The lead connected to the ptype material is called the anode and the lead connected to the ntype material is the cathode. Piv is the peakinversevoltage of the diode forward bias occurs when the ptype block is connected to the positive terminal of the battery and the ntype is connected to the negative terminal of the battery, as shown below. This page covers gunn diode basics and its applications. Gunn diode free download as powerpoint presentation. Gunn diode is one of the many microwave semiconductor devices in use today. Finally, we will use the gunn diode as an rf source to study the basic operation of a microwave. Gunn diode mode of operation parameter map 0 s o d v nl q. Output power and frequency as a function of voltage. A voltage variable capacitance of a reverse biased junction can be termed as a varactor diode. These characteristics are similar to the characteristics of the tunnel diode.
In certain semiconductors, notably gaas, electrons can exist in a highmass low velocity state as well as their normal lowmass highvelocity state and they can be forced into the highmass state by a steady electric field of sufficient strength. It is also termed as a transferred electron device. The gunn diode operation depends on the fact that it has a voltage controlled negative resistance this being dependent upon the fact that when a voltage is placed across the device, most of the voltage appears across the inner active region. The most common materials used in their manufacturing. The tunnel diode is used as a very fast switching device in computers.
To achieve this capacitance and shunt load resistance need to be tuned but not greater than negative resistance. A tunnel diode is a heavily doped pn junction diode in which the electric current decreases as the voltage increases. Gunn diode or ted transferredelectron device type of the semiconductor or vacuum form of diode, which is designed to operate in the range of microwave frequencies from single ghz to single thz. Microwave frequencies are electromagnetic radiation of tremendously high frequencies thf, maximum working frequency up to 3 thz, this depends on the material used in its structure. Microwave lab report final microwave lab report on. The layers are processed using proprietary techniques resulting in ultralow phase noise and 1f noise. Gunn diode with notch doping modified version of 1. Its characteristics are completely different from the pn junction diode. Gunn diode works as an oscillator f 0 1t d gunn diode operates in the limited space charge accumulation lsa mode no domains are formed. Rwh proposed this theory to explain the phenomenon of ve differential resistance ndr in certain bulk materials. These include generic diode, schotty diode, shockley diode, constantcurrent diode, zener diode, light emitting diode, photodiode, tunnel diode, varactor, vacuum tube, laser diode, pin diode, peltier diode, gunn diode, and so on.
Studies on the characteristics of ganbased gunn diode for. This is the only case new techniques for the study of gunn diode contacts table 4. A gunn diode is considered as a type of diode even though it does not contain any typical pn diode junction like the other diodes, but it consists of two electrodes. It can be observed the structure designed demonstrate the diameter is become wider when the diameter used is added up to 1micron to the left side and right side. In the reverse, when we reverse bias the diode the depletion. It has negative resistance property by which gunn diode act as oscillator. Gunn as a first person has observed that in the wafers of gallium arsenide with a very small. Because of the way this element was built, gunn diode is more often called ted transferred electron device. Recent listings manufacturer directory get instant insight into any electronic component. Gunn diodes jordan university of science and technology.
Matched termination xl400 ii description of equipment. Pdf studies on the characteristics of ganbased gunn diode. Gunn diodes can be made from the materials which consist of multiple, initiallyempty, closelyspaced energy valleys in. In this article you will get to know about the working, characteristic curvce, advantages, disadvantages and applications of gunn diode. We will measure the vi characteristics of the diode and its output power using a power meter and a spectrum analyzer. Gunn diodes can be made from the materials which consist of multiple, initiallyempty, closelyspaced energy valleys in their conduction band like gallium arsenide. V i gaas sample iv characteristic in gunn experiments ntype gaas metal metal 5v. Gunn oscilator, gunn power supply, pin modulator, isolator, frequency meter, variable attenuator, detector mount. This diode is also called as a transferred electronic device. Comparative study and investigation of least mse of v. Explain the significance of rwh model and two valley model in gunn diode. Gunn diode basics gunn diode applications,advantages. Tunnel diode definition, symbol, and working diode.
The diode is a device formed from a junction of ntype and ptype semiconductor material. A diode is the one way sign for electrical circuits. It is based on the gunn effect discovered in 1962 by physicist j. Explain the significance of rwh model and two valley model in. The zener diode is a diode designed to operate in the breakdown region and have a specific negative voltage called the zener voltage. Gunn diode transistor diode free 30day trial scribd. The gunn device will be damaged if the supply is reversed. The current is allowed to move through the diode in one direction only. As shown in the above graph, initially the current starts increasing in this diode. The cv characteristics of a typical varactor diode and its symbols are shown in the following figure. The diodes are classified into different types based on their working principles and characteristics. Gunn diode mounting precautions the gunn diode is a powergenerating device with a relatively low efficiency about 25%.
After certain level of voltage the current will exponentially decrease thus this exhibits the negative differential resistance. We will study the characteristics of a gunn diode oscillator and make power and frequency measurements. It is used to generate rf and microwave frequencies. Equipments gunn oscillator, gunn power supply, pin modulator, isolator, frequency meter, variable attenuator, detector mount, waveguide stands, swr meter, cables and accessories. The gunn effect can occur only in selected types of semiconductors from groups as a3b5 and a2b6. Gunndiode is mainly used as a local oscillator covering the microwave frequency range of 1 to 100ghz by means of the transferred electron mechanism, the negative resistance. Under a forward bias condition, this should be about. Each diode has a positive end, the anode, and a negative end, the. The result of damaging metal contacted diodes was in all cases to change the characteristics towards typea see table 4.
A tunnel diode is a special type of pn junction diode that shows the negative resistance between two values of forward voltage ie, between peak point voltage and valley point voltage. Block diagram matched termination xl 400 gunn power supply gunn oscillator xg 11. Diode characteristics diode and diode circuits diodes and. Gunn diode is fabricated with ntype semiconductor material only. Equipments gunn oscillator, gunn power supply, pin modulator, isolator, frequency meter, variable attenuator, detector mount, waveguide stands, swr meter, cables and. Their main feature is the specific arrangement of energy bands. A diodes iv characteristic is shown in figure 6 below. Gunn diode is a transferred electronic device, which is composed of only one type of semiconductor i. Gunn diode tips definition, characteristic and applications.
To study the characteristics of gunn diode and to determine the threshold voltage. Voltagecurrent characteristics turn the meter switch of gunn power supply to voltage position. What is a gunn diode a gunn diode is a microwave semiconductor diode designed to work in devices having microwave frequencies. To evaluate the gunn oscillation theoretically, it is necessary to incorporate their highfield transport characteristics in analytical models, or the use of some sort of simulations like monte carlo. The currentvoltage relationship characteristics of a gunn diode are shown in the above graph with its negative resistance region.
Explain the significance of rwh model and two valley model. I characteristics of gunn diode using neuro solution mr. Rs8960 308017 rs metal detector using 555 timer diagram of gunn diode gunn diode at power supply circuit 747 opamp gunn diode radar module gunn diode x band amplifier gunn diode radar text. Although mdt gunn diodes are designed with longterm reliability in mind with an mttf in excess of 10 6 hours at an active region temperature of 260c with rugged. That is why gunn diodes cannot be used for rectifying alternating current. Palankovski advanced material and device analysis group inst.
In the case of the gunn diode, the gunn effect will be explained in the form of gaas material. Measure the gunn diode current corresponding to the various voltage controlled by gunn bias knob through the panel meter and meter switch. It is our interest to evaluate the transittime and current density of a gunn diode operating in the transittime mode. A diode is simply a pn junction, but its applications are extensive in electronic circuits. Block diagram gunn oscillator xg 11 matched termination xl 400 xll isolator xi 621 pin. The present work specifies the design and construction of a gunn diode oscillator at x band 8. A gunn diode is a passive semiconductor device with two terminals, which composes of only an ndoped semiconductor material, unlike other diodes which consist of a pn junction. Experiment5 study of iv characteristics of gunn diodes.
It is also used in highfrequency oscillators and amplifiers. Dec 16, 2017 a tunnel diode is a special type of pn junction diode that shows the negative resistance between two values of forward voltage ie, between peak point voltage and valley point voltage. The tunnel diode was first introduced by leo esaki in 1958. Varactor diode is a semiconductor device in which the junction capacitance can be varied as a function of the reverse bias of the diode. A gunn diode, though very unlike other common semiconductor diodes, is a transferred electron device ted that presents a negative resistance after its threshold voltage is adequately exceeded. Microwave lab report final microwave lab report on study of. The depletion region of two ntype materials is very thin. A gunn diode, also known as a transferred electron device ted, is a form of diode, a twoterminal semiconductor electronic component, with negative resistance, used in highfrequency electronics. Gunn diode acts as oscillator and has negative differential region which helps it to act as microwave source. Tunnel diode basics, operation, vi characteristics. In general, the cathode of a diode is marked by a solid line on the diode.
Pin diode acts as modulator and is used alongwith gunn for square wave modulation. Mar 02, 2020 a gunn diode is a passive semiconductor device with two terminals, which composes of only an ndoped semiconductor material, unlike other diodes which consist of a pn junction. Introduction to gunn diode oscillators pasternack blog. The effect of gross damage caused by heating diode pv148a1 is illustrated in fig. A gunn diode is a semiconductor device formed by only ntype material. A new model is developed to study the microwavemm wave characteristics of twoterminal ganbased transfer electron devices teds, namely a gunn diode and an impact avalanche transit time impatt. The gunn diode or transferred electron device can be termed a diode because it has two electrodes. When voltage increases in the circuit the current also increases. Overview microsemis gaas gunn diodes are fabricated from epitaxial layers grown at microsemi by the vapor phase epitaxy technique. New techniques for the study of gunn diode contacts. In tunnel diode, electric current is caused by tunneling. Ntype and utilizes the negative resistance characteristics to generate current at high frequencies. The gunn diode in certain semiconductors, notably gaas, electrons can exist in a highmass low velocity state as well.
117 311 628 399 1274 1299 372 247 428 339 1467 1342 149 815 1522 165 1243 594 788 1274 1299 1223 108 284 1457 747 666 79 434 1343 597 1223 94 435 658 322 789 482 1305 1056 101 621