前饋式射頻IQ匹配誤差補償電路設計

Abstract

本論文提出一個採用前饋式迴路架構，直接在射頻處理I/Q匹配誤差的補償電路。這個電路採用一個簡單又有效率的運算法則，將I/Q訊號的不匹配等效成一個誤差矩陣，藉由反矩陣達到補償的效果。誤差補償的方法，是使用重疊定理，在前饋式架構中將調整過後的I/Q訊號相加，達到補償的目的。此電路整體架構中，包含匹配誤差偵測器、訊號倍率控制產生器、以及一組增益可調的轉導放大器。 本補償電路設計與驗證在2.5GHz到2.7GHz頻段，期望能運用在 WiMAX無線通訊系統。當輸入訊號最不匹配程度為 ±10% 振幅誤差與 ±10˚相位誤差時，本電路可將誤差改善至小於 ±2% 與 ±2˚。此補償電路採用台灣積體電路(TSMC)的0.18μm製程，整體(包含測試電路)的尺寸為1.5x1.0 mm2 ，核心電路的功率消耗為28.8mW。

The thesis proposes an I/Q mismatch compensation circuit with feed-forward topology applied directly into the radio frequency. The circuit adopts a simple but efficient algorithm to compensate for the signal mismatch in a matrix format by inversing the matrix. Mismatch compensation can be achieved by superposition of gain-controlled I/Q signals in the feed-forward topology. The entire compensation circuit includes a mismatch detector, a control-signal scaling generator, and a bank of variable-gain transconductor amplifiers. The compensation circuit is designed and demonstrated in the frequency band from 2.5GHz to 2.7GHz for the WiMAX wireless communication systems. With the worst input signal having ±10% magnitude mismatch and ±10˚ phase mismatch, this circuit can improve the mismatches to be less than ±2% and ±2˚, respectively. Fabricated in TSMC 0.18um CMOS technology, the total chip area is 1.5x1.0 mm2 and the power consumption of core circuit, including the mismatch detection and compensation circuits, is 28.8mW.