橋本 研也

This paper describes the coaxial integration of a Michelson interferometer (MI) and a Sagnac interferometer (SI) in a high-speed, phase-sensitive laser probe for surface acoustic wave/bulk acoustic wave devices. This combination enables the MI to be used for calibration of the vibration amplitude captured by the SI without sacrificing the measurement accuracy and speed of the SI-based laser probe. First, the system setup is detailed. Next, simultaneous measurement is performed using the SI and MI, and good coincidence is demonstrated between these measured results after correction of tiny misalignment between two optical axes. This means that the calibration can be performed simply by multiplying the data captured by SI by a coefficient of proportionality this value of this can be determined by comparison with the data captured by simultaneous measurement for a tiny area. Finally, the procedure for absolute vibration amplitude measurement is proposed and its validity is confirmed by actual measurement.

This paper proposes a detection electronics which enables ultimate suppression of leakage signals in high-speed and phase-sensitive laser probe for radio frequency surface and bulk acoustic wave devices. Another merit is simpler circuit configuration than the conventional one. First, the complete suppression of leakage signals is verified. Then impact of the oscillator phase noise is examined by utilizing oscillators with various phase noise performance. This is because the proposed electronics is expected to be more sensitive to the oscillator phase noise than the conventional one. The result indicates that although performance degradation appears, it is practically negligible. In this electronics, the absolute phase can not be determined. This is not a demerit for use in the laser probe because additional phase shift caused by cables and printed circuit board is hard to calibrate.

This article describes derivation of an equivalent circuit for nonlinear responses in film bulk acoustic resonators from the first-order perturbation analysis using the piezoelectric constitutive equations with the h-form. For simplicity, electrodes and piezoelectric layers are considered as mass and spring, respectively, in the derivation. Then, it is demonstrated that the second-and third-order harmonic responses can be simulated well by the circuit. In addition, nonlinearity in the Si substrate is also taken into account and its impact is discussed. It is also discussed how the frequency dependences vary with the nonlinearity mechanisms as a finding from the derived equivalent circuit.

It is known that nonlinear responses by transverse resonances are more emphasized than those by the main resonance in radio frequency bulk acoustic wave devices. This paper investigates this mechanism using the LCR-based nonlinear equivalent circuit proposed by the authors. Here a number of acoustic branches are newly added to take multiple transverse resonances into account, and amplitudes of nonlinear voltage sources in the model are determined by summation of currents flowing to acoustic branches. Parameters necessary for the analysis are determined experimentally. It is shown that simulated second and third harmonic responses agree well with the measurement. Next, the magnification mechanism is discussed. It is shown that mth harmonics generated by transverse modes are magnified by m-times approximately, and the factor of m is originated to that at the production between field components of transverse and main modes.

This paper discusses loss mechanisms of temperature compensated surface acoustic wave (TC-SAW) devices using the SiO2 overcoated 128°YX-LiNbO3 (128-LN) substrate. Analysis is based on the finite element method (FEM) combined with the hierarchical cascading technique and the general purpose graphics processing unit. Three kinds of FEM model, i.e. 2.5D, three dimensional (3D) periodic and full 3D are analyzed without taking additional losses, i.e. material viscous loss, dielectric loss and electrode ohmic loss, and influence of scattering at structural discontinuities is evaluated solely. It is shown that although Q reduction is significant with an increase of the simulation dimension, in other words, that of the number of acoustic scattering mechanisms, estimated Q value is still considerably higher than reported values even for full 3D simulation. This result indicates that acoustic scattering at structural discontinuities is not a dominant loss mechanism in current TC-SAW devices employing the SiO2 overcoated 128-LN substrate.

This article describes the application of the hierarchical cascading technique (HCT) to the 3-D finite-element method (FEM) analysis of transverse-mode behaviors in surface acoustic-wave (SAW) devices. Mirror cascading is proposed as a speed-up technique for the HCT operation using the general-purpose graphic processing unit (GPGPU). Two methods are implemented for the analysis: one is impedance calculation and the other is the calculation of SAW scattering coefficients at boundaries. It is demonstrated that HCT enables rapid calculation for successive simulation with scanning design parameters. Thus, techniques discussed in this article are quite effective for the optimization of device structures. It is also shown that GPGPU can accelerate HCT calculation dramatically, especially for 3-D cases discussed in this article.

This paper describes derivation of an equivalent circuit for nonlinear responses in film bulk acoustic resonators from the first-order perturbation analysis using the piezoelectric constitutive equations with the h-form. For simplicity, electrodes and piezoelectric layer are regarded as a mass and spring in the derivation. Then it is demonstrated that the H2 response can be simulated well by the circuit.

This paper describes 3D FEM simulation of scattering at a border between IDT and reflector in SAW resonators using hierarchical cascading technique and general purpose graphic processing unit. SH-type SAW on the 42°YX-LiTaO3 substrate is chosen. It is shown how the reflector design affects the scattering loss at the border. It is also shown that scattering fields can be observed selectively by the use of the wavenumber domain analysis.

This paper describes a suppression technique for the lowest-order plate mode in wafer bonded surface acoustic wave (SAW) devices using LiTaO3 (LT) thin plate. When LT plate thickness is close to the SAW wavelength, say micron order, the lowest-order plate mode appears near the main resonance. It is shown that the plate mode can be suppressed by choosing LT cut angle, electrode thickness and LT plate thickness properly. It is also shown that when the acoustic length is finite, the leaky nature causes additional loss even when the LT plate is extremely thin. Detailed discussions are also given how the additional loss changes with the plate thickness.

This paper proposes use of traveling wave type excitation sources for the scattering analysis of acoustic waveguides using the finite element method (FEM). This technique allows to generate only one particular mode selectively. Scattering behavior at arbitrary boundaries can be evaluated accurately and quickly in frequency domain. After describing and demonstrating its operation mechanism in detail, this technique is applied to two cases. First, wave scattering properties are discussed at the end of a two-dimensional closed waveguide. Then the technique is applied to a three-dimensional open waveguide including periodic gratings. The results reveal effectiveness of this technique.

This paper proposes a technique to analyze surface acoustic wave (SAW) scattering at discontinuity in grating structures using the hierarchical cascading technique. The traveling wave excitation is applied to generate a specific SAW mode. Then the displacement distribution is obtained for the passive regions. The incident, reflected, and transmitted components are selectively evaluated by the Fourier transform so as to determine the scattering coefficients at the discontinuity. Rayleigh SAWs on the SiO2/128°YX-LiNbO3 structure and SH SAWs on the 42°YX-LiTaO3 structure are used as examples, and the behavior of two kinds of discontinuity are analyzed, and the obtained results are compared with those obtained by the COM model.

This paper proposes a technique to estimate surface acoustic wave (SAW) power flow angle (PFA) in periodic grating structures. First, the thin plate model is extended to take into account non-zero PFA. The relation between the lateral wavenumber and the frequency is derived in an analytical form under the longitudinal resonance condition. Then, the complex power flows in lateral and longitudinal directions are derived and PFA is estimated from the model parameters. Finally, the parameters are extracted by fitting the derived relation between lateral wavenumber and frequency with that calculated by finite element method. The influence of grating electrode on PFA is investigated on quartz and langasite substrates. The results confirm the validity of the technique.

This paper describes application of the hierarchical cascading technique (HCT)to the 3D FEM analysis of transverse mode behaviors in Surface acoustic wave (SAW)devices. Two methods are implemented one is impedance calculation, and another is calculation of SAW scattering coefficients at boundaries. It is shown that HCT enables rapid calculation for successive simulation with scanning design parameters. Thus, techniques discussed in the paper are quite effective for optimization of device structures. It is also shown that GPGPU can accelerate the HCT calculation dramatically, especially for 3D cases discussed in this paper.

This paper proposes a technique to analysis SAW scattering at discontinuity in grating structures using the hierarchical cascading technique. The traveling wave excitation is applied to generate a specific SAW mode. Then the displacement distribution is obtained for the passive regions. The incident, reflected and transmitted components are selectively evaluated by the Fourier transform so as to determine the scattering coefficients at the discontinuity. Rayleigh SAWs on the SiO 2 /128°YX-LiNbO 3 structure are used as an example, and the behavior of discontinuity is analyzed, and obtained results are compared with those obtained by the COM model. These results agreed very well for this case.

This paper investigates the influence of coupling between Rayleigh and shear-horizontal (SH) surface acoustic waves (SAWs) on rotated Y-cut LiNbO3 to their electromechanical coupling. For the purpose, a coupling-of-mode (COM) model including the coupling between two SAWs is developed, and the coupling influences to their excitation in addition to electromechanical coupling factors are discussed. Then, its validity is confirmed by comparison of its results with the finite-element method analysis. Comparing with the conventional COM shows this extended COM model could fit the complex value area much better in the dispersion curve analysis. After that, variation of COM parameters with the device design is discussed. Then, all COM parameters are fit by polynomial equations and the procedures to find the optimal rotation angle are obtained in terms of the SH mode suppression. It indicates that the optimal angle changes rapidly at certain Cu thickness, which is due to decoupling between two SAW modes. At last, structure based on the low-cut LiNbO3 is discussed and the validity of this COM model is further confirmed.

This paper investigates piston mode operation (PMO) when two kinds of surface acoustic waves (SAWs) exist and are coupled to each other. The extended thin plate model is used for the analysis. First, a PMO condition is derived in a closed form. It is verified that PMO is possible without adding phase shifters by the use of two SAW coupling. It is also shown that this operation offers suppression of the transverse modes for a wider frequency range than the conventional PMO. Then, parameters defined in the model are extracted for various SiO2-overlay/Al-grating/128° YX-LiNbO3 substrate structures, and the structure satisfying the PMO condition is designed. Finally, the structure is also analyzed using the 3-D finite element method. The result agrees well with that calculated by the extended thin plate model.

This paper investigates applicability of double raised borders to the piston mode film bulk acoustic resonator (FBAR). It is shown that it offers significant improvement of the quality factor at the antiresonance without sacrificing the spurious level when the structure is designed appropriately. This enhancement is attributed to the reduction of the mode-conversion and the increase of the reflection coefficient at the border region.

This paper discusses lateral propagation of surface acoustic waves (SAWs) in periodic grating structures when two types of SAWs exist simultaneously and are coupled. The thin plate model proposed by the authors is extended to include the coupling between two different SAW modes. First, lateral SAW propagation in an infinitely long periodic grating is modeled and discussed. Then, the model is applied to the Al-grating/42 degrees YX-LiTaO3 (42-LT) substrate structure, and it is shown that the slowness curve shape changes from concave to convex with the Al grating thickness. The transverse responses are also analyzed on an infinitely long interdigital transducer on the structure, and good agreement is achieved between the present and the finite-element method analyses. Finally, SAW resonators are fabricated on the Cu grating/42-LT substrate structure, and it is experimentally verified that the slowness curve shape of the shear horizontal SAW changes with the Cu thickness.

This paper discusses design of surface acoustic wave/bulk acoustic wave (SAW/BAW)-based band reject filters composed of the impedance converters, where capacitive elements are replaced with SAW/BAW resonators. First, basic properties of the unit cell are studied. It is shown how basic properties of a unit cell change with the design. It is also shown that when two notches caused by the resonators are placed in proximity, two synergy effects occur: 1) an extra matching point appears on one side of the transition band. This makes the insertion loss at the point smaller and the transition band steeper and 2) the dip level becomes deeper, and the total rejection level improves. Then, two resonators are fabricated, measured, and combined with inductors in circuit simulator to demonstrate functionality of the basic cell design. Finally, the wide rejection band filter is designed by cascading multistages, and effectiveness of the device configurations is demonstrated.

This paper discusses the possibility of realizing multimode filters composed of multiple single-mode resonators by using radio frequency surface and bulk acoustic wave (SAW/BAW) technologies. First, the filter operation and design principle are given. It is shown that excellent filter characteristics are achievable by combining multiple single-mode resonators with identical capacitance ratios provided that their resonance frequencies and clamped capacitances are set properly. Next, the effect of balun performance is investigated. It is shown that the total filter performance is significantly degraded by balun imperfections such as the common-mode rejection. Then, two circuits are proposed to improve the common-mode rejection, and their effectiveness is demonstrated. (C) 2017 The Japan Society of Applied Physics

In this paper, we investigate the impact of the coupling with shear horizontal (SH) surface acoustic wave (SAW) on the propagation of Rayleigh SAW in periodic grating structures on 128 degrees YX-LiNbO3. First, the frequency dispersion behavior with longitudinal and lateral wavenumbers of Rayleigh SAW is calculated using the finite element method (FEM) software COMSOL. It is shown that the coupling causes (1) the satellite stopband and (2) variation of the anisotropy factor. It is also shown these phenomena remain even when the electromechanical coupling factor of SH SAW is zero. Then, the extended thin plate model which can take coupling between two SAWs into account, is applied to simulate the result of FEM. Good agreement between these results indicated that the mechanical coupling is responsible for these two phenomena. Finally, including electrical excitation and detection, the model is applied to the infinitely long interdigital transducer (IDT) structure and the calculated result is compared with that obtained by the three-dimensional FEM. The excellent agreement of both results confirms the effectiveness of the extended thin plate model. (C) 2017 The Japan Society of Applied Physics

The authors has been developing phase-sensitive and fast mechanical scanning laser probe system as a diagnosis tool for RF SAW/BAW devices. This paper describes implementation of the frequency scanning function to the system. Little modification of the preexisting hardware and a newly developed Windows GUI program enable automated frequency scanning operation without sacrificing original functions. A data filtering program optimized for use in batch processing was newly developed for post processing of vast data acquired by the frequency scanning. As a demonstration, field distributions of a one-port SAW resonator on 42YX-LiTaO3 were captured for the frequency span from 820 to 880 [MHz] with every 0.25 MHz step (241 frequency points). After around 31.5 hours in total, we got an animation revealing how SAW field changes with the frequency.

This paper is aimed at examining the validity of material constants reported for the use in surface acoustic wave (SAW) device simulations. At first, based on the full set of material constants calculated by the first principle, bulk acoustic wave (BAW) velocities are calculated for ScxAl1-xN and compared with published experimental results. Then, the effects of ScxAl1-xN material constants with different Sc contents on acoustic characteristics are calculated and the influences of shear vibrations on SAW characteristics are recognized. Then series of SAW devices are fabricated on ScxAl1-xN film/Si substrate structure with various Cu and ScAlN thicknesses hCu and hScAlN, respectively, and measured variations of phase velocity V and effective electromechanical coupling factor Ke2 with these parameters are compared with the calculation. The fairly well agreed results indicate a reliable set of ScxAl1-xN material constants for SAW device simulations.

This paper is aimed at examining the validity of material constants reported for use in surface acoustic wave (SAW) device simulations. First, based on the full set of material constants calculated by first principle, bulk acoustic wave velocities are calculated for ScxAl1-xN and compared with published experimental results. Then, the effects of the ScxAl1-xN material constants with different Sc content on acoustic characteristics are calculated and the influence of shear vibrations on SAW characteristics are recognized. Then, a series of SAW devices are fabricated on ScxAl1-xN film/Si substrate structure with various Cu and ScAlN thicknesses h Cu and h ScAlN, respectively, and measured variations of phase velocity V and effective electromechanical coupling factor with these parameters are compared with the calculation. The fairly well-agreed results indicate a reliable set of ScxAl1-xN material constants for SAW device simulations.

In this paper, we propose the use of the "longitudinal resonance condition" for the characterization of the two-dimensional propagation of surface acoustic waves (SAWs) in periodic grating structures, and also show a procedure for extracting parameters required in the behavior model from the full-wave analysis. The condition is given by beta(x)p = p, where p is the grating period and beta(x) is the wavenumber of the grating mode in the longitudinal direction (x). This is based on the fact that in conventional SAW resonators, acoustic resonances including transverse ones occur when beta(x) is real but the longitudinal resonance condition is mostly satisfied. The longitudinal resonance condition is applied to a simple model, and the wavenumber beta(y) in the lateral direction (y) is expressed as a simple function of the angular frequency omega. The full-wave analysis is applied for SAWs propagating in an infinite grating on a 128 degrees YX-LiNbO3 substrate, and the anisotropy parameter gamma is extracted by the fitting with the derived equation. The fitted result agrees well with the original numerical result. It is also indicated that gamma estimated by this technique is significantly different from the value estimated without taking the effects of the grating structure into account. (C) 2016 The Japan Society of Applied Physics

In this paper, we propose a physical model for the analysis of transverse modes in surface acoustic wave (SAW) devices. It is mostly equivalent to the scalar potential (SP) theory, but sufficiently flexible to include various effects such as anisotropy, coupling between multiple modes, etc. First, fundamentals of the proposed model are established and procedures for determining the model parameters are given in detailed. Then the model is implemented in the partial differential equation mode of the commercial finite element analysis software COMSOL. The analysis is carried out for an infinitely long interdigital transducer on the 128 degrees YX-LiNbO3 substrate. As a demonstration, it is shown how the energy leakage changes with the frequency and the device design. (C) 2016 The Japan Society of Applied Physics

A direct-conversion receiver (DCR) can reduce the power consumption and cost. However, a DCR with orthogonal frequency-division multiplex (OFDM) suffers from IQ imbalance. Until this time, many algorithms have been proposed to compensate IQ imbalance in OFDM systems. However, the calculation complexity is still a considerable work to achieve the implementation of a DCR. Moreover, an accurate channel identification is also necessary for a DCR. Recently, time-frequency interferometry-OFDM (TFI-OFDM) system has been proposed to achieve an accurate channel identification property with small number of pilot symbols, and it has a periodicity of pilot amplitude. In this paper, we focus on the feature of TFI and propose a novel IQ imbalance estimation and compensation schemes using TFI-OFDM system. In the proposed system, by using the feature of the TFI pilot symbols, we can identify an IQ imbalance without high calculation complexity. Furthermore, by using subcarrier selection, the influence of the noise power can be reduced. From the simulation results, the proposed scheme can achieve the low complexity for IQ imbalance estimation and compensation without a degradation of the bit error rate performance. Copyright (c) 2014 John Wiley & Sons, Ltd.

ScAlN thin films were deposited by a conventional radiofrequency (RF)-magnetron sputtering system using two Sc-Al alloy metal targets with different Sc/Al ratios. A 10 h deposition time resulted in highly c-axis-oriented ScAlN thin films with Sc concentrations of 32 at% and 22 at% on Sc0.43-Al0.57 and Sc0.32-Al0.68 targets, respectively. C-axis orientation was lost in thin films deposited on the Sc0.43-Al0.57 target after sputtering times of over 50 h. XDS analysis showed a high-Sc-content ScAlN film with an amorphous phase layer near the Si substrate surface. A seed layer of c-axis-oriented ScAIN allowed for &gt 50 h deposition on the Sc0.43-Al0.57 target to result in highly c-axisoriented ScAlN films. A one-port surface acoustic wave (SAW) resonator based on the ScAlN/Si structure has a K2 value of 2.7% at 2 GHz, six times larger than for that based on the AlN/Si structure.

This paper discusses the measurement setup of non-linearity caused in radio frequency (RF) surface and bulk acoustic wave (SAW/BAW) devices with high signal-to-noise ratio (SNR). It is shown that when some important points are considered, the background level can be suppressed better than -135 dBm, and the non-linearity signals can be measured in high SNR. Finally, measured results are compared with those measured independently by Murata Manufacturing, and validity of the measurement is cross-checked. (C) 2015 The Japan Society of Applied Physics

This paper describes the trial of time-to-failure (TTF) estimation of RF SAW devices for IEC standardization. An on-wafer measurement system was constructed so as to perform the acceleration test in terms of applied power and/or chip temperature. The ladder type SAW filters in the 2GHz range fabricated on a 42 degrees YX-LiTaO3 wafer were used as the DUT, and their TTFs were measured. The experiments showed that the acceleration by temperature and applied power obeys the Eyring's model well. It was also demonstrated that the chip temperature can be estimated form the cutoff frequency of the BAWradiation, which is identified easily from the VNA data. This technique seems quite feasible to monitor chip temperature of packaged RF SAW devices during the TTF measurement because no modification is necessary for the SAW device design.

This paper describes evaluation of stiffnesses of SiO2 thin films when the anisotropy in elasticity is taken into account. The authors measured the propagation direction theta dependence of the water-loaded surface acoustic waves (SAW) velocity, and tried to estimate stiffnesses of SiO2 films from the measured theta dependence. The result indicates that SiO2 films possess the strong 6mm anisotropy. Namely, stiffnesses normal to the surface are significantly lager than those along the surface. This anisotropy may be induced during the deposition or caused by variation of film properties in the thickness direction.

Recently, visible light communication(VLC) is widely researched due to the spreading of LED usage. It satisfies demands of ubiquity and high speed communication. However, it is impossible to transmit the phase information and frequency information due to limitation of LED. From this reason, the achievable transmission rate is worse than that of wireless communications. To solve this problem, color clustered MIMO(multiple-input multiple-output) system that takes advantage of independency of the three primary colors of the light has been proposed. However, color filters which use on this system are supposed ideal one that extracts only a desired signal. Realistic color filters have the incompleteness which extract signals except a desired signal. Therefore, in this paper, we evaluate and clarify the spatial performance of color clustered VLC-MIMO system with incompleteness of color filters.

Massive MIMO has been recognized as promising ways to provide high speed data transmission. However, since the number of pilot symbol is proportionally depending on the number of transmit antenna, the total transmission rate of massive MIMO would be degraded. To solve this problem, channel estimation by virtual pilot signal (VPS) with a few pilot signals has been proposed. However, since the conventional method iteratively identifies the channel state information (CSI), the complexity is considerable work. Then again, time-frequency interferometry (TFI)-OFDM has been proposed. This method can achieve a good BER performance with a few pilot symbols. In this paper, we propose a novel channel compensation based on VPS and TFI for massive MIMO without increasing the system complexity. The proposed scheme has a low complexity, with improving BER performance to compared with the conventional method using linear interpolation and FFT/IFFT after specific operations. From the simulation results, the proposed scheme can improve BER performance to compared with the conventional method in 4 x 4 and 8 x 8MIMO systems.

In this paper, we propose a polarization diversity scheme to enhance maritime VHF communications. Multiple antenna systems require an antenna separation of 5-10 wavelengths to keep the correlation coefficient below 0.7 to permit the realization of space diversity. However, this may be difficult to implement in a maritime VHF system, because the maritime VHF is working in the frequency range from 156 to 174 MHz, with wavelength of approximately 2 m. On the other hand, the polarization device technique allows two co-located antennas by using a micro-strip technique. For this reason, the polarization technique is a practical method of attaining diversity. However, the theoretical model of polarization is very difficult and complex. Therefore, we express the cross correlation of each polarization antenna and the cross polarization discrimination of multiple polarization antennas with a simple model. Simulations show that the polarization diversity of a maritime VHF system shows better BER performance than that of the conventional reception diversity on the basis of vertical antenna with the antenna separation of 10 wavelengths. Copyright (C) 2012 John Wiley & Sons, Ltd.

This paper discusses the use of periodically slotted top electrodes in the film bulk acoustic resonator (FBAR) structure for the realization of wideband coupled-resonator filters (CRFs), where evanescent modes in the periodic structure are used for the coupling between adjacent electrodes. First, wave propagation in this structure is investigated. Finite element analysis is performed for the Mo/ZnO/Mo structure. The result suggests that lateral wave propagation is controlled by the Bragg reflection, and that transverse modes can be suppressed when the structure is properly designed. Next, a CRF is designed. It is shown that wideband CRFs are realizable when the period, thickness, and width of slotted electrodes are properly set.

This paper discusses generation mechanisms of the second-order distortion in SAW devices. Crystal symmetry of the substrate is considered. It is shown that three mechanisms cause the second-order distortion. Namely, (a) self-mixing of the electrostatic field, (b) mixing of the electrostatic field with the strain field of the SAW main mode, and (c) mixing of the electrostatic field with the strain field of the SAW transverse modes. Then the frequency response of the second harmonics generation is discussed by using the coupling-of-mode theory.

In 2008, the authors reported development of a type of the laser probe system based on the Sagnac interferometer for the diagnosis of radio frequency (RF) surface and bulk acoustic wave (SAW/BAW) devices. This paper describes extension of its maximum operation frequency to the low SHF (several GHz) range without performance degradation. First, electronic components used in the system were re-examined, and some of them were replaced with appropriate ones. Second, a miniature wafer probing system was newly developed for the operation under a high magnification (x100) lens with a tiny working distance (similar to 3.4 mm). This enables us to avoid wire-bonding between a device under the test and a printed circuit board; wire inductance gives large impact to the device characteristic in the GHz range. RF SAW/BAW devices operating in 5 GHz were characterized by the laser probe, and its effectiveness was demonstrated.

This paper reviews a phase-sensitive and fast-scanning laser probe system developed by the authors' group for the diagnosis of radio frequency (RF) surface and bulk acoustic wave (SAW/BAW) devices. The system is based on the Sagnac interferometer, which is insensitive to low frequency vibration. This feature allows us to maximize the scanning speed without sacrificing the signal-to-noise ratio of the measurement. It is demonstrated that high quality two-dimensional (2D) image of SAW/BAW field patterns can be captured in minutes order. Currently the maximum applicable frequency is 6 GHz. Because of the phase sensitivity, the measured field in the space domain is readily converted into the wavenumber domain by the 2D Fourier Transform.