Development overview of 1.85mm connector in RF power amplifier(1)

Microwave power amplifiers are mainly divided into two forms: vacuum and solid state. The coaxial 1.85mm connector power amplifier based on vacuum devices has played an important role in the development history of military equipment, and due to its advantages in power and efficiency, it is still widely used in radar, communication, electronic countermeasures and other fields. Later, with the advent of GaAs transistors, solid-state devices began to replace vacuum tubes in low frequency bands. Especially with the application of new materials such as GaN and SiC, the competitiveness of solid-state devices has been greatly improved. This paper will introduce and analyze the development of the two devices and the product of their competition and fusion—Microwave Power Module (MPM), so as to fully understand the international advanced level and help promote the development of domestic technology.

coaxial 1.85mm connector amplifier

Compared with solid-state devices, the main advantages of coaxial 1.85mm connector amplifier devices are high operating frequency, frequency bandwidth, high power, and high efficiency. The main disadvantage is that the volume and quality are large. 1.85mm connector amplifier mainly includes traveling wave tube, magnetron and klystron, coaxial 1.85mm connector, they have their own advantages and are used in different fields. Among them, the main advantage of traveling wave tube is frequency bandwidth, the main advantage of klystron is high power, and the main advantage of magnetron is high efficiency. Traveling wave tubes are the most widely used, so this paper mainly takes the traveling wave tube as an example to introduce vacuum devices.

The development of coaxial 1.85mm connector amplifier electronics can be traced back to World War II. In 1963, TWTA technology made substantial progress in design changes, increasing the power and efficiency of the RF output, and the packaging was more compact. In 1973, the first traveling wave tube amplifier in Europe was successfully developed. However, in the mid-1970s, semiconductor devices suddenly emerged, and the investment in coaxial 1.85mm connector amplifier devices was greatly reduced, and its development encountered great difficulties. Until the beginning of the 21st century, the U.S. Armed Forces Ad Hoc Committee discussed in detail the history, status and development of power devices, pointing out a balanced investment strategy between vacuum devices and solid-state devices. In 2015, DARPA launched the INVEST and HAVOC programs respectively to support the development of coaxial 1.85mm connector amplifier devices and the growing needs of military systems, especially millimeter wave and THz traveling wave tubes. At present, vacuum devices have made great progress and are widely used in radar, communication, electronic warfare and other systems.

With the continuous advancement of technology, the traveling wave tube at this stage mainly presents the following characteristics. The coaxial 1.85mm connectorfirst is the characteristics of high frequency, broadband and high efficiency, which can effectively reduce the volume, weight, power consumption and heat consumption of the system. The advantage is outstanding. The second is the high temperature resistance, which makes the power and phase of the traveling wave tube fluctuate slightly with the change of temperature, which greatly reduces the environmental control requirements of the system. The third is the anti-strong electromagnetic interference and attack characteristics, which makes it show solid survivability in the confrontation of coaxial 1.85mm connector amplifier components and microwave bombs. Fourth, the service life is greatly improved. Statistical research shows that the service life of high-power traveling wave tubes is generally more than 5000h, and the service life of medium and small power products is more than 10000h, reaching the full life cycle of weapons. Figure 1 shows the mean time to failure (MTTF) statistics of products before 2000. It can be seen that the stability of coaxial 1.85mm connector amplifiers in various systems has improved, and the MTTF of space traveling wave tubes has reached millions of hours. level, showing extremely high reliability.