Adaptive RF Front-Ends for Hand-held Applications (Analog Circuits and Signal Processing)

The RF front-end – antenna combination is a vital part of a mobile phone because its performance is very relevant to the link quality between hand-set and cellular network base-stations. The RF front-end performance suffers from changes in operating environment, like hand-effects, that are often unpredictable. __Adaptive RF Front-Ends for Hand-Held Applications__ presents an analysis on the impact of fluctuating environmental parameters. In order to overcome undesired behavior two different adaptive control methods are treated that make RF frond-ends more resilient: adaptive impedance control, and adaptive power control. Several adaptive impedance control techniques are discussed, using a priori knowledge on matching network properties, in order to simplify robust 2-dimensional control. A generic protection concept is presented, based on adaptive power control, which improves the ruggedness of a power amplifier or preserves its linearity under extremes. It comprises over-voltage, over-temperature, and under-voltage protection. The RF front-end - antenna combination is a vital part of a mobile phone. This book offers a unique account of adaptive RF front-ends. It includes an analysis on the impact of fluctuating environmental parameters, and a generic protection concept is presented. Front Matter....Pages i-xv Introduction....Pages 1-8 Adaptive RF Front-Ends....Pages 9-33 Adaptive Impedance Control....Pages 35-106 Adaptive Power Control....Pages 107-128 Conclusions....Pages 129-130 Back Matter....Pages 131-153