is around 0.8.

High Q, high frequency, high overtone bulk acoustic resonator with ZnO films

Bulk acoustic wave resonators with piezoelectric films have been widely explored for the small size and high quality factor (Q) at GHz. This paper describes a high overtone bulk acoustic resonator (HBAR) based on Al/ZnO/Al sandwich layers and c-axis sapphire substrate. ZnO film with high quality c-axis orientation has been obtained using DC magnetron sputtering. The fabricated HBAR presents high Q at the multiple resonances from a 0.5–4.0 GHz wide band with a total size (including the contact pads) of 0.6 mm×0.3 mm×0.4 mm. The device exhibits the best acoustic coupling at around 2.4 GHz, which agrees with the simulation results based on the one-dimensional Mason equivalent circuit model. The HBAR also demonstrates Q values of 30 000, 25 000, and 6500 at 1.49, 2.43, and 3.40 GHz, respectively. It is indicated that the HBAR has potential applications for the low phase noise high frequency oscillator or microwave signal source.

MIMO multiplexer based on film bulk acoustic resonator

A miniature multiplexer based on Film Bulk Acoustic Resonator (FBAR) is designed for Multiple-Input Multiple-Output (MIMO) terminal combined 1900MHz PCS duplexer with 800MHz Cellular duplexer in this paper. FBAR multiplexer is simulated based on a new FBAR model which combines Mason equivalent circuit model with parasitics model. The parasitics, including RF pads, bonding wires and substrate coupling, have some effects on multiplexer insertion loss and stopband rejection. The methods of modifying bandwidth, improving power capacity and temperature coefficient are also discussed.

Rosen형 적층 압전변압기의 등가회로 모델링

In this paper, the equivalent circuit model of a Rosen-type multilayer piezoelectric transformer(MPT) has been proposed based on the Mason's equivalent circuit model and the principle of single layer piezoelectric plate. From the piezoelectric direct and converse effects, the symbolic expressions between the electric inputs and outputs of the MPT have been derived from the equivalent circuit model. A simplified equivalent circuit model of the MPT whose driving part has a single input form has been proposed. The symbolic expressions of the driving part have been derived from the simplified equivalent circuit model and the model was compared with the multi-input equivalent circuit model through the simulation. In the comparisons between the simulation results and the experimental data, output voltage is 630 Vp-p in case of 11-layered MPT and 670 Vp-p for 13-layered MPT over the experiment range. As the load resistance increases, output voltage increases and saturates over <TEX>$300k{\Omega}$</TEX> and the resonant frequency changes from 102 kHz to 103 kHz. The simulation and the experimental results agree well over different load resistances and frequencies.

A finite-element equivalent bond graph modeling approach with application to the piezoelectric thickness vibrator

A bond graph modeling approach that is equivalent to a finite-element method is formulated. This formulation leads to a new definition of the generalized displacements for a continuous system. The newly defined coordinates are easily interpreted physically and easily used in analysis of the system performance. The new bond graph modeling approach is applied to the piezoelectric thickness vibrator. Compared to the Mason equivalent circuit model, the bond graph model offers the primary advantage of physical realizability. Compared to circuit models based on standard discrete electrical elements, the main advantage of the bond graph model is a greater physical accuracy because of the use of multiport energic elements. While results are presented here for the thickness vibrator, the modeling method presented is general in scope and can be applied to arbitrary physical systems.