How does a Gunn diode work?

The diode is mounted inside the cavity (metal box), which functions as a resonator to determine the frequency. The negative resistance of the diode excites microwave oscillations in the cavity which radiate out the rectangular hole into a waveguide (not shown).

What is the meaning of Gunn diode?

Definition: Gunn diode is a transferred electronic device, which is composed of only one type of semiconductor i.e. N-type and utilizes the negative resistance characteristics to generate current at high frequencies. It is used to generate RF and microwave frequencies.

What is meant by Gunn effect?

Gunn effect, high-frequency oscillation of electrical current flowing through certain semiconducting solids. The effect is used in a solid-state device, the Gunn diode, to produce short radio waves called microwaves. When an electrical voltage is applied, all its electrons begin to move just as in ordinary conductors.

What are the characteristics of Gunn diode?

Gunn diodes are used to build oscillators for generating microwaves with frequencies ranging from 10 GHz to THz. It is a Negative Differential Resistance device – also called as transferred electron device oscillator – which is a tuned circuit consisting of Gunn diode with DC bias voltage applied to it.

Is Gunn diode a pn junction?

The Gunn diode is a unique component – even though it is called a diode, it does not contain a PN diode junction. The Gunn diode or transferred electron device can be termed a diode because it has two electrodes. However it is the Gunn diode oscillators are the most commonly used.

What is Gunn diode threshold voltage?

The threshold voltage corresponds to the value of 1.2 V. Such a current-voltage characteristic testifies upon the capability of the device being investigated to generate high-frequency …

What is Gunn effect and negative resistance?

The Gunn Effect In some materials (III-V compounds such as GaAs and InP), after an electric field in the material reaches a threshold level, the mobility of electrons decrease as the electric field is increased, thereby producing negative resistance.

What are the disadvantages of Gunn diode?

Gunn diode disadvantages

• Low efficiency below about 10 GHz.
• Poor stability – frequency varies with bias and temperature.
• FM noise high for some applications.
• Small tuning range.

How Gunn diode is different from IMPATT diode?

In the Gunn diode, the electric field remains almost constant throughout the active region and thus the integrated bias voltage is less than that of the IMPATT diode leading to higher power generation from the IMPATT than the Gunn diode. This shows that IMPATT diodes have better efficiency than Gunn diodes.

What are the main components of a Gunn oscillator?

A Gunn oscillator is comprised of two major components: (i) A DC bias and (ii) A tuning circuit.