| In recent years, there has been a great deal of interest in MEMS reconfigurable circuits for applications in miniaturized multifunctional microwave systems. RF-MEMS switches have demonstrated low loss, linear operation and low static power consumption, malting them suitable components in a high-performance, reconfigurable circuit.; A principle component in a reconfigurable power amplifier is an impedance tuner. Although a number of universities have published tuners with impedance constellations covering large percentages of the Smith Chart, adoption of these tuners into front-end circuits has been slow. Current demonstrations of reconfigurable power amplifiers are limited to very simple circuits to enable frequency hopping.; This thesis analyzes this trend and determines the criteria for integrating a tuner with a power amplifier, design of impedance tuners to meet amplifier specifications, and a performance analysis of a 10 GHz power amplifier that reconfigures from a high-linearity class-A mode to a high-efficiency class-E mode. This reconfigurable amplifier is compared to conventional non-reconfigurable class-A and class-E amplifiers. It is shown that a simple reconfigurable power amplifier can be designed with less than 5% degradation in power-added efficiency.; This thesis also presents the design of a low-loss 80-state impedance tuner and a generalized analysis of impedance tuners, including constellation density, bandwidth, redundant coverage, insertion loss, and failure degradation, using a MEMS-switched double-slug tuner as an example. A high-performance micromachined inductor, compatible with flip-chip integration in hybrid circuits, is also designed and characterized for use in miniaturized biasing circuits. |
