Attenuation measurement theory in microwave lab manual pdf

Fortunately, we do not need all the information that a fullwave electromagnetic analysis. The reflex klystron is a single cavity variable frequency microwave generator of low power and low efficiency. Pulse and digital circuits lab manual only for reference 1 pulse and digital circuits lab manual only for reference experiment no. Optic technicians manual, is one choice, but at a college level, a text with more theory, such as fiber optic communications by jim downing or jeff hechts understanding fiber optics several laboratory writeups suggested that the students do the experiment with more than one type of fiber.

It converts rf power at one frequency into power at another frequency to make signal processing easier and less expensive. The relative attenuation a at this setting is a 10 10glo 140 1. In physics, attenuation or, in some contexts, extinction is the gradual loss of flux intensity through a medium. Measurement of radiation patterns for basic microwave antennas like horn. Content beyond syllabi 1 time division multiplexing of 2band limited signals. Attenuation a db 10 log p1p2 where p1 power detected by the load without the attenuator in the line p2 power detected by the load with the attenuator in the line. Transmitter generates interme diate frequency which can be selected as one of the four different frequency separated channels, with frequency separation of 27 mhz. Department of electronics and communication engineering ec 2405 optical and microwave lab manual vii sem ece 1 prepared by m.

This handy web application can help you save both time and effort as you browse the web to find a particular manual. Attenuation measures the reduction in signal strength by comparing the output power with input power. Telecommunications microwave microwave fundamentals courseware sample 85756f0. The presence of reflected waves can lead to the wrong measurement information, consequently a wrong diagnostic result interpretation applied to a specific patient.

The basic measurement for loss is done by taking the logarithmic ratio of input power p i to the output power p o. Attenuation occurring as a result of either a bend in an optical fibre. The measurement environment at microwave frequencies is also unique. Compare the measurement graphs of the attenuation paragraphs 7 and9tothesimulationgraphsparagraphs2and4. Pulse and digital circuits lab manual only for reference. Microwave attenuation measurements and standards nist page.

Aug 07, 2017 attenuation in an optical fiber is a result of number of a effects. Laboratory measurement of dispersion and attenuation in the. Microwave engineering pdf notes mwe notes pdf smartzworld. The process is affected by an impedance transformer between the space and source, known as antenna. High attenuation measurement of step attenuators cal lab. This phenomenon is called acoustic attenuation and is.

The attenuation outside of the passband is increasing monotonically with frequency for c. Microwave attenuation measurements with accuracies from 0. In addition, you will measure the transmission loss attenuation for sm and mm fiber at three commonly used communications wavelengths, 850nm, 0nm and 1550nm. Termination of various lengths plastic optical fibers into a metallic, m, sta fiber optic connector for plastic fiber. In medical application vswr gets a specific importance. The velocity of the ultrasonic waves is influenced by the elastic moduli and the density of the material, which in turn are mainly governed by the amount of various phases present and the damage in the material. Also, you will verify the filtering process by applying the sum of two sinusoids at the input and measuring the attenuation caused by. Fixed attenuators are available for 3,6 or 10 db attenuation values, but any. In optical fiber communication system, electrical signal is first converted into. On the other hand, there are many parameters, like attenuation or reflection coefficient that are normally not used in the low frequency domain. Microwave frequency measurement uses harmonic mixing. Rf and microwave theory ebookpdfppt download microwave engineering full notes, pdf, ebook product and plant engineering lab manual full notes ebook free download pdf. This method is to compute the sparameters of high attenuation 80 db using the measured sparameters of lower attenuation microwave systems. Introduction to microwave theory and measurement, written by algie l.

Page 24 absolute amplitude in dbm relative amplitude in db relative frequency. By far the best power meter to put into your microwave test setup is the hewlett packard or agilent 438a dual power meter or keysight e4419b dual power meter for those of you with a more modern lab, since the. Theory of measurement one could make an attenuation measutement by measuring the microwave powers pi and p2 absorbed by the bolometer mount mi when the attenuator is set first on zero, then to some other setting. This means, for example, that measurement of power cannot be done by simply measuring voltage and current. Pdf nisttraceable microwave power measurement in a. The attenuator is a two port bidirectional device which attenuates some power when inserted into a transmission line. Attenuation loss or path propagation loss is the reduction in power density attenuation of an electromagnetic wave as it propagates through space. Original article design and implementation of microwave attenuation measurements to estimate the dry rubber content of natural rubber latex pattara aiyarak1 and piti sunheem2 1 department of computer science, 2 department of physics, faculty of science prince of. Ultrasonic wave propagation is influenced by the microstructure of the material through which it propagates. In engineering, attenuation is usually measured in units of decibels per unit length of medium dbcm, dbkm, etc. Microwave frequency can be measured by either electronic or.

By assuming direct proportionality of the total solids content and drc, the drc can be estimated from microwave attenuation. Determination of attenuation and penetration depth of. Design and implementation of microwave attenuation. For measurement of attenuation of fixed and variable attenuator place the test. To provide a resonant circuit at uhf and higher frequencies. The last three experiments deal with the characterization of some. In practice, microwave components and devices often provide some attenuation. Microwave waveguide attenuator waveguide attenuator.

Fundamentally, this high attenuation measurement method is based on the cascaded 2port network and sparameter theory. Laboratory measurement of dispersion and attenuation in the seismic frequency qi huang, dehua han, hui li, rock physics laboratory, university of houston summary we have continuously made progress in dispersion attenuation study in laboratory measurement. Fundamentals of rf and microwave power measurements. The schematic diagram of a reflex klystron tube is shown in fig. A microwave circulator is a multi port junction device where the power may flow.

The attenuator is a two port bidirectional device which attenuates some power. Measurement of standing wave distribution on a slotted line, with short circuit and open circuit termination. It is intended to develop your manual dexterity while teaching you the proper installation of an st connector on the ends of a plastic optical fiber. The laboratory testing method in the l band frequency range. A directional coupler is a device with which it is possible to measure the. To study loss and attenuation measurement of attenuator. Using a microwave propagation model for atmosphere and radiosonde data, we simulated the atmospheric attenuation measurements. Frequency standing wave measurements measurement of low and high vswr, cavity q. Choosing a backup generator plus 3 legal house connection options transfer switch and more duration. The laboratory scheme used for vswr measurement in. Description of microwave bench different blocks and their features, errors and precautions. We calibrated the lab low frequency measurement system for.

Measurement of high vswr by double minimum method list of equipment. The reflex klystron is an oscillator tube with built in feedback mechanism. Pdf microwave attenuation measurements in atmospheric. Central to all microwave measurements is the determination of the microwave power available at ports in the measurement circuit. Reflex klystron or gunn diode characteristics and basic microwave parameter measurement such as vswr, frequency, wavelength. Lance in 1964, has been the most popular course text. Experiment4 study of the characteristics of the klystron tube.

The microwave source, the isolator, the adjustable attenuator, the receiving antenna, the temperature sensor and the single chip microcomputer scm system are all selected and designed. In many cases, attenuation is an exponential function of the path length through the medium. The attenuation of microwaves in a lossy medium follows expo. Nine out of ten microwave engineers prefer decibels for power measurements, and you will too once you understand how to think in db. In view of the wide range of options on attenuation range and frequency band customers are requested to consult cfct, npl on the cost and details for calibrations requirements. The degree of attenuation depends on the wavelength of light transmitted. This whole setup, with few alternations, is able to measure many values like guide wavelength, free space wavelength, cutoff.

The rf and microwave lab requires very expensive equipment and software. Ec6712optical and microwave laboratory varuvan vadivelan. Sparameter measurement of the following microwave components. The amount of attenuation offered can be measured in two ways. Rittersdorf lab 4 geigermueller counting 1 abstract in this lab we used the geiger counter to take counts of di. Attenuation is the ratio of input power to the output power and is normally expressed in decibels. The attenuators are basically passive devices which control power levels in microwave system by absorpsion of the signal. The mixer is a critical component in the instrumentation of antenna measurements. The basic characteristics of an antenna are expressed in terms of field pattern, directivity, bandwidth and gain. Prediction of rain attenuation and impact of rain in wave. For example at 5 ghz, the transmitted power might be one megawatt and the attenuation only 4 db100 m. From these counts, we observed the pulse height against the ionization type and energy, pulse height and counting curve against high voltage, beta attenuation coe. This also measures the als in microwave loss tangent of materi frequency band. Power and attenuation measurements 68 steps to perform when starting the swr meter of lvdam.

S parameter measurement of the following microwave components isolator. Microwave devices and circuits, third edition, edition, samuel y. This is a great resource for people who tend to misplace important documents, especially those that dont see much use. Among the microwave measurement devices, a setup of microwave bench, which consists of microwave devices has a prominent place. The measurement of microwave attenuation is a rather complex sub ject about. To study the substitution method for measurement of attenuation and hence. Beatty january 15, 1060 the appli cation of certain power stabili zation and measurement techniques to t he problem of attenuation measurement has yielded a measurement system with a stability. Klystron is a microwave vacuum tube employing velocity modulation. Attenuation loss is a major component in the analysis and design of the link budget of a telecommunication system. To measure attenuation and insertion loss of a fixed and variable attenuator. Reexamination of mismatch uncertainty when measuring. Attenuation measurements over the frequency range 30 mhz to 18 ghz are based on an if substitution system using 30mhz attenuator and signal calibrator. Theory in microwave communications, the transmission and reception of microwave power tofrom space, is a primary necessity. The measurement frequency is downconverted to 30 mhz, at which it is traceable to primary standard of npli.

Measurement of scattering parameters of a circulators. We will confine our studies to measurement of attenuation in two fiber cables cable 1m and cable2 5m employing an smasma in line adopter. In chemical spectroscopy, this is known as the beerlambert law. Power meters are used for a wide variety of measurement tasks. Study on a moisture measurement method based on microwave. Nisttraceable microwave power measurement in a waveguide calorimeter with correlated uncertainties article pdf available in ieee transactions on instrumentation and measurement pp99. The new results confirm the original method of calculation for simple power measurement comparison 2, 3. It can be seen from figure 1 that for higher orders, the attenuation outside the passband is higher, which means that the. Introduction, microwave spectrum and bands, applications of microwaves. The rate of the increasing of the insertion loss out side the passband is 20ndbdecade. Rectangular waveguides solution of wave equations in rectangular coordinates. The most classical approach of determining rain attenuation for radiowave frequency has been to theoretically determine the specific attenuation. To familiarize with the measurement technique using slotted line.

Measurement and calibration capabilities for microwave attenuation. The first three involve basic microwave measurement techniques for power, frequency, wavelength, standing wave ratio, impedance, and s parameters. These simple experiments are intended to give you practice in basic fiber preparation and measurement. A cylinder or rod of transparent material forming a core surrounded by an external cladding with a slightly different material. Attenuator which attenuates the rf signal in a waveguide system is referred as waveguide attenuator. Updated jan, 2011 spectrum analyzer based measurements groups of 2 may omit part 2. Telecommunications microwave microwave fundamentals. Theory reflex klystron is one of the most commonly used microwave low power generators. Tegams attenuation measurement system model 14 is suitable for national metrology institutes, primary standards laboratories or anyone seeking to calibrate artifacts for use by secondary laboratories. To determine the standingwave ratio and reflection coefficient. A moisture measurement method based on microwave attenuation has been proposed. Microwave attenuation national physical laboratory. At frequency over 10 ghz, rain and precipitation can influence the attenuation a lot. This whole setup, with few alternations, is able to measure many values like guide wavelength, free space wavelength, cutoff wavelength, impedance, frequency, vswr, klystron characteristics, gunn diode characteristics, power measurements, etc.

In situations where there are significant budgetary constraints, our students can benefit from new budgetpriced rf and microwave measurement equipment and from instrumentation developed as part of senior projects. The meter itself can be calibrated in terms of vswr iii. Measurement of the dielectric constant and loss tangent of materials in microwave frequency band. There are a total of six laboratory experiments described in this manual. Laser propagation in dielectric capillaries is understood quite well 20,21, and experimental observations agree with the theory,22. For instance, dark glasses attenuate sunlight, lead attenuates xrays, and water and air attenuate both light and sound at variable attenuation rates hearing protectors help reduce acoustic flux from flowing into the ears. Basically, here we perform comparison of the responses of empty cavity and the cavity filled with sample material. Attenuation measurement in fibers microwave experiments 1. The principles of the method were analyzed theoretically and the structure of the moisture measurement instrument was designed. For example, attenuation measurement of the component parts of a radar system will enable a designer to calculate the power delivered to the antenna. Crp718 rf and microwave measurements laboratory experiment mw2 handout. The following safety and common symbols may be used in this manual and on the equipment. This experiment is designed to familiarize the user with oft. Measurement of scattering parameter of a magic tee.