Design Support

Components for Radar and Linac

Microwave electron tubes

About Electron Tube

An electron tube is a device that can be used in many critical applications by controlling the electron flow in a vacuum using electric and magnetic fields. These devices have been utilized for rectification of AC to DC and RF oscillation and amplification of the signal and power source. Electron tubes have inherit advantages over semiconductor devices, especially when install into high power and high frequency operating applications. These advantages occurs due to a very low transmission loss in the vacuum which, reduces the overheat problem caused by the high dielectric loss in the semiconductors.

Microwave electron tube

Some electron tubes are known as a microwave tubes or more commonly referred to as; "Magnetrons", "Klystrons", "Traveling Wave Tubes", and "Gyrotrons". These devices are especially useful when utilized in microwave and mili-meter wave applications. Applications are such as a microwave oven, radar systems and Linac / X ray systems, including cancer treatment, non-destructive testing system, and cargo scanning system. These are perfect examples of applications where microwave tubes are more beneficial.

Marine magnetron 4kW
Linac magnetron 3.1MW

Marine Radar Equipment

What is Marine Radar?

Marine radar is equipment required on most sea going vessels which transmits radio waves (microwaves) and receives a reflected signals from an objects such other vessels at sea. This allows the equipment to determine their direction and distance of the object. The use of radio waves allows the radar to operate during adverse weather conditions such as rain, fog and at night, enabling it to play a vital role in ensuring safe ship navigation.

Marine radar device
Marine radar devices on a ship

Suppressing unwanted emissions from marine radar equipment

Unwanted emission regulations

In recent years, many applications are requiring an increasing number of radio wave channels has required the ITU (International Telecommunication Union) to regulate emission levels closely to avoid interference from unwanted emissions of radio waves transmission. This is also true in radar allocated bandwidth.


Nisshinbo Micro Devices Inc. has researched and developed a technical design to suppress unwanted emissions from magnetrons. This technology is used in most currently manufactured marine radar to assist the manufacturer in meeting the latest ITU regulation a 40 dB/decade mask. This ITU requirement is based on the future “Design objective” in the ITU recommendation ITU-R SM.1541. Our technology of frequency spectrum band narrowing has been termed asimage.

Please see “Technical Information Advantage of V9 Technology”.

Technical references of V9 Technology has been published in IEEE paper, which link is below.

Measurement Method of Unwanted Emission Levels

This measurement method is specified in ITU-R M-1177. The level of unwanted emission is affected not only by the magnetron’s emission but also by the waveform of the modulator. Nisshinbo Micro Devices Inc. can technically advise how to reduce unwanted emission levels by analyzing each customers’ anode voltage and current waveforms and output spectrum from radar set.