Application of the Electrostatic Micro-Speakers for Producing Audible Directional Sound

2020 ◽  
Vol 12 (04) ◽  
pp. 2050045
Author(s):  
Mohammad Homaei ◽  
Mohammad Fathalilou ◽  
Rasoul Shabani ◽  
Ghader Rezazadeh
Keyword(s):  
Radiation Pattern ◽  
Mechanical Systems ◽  
Sound Radiation ◽  
Sound Power ◽  
Sound Waves ◽  
Radiation Patterns ◽  
Micro Electro Mechanical Systems ◽  
Hearing Range ◽  
Human Hearing ◽  
Square Array

In recent years, the demand for control of sound power and radiation patterns in personal messaging, calls, automotive entertainment, and gaming has brought a new interest in the audio world. The aim of this paper is to investigate the feasibility of producing the sound waves in the audible range and directing them in the desired listening zone by electrostatic micro-speakers. Therefore, a capacitive circular micro-plate has been modeled as an electrostatic micro-speaker. Then a Bessel panel array has been developed using a number of these plates arranged in a square array. The equations governing the vibrations of the micro-speaker’s diaphragm, as well as radiation pattern of the sound waves, have been introduced and solved. The results have shown that the Micro-Electro Mechanical Systems (MEMS) electrostatic diaphragms have the capability of producing the directional sound in the human hearing range. Moreover, we have investigated the effect of different excitation frequencies, radii size and the number of the diaphragms as well as the inter-element spacing on the sound radiation pattern of the Bessel panel array.

Application of MEMS Technology to a Lightwave Antenna for Communication in Space and Aeronautics

2006 ◽  
Author(s):  
Yasushi Munemasa ◽  
Masatoshi Sano ◽  
Makoto Mita ◽  
Tadashi Takano
Keyword(s):  
Radiation Pattern ◽  
High Performance ◽  
Light Wave ◽  
Mechanical Systems ◽  
Optical Antenna ◽  
Curved Surfaces ◽  
Micro Electro Mechanical Systems ◽  
Measurement Results ◽  
Mems Technology ◽  
Power Radiation

This paper reports a novel MEMS (Micro Electro Mechanical Systems) lightwave (optical) antenna as a telecommunication device in space and aeronautics. The high performance antenna at light wave frequency requires optimal curved surfaces and high mechanical precision to acquire high aperture efficiency. We have developed a novel micro lightwave antenna by applying MEMS (Micro Electro Mechanical Systems) technology. The antenna of transparent type (lens) is fabricated as a trial antenna, which has a 3-level step structure with diameter of 4 mm, to show the advantage of the antenna. The characteristics of the fabricated antenna have been measured. The measurement results of gain and power radiation pattern are in agreement with simulation result.

DE-based capacitive micro-speakers for generating directional audible sound

2020 ◽  
Vol 234 (10) ◽  
pp. 1325-1334
Author(s):  
Mohammad Soosani ◽  
Mohammad Fathalilou ◽  
Ghader Rezazadeh ◽  
Mohammad Homaei
Keyword(s):  
Smart Materials ◽  
Sound Pressure ◽  
Poor Performance ◽  
Fast Response ◽  
Deformation Energy ◽  
Dielectric Elastomer ◽  
Sound Waves ◽  
Micro Electro Mechanical Systems ◽  
Audible Sound ◽  
Human Hearing

Although silicon is the most used material in micro-electro-mechanical-systems, due to the excellent mechanical properties, it has poor performance for generating audible sound by capacitive micro-speakers. This paper studies the capability of dielectric elastomer material instead for generating the directional sound in the human hearing regime. Dielectric elastomers are a branch of smart materials with high desired and practical specifications such as large deformation, energy-efficient, lightweight, biocompatible, and fast response which share the common characteristics of changing their shape under an applied electrical voltage or charge. An elastic circular dielectric elastomer micro-plate with compliant electrodes on both sides suspended over the unmoving plate as a capacitive micro-structure has been modeled as a diaphragm of the micro-speaker. Then the Bessel panel array has been considered in a square matrix form composed of the number of dielectric elastomer micro-speakers. The nonlinear equation of the vibrations of a micro-speaker’s diaphragm under an electrostatic loading and equations of the sound pressure and sound radiation pattern have been presented and solved. The results have shown that utilizing dielectric elastomer-based micro-speakers in a Bessel panel array can generate a directional audible sound pressure in the human hearing range. In addition, the results clear that the desired sound waves in the human audible range and a private or personal listening zone can be produced through adopting an optimal value among the excitation frequencies, diaphragm numbers, radii and inter-element spaces of a Bessel panel array.

Sonoorganic Synthesis Engineering

2001 ◽  
Author(s):  
L. K. Doraiswamy
Keyword(s):  
Scale Up ◽  
Reaction Rates ◽  
Hydrodynamic Cavitation ◽  
Sound Waves ◽  
Alternative Means ◽  
Normal Human ◽  
Hearing Range ◽  
Human Hearing ◽  
Human Ear ◽  
Economic Considerations

Ultrasonics or ultrasound refers to sound waves beyond the audible range of the human ear. The normal human hearing range is 16-16,000 cycles per second. The accepted terminology for one cycle per second is the Hertz (or Hz), and hence the hearing range is expressed as 16 Hz to 16kHz. Ultrasound is normally considered to lie approximately in the range of 15kHz to 10 MHz, that is, 15 x 103 to 10000 x 103 cycles per second, with acoustic wavelengths of 10 to 0.01 cm. Like any sound wave, ultrasound is propagated through a medium in alternating cycles of compression and stretching or rarefaction. These produce certain effects in the medium that can be usefully exploited. One such application is in the field of synthetic organic chemistry, first reported by Richards and Loomis (1927) and designated sonochemistry. The most appealing feature of sonochemistry is its ability to enhance reaction rates, often to remarkably high levels under environmentally benign conditions. Despite this potential, economic considerations have precluded the use of sonochemical processes. It is noteworthy, however, that a change in perspective appears to be emerging, as evidenced by the fact that a pilot plant is currently being funded by a French company to sonochemically oxidize cyclohexanol to cyclohexanone, and developmental work is underway in Germany to produce 4 tons of Grignard reagent per year (Ondrey et al., 1996). A number of books and reviews covering mostly the chemical aspects of sonochemistry have appeared over the years, for example, Suslick, 1988, 198, 1990a,b; Ley and Low, 1989; Mason, 1986, 1990a,b, 1991; Mason and Lorime 1989; Price, 1992; Bremner, 1994; Low, 1995; Luche, 1998. A recent review Thompson and Doraiswamy (1999) covers both the chemical and engineering aspects of sonochemistry and another by Keil and Swamy (1999) examines the present state of our understanding of sonoreactor design. Sonochemical enhancement of reaction rates is caused by a phenomenon called cavitation. Therefore, we largely confine the treatment in this chapter to the chemical and reaction engineering (scale-up) aspects of cavitation and its associated effects (see Shah et al., 1999, for a detailed treatment). An alternative means of achieving the same result is by mimicking the ultrasonic effect by inducing “hydrodynamic cavitation.”

scholarly journals The Basics of Ultrasonography

2017 ◽  
Vol 46 (1) ◽  
pp. 44-47
Author(s):  
Sabrina Q Rashid
Keyword(s):  
Human Body ◽  
The Body ◽  
Sound Waves ◽  
Internal Organs ◽  
Ultrasound Waves ◽  
Internal Structures ◽  
Hearing Range ◽  
Human Hearing ◽  
Different Tissues

Ultrasound is sound whose frequency is above the human hearing range. It is nowadays widely used for the evaluation of a patient’s internal organs. Ultrasound waves are transmitted into the human body by an instrument called the transducer. Inside the body the sound waves are reflected and scattered differently by the different tissues and organs. The reflected sound waves are used by the computer to form an image of the internal structures and tissues. Use of ultrasound is safe with negligible bio-effects.Bangladesh Med J. 2017 Jan; 46 (1): 44-47

scholarly journals An Update on Applications of Power Ultrasound in Drying Food: A Review

2019 ◽  
Vol 8 (1) ◽  
pp. 29-38 ◽  
Author(s):  
Vahid Baeghbali ◽  
Mehrdad Niakousari ◽  
Michael Ngadi
Keyword(s):  
Nutritional Value ◽  
Synergistic Effects ◽  
Drying Methods ◽  
Sound Waves ◽  
Power Ultrasound ◽  
History Of ◽  
Hearing Range ◽  
Human Hearing ◽  
Drying Conditions

Ultrasound is sound waves with above the human hearing range frequency that is approximately 20 kHz. Application of power ultrasound in combination with other food processing methods including drying, is considered to be an emerging and promising technology. The use of novel non-thermal technologies, such as power ultrasound, is suitable to facilitate the drying of heat sensitive food materials. Ultrasound enhance heat and mas transfer which result in faster moisture removal during drying due to heating, vibration and synergistic effects. These effects could lead to product quality preservation in terms of color, texture, vitamin C and antioxidants content, by the use of milder drying conditions, and in some cases can promote better energy efficiency. In this article, after a brief review on the history of ultrasonic drying, different methods are categorized and combinations of ultrasound with novel drying methods and their effects on phytochemicals are discussed with the focus on the recently published articles. Studies showed that the quality of ultrasonically dried products was usually higher than conventionally dried products. However, the effect of ultrasonic drying on the texture and nutritional value of the products should be further investigated.

Optical phase modulators using deformable waveguides actuated by micro-electro-mechanical systems

2011 ◽  
Vol 36 (7) ◽  
pp. 1089 ◽  
Author(s):  
Wei-Chao Chiu ◽  
Chun-Che Chang ◽  
Jiun-Ming Wu ◽  
Ming-Chang M. Lee ◽  
Jia-Min Shieh
Keyword(s):  
Mechanical Systems ◽  
Micro Electro Mechanical Systems ◽  
Optical Phase ◽  
Phase Modulators ◽  
Optical Phase Modulators

scholarly journals Wash Testing of Electronic Yarn

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1228 ◽  
Author(s):  
Dorothy Anne Hardy ◽  
Zahra Rahemtulla ◽  
Achala Satharasinghe ◽  
Arash Shahidi ◽  
Carlos Oliveira ◽  
...  
Keyword(s):  
Research Group ◽  
Copper Wire ◽  
Mechanical Systems ◽  
Consumer Products ◽  
Temperature Sensing ◽  
Micro Electro Mechanical Systems ◽  
Acoustic Sensing ◽  
Protective Polymer ◽  
Wash Durability

Electronically active yarn (E-yarn) pioneered by the Advanced Textiles Research Group of Nottingham Trent University contains a fine conductive copper wire soldered onto a package die, micro-electro-mechanical systems device or flexible circuit. The die or circuit is then held within a protective polymer packaging (micro-pod) and the ensemble is inserted into a textile sheath, forming a flexible yarn with electronic functionality such as sensing or illumination. It is vital to be able to wash E-yarns, so that the textiles into which they are incorporated can be treated as normal consumer products. The wash durability of E-yarns is summarized in this publication. Wash tests followed a modified version of BS EN ISO 6330:2012 procedure 4N. It was observed that E-yarns containing only a fine multi-strand copper wire survived 25 cycles of machine washing and line drying; and between 5 and 15 cycles of machine washing followed by tumble-drying. Four out of five temperature sensing E-yarns (crafted with thermistors) and single pairs of LEDs within E-yarns functioned correctly after 25 cycles of machine washing and line drying. E-yarns that required larger micro-pods (i.e., 4 mm diameter or 9 mm length) were less resilient to washing. Only one out of five acoustic sensing E-yarns (4 mm diameter micro-pod) operated correctly after 20 cycles of washing with either line drying or tumble-drying. Creating an E-yarn with an embedded flexible circuit populated with components also required a relatively large micro-pod (diameter 0.93 mm, length 9.23 mm). Only one embedded circuit functioned after 25 cycles of washing and line drying. The tests showed that E-yarns are suitable for inclusion in textiles that require washing, with some limitations when larger micro-pods were used. Reduction in the circuit’s size and therefore the size of the micro-pod, may increase wash resilience.

Micro-spectrophotometer based on micro electro-mechanical systems technology

2008 ◽  
Vol 3 (1) ◽  
pp. 37-43
Author(s):  
Lianqun Zhou ◽  
Yihui Wu ◽  
Ping Zhang ◽  
Ming Xuan ◽  
Zhenggang Li ◽  
...  
Keyword(s):  
Mechanical Systems ◽  
Micro Electro Mechanical Systems
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