| Summary: | 碩士 === 國立臺北科技大學 === 電腦與通訊研究所 === 99 === This thesis discussed the design and implementation of active adaptive antenna array for WiMAX systems which use Orthogonal frequency-division multiplexing (OFDM) modulation method and require Peak-to-Average Power Ratio reduction and high level linearity of power amplifier (PA). The subject of thesis focus on pre-correction phase error and controlling PA output power for each output path with perfect linearity output power of PA. In this way, the performance is better than traditional combined power method.
The system architecture functions are simulated and compared with the result of the circuit experiment. The developed active adaptive array antenna system includes phase shifters, digital programming attenuators, functional filters, power amplifiers, and power dividers. Before combination each subsystem, every subsystem functional specifications, such as S-parameter, gain, and phase error, are validated.
A parameter table is adopted for fast calibration in each path. After error-correction, the active array antennas generate beams and combine beams using synthesize algorithm in free space. The proposed system uses the active array antennas with benefit of high gain and flexible feasibility in direction finding which promotes efficiency communication system especially in WiMAX system.
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