دانلود کتاب فناوری‌های RF، مایکروویو و موج میلی‌متری

In the conceptual period of the development of wireless systems, only the lower-frequency band was utilized because of various limitations. Later, researchers became more cognizant of higher-frequency spectrum for efficient transmission/reception, which includes radio frequency (RF), microwaves, and mm waves. In very generic terms, RF, microwaves, and mm waves are used to describe electromagnetic waves with frequency range from 1 MHz to 300 GHz. The corresponding wavelengths range is from 300 m to 1 mm. The whole electromagnetic spectrum is shown in Fig. 1. Starting from the power supply band to cosmic rays, various bands with their frequency range and corresponding wave lengths are depicted in the diagram. From here, the relative position of various bands can be estimated. There is an important band of terahertz (1012 Hz), which is sandwiched between mm wave and optical region. Terahertz waves have become popular in recent years for their distinct features. In this chapter, terahertz will not be discussed further and is treated as higher end of mm waves. This figure also shows electromagnetic interference (EMI) shielding range for electromagnetic compatibility (EMC) of electronic systems. Though the position of high frequency waves, radio waves, and microwaves are indicated in the Figure, it requires further discussions and quantification (high-frequency waves are not meant here as “HF,” which will be elaborated later).