Piezoelectric transducer tuned bandstop filter

A tunable bandstop filter with a wide tuning range is presented. A piezoelectric transducer with an attached dielectric perturber is used to perturb the filter to obtain a wide tuning range. Without changing the dimensions of the bandstop filter the tunable bandstop can provide a wide tuning range of 25% from 4.5 to 6 GHz. The high performance bandstop filter is useful for many microwave applications     

Piezoelectric thin film unidirectional SAW transducer and filter

Small passband ripple piezoelectric thin film unidirectional transducers and filters are presented. ZnO thin film deposited on a fused silica was used in the experiment. As the result, the characteristics of no pass-band ripple and minimum insertion loss of 5.2 dB, and also the directionality of 22 to 29 dB per one transducer are obtained.     

Piezoelectric transducer controlled multiple beam phased array using microstrip Rotman lens

A simple and low-cost multiple beam phased array is designed using a microstrip Rotman lens and multi-line phase shifter controlled by a piezoelectric transducer (PET) at Ka-band. A microstrip Rotman lens with five beam ports and nine array ports is used as a feed for a multiple beam antenna array to generate five beams centered at the angles of 0/spl deg/, /spl plusmn/15/spl deg/, and /spl plusmn/30/spl deg/. The lens fed nine-element patch array shows the antenna gain of 10 dBi and sidelobe suppression of 10 dB. Each beam is steered over /spl plusmn/8/spl deg/ using two PET-controlled phase shifters, and the five beams cover /spl plusmn/38/spl deg/ from the broadside.     

Tuning of transducer elements in transducer array

It is found that the resonance frequencies of various identical transducer elements used in a transducer array differ slightly. Due to this, relatively high power sources are required to radiate a certain amount of power. A possible solution to this problem which can be easily realised in practice for a ceramic transducer array is presented.     

压电马达用压电陶瓷的研究

采用传统的电子陶瓷工艺制备了高性能四元系压电陶瓷 (PZN- PMS- PZT- r Mn O2 )。考察了不同剂量的锰掺杂对压电陶瓷的介电性能和压电性能的影响 ,即室温介电常数 ε、介电损耗 tanδ、居里温度 Tc、机电耦合系数 kp、压电常数 d33和机械品质因数 Qm。随着 Mn含量的增加 ,ε和 tanδ均减小 ;由于内偏置场的影响 ,居里温度 Tc随锰含量的增加而增加。kp 和 d33随 Mn含量的增加而减小 ;而 Qm 表现出较复杂的变化规律 ,随 Mn含量的增加 Qm先增加 ,当 r=0 .2 %时 ,达到最大值 10 0 0 ,当 r>0 .2 %时 ,Qm 下降。实验结果表明 :当 r=0 .2 %的锰掺杂压电陶瓷比较适合制作压电马达 ,其压电性能为 ε=12 0 0、tanδ=0 .0 0 4、Tc=349°C、kp=0 .6 0、d33=380 p C/ N和 Qm=10 0 0     

在压电谐振基波附近的压电应变研究

本文根据PZT压电陶瓷的压电与弹性特性,应用谐振理论对其压电基波频率附近的压电位移作了计算;另一方面,采用一种高频激光双束干涉仪,测量了压电位移的位移量。其实测值和理论计算值是一致的。     

TE On o -to- mode transducer designmode transducer design

This paper gives a structure on the mode converter from TE _0n ^O mode of gyrotron output to the main mode of the circular groove guide. The design consists of two parts: the first part is to convert TE _0n ^O to TE ₀₁ ^O using an advanced periodic wall perturbation technology, the second part is to convert TE ₀₁ ^O to mode basing on the method of gradually changing the wave guide cross section. An example at 37.5Ghz is given. For the first part, the efficiency is 94.71%, the length is 1.868m. For the second part, the theoretic figure of reflectance coefficient vs. frequency is given.     

基于压电效应的能量收集

介绍了利用压电陶瓷元素进行能量收集,并对其进行了理论分析.为能对负载进行供电,使用DC-DC变换器对电压进行变换,同时增加了输出功率.最后实验结果对前面的模型理论分析进行了验证.     

基于分块压电悬臂梁的压电地板单元研制

为了提高压电地板的发电功率,将压电圆盘或正方形压电结构分块成悬臂梁。有限元静态分析表明,当承重和材料体积相近时,三角形分块的输出功率分别是方形分块和压电圆盘的20倍、7倍;对比分析了顶角为60°、90°、120°的三角形悬臂梁压电地板单元的发电性能,发现减薄压电片和基板厚度使踩踏位移相同时,3种压电地板单元的输出功率相同;若压电片和基板厚度相同,顶角为60°的三角形分块压电地板单元输出功率最大。用6个60°三角形压电悬臂梁制作压电地板单元,以手按压,可轮流点亮两个发光二极管。     

Acoustic bulk-surface-wave transducer

Bulk and surface waves are strongly coupled at a corrugated surface. Experiments have demonstrated transduction losses of less than 1dB and bandwidths of 20%. Methods of implementation at high frequencies are discussed.     

Tunable sonar transducer

Details are given of an underwater transducer which is tunable over the frequency range 250 kHz to 700 kHz. The structure comprises a pair of 50 mm-diameter lead zirconate titanate ceramic plates suitably mounted. The resonant frequency of the structure is electronically controlled by varying in a predetermined manner the amplitude and phase of the voltage applied to one of the ceramics.     

Tunable sandwich transducer

A tunable sandwich transducer is reported which has its fundamental resonant frequency controlled by varying a passive reactive load. The structure consists of four PZT-4 rings sandwiched between an aluminium head-mass and a brass tail-mass. The electromechanical coupling coefficient and the radiation efficiency into water of the transducer are given over the frequency range 25 to 75 kHz. A theoretical analysis based on an electromechanical equivalent circuit shows good agreement with the experimental results     

Surface-acoustic-wave pulse transducer

Short pulses of surface acoustic waves are launched efficiently by an inline assembly of several finger-pair interdigital transducers, which are connected to successive taps of an electrical delay line, where the electrical time lag between two taps is equal to the acoustic delay between corresponding transducers.     

压电薄膜特性参数的测量方法

随着电子元器件向微型、高灵敏、集成等方向发展,薄膜材料及器件在微机电(MEMS)系统中得到广泛应用,而测量压电薄膜特性参数的方法与体材料相比有很大的不同.介绍了当前测量压电薄膜特性参数的两大类方法:直接测量法(包括气腔压力法、悬臂梁法、激光干涉法和激光多普勒振动法)和间接测量法(传统阻抗分析法),详细分析了这些方法的基本原理、测试表征、应用状况及存在的问题,比较了这些方法的优缺点,并对未来压电薄膜特性参数的测试表征作了展望.     

压电器件用KNN基无铅压电陶瓷的研究进展

(K, Na)NbO₃(KNN)基无铅压电陶瓷作为一种环境友好型材料,兼具较高的居里温度和可调控的相界结构,在压电器件领域展示出潜在的应用前景,引起了广泛关注和大量研究。对其物相组成、制备工艺、性能调控等方面的研究进展进行了评述,并重点介绍了其在压电器件领域的实际应用,最后对KNN及其在器件应用方面未来的研究和发展方向进行了总结展望。     

大行程纳米级压电电动机的驱动控制系统

介绍了一种基于尺蠖运动原理的大范围纳米级步距压电电动机.根据其运动原理和机械结构特点,设计完成了该压电电动机的控制系统,通过控制电压变化来控制压电晶体的伸缩,从而完成夹紧器的夹紧、放松与驱动器的微位移,巧妙的将压电陶瓷的形变通过机械装置输出,并对该控制系统进行了波形测试.实验表明,该控制系统产生的三角波、方波信号纹波电压小,信号稳定,满足电动机驱动要求.     

Piezoelectric silicone rubbers

A technique for the manufacture of flexible compressible transducers is presented based on the use of piezoelectric ceramic powder dispersed in a silicone rubber medium. Potential applications are discussed.     

一种由压电双晶片测量压电常数d31的方法

提出了一种新的测量方法 ,由一种实用元件——压电双晶片测量压电材料的压电常数 d31的方法。这种测量方法不同于通常的由标准试样测量压电材料参数的方法。文中给出了测量原理、测量装置及由一种 PZT样本的测量结果 ,并同时给出了 IEEE标准测量方法的结果。理论和实验结果表明 :这种新的测量方法是可行的。     

Solid-state digital pressure transducer

The solid-state digital transducer represents a new standard in precision pressure transduction for the next generation of airborne sensors. The pressure transducer produces pulse train outputs as a measure of pressure by developing strains in a silicon diaphragm which incorporates piezoresistive sensing elements. These elements are distributed resistance-capacitance (RC) networks which are diffused into a diaphragm surface as the control elements of phase shift oscillators. By this approach, a digital (frequency) signal generated at the source can be transmitted without noise and distance limitations and the need for precision analog to digital conversion is eliminated. The device exhibits advantages in the areas of reliability, accuracy, size and cost over present day analog devices. The solid-state digital pressure transducer is being developed to meet the requirements of supersonic and subsonic air data applications when coupled with a high-performance air data computer. This application requires low hysteresis with repeatability and stability which are the main features of the solid-state pressure transducer. Other possible applications are FM data acquisition systems and industrial robots.     

Novel variable-focus ultrasonic transducer

A focusing p.v.f.2 transducer is described. By controlled deformation of a stretched p.v.f.2 membrane, the focal spot may be scanned axially. This action is demonstrated and is shown to correspond well with the predictions of simple theory. There are potential applications for such a device in medical imaging.