Magnetrons are characterized by high power, high efficiency, low operating voltage, small size, light weight and low cost. The magnetron is mainly composed of five parts: cathode, anode, energy coupling device, magnetic circuit and tuning device (Figure 1). There is no tuning device in the fixed frequency magnetron.
Classification and Application
Magnetrons can be divided into pulse magnetrons and continuous wave magnetrons according to the working state; they can be divided into ordinary magnetrons, coaxial magnetrons and anti-coaxial magnetrons according to their structural characteristics; No, it can be divided into fixed frequency magnetron and frequency adjustable magnetron. Frequency-tunable magnetrons can be further divided into mechanically tuned magnetrons and frequency-agile magnetrons. There is also a class of voltage-tuned magnetrons that achieve frequency tuning by changing the anode voltage.
The working pulse width of the pulsed magnetron can be changed in the range of 0.004 to 60 microseconds, the operating frequency range is between 250 MHz and 120 GHz, the pulse power is from tens of watts to tens of megawatts, and the efficiency can reach 70%. The lifespan can reach tens of thousands of hours. Pulse magnetrons are widely used in various radars such as guidance, fire control, altimetry, airborne, shipborne, and meteorology.
Continuous wave magnetrons are used in electronic countermeasures, industrial heating and microwave physiotherapy. Inexpensive continuous wave magnetrons with powers between 400 and 1000 watts are also widely used in domestic microwave cookers. In order not to interfere with the normal operation of radar and communication equipment, the operating frequencies of magnetrons for medical, industrial heating and cooking are usually 915 ± 25 MHz and 2450 ± 50 MHz.
Frequency adjustable magnetron, especially frequency agile magnetron, can improve the anti-jamming ability of radar.
Continuous Wave Magnetron
Voltage-tuned magnetrons are often used as power sources for electronic countermeasures equipment, providing continuous wave power from a few watts to hundreds of watts. It has the advantages of fast tuning speed and good tuning linearity. The low-power voltage-tuned magnetron has a tuning range of 2:1, 4:1, and even 20:1, which can greatly improve the electronic countermeasures of various radars. Its main disadvantage is that the output power is not large enough to be used for electronic countermeasures against radar.