| In this thesis, traditionally low-frequency switched-mode class-E and -F high efficiency amplifier circuits have been extended in operation to 10 and 20 Gliz with record efficiencies ranging from a 74% efficient power amplifier at 10 GHz to a 42% efficient power doubler at 20.8 GHz. These circuits are designed for integration with antennas in an active array configuration.; The design of the 10 GHz class-E power amplifier is a non conventional integrated circuit-field design well suited for active antenna arrays with small unit-cell size. A smaller unit cell size allows greater packing density in the array, which in turn allows for lower array losses, and therefore higher power combining efficiency. With the proper biasing and RF input to a class-E amplifier, the circuit presented to the output terminals of the MESFET enables high efficiency operation by offsetting the phase of the current relative that to the voltage waveform, thereby minimizing losses.; Having optimized unit cell efficiency and size using a novel integrated active antenna, suitable linearization methods must be applied when using these circuits in transmitter systems. In most modern wireless communications systems, the envelope-varying modulation techniques require linearity of the PA for low signal distortion. Linear amplifiers such as class-A and -B, on the other hand, have inherently low efficiencies; for example, the efficiency of class-A amplifiers is limited to 50%. Where high efficiency is needed, the solution is to linearize high-efficiency nonlinear amplifiers. In this work, an 8.4 GHz class-F PA was characterized when different linearization techniques are applied. The two-tone intermodulation distortion and overall efficiency were compared for the different techniques, leading to a technique for which the average efficiency for multicarrier signals was increased from 10% without linearization to 44% with linearization. With the linearization, the intermodulation distortion was reduced from −17 dBc to −28 dBc.; In this thesis, the work in class-E PAs has been extended to a 10.4 to 20.8 GHz frequency doubler that achieved 0.83 dB conversion gain and 7.1 dBm output power with 42% drain efficiency and 31% overall efficiency. (Abstract shortened by UMI.)... |
