| 摘要: | 本論文主要研究運用於微波及毫米波之射頻前端接收機中的低雜訊放大器與混波器積體電路。第二章為設計一單端寬頻混波器電路使用0.18 μm SiGe BiCMOS製程，所提出電路架構是利用混合型的NMOS-HBT(異質接面雙極性電晶體)達靈頓單元，比起傳統的達靈頓單元混波器可以有效地改善頻寬及轉換增益。混波器具有寬廣的射頻頻寬可從12到67 GHz，同時擁有較低的本地振盪驅動功率為2 dBm和最大的轉換增益為5 dB，並擁有最佳的性能指標，此混波器亦可當作解調器使用，其解調速度可達2 Gbps以上。
在第三章，利用砷化鎵異質接面雙極性電晶體(HBT)及高速電子遷移率電晶體(HEMT)製程技術來實現吉伯爾單元混波器，並運用電感補償技巧來改善高頻響應，同時量測驗證開關級與轉導級在不同電晶體組合下的轉換增益及頻寬結果，在四種吉伯爾混波器組合中，異質接面雙極性電晶體-高速電子遷移率電晶體吉伯爾混波器擁有最寬的頻寬及最佳的增益頻寬乘積。另外，此電路利用功率分配器及90度耦合器組成一正交混波器，進一步進行數位解調變測試，其量測到的QPSK解調變訊號頻譜的誤差向量振幅為7.4 %，並成功驗證到2.5 Gbps眼圖。
在第四章，使用0.15 μm GaAs pHEMT及0.1 μm GaAs pHEMT製程開發設計Q頻段低雜訊放大器，其可應用於寬頻帶通訊系統和電波遙測接收器上，在0.15 μm製程中低雜訊放大器頻率為21.8到45.5 GHz間，其小訊號增益高於19.5 dB，而頻率為37 GHz時有最小雜訊指數為2.3 dB，增益頻寬乘積(GBPA)為266 GHz。在0.1 μm製程中頻率為26.8到50.4 GHz間，其小訊號增益高於21.6 dB，而頻率為36 GHz時有最小雜訊指數為2.8 dB，增益頻寬乘積為395 GHz，兩者晶片面積皆為2×1 mm2。本低雜訊放大器電路皆具有寬頻、高增益、低雜訊指數及緊密的電路佈局，此外其同時擁有Q頻段低雜訊放大器中最佳的增益頻寬乘積。
最後，總結本篇論文所提出的電路設計與未來可改善的研究方向。
;Several low noise amplifiers and mixers used in microwave and millimeter-wave radio front-end receiver are presented in this thesis. A broadband single-ended mixer using 0.18 μm SiGe BiCMOS process is presented in Chapter 2. A hybrid modified NMOS-HBT Darlington cell is proposed for the circuit design. The bandwidth and conversion are further improved as compared to the conventional Darlington cell mixer. The mixer exhibits a broad RF bandwidth of from 25 to 70 GHz with a lower driving LO power of 2 dBm, a maximum conversion gain of 5 dB. Moreover, this work has the best figure of merit, and the mixer can be performed a broadband digital demodulator with a data rate of up to 2 Gbps.
Four Gilbert-cell mixers are implemented in GaAs 2 μm heterojunction bipolar transistor (HBT) and 0.5 μm high electron mobility transistor (HEMT) process are presented in Chapter 3. These Gilbert-cell mixers employ an inductive peaking technique to improve the high frequency response. The switch stage and the transconductance stage are designed using variable transistor combinations to enhance the conversion gain and bandwidth. Among these configurations, the HBT-HEMT Gilbert-cell mixer exhibits the best gain-bandwidth product and the widest bandwidth. Moreover, an IQ mixer is developed using the HBT-HEMT Gilbert-cell mixer, a power divider, and a 90。Hybrid couplers. For the QPSK demodulation, the measured error vector magnitude (EVM) is less than 7.4%. The measured eye diagram is evaluated up to 2.5 Gbps.
Two Q-band low noise amplifiers using 0.15 μm GaAs pHEMT (LNA1) and 0.1 μm GaAs pHEMT (LNA2) process for broadband communication and radio astronomy applications are presented in Chapter 4. Between 21.8 and 45.5 GHz, the LNA1 features a small signal gain of higher than 19.5 dB, a minimum noise figure of 2.3 dB at 37 GHz, and a gain-bandwidth product (GBPA) of 266 GHz. Between 26.8 and 50.4 GHz, the LNA2 features a small signal gain of higher than 21.6 dB, a minimum noise figure of 2.8 dB at 36 GHz, and a GBPA of 395 GHz. The chip sizes of the LNA1 and LNA2 are both 2×1 mm2. The LNAs demonstrate broad bandwidth, high gain, low noise figure, and compact chip size. Moreover, this work demonstrates the highest GBPA among all the reported Q-band LNAs.
Finally, the conclusions and future works are addressed in Chapter 5. |
