低電壓５-GHz互補式金氧半電晶體直接降頻式射頻前端接收器

Abstract

低耗電與高資料傳輸特性使得無線區域網路的發展日漸蓬勃，在無線區域網路802.11a規格頻譜中，特別將52個次頻道中，保留編號0的次頻道不予發送，這對於選用架構簡單的直接移頻接收器十分有利，並且也增加了單晶片整合的機會。本論文使用互補式金氧半電晶體製作一個直接移頻接收器，透過國家晶片系統設計中心，以臺灣積體電路製造股份有限公司提供的0.18 μm製程技術實現。論文最大的重點在於處理直接移頻架構的自我混波問題，提出一個新的準位偏移補償電路，並當作混波器的負載，直接消除因自我混波所產生的直流準位偏移電壓。射頻接收器所含電路有低雜訊放大器、正交壓控振盪器及降頻器。 量測結果顯示，所設計的射頻前端接收器可於1.1 V電源下正常運作。射頻接收器在規範的頻寬中均有–15 dB輸入反射因數、17.8 dB電壓增益、14.9 dB雜訊指數、–23 dBm之1 dB增益壓縮點，當接收器輸入端灌入一組與振盪器同頻且強度為-50 dBm的信號時，其自我混波後的直流準位偏移電壓為1 ~ 3 mV。此外，接收器消耗功率為37.56 mW，晶片面積為2.09 mm2。

Wireless local network is a fast growing market that enables lower power dissipation and higher data rates. The IEEE 802.11a standard which channel 0 is useless among 52 sub-carriers; this is favorable for direct-conversion architecture. This thesis proposes a CMOS direct-conversion receiver, and is realized by TSMC 0.18μm technology via Chip Implementation Center. The major issue in the direct-conversion architecture is self-mixing problem; a new offset compensation circuit is used as the mixer loads to alleviate the DC offset. The receiver comprises a low-noise-amplifier, a quadrature voltage-controlled oscillator and downconverter. Measured results reveal that the designed receiver can operate well at 1.1 V power supply. It performs –15 dB input refection coefficient in interesting band, 17.8 dB conversion gain, 14.9 dB noise figure, -23 dBm 1 dB compression point. The DC offset voltage is 1 ~ 3 mV with input injected power of –50 dBm. It consumes 37.56 mW and die area is 2.09mm2.