Contents Introduction
Vacuum Microwave Integrated Circuits (VMIC) has been suggested [1] for design of radar front-end with high resistance against ionizing radiation and high power electromagnetic impulse radiation. Actually it is a new innovative application of vacuum microwave electronics is suggested. Semiconductor based technology dominates in nowadays radar and especially in its receiver units. It is difficult to imaging design of modern radar systems without application of chips, diodes, transistors and microwave integrated circuits (MMIC). However all semiconductor based devices have one drawback which makes all radar equipment rather sensitive to both ionizing radiation and high power electromagnetic signals. The latter is specifically important in the antiterrorism content. It is well known that vacuum electronic devices are much more resistant against ionizing radiation and high power electromagnetic fields. Actually idea of devising vacuum microelectronic devices is a very old one [2]. As it was noticed in [2], about 40 years ago, K.R. Shoulders of Stanford Research Institute (SRI) presented a device concept in his article entitled “Microelectronics using electron-beam-activated machining techniques” [3]. At that time, the known today micro fabrication technology did not exist. Nevertheless, K. R. Shoulders, proposed “to devise vacuum tunnel effect devices of micron sizes with switching times in 0.1 ns that (i) operate at 50 V, (ii) have high input impedance, (iii) are insensitive to temperature effects up to 1000°C, (iv) are insensitive to ionizing radiation effects up to the limits of the best known dielectric materials, and (v) have a useful lifetime of many hundreds of years.” However absence of mature technology for micro fabrication of vacuum devices and appearance at the same year (!) of the first results on semiconductor integrated circuits (IC) and further great success in their developments has blocked elaboration of that idea and did not draw proper attention to that paper. At the same time, nowadays Vacuum Microelectronics demonstrates significant achievements in the areas of both field emission cathodes and microwave devices exploiting these cathodes. The results obtained encourage researchers to extend applications areas for Vacuum Microelectronics.
