ABSTRACT

The complexity of cellular devices has increased at a very rapid rate due to the exponential growth in mobile data demand. The use of more spectrally efcient higherorder modulation schemes has enabled transmitting and receiving signicantly more bits per Hertz of radio spectrum, but additional frequency bands must be added to the cellular device to cover global operation and various frequency band allocations. This spectrum growth not only increases the number of duplex lters, antenna switch

7.1 Introduction-Toward a Fully Integrated Recongurable Cellular RF Front End ...................................................................................................... 145

7.2 Fundamentals and Design Trade-Offs of Semiconductor Switched Capacitors ..................................................................................................... 146 7.2.1 Basic Concepts and Fundamental Trade-Offs .................................. 146 7.2.2 Real-Life Performance Is Dominated by Parasitic Effects .............. 149 7.2.3 Component Quality Factor ............................................................... 151

7.3 Impedance Tuning Networks ........................................................................ 152 7.3.1 Tuning Network Circuit Topology and Trade-Offs .......................... 152 7.3.2 Cellular System Level Considerations .............................................. 154 7.3.3 Dealing with Exponential Complexity ............................................. 154 7.3.4 Impedance Tuner Compact Model ................................................... 155 7.3.5 Impedance Tuner Visualization ........................................................ 158 7.3.6 Smith Chart Constellations ............................................................... 158 7.3.7 Smith Chart Surfaces ........................................................................ 158 7.3.8 Transducer Gain Contours ................................................................ 159 7.3.9 Density Plots for Visualizing Large Amounts of Data ..................... 161

7.4 Conclusions ................................................................................................... 162 References .............................................................................................................. 162

throws, and antennas, but also requires fundamental modications to the radio frequency (RF) front-end architecture to support exibility and recongurability.