Phased Array Transducer Research Articles

Numerical analysis of the phased array imaging with a stacked plate buffer

Abstract This paper discusses the imaging with a phased array transducer attached with a stacked thin plate buffer using the calculations of wave propagation. The buffer is designed to guarantee the performance of phased array transducer based on the properties of dispersion nature of the S0 mode of Lamb wave. First, numerical analyses showed the limitations of the imaging with a stacked plate buffer due to the multiple reflections at the buffer ends. Then the effective detecting region (EDR) of the phased array transducer with a stacked plate buffer was investigated theoretically and numerically. The imaging results of the numerical calculations agreed with the theoretical predictions on the EDR. Final numerical analyses also presented the longer buffer provides the wider EDR as predicted by the theoretical investigations.

Electronic Focus Steering Capabilities of a Diagnostic-Type Linear Ultrasound Array Designed for High Power Therapy and Its Visualization

The focus steering capabilities of a 1 MHz linear phased array transducer (64 rectangular elements, 14.8 × 51.2 mm aperture) intended for drug delivery applications in abdominal organs were assessed and compared with its design-stage computer model. Acoustic fields generated by the transducer and predicted by the models of an ideal array with uniformly vibrating elements and either a plane or a cylindrically focused surface were simulated using the Rayleigh integral and angular spectrum methods. The boundary conditions for the transducer were reconstructed from acoustic holography measurements performed for selected focusing configurations of the array and also synthesized from holography data measured for each of its individual elements. It was shown that the transducer field with electronic focus steering can be accurately synthesized based on the holography data of its elements, which significantly simplified acoustic field characterization. Variability of the power and directivity patterns of the array elements were analyzed. A twofold smaller range of electronic steering in the transverse direction for the transducer compared to its computer model is discussed.

Acoustic levitation and manipulation of columns of droplets with integrated optical detection for parallelisation of reactions.

The most common methodology for performing multiple chemical and biological reactions in parallel is to use microtitre plates with either manual or robotic dispensing of reactants and wash solutions. We envision a paradigm shift where acoustically levitated droplets serve as wells of microtitre plates and are acoustically manipulated to perform chemical and biological reactions in a non-contact fashion. This in turn requires that lines of droplets can be levitated and manipulated simultaneously so that the same operations (merge, mix, and detect) can be performed on them in parallel. However, this has not been demonstrated until this work. Because of the nature of acoustic standing waves, a single focus has more than one trap, and can allow levitation of columns of droplets at the focal point and at half a wavelength above and below that point. Using this approach, we increased the number of acoustically levitated and merged droplets to 6 compared to 2 in the state-of-the-art. We showed that droplets in a column can be moved and merged with droplets in another column simultaneously and in a controlled manner to perform repeats and/or parallelisation of chemical and biological reactions. To demonstrate our approach experimentally, we built an acoustic levitator with top and bottom surfaces made of a 16 × 16 grid of 40 kHz phased array transducers and integrated optical detection system, studied two acoustic trap generation and movement algorithms, and performed an exemplar enzyme assay. This work has made significant steps towards acoustic levitation and manipulation of large numbers of droplets to eventually significantly reduce the use of the current state-of-the-art tools, microtitre plates and robots, for performing parallelised chemical and biological reactions.

Surface breaking crack sizing method using pulse-echo Rayleigh waves

Surface cracks are common in various industries. Eddy current testing (ECT) is commonly used for crack sizing but necessitates complex calibration standards and a highly trained inspector. Moreover, for large-area inspections, it requires additional scanning arrangements. In recent years the wedge technique-based Rayleigh wave crack sizing method has attracted significant research interest due to its unidirectional excitability. However, Rayleigh wave features generated at crack tips are often weak and masked under noise, and they mostly attenuate before reaching the receiving probe due to the couplant between the wedge-test specimen interface. Consequently, sizing the crack depth is difficult using a pulse-echo setup. This work presents a wedge-free pulse-echo Rayleigh wave method for surface crack sizing using a conventional phased array transducer. Eliminating the wedge removes a couplant layer leading to lower attenuation, enabling the transducer to capture crack tip features. This allows the sizing of surface cracks in pulse-echo using the time-of-flight (ToF) information. Furthermore, leveraging the phased array system, an averaging technique employed to the time trace signals captured by the transducer elements effectively averages out the other wave modes generated at crack geometries by the scattering of Rayleigh waves. This significantly minimizes sizing errors and enhances the signal-to-noise ratio (SNR). The performance of the proposed method is demonstrated through finite element simulations and experiments. Experiments with electric discharged machined (EDM) notches on test specimen surface at various angles and depths mimicking surface-breaking cracks show accurate sizing within a 5% error. The proposed method offers flexibility in performing inspections using a wide frequency range and can be easily applied to different materials using any conventional phased array transducer. This enhances its adaptability for industrial applications in the characterization of surface cracks.

Experience in the use of a roller multi-element phased array transducer for estimating the thickness of the pipeline wall

Scanning with a roller multi-element transducer on phased arrays of underground gas pipelines without removing the tape insulating coating was carried out in order to determine the thickness of the pipe wall

Acousto-Optic Transfer Function Control by a Phased-Array Piezoelectric Transducer

We present analysis and numerical simulations of the acousto-optic spatial filter (AOSF) transfer function under the condition of dual-transducer operation and phase control. Based on these simulations, the AOSF crystal configuration is optimized for operation in the near-infrared wavelength region from 0.7 to 1.0 μm. We demonstrate that ultrasonic phase control can provide efficient tuning of the transfer function, which is independent of conventional frequency control. Thus, the application of phase control coupled with frequency control can reduce the transfer function asymmetry that is inherent to anisotropic Bragg diffraction in uniaxial crystals.

Real-Time Passive Acoustic Mapping With Enhanced Spatial Resolution in Neuronavigation-Guided Focused Ultrasound for Blood-Brain Barrier Opening.

Passive acoustic mapping (PAM) provides the spatial information of acoustic energy emitted from microbubbles during focused ultrasound (FUS), which can be used for safety and efficacy monitoring of blood-brain barrier (BBB) opening. In our previous work with a neuronavigation-guided FUS system, only part of the cavitation signal could be monitored in real time due to the computational burden although full-burst analysis is required to detect transient and stochastic cavitation activity. In addition, the spatial resolution of PAM can be limited for a small-aperture receiving array transducer. For full-burst real-time PAM with enhanced resolution, we developed a parallel processing scheme for coherence-factor-based PAM (CF-PAM) and implemented it onto the neuronavigation-guided FUS system using a co-axial phased-array imaging transducer. Simulation and in-vitro human skull studies were conducted for the performance evaluation of the proposed method in terms of spatial resolution and processing speed. We also carried out real-time cavitation mapping during BBB opening in non-human primates (NHPs). CF-PAM with the proposed processing scheme provided better resolution than that of traditional time-exposure-acoustics PAM with a higher processing speed than that of eigenspace-based robust Capon beamformer, which facilitated the full-burst PAM with the integration time of 10 ms at a rate of 2 Hz. In vivo feasibility of PAM with the co-axial imaging transducer was also demonstrated in two NHPs, showing the advantages of using real-time B-mode and full-burst PAM for accurate targeting and safe treatment monitoring. This full-burst PAM with enhanced resolution will facilitate the clinical translation of online cavitation monitoring for safe and efficient BBB opening.

An alternative Rayleigh wave excitation method using an ultrasonic phased array

Ultrasonic Rayleigh waves have been employed for in-service NDT inspection in a wide range of industries for years. The excitation of Rayleigh waves can be achieved using a variety of methods, with the so-called wedge technique being the most widely used. Recent years have seen considerable research interest in surface crack detection and sizing using Rayleigh waves excited and detected with the wedge technique. However, in this method, Rayleigh waves experience transmission loss at the wedge interfaces. Moreover, the flexibility to generate Rayleigh waves on different waveguides using the same wedge is limited, as the wedge angle depends on the Rayleigh wave wavelength. This work demonstrates a method that provides an alternative Rayleigh wave excitation method. In this, a conventional ultrasonic phased array transducer is used. As there is an appropriate excitation delay between each piezoelectric element of the array transducer, Rayleigh waves can be generated in a wide range of materials using the same phased array transducer. The delay can be estimated based on the elementary pitch of the transducer and the Rayleigh wave velocity of the waveguide. The proposed Rayleigh wave excitation method is demonstrated through both experiments and FE simulations. Furthermore, a finite element model is used to better understand the features of the generated waves and to validate them through their characteristics as Rayleigh wave. A quantitative comparison between the proposed and existing methods is also presented. The directivity and beam divergence of the generated Rayleigh waves are quantified. The results obtained from experiments are in agreement with finite element simulations and demonstrate the possibility of unidirectional and selective excitation of Rayleigh waves through the proposed method. They also highlight the potential for this new excitation method to be used to develop new Rayleigh wave-based inspection methods.

In Vivo Thermal Ablation of Deep Intrahepatic Targets Using a Super-Convergent MRgHIFU Applicator and a Pseudo-Tumor Model.

HIFU ablation of liver malignancies is particularly challenging due to respiratory motion, high tissue perfusion and the presence of the rib cage. Based on our previous development of a super-convergent phased-array transducer, we aimed to further investigate, in vivo, its applicability to deep intrahepatic targets. In a series of six pigs, a pseudo-tumor model was used as target, visible both on intra-operatory MRI and post-mortem gross pathology. The transcostal MRgHIFU ablation was prescribed coplanar with the pseudo-tumor, either axial or sagittal, but deliberately shifted 7 to 18 mm to the side. No specific means of protection of the ribs were implemented. Post-treatment MRI follow-up was performed at D7, followed by animal necropsy and gross pathology of the liver. The pseudo-tumor was clearly identified on T1w MR imaging and subsequently allowed the MRgHIFU planning. The peak temperature at the focal point ranged from 58-87 °C. Gross pathology confirmed the presence of the pseudo-tumor and the well-delineated MRgHIFU ablation at the expected locations. The specific design of the transducer enabled a reliable workflow. It demonstrated a good safety profile for in vivo transcostal MRgHIFU ablation of deep-liver targets, graded as challenging for standard surgery.

A simulation study on the sensitivity of transcranial ray-tracing ultrasound modeling to skull properties.

In transcranial focused ultrasound therapies, such as treating essential tremor via thermal ablation in the thalamus, acoustic energy is focused through the skull using a phased-array transducer. Ray tracing is a computationally efficient method that can correct skull-induced phase aberrations via per-element phase delay calculations using patient-specific computed tomography (CT) data. However, recent studies show that variations in CT-derived Hounsfield unit may account for only 50% of the speed of sound variability in human skull specimens, potentially limiting clinical transcranial ultrasound applications. Therefore, understanding the sensitivity of treatment planning methods to material parameter variations is essential. The present work uses a ray-tracing simulation model to explore how imprecision in model inputs, arising from clinically significant uncertainties in skull properties or considerations of acoustic phenomena, affects acoustic focusing quality through the skull. We propose and validate new methods to optimize ray-tracing skull simulations for clinical treatment planning, relevant for predicting intracranial target's thermal rise, using experimental data from ex-vivo human skulls.

Ultrasonic sectorial inspection in the presence of temperature gradients

Ultrasonic nondestructive testing is a precise tool for equipment inspections. Among the usual methods, sectorial scanning stands out within contact-based techniques, as it provides broad angular sweeps without the need to physically steer the transducer, and the configuration of the beams hinges on the geometry of the tested objects. However, in high-temperature scenarios (e.g., oil treatment vessels), thermal gradients along the propagation path result in inaccurate sizing of discontinuities, given that the presence of such gradients is responsible for variations in the velocities and distortions of the ultrasonic beams. This paper proposes a method to compensate for these distortions during the sectorial inspection. Optimal linear approximation parameters are determined offline from a controlled Full Matrix Capture (FMC) test, in which the setup consists of a phased array transducer, a high-temperature resistant wedge and an aluminium test block with flaws at known positions. The positions of the flaws are measured on the Total Focusing Method (TFM) reconstructions, and the parametric velocity models for specific instants of heating time are estimated through the minimization of a cost function. Then, focal laws are calculated from the parameters using the ray tracing technique and stored in a text file to be interpreted by the instruments as a native focal law. An online test is proposed for validating the method at the controlled temperature of 70oC. The results show that the positions of the flaws, and the distance between them in the S-scan image, present improved accuracy (with errors reduced by approximately 64%) when the proposed correction is applied.

Longitudinal Assessment of Cerebral Blood Volume Variation in Human Neonates Using Ultrafast Power Doppler and Diverging Waves

Longitudinal assessment of brain perfusion is a critical parameter for neurodevelopmental outcome of neonates undergoing cardiopulmonary bypass procedure. In this study, we aim to measure the variations of cerebral blood volume (CBV) in human neonates during cardiac surgery, using Ultrafast Power Doppler and freehand scanning. To be clinically relevant, this method must satisfy three criteria: being able to image a wide field of view in the brain, show significant longitudinal CBV variations, and present reproducible results. To address the first point, we performed for the first time transfontanellar Ultrafast Power Doppler using a hand-held phased-array transducer with diverging waves. This increased the field of view more than threefold compared to previous studies using linear transducers and plane waves. We were able to image vessels in the cortical areas as well as the deep grey matter and temporal lobes. Second, we measured the longitudinal variations of CBV on human neonates undergoing cardiopulmonary bypass. When compared to a pre-operative baseline acquisition, the CBV exhibited significant variation during bypass: on average, +20±3% in the mid-sagittal full sector (p<0.0001), -11±3% in the cortical regions (p<0.01) and -10±4% in the basal ganglia (p<0.01). Third, a trained operator performing identical scans was able to reproduce CBV estimates with a variability of 4% to 7.5% depending on the regions considered. We also investigated whether vessel segmentation could further improve reproducibility, but found that it actually introduced greater variability in the results. Overall, this study demonstrates the clinical translation of ultrafast power Doppler with diverging-waves and freehand scanning.

Thermoacoustic phased-array radiators – Theory, characteristics, and applications

Standard non-invasive acoustic non-destructive testing (NDT) methods like testing in contact or using immersion tank arrangements are limited since the probes need to be in direct contact with the test piece or using a fluid as coupling media. Air-coupled ultrasonic testing avoids these limitations and enables new testing methods. Two up-and-coming transducer technologies are recognized as promising: transducers using ferroelectrets and transmitters based on the thermoacoustic principle. Thermoacoustic radiators based on thin-film technology offer a resonant-free generation of ultrasound. The resonance-free operation enables the wideband generation of acoustics waves and promises advantages for existing NDT methods. Using specially shaped substrates and electrodes enables the fabrication of planar and focused thermoacoustic radiators. This contribution presents the latest results of our ongoing research regarding thermoacoustic radiators, which is the thermoacoustic phased-array. Phased-array transducers offer the on-the-fly change of the steering angle and the position of the focal point without moving or modifying the transducer itself. Combining both technologies, thermoacoustic emitter and the phasedarray principle broaden the spectrum of classical NDT applications and modern approaches like the excitation of guided waves or structural health monitoring. In detail, we modelled the sound field of a self-fabricated thermoacoustic phased-array radiator, characterised the emitter elementwise and tested several application scenarios (e.g., transmission, beam steering, focusing and the excitation of guided waves).

An Algorithm for Rendering Force Fields at Many and Close Control Points Using Acoustic Holography for Ultrasound Therapy

Abstract Ultrasound therapy is advantageous because it is a noninvasive treatment for the body. Low-intensity pulsed ultrasound can aid fracture healing. We focus on phased array transducers (PATs) to render force fields and realize the improvement in medical equipment to enhance this therapy. This can both render an arbitrary acoustic field and quickly change it by controlling the output and phase of each transducer. There are some algorithms for controlling PATs; however, the effectiveness of these algorithms is limited at sparse control points. We propose a novel algorithm to control PATs at many and close control points in this research. We compare the proposed algorithm with previous ones and assess the avoidance of negative effects outside the target area. The findings show that the proposed algorithm achieves both excellent reconstruction performance and low computational cost, and it can render an acoustic field sufficient to prevent negative effects on the body.

Microbubble contrast agent as a minimally invasive pressure sensor at body temperature and reduced concentrations in an ultrasound flow phantom

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): MRC. Background Cardiac catheterisation is the gold standard for assessing cardiac pressures. However, this is an invasive and costly procedure. A minimally invasive alternative may be to use the subharmonic signal of microbubble ultrasound contrast agents to estimate pressure using echocardiography (Sub-Harmonic Assisted Pressure Estimation: SHAPE). Purpose The aim of this work was to investigate the ability of SHAPE to track dynamic diastolic pressures in a flow phantom at body temperature and at reduced microbubble concentrations. Methods A priming dose of 0.4 mL/L of sulphur hexafluoride microbubbles was circulated through a silicone tube using a peristaltic pump at a flow rate of 375 mL/min (generating 376 pressure cycles/min and maximum pressure gradient of 1.9 mmHg/ms; Fig. 1). The ULtrasound Advanced Open Platform (ULA-OP) was used with a cardiac phased array transducer to transmit a pulse-inversion sequence at 2.1 MHz. Radiofrequency data were recorded at five acoustic pressures (71–228 kPa peak-negative). To investigate the effects of temperature, the subharmonic-pressure relationship was measured over 60 min at both room and body temperature (37°C). Microbubble concentration was maintained by regular top-up (0.15 mL/L every 3–5 min). To investigate the effect of lower concentrations on the subharmonic-pressure relationship, a priming dose of 0.4, 0.3 or 0.2 mL/L was administered before a single acquisition was made. The system was immediately purged before testing the next concentration. The subharmonic (1.05 MHz) amplitude of the microbubbles was calculated over a 40% bandwidth. A solid-state catheter recorded ground-truth pressures. Correlation coefficient (r) and sensitivity (dB/mmHg) of the subharmonic signal to the pressure values were calculated. Results The mean correlation coefficient (r = 0.91 ± 0.04; Fig. 2) and sensitivity (0.20 ± 0.04 dB/mmHg) at body temperature (n = 20) were significantly greater than those for the same batch of microbubbles at room temperature (r = 0.81 ± 0.07 and 0.14 ± 0.02; n = 18; p &amp;lt; 0.05) at the optimal acoustic pressure (Fig. 2). No significant differences in the subharmonic-pressure relationship were observed between the three different microbubble concentrations (Correlation: r = 0.96 ± 0.00, 0.96 ± 0.01, 0.97 ± 0.01. Sensitivity: 0.26 ± 0.02, 0.26 ± 0.03, 0.28 ± 0.02 mmHg/dB for 0.4, 0.3 and 0.2 mL/L, respectively; n = 3) at the optimal acoustic pressure. Conclusions SHAPE can accurately track diastolic pressures five times faster than the average resting heart rate at body temperature and with reduced microbubble concentrations. SHAPE is a potential method for assessing cardiac diastolic pressures using ultrasound in a minimally invasive fashion, being suitable for use in patients with faster microbubble clearance or in the event of delayed acquisition. The use of SHAPE fits into routine clinical procedures and has the potential to improve the diagnosis and monitoring of cardiovascular diseases.

Lung ultrasound: A comparison of image interpretation accuracy between curvilinear and phased array transducers.

Both curvilinear and phased array transducers are commonly used to perform lung ultrasound (LUS). This study seeks to compare LUS interpretation accuracy of images obtained using a curvilinear transducer with those obtained using a phased array transducer. We invited 166 internists and trainees to interpret 16 LUS images/cineloops of eight patients in an online survey: eight curvilinear and eight phased array, performed on the same lung location. Images depicted normal lung, pneumothorax, pleural irregularities, consolidation/hepatisation, pleural effusions and B-lines. Primary outcome for each participant is the difference in image interpretation accuracy scores between the two transducers. A total of 112 (67%) participants completed the survey. The mean paired accuracy score difference between the curvilinear and phased array images was 3.0% (95% CI: 0.6 to 5.4%, P = 0.015). For novices, scores were higher on curvilinear images (mean difference: 5.4%, 95% CI: 0.9 to 9.9%, P = 0.020). For non-novices, there were no differences between the two transducers (mean difference: 1.4%, 95% CI: -1.1 to 3.9%, P = 0.263). For pleural-based findings, the mean of the paired differences between transducers was higher in the novice group (estimated mean difference-in-differences: 9.5%, 95% CI: 0.6 to 18.4%; P = 0.036). No difference in mean accuracies was noted between novices and non-novices for non-pleural-based pathologies (estimated mean difference-in-differences: 0.6%, 95% CI to 5.4-6.6%; P = 0.837). Lung ultrasound images obtained using the curvilinear transducer are associated with higher interpretation accuracy than the phased array transducer. This is especially true for novices interpreting pleural-based pathologies.

A Real Time Method Based on Deep Learning for Reconstructing Holographic Acoustic Fields from Phased Transducer Arrays.

Phased transducer arrays (PTA) can control ultrasonic waves to produce a holographic acoustic field. However, obtaining the phase of the corresponding PTA from a given holographic acoustic field is an inverse propagation problem, which is a mathematically unsolvable nonlinear system. Most of the existing methods use iterative methods, which are complex and time-consuming. To better solve this problem, this paper proposed a novel method based on deep learning to reconstruct the holographic sound field from PTA. For the imbalance and randomness of the focal point distribution in the holographic acoustic field, we constructed a novel neural network structure incorporating attention mechanisms to focus on useful focal point information in the holographic sound field. The results showed that the transducer phase distribution obtained from the neural network fully supports the PTA to generate the corresponding holographic sound field, and the simulated holographic sound field can be reconstructed with high efficiency and quality. The method proposed in this paper has the advantage of real-time performance that is difficult to achieve by traditional iterative methods and has the advantage of higher accuracy compared with the novel AcousNet methods.

Full-duplex underwater acoustic communications via self-interference cancellation in space

Traditionally, underwater acoustic communications are half-duplex (HD), i.e., the hydrophones and transducers operate in non-overlapping time-slots/frequency-bands in one direction. To double the spectral efficiency into the full-duplex (FD) mode, which transmit and receive signals simultaneously, a self-interference cancellation (SIC) technique in space is introduced and deployed. Specifically, a novel underwater acoustic system is proposed to perform FD-SIC efficiently via an integrated design combining underwater acoustic vector sensor (AVS) and phased array transducer (PAT) to realize the spatial SIC. The energy focusing function of the beamformer (BF) helps PAT avoid self and mutual spatial interference. The AVS keeps updating the direction of arrival information to let BF adjust the steering angle via an adaptive protocol. The field-programmable gate array (FPGA) Direction of Arrival Estimation (DOA) estimation is done by a 12-element AVS, run-time is 1.22×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−4</sup> s by MUSIC method, which is promising for real-time applications. In this work, phase-shift keying (PSK) and PSK-based orthogonal frequency-division multiplexing (OFDM) are deployed as the FD transmission modulation methods in the spacial SIC. The proposal is evaluated and verified via both simulations and emulations in real underwater acoustic channels collected in the Gulf of La Spezia, Italy, and it is able to achieve 59 dB SIC while modulating with binary phase-shift keying (BPSK) with carrier wave frequency 80 kHz and AVS steering angle −5°. Moreover, it has at least 37 dB SIC within the steering angle region.

A Miniature Forward-Looking Phased-Array Transducer for Interventional Biopsy Guidance

Ultrasound-guided interventional biopsy is becoming an increasingly popular and valuable tool in the clinic. Conventionally, low-frequency (1–5 MHz) ultrasound probes are employed on the patient’s body surface for guiding interventional procedures, leading to low imaging resolution and low puncture accuracy. Several efforts have been made to achieve precise punctures, such as inserting a miniaturized high-frequency phased-array transducer into the patient’s body. However, the interventional devices (introducer biopsy needles) are all separate from those ultrasound probes, which will cause additional damage and operation complexity. Therefore, in this work, a miniature higher frequency phased-array probe integrated with a 0.4 mm intervention working channel is developed, which had 48 array elements and an outer diameter of only 3 mm. The center frequency and −6 dB bandwidth of this probe are measured as 26.2 MHz and 59.6%, respectively. For evaluating its guiding performance, the wire-phantom, ex vivo tissue, and tissue-mimicking phantom experiments were tested. According to the experiments, the axial imaging resolution and lateral resolution can be calculated as 88 and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$278~\mu \text{m}$ </tex-math></inline-formula> at a distance of 2 mm far away, respectively, and the effective detecting depth is 12 mm. All these results show that our proposed ultrasound transducer and method can adapt to the works in high-precision interventional guidance.

Time-delayed layer-based piezoelectric transducer for unidirectional excitation and reception of SH guided wave

Unidirectional excitation of a single-mode guided wave (GW) is of great significance in GW-based structural health monitoring (SHM) and nondestructive testing (NDT). Currently, very few transducers are capable of generating unidirectional propagation GW in plate-like structures, so such a goal is usually achieved by using phased array transducers, which are relatively expensive and only work within a narrow frequency range. In this work, a time-delayed layer-based piezoelectric transducer (TDLBPT) is developed for unidirectionally generating and receiving pure SH0 wave (zero-order shear horizontal wave). The TDLBPT consists of a time-delayed layer and two rectangular thickness-shear (d15) mode piezoelectric wafers. The time-delayed layer component is designed for achieving the phase gradient over a wide range of frequencies, so in both unidirectional excitation and reception, no extra time delay is required for the proposed TDLBPT. An analytic model is proposed to predict the SH0 wavefields generated by the TDLBPT, which can provide guidelines for designing the TDLBPT. Finite element (FE) simulations and experiments are performed to examine the performance of the developed TDLBPT. Both simulated and experimental results show that the TDLBPT can generate pure SH0 wave and focus the wave energy along a given direction in a plate over a wide range of frequencies. Moreover, the reception performance of the TDLBPT also shows excellent unidirectionality. Due to the excellent performance and easy fabrication, the proposed TDLBPT will be very useful in unidirectional excitation and reception of SH0 wave in SHM and NDT.