射頻功率偵測器的應用

Abstract

本論文提出兩個射頻功率偵測器的應用電路。主要是利用現有的射頻電路架構搭配一些功能性的類比電路，而以功率比較的方式達成射頻偵測的目的。第一個電路應用在WiMAX傳送端上。為了能完成I/Q自動校正的閉迴路系統，一個具有較寬動態範圍的射頻功率偵測電路是必須的。此電路使用了台積電0.18um，而模擬結果顯示在本地振盪器漏訊號，IQ增益及相位誤差補償模式下都符合規格要求。 另一個應用則是5GHz低雜訊放大器的自我測試電路。偵測待側電路增益的方法是以可調整式衰減器及兩個射頻功率偵測器的輸出進行比較的方式達成。後模擬結果顯示，可以完成一個增益為15.68dB的低雜訊放大器的偵測。不幸地，因為天線效應的影響，量測沒辦法和模擬結果相互驗證。之後，提出另一個自我測試電路的架構，主要是以電阻分壓的方式來克服對溫度及製程變異的影響。

In this thesis, two applications of RF power detector are designed using power comparing methodology as a design principle. The first application is the power detection design in WiMAX transmitter. In order to form a closed loop I/Q auto-calibrated system, a wide dynamic range power and detection circuit is necessary. Simulations results show that the power detection circuitry designed in TSMC 0.18um technology meets the specifications in all compensation mode, such as LO feedthrough, gain imbalance, and phase imbalance. Another application of RF power detector is the built-in self-test design for a 5GHz LNA. The circuit under test is test by a variable attenuator and comparing the DC output of the power detectors. The post-simulation results show that the circuit achieves gain test for a 15.68dB, 5GHz LNA. Unfortunately, function verifications cannot be made due violations of the antenna rule. Another BIST architecture using voltage division by a resistor string is also proposed to break-through the bottlenecks of sensitive to process and temperature variations.