應用於極座標系統中具有相位補償之互補金氧半三頻帶E類功率放大器設計

Abstract

本論文提出了第一個可應用於極座標發射器中操作於2.5GHz/3.5GHz/5.2GHz之三頻帶並且完全整合在單一晶片上的CMOS E類功率放大器。此三頻帶E類功率放大器使用0.18□m製程並且藉由調整共基極電晶體和匹配電路以達成三頻帶的操作。藉由獨特的共基極電晶體的偏壓和補償電容補償此E類功率放大器因為供給電壓的變動造成的相位失真。為了使此E類功率放大器有更好的效能，本電路中使用微機電製程將E類放大器之電感基底掏空，降低電感的基底所造成之基底損耗。量測結果顯示:在2.8V的供給電壓及6dBm的輸入功率下，在3.5GHz的頻帶有最大的汲極效能:13.2%，輸出功率:10.3dBm。在供給電壓範圍為0.5V到3V範圍之間，此時之相位失真被壓抑在6度以內。為了驗證所提出之相位補償技術對於三頻帶E類放大器應用於極座標發射器中可增加調變訊號之準確度，本論文建構了一個系統和電路的共同模擬環境。模擬結果顯示:本論文所提出之相位補償技術提升了發射器之RCE值使得能符合WiMAX和802.11之系統規格要求。

A first fully integrated cascode Class-E power amplifier (PA) operating in 2.5GHz/3.5GHz/5.2GHz frequency bands for polar transmitters is proposed in this thesis and fabricated in 0.18□m CMOS technology. The tri-band amplification is achieved by adaptation of the common-gate transistor size and the matching networks. The phase distortion from supply modulation of the Class-E PA is compensated by controlling the common-gate transistor gate voltage and a compensative capacitor. To enhance the performance of PA, Micro-Electro-Mechanical-Systems (MEMS) process is applied to release the substrate of the inductors. Measurement results show that the maximum drain efficiency of 13.2% and output power of 10.3dBm can be achieved at the input power level of 6dBm from 2.8V supply in 3.5GHz frequency band. The phase distortion can be compensated to 6° under supply voltage of 0.5V to 3V in 3.5GHz frequency band. A system co-simulation has been established for relative constellation error (RCE) evaluation and it reveals that the proposed compensations techniques make the RCE improve to meet the system requirements of WiMAX and 802.11a systems in the tri-band.