Minuscule devices, called RFID tags are attached to objects and persons and emit information which positioned readers may capture wirelessly. Many methods of identification have been used, but that of most common is to use a unique serial number for identification of person or object. RFID tags can be characterized as either active or passive [1,2]. Traditional passive tags are typically in “sleep” state until awakened by the reader’s emitted field. In passive tags, the reader’s field acts to charge the capacitor that powers the badge and this can be a combination of antenna and barcodes obtained with SAW( Surface Acoustic Wave) devices [1,2,3] . The antenna in an RFID tag is a conductive element that permits the tag to exchange data with the reader. The paper contribution are targeted to antenna for passive RFID tags. The electromagnetic field generated by the reader is somehow oriented by the reader antenna and power is induced in the tag only if the orientation of the tag antenna is appropriate. A tag placed orthogonal to the reader yield field will not be read. This is the reason that guided manufacturers to build circular polarized antenna capable of propagating a field that is alternatively polarized on all planes passing on the diffusion axis. Passive RFID tags are operated at the UHF frequencies of 868MHz (Europe) and 915MHz (USA) and at the microwave frequencies of 2,45 GHz and 5,8 GHz . Because the tags are small dimensions, in paper, we present the possibility to use circular polarization microstrip antenna with fractal edge .
At long ranges and under low visibility conditions, Advanced Optoelectronic Device provides the signal-to-noise ratio and image quality in the Short-wave Infra-red – SWIR (wavelengths between 1,1 ÷2,5 μm), significantly better than in the near wave infrared – NWIR and visible spectral bands [1,2]. The quality of image is nearly independent of the polarization in the incoming light, but it is influenced by the relative movement between the optical system and the observer (the operators' handshake), and the movement towards the support system (land and air vehicles). All these make it difficult to detect objectives observation in real time.
This paper presents some systems enhance which the ability of observation and sighting through the optical systems without the use of the stands, tripods or other means. We have to eliminate the effect of "tremors of the hands" and the vibration in order to allow the use of optical devices by operators on the moving vehicles on land, on aircraft, or on boats, and to provide additional comfort for the user to track the moving object through the optical system, without losing the control in the process of detection and tracking. The practical applications of stabilization image process, in SWIR, are the most advanced part of the optical observation systems available worldwide [3,4,5]. This application has a didactic nature, because it ensures understanding by the students about image stabilization and their participation in research.
Optoelectronics is facing with an ever dynamic increasing in our lives. We feel a growing demand for specialists in design and operation of optoelectronic systems. In accord with this demand Politehnica University of Bucharest (PUB) has introduced optoelectronics curricula since 1992 year. The theoretical courses are covered by laboratory activities, to provide the students with actual experience of optoelectronic systems. Some experiments are presented in this paper. To get a good efficiency of experiments, the student should study Laboratory guide manual, before entering the laboratory. PUB in collaboration with SPIE organization is intending to develop an integrated optoelectronics laboratory for education ofoptoelectronics specialization students with the following principles: define the educational goals and experimental laboratory courses to fulfill the objectives, design the instrumentation and systems to enable practical, experimental investigation and measurements; elaboration of experimental algorithms and laboratory guide for students, which include exercises and problems with responses connected with real world of optoelectronics specialists demand. This paper focuses on the presentation of laboratory courses that would be developed a meaningful understanding of optoelectronic devices, and systems.
The demand for high-frequency low-loss surface acoustic wave - SAW - filters for telecommunications and remote
sensing has led to extensive research focusing on new SAW microdevices. SAW devices have been the subject of
increasing interest since 1960 till present and the applicability of optical measurement techniques to detection of SAWs
were published in the late 1960s. As a consequence, many types of both constructive and operating characterization
methods have been developed. The paper provides a short introduction regarding the developed level of SAW microdevices.
Some optoelectronic techniques used for constructive characterization of SAW micro-devices are reviewed.
Three optoelectronic measurement techniques are known for detection of surface acoustic waves: diffraction grating
technique, the knife-edge technique, and the detection of ultrasonic vibrations using optical interferometry. We describe
the results of literature investigation research of optoelectronic techniques for constructive characterization of SAW
microdevices. The research work given in this paper concentrates on describing of optoelectronic techniques used for
constructive characterization of SAW microdevices. Samples of SAW quartz filters were measured. The input and
output inter digital transducers (IDTs) contain 22 paired electrodes which were photolithographed on the quartz
substrates (20mm x 18mm x 0.5mm). The space between electrodes of measured channel was 11.25 μm. Finally, we try
to draw some conclusions where: optoelectronics tchniques are predicted to be the fundamental measurement methods
for measurement of future SAW microdevices.
Surface Acoustic Wave sensors - SAW have been recognized for their efficiency and versatility in the electrical signals processing. The majority of results reported till the present, regarding SAW sensors, have been used Rayleigh SAW, on the principle of delay line. Reflexive delay line can be used for passive sensing and remote control. In the paper is presented a short introduction regarding the actual level of SAW devices development and their applications. A comparative study in connection with diversity of piezoelectric materials used for SAW devices manufacturing, (Quartz, LiNbO3, LGS with emphasis on GaPO4) evidence the advantages of GaPO4. The development directions of SAW sensor devices are shown: telecommunication, RFID SAW systems, SAW devices for remote monitoring, SAW sensors for early cancer diagnostics. Some applications of SAW sensor devices with GAPO4 are presented in the directions: remote monitoring and identification of gas. Some conclusions regarding trends in the development of SAW sensor devices are presented in the end of the work.
Stationary Fizeau fringes, phase shift interferometric fringes, fringes obtained in Murty lateral shear interferometry, vibration interference pattern as seen by digital speckle pattern interferometer all are digitally captured in specific interferometer set- ups. IntelliWave software produced by Engineering Synthesis Design, Inc. (ESDI) is used to process the fringe patterns. For all these fringe patterns the physical principle and set up for obtaining them are described. This could be a resume for student and young researcher guiding in experimental interferometry.
Spectroscopy is one of the most important tools for studying the structures of atoms and molecules. Paper underlines the procedures required for the determination of metal contents in tobacco samples. Sampling procedures, sample preparation, and atomic absorption instrumentation requirements are presented. Particular attention is given to the determination of metals as Pb, Cr, Li, Cu, Au, Co using atomic absorption spectroscopy. A dual-beam Atomic Absorption Spectrophotometer was used for the measurements. The concentration of these metals in five different tobacco samples is given.
In this paper we are going to present some results regarding the optical trapping and manipulation of dielectric
microparticles immersed in fluids. The experiments will be done in Mie regime, i.e diameter of the particles is larger
than the laser wavelength. We will report optical trapping of multiple particles and their manipulation by means of
optical tweezers setup. To catch microobjects we will use a Gaussian laser beam and to manipulate them we are going to
calculate diffractive optical elements (DOEs) by iterative algorithm and spherical wave method.
In so rapidly growing sensing technology, Autonomous Surface Acoustic Waves (SAW) based sensors, offer high
flexibility for modern identification/sensing systems, and represent a new perspective for remote monitoring and
control. This paper gives a presentation of operating principles of wireless SAW sensors with separation in
frequency (frequency domain division-FDD) and separation in time (time domain division-TDD). The design of
interdigitated transducers (IDT), and reflectors on the different types of substrate materials as piezo crystals LiNbO3,
LiTaO3 or quartz in connection with application domains is presented. A comparison between Time Domain
Sampling-TDS and Frequency Domain Sampling-FDS principles of transmitter and receiver, gives evidence of their
advantages and disadvantages. A part of the paper dealt with the measurement results.
Between other sensing and identification technologies that of Surface Acoustic Waves, (SAW), is a unique sensing
system. The principal advantage to most SAW systems is that they can use two or three SAW sensors and compare the
measurements between them, providing a good accuracy. We have carried out the design of both piezoelectric substrate
and interdigital transducers, (IDTs), and has tested them in a delay line mode operation. The measurement of changes in
the surface waves characteristics were materialized by applying of a radio frequency electric field to the piezoelectric
crystal by means of IDTs. The finger width of the IDTs was measured by high accuracy optical coherent method. The
results are presented in the work. The potential development of microsensors as an array of four or five miniature
sensors, sensitive to Werent chemicals may be used as mobile chemical detecting units carried by remote control
vehicles to the site chemical contamination.
In this paper we analyze the electromagnetic modes in photonic crystals. This is important because of the wide range of potential applications of structures which allow a complete control over light propagating in them. We focus to study the fundamental behavior of one- and two-dimensional photonic crystals, which are easier to investigate than three-dimensional structures. We will study the photonic band structure in the TM modes (E-polarization) and in the TE modes (H-polarization).