An Overview on Millimeter Wave Technology for Future Wireless Communications

Almost all mobile communication systems today use spectrum in the range of 300 MHz-3 GHz. Due to the increasing popularity of smart phones and other mobile data devices such as netbooks and ebook readers, mobile data traffic is experiencing unprecedented growth. In order to meet this exponential growth, improvements in air interface capacity and allocation of new spectrum are of chief important. As the mobile data demand grows, the sub-3 GHz spectrum is becoming increasingly crowded. On the other hand, a vast amount of spectrum in the 3-300 GHz range remains underutilized. The 3-30 GHz spectrum is generally referred to as the Super High Frequency (SHF) band, while 30-300 GHz is referred to as the Extremely High Frequency (EHF) or millimeter-wave band. Since radio waves in the SHF and EHF bands share similar propagation characteristics, we refer to 3-300 GHz spectrum collectively as millimeter-wave bands with wavelengths ranging from 1 to 100 mm. The availability of the 60 GHz band as unlicensed spectrum has inspires interest in gigabit-per-second. In this paper, we justify why the wireless community starts looking at the 3-300 GHz spectrum for mobile broadband applications. The applications of mmWave are immense:wireless local and personal area networks in the unlicensed band, 5G cellular systems, vehicular area networks, ad hoc networks, and wearables.