ABSTRACT
Continuous developments and technological advances in Silicon Germanium (SiGe), Silicon Carbide (SiC), Gallium Arsenide (GaAs), Indium Phosphide (InP), insulation and substrate materials, microwave monolithic integrated circuit (MMIC), application specific integrated circuit (ASIC), System on Chip (SoC), System in Package (SiP), microprocessors, analog/digital signal processing (A/DSP), and battery technology, supported by computer-aided design (CAD) and robotics manufacturing allow a viable implementation of miniature radio transceivers at radio frequencies as high as 100 GHz, that is, at wavelengths as short as about 3 mm. At frequency bands up to about 6 GHz, additional spectra have been assigned to mobile services, see Figure 2.1; corresponding shorter wavelengths allow a viable implementation of adaptive antennas and diversity schemes empowered with powerful spatial turbo coding schemes; these Multiple Input multiple output (MIMO) systems are capable of offering higher quality of transmission and higher spatial frequency spectrum efficiency.
