Multi-Band Multi-Standard CMOS Receiver Front-Ends for 4G Mobile Applications

The development of the transistor and its continuous down-scaling has allowed during the last decades the appearance of cheap wireless communication systems targeting consumer products. The complexity of these systems has increased dramatically during the last years, mainly fueled by both the Moore law and improvements in communication theory. Originally, the radio transceivers were composed of only a few transistors, and supported simple analog modulation schemes. Currently, radio transceivers are composed of thousands of transistors including not only radio/analog blocks but also a huge amount of digital circuitry as well. These radios use advanced digital modulation schemes, channel coding, and multiple access schemes. Despite the fact that digital circuits currently offer an impressive performance, pure digital signal processing of radio signals remains limited for relatively low frequencies below a few hundred MHz. On the other hand, frequency bands used in current mobile applications span from around 800MHz up to 6 GHz and hence demand the use of analog circuits to down-convert the radio signals to lower frequencies that are suitable for digital processing. The group of circuits that form this part of the receiver is known as the radio receiver front-end. The design of modern radio receiver front-ends has many challenges. One requirement is support of a multitude of standards with bands that are scattered all along the mobile radio spectrum. Accordingly, the noise and linearity specifications for these front-ends are very stringent. Also, these specifications have to be accomplished using low-power, low-cost, highly integrated circuit solutions. This thesis presents the design of multi-band multi-standard receiver front-ends for fourth generation mobile communications. A novel methodology that speeds up the development of multi-band multi-standard RF blocks by automating some steps in the design is shown. Examples of submicron and nanometer CMOS wideband receiver front-ends targeting 4G mobile applications are presented. New techniques for inductorless wideband front-ends using current-mode technology are presented. Finally, novel RF calibration techniques to cope with process, voltage, and temperature variations in modern CMOS processes are demonstrated.