4. Conclusion

The electronic functions described in this article - amplifiers, attenuators, phase shifters, etc. - are the basic functions of electronic systems (measurement chain, transmitter/receiver). Although the principles and architectures are those of conventional electronics, in high-frequency applications, the design and implementation of such functions call for special concepts and technologies. Even if totally digital solutions (software-defined radio) are realistic, analog functions as detailed in this article remain the solution for systems operating above ten GHz or for special applications (ultra-low noise, high power, etc.).