Category: Microwave Tubes and Circuits

Crossed Field Amplifier

Crossed Field Amplifier: The Crossed Field Amplifier is a microwave power amplifier based on the magnetron and looking very much like it. It is a cross between the TWT and the magnetron in its operation. It uses an essentially magnetron structure to provide an interaction between crossed dc electric and magnetic fields and an RF […]

Types of Travelling Wave Tubes

Types of Travelling Wave Tubes: The TWT is the most versatile and most frequently used microwave tube. Four Types of Travelling Wave Tubes, each with particular applications and performance requirements. These are now described. TWT Types: The most fruitful method of categorizing traveling-wave tubes seems to be according to size, power levels and type of […]

Traveling Wave Tube Working

Traveling Wave Tube Working(TWT): Like the multicavity klystron, the Traveling Wave Tube Working is a linear-beam tube used as a microwave amplifier. Unlike the klystron, however, it is a device in which the interaction between the beam and the RF field is continuous. The TWT was invented independently by Kompfner in Britain and then Pierce […]

Types of Magnetron

Types of Magnetron: The Various Types of Magnetron are 20-kW Conventional Metal Ceramic Magnetron 5-MW Long Anode Coaxial Magnetron Frequency agile or Dither tuned Magnetron Voltage Tunable Magnetron The Magnetron, perhaps more than any other microwave tube, lends itself to a variety of types, designs and arrangements. Magnetrons using hole-¬≠and-slot, vane and rising-sun cavities have […]

Cavity Magnetron Working

Cavity Magnetron Working: The Cavity Magnetron Working, which will be referred to as the magnetron, is a diode, usually of cylindrical construction. It employs a radial electric field, an axial magnetic field and an anode structure with permanent cavities. As shown in Figure 11-10, the cylindrical cathode is surrounded by the anode with cavities, and […]

Reflex Klystron Oscillator

Reflex Klystron Oscillator: It is possible to produce oscillations in a klystron device which has only one cavity, through which electrons pass twice. This is the Reflex Klystron Oscillator, which will now be described. The Reflex Klystron Oscillator is a low-power, low-efficiency microwave oscillator, illustrated schematically in Figure 11-8. It has an electron gun similar […]

Multicavity Klystron

Multicavity Klystron: The design of the multicavity klystron, together with all the remaining tubes described here, relies on the fact that transit time will sooner or later terminate the usefulness of any orthodox tube. They therefore use the transit time, instead of fighting it. The Multicavity Klystron was invented just before World War II by […]

Planar Triode Construction

Planar Triode Construction: Planar Triode Construction – A short transit time is essential if grid loss and noise are to be minimized, as is the reduction of internal capacitances and inductances. Also, since coaxial resonant lines and cavities are used as tuned circuits at these frequencies, tubes should be built so as to connect to […]

Triode Equivalent Circuit

Triode Equivalent Circuit: Triode Equivalent Circuit – As frequency is raised, vacuum tubes suffer from two general kinds of problems. The first is concerned with interelectrode capacitances and inductances, and the second is caused by the finite time that electrons take to travel from one electrode to another in a tube. Noise tends to increase […]