Wireless identification and sensing using surface acoustic wave devices

Today Surface Acoustic Wave (SAW) devices are used in many electronic products, e.g. as filters in communications applications or for signal processing in radar systems. Due to the dependence of the propagation characteristic of the microacoustic wave on many physical parameters (e.g. temperature or strain) it is possible to build SAW sensors for a great variety of physical, chemical and biological parameters. SAW sensors are not only small, rugged and show small aging rates, they also can be used as wirelessly interrogable and completely passive sensors for many hostile environments. In this contribution the SAW device principles, design procedures and technological issues as well as examples of their use in certain measurement and identification applications are reviewed.     

薄膜声表面波器件的制备研究进展

介绍了薄膜声表面波器件的发展历史和特点,以及压电薄膜声表面波器件近年来国际上的研究进展,包括理论研究与实验进展的一些概况,并展望了其今后的发展趋势。     

On the theory of linear surface acoustic wave devices

Stationary distribution of the efficient wave sources excited by interdigital transducers (IDT) of arbitrary configuration has been derived on the basis of reciprocity of the generation and reception of surface acoustic waves (SAW) in piezoelectrics. It was shown that these sources represent a linear combination of two stationary distributions on the surface S between the piezoelectric and IDT: the distribution of the normal component of SAW flux density formed in the mode of SAW reception by the short-circuit IDT and the field distribution of the SAW electric potential at the same surface S but in the absence of piezoelectric. The Y-parameter matrix of the device was obtained as an electric M×2-terminal network containing M IDT. It was shown that the SAW transfer admittances and SAW radiation admittances contained additional frequency-dependent multipliers. The characteristics take into account the smoothed diffraction, spatial dispersion in IDT, reflections from IDT, and electric loads of the device.     

High speed receiver designs based on surface acoustic wave devices

The principles of operation and several types of surface acoustic wave devices are reviewed. One device, the interdigital transducer device, can accomplish matched filtering for complex bandwidth-efficient phase modulations. Data speeds in excess of 120 Mb/s are accomplished with existing thin film lithography. Filters are cheap and small, and show little mismatch to the desired response. A number of receiver designs are proposed that are based on these filters. A bank-of-matched-filters approach seems superior to the Viterbi algorithm at high speeds.     

An application of acoustic surface wave devices to communication receivers

In this paper we present a new acoustic surface wave phase-locked loop FM demodulator. This device uses the nonlinear coupling characteristics of an insulating piezoelectric to an adjacent semiconductor to generate an electric field in the semiconductor. The low-frequency voltage resulting from the spatial integration of the electric field along the semiconductor is used as the controlling voltage of a voltage controlled oscillator. The above device acts as a phase-locked loop of either the first order or the second order, depending on the amplitude of the input waves, the characteristics of the coupling device, and the integration length of the electric field in the semiconductor. Both theoretical and experimental results relating to the lock range, frequency tracking, and FM demodulation characteristics of the novel device are described.     

Test method of frequency response based on diamond surface acoustic wave devices

In order to reduce the noises affixed to the signals when testing high frequency devices,a single-port test mode(S11) is used to test frequency response of high frequency(GHz) and dual-port surface acoustic wave devices(SAWDs) in this paper.The feasibility of the test is proved by simulating the Fabry-perot model.The frequency response of the high-frequency dual-port resonant-type diamond SAWD is measured by S11 and the dual-port test mode(S21),respectively.The results show that the quality factor of the device is 51.29 and the 3 dB bandwidth is 27.8 MHz by S11-mode measurement,which is better than the S21 mode,and is consistent with the frequency response curve by simulation.     

The influence of rotation on a phase deviation in surface acoustic wave devices

The piezoelectric medium movement equations and the piezoelectric half-space boundary conditions including the Coriolis force are obtained. The phase deviation in surface acoustic wave devices in the presence of rotation is defined. It can achieve a value of 0.001° when the angular velocity of rotation is 1 rps.     

Surface acoustic wave devices for sensor applications

Surface acoustic wave (SAW) devices have been widely used in different fields and will continue to be of great importance in the foreseeable future. These devices are compact, cost efficient, easy to fabricate, and have a high performance, among other advantages. SAW devices can work as filters, signal processing units, sensors and actuators. They can even work without batteries and operate under harsh environments. In this review, the operating principles of SAW sensors, including temperature sensors, pressure sensors, humidity sensors and biosensors, will be discussed. Several examples and related issues will be presented. Technological trends and future developments will also be discussed.     

MEMS-IDT声表面波陀螺

声表面波陀螺的概念出现在70年代初期,发展为MEMS-IDT声表面波陀螺仅是最近几年的事情。MEMS-IDT声表面波陀螺仪是一种MEMS微机械振动陀螺,这种陀螺为单层平面结构,采用标准IC工艺就可完成加工,勿需悬浮的振动元件,有很强的抗冲击振动能力,可靠性高,可不用真空封装而保持较高的灵敏度。     

Frequency-selective scanning of acoustic surface wave

An acoustic-surface-wave point source is obtained when an interdigital transducer with concentric curved fingers is used. An array transducer composed of 80 point sources has been tested. The direction of propagation of the surface-wave beam emitted by this transducer depends on the frequency. A transmitting-array transducer and five receiving transducers are deposited on a quartz substrate. Each of these five outputs corresponds to a given frequency and delay prescribed by the positioning. At 12°, scanning was attained for a frequency variation of 7.6 MHz around a central frequency of about 60 MHz, corresponding to a delay variation of 18.2 ?s.     

A high-frequency surface acoustic wave resonator

The results of mathematical modeling of an interdigital converter of surface acoustic waves are presented. An equivalent circuit model is used. It is shown that the choice of the number of electrodes in the converter makes it possible to use it as a miniature high-quality resonator.     

A surface acoustic wave delay line phase amplifier

Theoretical analysis of surface acoustic wave (SAW) delay line resonators is extended to show the possibility of a novel circuit, which can be used to amplify the phase shift of a fixed frequency signal associated with an electronic circuit.     

GHz-range surface acoustic wave interdigital transducers and applications

GHz-range SAW interdigital transducers, unidirectional transducers and SAW filters are described. Also, new fabrication technologies which can achieve higher operating frequencies are presented.     

Development of a GaAs monolithic surface acoustic wave integratedcircuit

An oscillator technology using surface acoustic wave (SAW) delay lines integrated with GaAs MESFET electronics has been developed for GaAs-based integrated microsensor applications. The oscillator consists of a two-port SAW delay line in a feedback loop with a four-stage GaAs MESFET amplifier. Oscillators with frequencies of 470, 350, and 200 MHz have been designed and fabricated. This oscillator technology is most suitable for sensor applications but can logically be extended to radio-frequency oscillator and filter applications by methods well known for other piezoelectric substrates     

Tunable surface acoustic wave oscillators using magnetostrictive thin films

RF sputtered thin films of nickel deposited on YZ-LiNbO3have been used for magnetically tunable oscillators and delay lines. Velocity variations Δv/v of 7 × 10^-at 189 MHz were observed at magnetic fields of 110 Oe, a significant improvement over similar thermally evaporated films. Detailed experimental results are given for both variable delay lines and tunable oscillators.     

High frequency ZnO-SiO2-Si surface acoustic wave convolvers

The separate comb grating transducer configuration is used in the fabrication of high frequency convolvers in the metal-ZnO-SiO2-Si surface acoustic wave device structure. A Rayleigh convolver with an operating frequency of 285 MHz and a Sezawa convolver with an operating frequency of 355 MHz are reported.     

An all fiber-optic sensor for surface acoustic wave measurements

A surface acoustic wave (SAW) sensor constructed from single-mode fiber-optic components is described. An analysis of reciprocal and nonreciprocal modes of operation of the sensor is presented. Results from measurements on a variety of SAW devices illustrate the use of the sensor. The amplitude sensitivity is 0.0003 Å for an integration time of 0.1 s.     

LGS声表面波滤波器设计

本文设计了LGS声表面波滤波器（SAWF）,介绍其结构,计算了声表面波滤波器的频率响应特性,与石英进行比较。发现LGS声表面波滤波器比石英声表面波滤波器的插入损耗要小很多,是应用于小型化中频带宽滤波器的优选材料之一。     

On a surface wave amplifier for negative resistance devices

A traveling-wave negative resistance amplifier is proposed using a corrugated surface wave structure. A simple gain equation is derived based on a two-dimensional model. The proposed amplifier is simple to construct and is capable of high-power operation.