The zener diode is a diode designed to operate in the breakdown region and have a specific negative voltage called the zener voltage. Rwh proposed this theory to explain the phenomenon of ve differential resistance ndr in certain bulk materials. View test prep microwave lab report final from general kn 238 at university of washington. A tunnel diode is a heavily doped pn junction diode in which the electric current decreases as the voltage increases. The lead connected to the ptype material is called the anode and the lead connected to the ntype material is the cathode. The cv characteristics of a typical varactor diode and its symbols are shown in the following figure. Matched termination xl400 ii description of equipment. In the reverse, when we reverse bias the diode the depletion. 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. In tunnel diode, electric current is caused by tunneling. The diodes are classified into different types based on their working principles and characteristics. This diode is a negative differential resistance device, which is frequently used as a lowpowe.
Palankovski advanced material and device analysis group inst. 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. Three important characteristics of a diode are, first of all, the forward voltage drop. 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. After certain level of voltage the current will exponentially decrease thus this exhibits the negative differential resistance. Output power and frequency as a function of voltage. New techniques for the study of gunn diode contacts. The gunn effect can occur only in selected types of semiconductors from groups as a3b5 and a2b6. Block diagram matched termination xl 400 gunn power supply gunn oscillator xg 11. In general, the cathode of a diode is marked by a solid line on the diode. Under a forward bias condition, this should be about. The effect of gross damage caused by heating diode pv148a1 is illustrated in fig. 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.
Finally, we will use the gunn diode as an rf source to study the basic operation of a microwave. 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. Gunn diode mounting precautions the gunn diode is a powergenerating device with a relatively low efficiency about 25%. A gunn diode is a semiconductor device formed by only ntype material. Tunnel diode basics, operation, vi characteristics. V i gaas sample iv characteristic in gunn experiments ntype gaas metal metal 5v. Microwave lab report final microwave lab report on study of. 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 depletion region of two ntype materials is very thin. 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. Diode characteristics diode and diode circuits diodes and. Ntype and utilizes the negative resistance characteristics to generate current at high frequencies. Gunn as a first person has observed that in the wafers of gallium arsenide with a very small.
It has negative resistance property by which gunn diode act as oscillator. In this article you will get to know about the working, characteristic curvce, advantages, disadvantages and applications of gunn diode. Gunn diode basics gunn diode applications,advantages. Gunn diode is a transferred electronic device, which is composed of only one type of semiconductor i. The present work specifies the design and construction of a gunn diode oscillator at x band 8. Explain the significance of rwh model and two valley model in. The tunnel diode is used as a very fast switching device in computers. The layers are processed using proprietary techniques resulting in ultralow phase noise and 1f noise. It is our interest to evaluate the transittime and current density of a gunn diode operating in the transittime mode. The diode is a device formed from a junction of ntype and ptype semiconductor material. Gunn diode is fabricated with ntype semiconductor material only. Tunnel diode definition, symbol, and working diode. Gunn diodes can be made from the materials which consist of multiple, initiallyempty, closelyspaced energy valleys in.
Gunn diode acts as oscillator and has negative differential region which helps it to act as microwave source. Recent listings manufacturer directory get instant insight into any electronic component. The controllable negative resistance properties of a gunn diode allows it to be used as a microwave oscillator, and these devices are often used in microwave communications. This is the only case new techniques for the study of gunn diode contacts table 4. Microwave lab report final microwave lab report on. Explain the significance of rwh model and two valley model in gunn diode. We will measure the vi characteristics of the diode and its output power using a power meter and a spectrum analyzer. Gunn diode transistor diode free 30day trial scribd. 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. Studies on the characteristics of ganbased gunn diode for. The current is allowed to move through the diode in one direction only.
A diodes iv characteristic is shown in figure 6 below. Gunn diode is one of the many microwave semiconductor devices in use today. This page covers gunn diode basics and its applications. Gunn diodes can be made from the materials which consist of multiple, initiallyempty, closelyspaced energy valleys in their conduction band like gallium arsenide. Gunn diodes jordan university of science and technology. Block diagram gunn oscillator xg 11 matched termination xl 400 xll isolator xi 621 pin. A voltage variable capacitance of a reverse biased junction can be termed as a varactor diode. Gunn diode free download as powerpoint presentation. The tunnel diode was first introduced by leo esaki in 1958. A diode is simply a pn junction, but its applications are extensive in electronic circuits. It is based on the gunn effect discovered in 1962 by physicist j. The result of damaging metal contacted diodes was in all cases to change the characteristics towards typea see table 4.
The currentvoltage relationship characteristics of a gunn diode are shown in the above graph with its negative resistance region. Equipments gunn oscillator, gunn power supply, pin modulator, isolator, frequency meter, variable attenuator, detector mount, waveguide stands, swr meter, cables and. 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. Their main feature is the specific arrangement of energy bands. This diode is also called as a transferred electronic device. Equipments gunn oscillator, gunn power supply, pin modulator, isolator, frequency meter, variable attenuator, detector mount, waveguide stands, swr meter, cables and accessories.
Voltagecurrent characteristics turn the meter switch of gunn power supply to voltage position. As shown in the above graph, initially the current starts increasing in this diode, but after reaching a certain voltage level at a. 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. Gunn diode mode of operation parameter map 0 s o d v nl q. The gunn device will be damaged if the supply is reversed. That is why gunn diodes cannot be used for rectifying alternating current. 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.
To study the characteristics of gunn diode and to determine the threshold voltage. To achieve this capacitance and shunt load resistance need to be tuned but not greater than negative resistance. 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. These characteristics are similar to the characteristics of the tunnel diode. As shown in the above graph, initially the current starts increasing in this diode.
In the case of the gunn diode, the gunn effect will be explained in the form of gaas material. 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. Comparative study and investigation of least mse of v. The most common materials used in their manufacturing. Gunn diode tips definition, characteristic and applications. Measure the gunn diode current corresponding to the various voltage controlled by gunn bias knob through the panel meter and meter switch. Gunn oscilator, gunn power supply, pin modulator, isolator, frequency meter, variable attenuator, detector mount.
A diode is the one way sign for electrical circuits. Overview microsemis gaas gunn diodes are fabricated from epitaxial layers grown at microsemi by the vapor phase epitaxy technique. It is used to generate rf and microwave frequencies. 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. It is also termed as a transferred electron device.
Experiment5 study of iv characteristics of gunn diodes. Gunn diode with notch doping modified version of 1. I characteristics of gunn diode using neuro solution mr. Because of the way this element was built, gunn diode is more often called ted transferred electron device. Pdf studies on the characteristics of ganbased gunn diode. 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. Explain the significance of rwh model and two valley model. 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. When voltage increases in the circuit the current also increases. Study of iv characteristics of gunn diodes objectives 1. What is a gunn diode a gunn diode is a microwave semiconductor diode designed to work in devices having microwave frequencies. The gunn diode operating principle is based on the socalled gunn effect from the name of its inventor. We will study the characteristics of a gunn diode oscillator and make power and frequency measurements. Pin diode acts as modulator and is used alongwith gunn for square wave modulation.