scholarly journals A Novel Racing Array Transducer for Noninvasive Ultrasonic Retinal Stimulation: A Simulation Study

Sensors ◽  
2019 ◽  
Vol 19 (8) ◽  
pp. 1825 ◽  
Author(s):  
Yanyan Yu ◽  
Zhiqiang Zhang ◽  
Feiyan Cai ◽  
Min Su ◽  
Qiuju Jiang ◽  
...  
Keyword(s):  
Contact Lens ◽  
Retinal Prosthesis ◽  
Acoustic Absorption ◽  
Retinal Diseases ◽  
Array Design ◽  
Array Configuration ◽  
Retinal Stimulation ◽  
Array Transducer ◽  
Element Number ◽  
Acoustic Field Simulation

Neurostimulation has proved to be an effective method for the restoration of visual perception lost due to retinal diseases. However, the clinically available retinal neurostimulation method is based on invasive electrodes, making it a high-cost and high-risk procedure. Recently, ultrasound has been demonstrated to be an effective way to achieve noninvasive neurostimulation. In this work, a novel racing array transducer with a contact lens shape is proposed for ultrasonic retinal stimulation. The transducer is flexible and placed outside the eyeball, similar to the application of a contact lens. Ultrasound emitted from the transducer can reach the retina without passing through the lens, thus greatly minimizing the acoustic absorption in the lens. The discretized Rayleigh–Sommerfeld method was employed for the acoustic field simulation, and patterned stimulation was achieved. A 5 MHz racing array transducer with different element numbers was simulated to optimize the array configuration. The results show that a 512-element racing array is the most appropriate configuration considering the necessary tradeoff between the element number and the stimulation resolution. The stimulation resolution at a focus of 24 mm is about 0.6 mm. The obtained results indicate that the proposed racing array design of the ultrasound transducer can improve the feasibility of an ultrasound retinal prosthesis.

scholarly journals Ultrasonic Retinal Neuromodulation and Acoustic Retinal Prosthesis

Micromachines ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 929 ◽  
Author(s):  
Pei-An Lo ◽  
Kyana Huang ◽  
Qifa Zhou ◽  
Mark S. Humayun ◽  
Lan Yue
Keyword(s):  
Therapeutic Potential ◽  
Early Stage ◽  
Retinal Prosthesis ◽  
Ultrasound Exposure ◽  
Pilot Studies ◽  
Acoustic Frequency ◽  
Non Invasive ◽  
Neural Activities ◽  
Retinal Stimulation ◽  
Ultrasonic Stimulation

Ultrasound is an emerging method for non-invasive neuromodulation. Studies in the past have demonstrated that ultrasound can reversibly activate and inhibit neural activities in the brain. Recent research shows the possibility of using ultrasound ranging from 0.5 to 43 MHz in acoustic frequency to activate the retinal neurons without causing detectable damages to the cells. This review recapitulates pilot studies that explored retinal responses to the ultrasound exposure, discusses the advantages and limitations of the ultrasonic stimulation, and offers an overview of engineering perspectives in developing an acoustic retinal prosthesis. For comparison, this article also presents studies in the ultrasonic stimulation of the visual cortex. Despite that, the summarized research is still in an early stage; ultrasonic retinal stimulation appears to be a viable technology that exhibits enormous therapeutic potential for non-invasive vision restoration.

scholarly journals Design of 2D Sparse Array Transducers for Anomaly Detection in Medical Phantoms

Sensors ◽  
2020 ◽  
Vol 20 (18) ◽  
pp. 5370
Author(s):  
Xiaotong Li ◽  
Anthony Gachagan ◽  
Paul Murray
Keyword(s):  
Fibre Composite ◽  
Evaluation Criteria ◽  
Array Configuration ◽  
Array Pattern ◽  
Array Transducer ◽  
Random Array ◽  
Spiral Array ◽  
Imaging Performance ◽  
Tissue Mimicking Material ◽  
Tube Structure

Aperiodic sparse 2D ultrasonic array configurations, including random array, log spiral array, and sunflower array, have been considered for their potential as conformable transducers able to image within a focal range of 30–80 mm, at an operating frequency of 2 MHz. Optimisation of the imaging performance of potential array patterns has been undertaken based on their simulated far field directivity functions. Two evaluation criteria, peak sidelobe level (PSL) and integrated sidelobe ratio (ISLR), are used to access the performance of each array configuration. Subsequently, a log spiral array pattern with −19.33 dB PSL and 2.71 dB ISLR has been selected as the overall optimal design. Two prototype transducers with the selected log spiral array pattern have been fabricated and characterised, one using a fibre composite element composite array transducer (CECAT) structure, the other using a conventional 1–3 composite (C1–3) structure. The CECAT device demonstrates improved coupling coefficient (0.64 to 0.59), reduced mechanical cross-talk between neighbouring array elements (by 10 dB) and improved operational bandwidth (by 16.5%), while the C1–3 device performs better in terms of sensitivity (~50%). Image processing algorithms, such as Hough transform and morphological opening, have been implemented to automatically detect and dimension particles located within a fluid-filled tube structure, in a variety of experimental scenarios, including bespoke phantoms using tissue mimicking material. Experiments using the fabricated CECAT log spiral 2D array transducer demonstrated that this algorithmic approach was able to detect the walls of the tube structure and stationary anomalies within the tube with a precision of ~0.1 mm.

scholarly journals A 1-to-8 Fully Modular Stacked SIW Antenna Array for Millimeter-Wave Applications

2022 ◽  
Author(s):  
Cleofás Segura-Gómez ◽  
Ángel Palomares-Caballero ◽  
Pablo Padilla
Keyword(s):  
Antenna Array ◽  
Power Distribution ◽  
Main Beam ◽  
Impedance Bandwidth ◽  
Beam Direction ◽  
Array Design ◽  
Horn Antennas ◽  
Array Configuration ◽  
Minimum Number ◽  
Measured Impedance

This paper presents a vertically stacked SIW antenna array that enables different array configurations with the minimum number of SIW layers. This achievement lies in the modular feature offered by the proposed design. Specifically, 4 distinct array configurations can be produced with only 3 different design of SIW layers. Depending on the number of SIW layers employed in the stacked antenna, the directivity in the E-plane of radiation is modified. To obtain an equal and in-phase power distribution among the array elements, H- and E-plane corporate feeding networks are efficiently implemented in each array configuration. Array configurations of 1, 2, 4 and 8 radiating layers are offered by the proposed modular array, where each radiating layer is formed by 8 H-plane SIW horn antennas. The simulated directivity for the array configurations ranges from 15.8 dBi to 23.8 dBi and the main beam direction remains fixed along the operating frequency band. The array design has been manufactured and proper agreement between simulated and measured results are observed. The measured impedance bandwidth in all the array configurations is from 35 GHz to 41 GHz (15.79% bandwidth) with a reduction in the E-plane beamwidth as the number of radiating layers increases.

scholarly journals Substrate Integrated Slot Array Antenna with Required Radiation Pattern Envelope

2016 ◽  
Vol 2016 ◽  
pp. 1-4 ◽  
Author(s):  
M. M. Zhou ◽  
Y. J. Cheng ◽  
W. N. Huang
Keyword(s):  
Radiation Pattern ◽  
Array Antenna ◽  
Systematic Method ◽  
Standard Pattern ◽  
Antenna Radiation Pattern ◽  
Array Configuration ◽  
Excitation Coefficient ◽  
Planar Array ◽  
Element Number ◽  
Good Agreement

A substrate integrated slot array antenna with a prescribed radiation pattern is investigated in this paper. To meet the requirement of a certain standard radiation pattern envelope, the array configuration and the element excitation coefficient should be considered together. An efficient and systematic method is proposed to determine the element number and element weights in a planar array. After that, the geometrical dimension of the substrate integrated slot array can be synthesized. As an example, aK-band 16 × 22 slot array antenna based on the substrate integrated waveguide (SIW) technology is designed, fabricated, and measured. Its radiation pattern can meet the class 3 antenna radiation pattern envelope of the European Telecommunications Standards Institute (ETSI) standard pattern. Experimental results are in good agreement with simulated ones.

Sign in / Sign up

Export Citation Format

Share Document