ABSTRACT
The world of wireless communications started to grow rapidly. Cellular handsets are the largest consumer market in the world. The main trigger was the introduction of digital coding and digital signal processing in wireless communications. The aggressive scaling of CMOS process technology driven by the memory and microprocessor market made CMOS a logical choice for integration of digital signal processing in wireless applications. The development of this high performance, low-cost CMOS technologies allowed integration of enormous amount of digital functionality on one chip. This enabled the use of sophisticated modulation schemes, complex demodulation algorithms, and high-quality error detection and correction to produce high data rate communication channels bringing the Shannon limit in sight. The radio frequency front-ends are the interface between the antenna and the digital modem of the wireless transceiver. They have to detect very weak signals that come in at a very high frequency, and at the same time transmit high-power levels at the same high frequencies.
