本論文研究目標為研製一微波帶通低雜訊放大器，整合帶通濾波器與低雜訊放大器的功能於一個元件，而能改良傳統收發機接收端架構，藉此縮小收發機面積，提高系統整合度。 本論文以可匹配至複數阻抗之帶通濾波器來設計低雜訊放大器的匹配電路，使其具有帶通的響應，提出的設計公式先以微波基板設計射頻帶通低雜訊放大器驗證可行性，藉由可產生傳輸零點的匹配電路，提高帶通低雜訊放大器選擇度並達到更寬頻的止帶，並探討集總式與分佈式的佈局差異，尋求最佳的電路實現方式，以兩級串接分佈式設計的電路量測結果為例，在通帶2.3?2.5 GHz之間，雜訊指數為1.6±0.14 dB，小訊號增益為25.2±0.7 dB，選擇度方面，在頻率1.81 GHz以下和3.12 GHz?20 GHz之間，皆有逾40 dB的衰減量，與相關文獻比較，確實達到兼具低雜訊、平坦的增益以及高頻率選擇度的特性；再利用砷化鎵積體電路實現單晶片K頻段帶通低雜訊放大器，期能藉此提昇元件之間的整合度，大幅減小FMCW汽車雷達系統模組體積。 本論文提出的帶通低雜訊放大器，具有簡單明瞭的設計流程，在射頻帶通低雜訊放大器的實做上達到設計目標，而使用砷化鎵積體電路製程所設計的電路，量測結果雖不符合預期，但亦詳盡討論模擬與量測不符的原因，同時也為未來進一步的改良提供更多的設計經驗。 Microwave bandpass low noise amplifier design that combines the functions of bandpass filter (BPF) and low noise amplifier (LNA) is proposed in this thesis. It’s believed to have great potential in revising the general receiver structure and largely reducing the circuit area of transceiver by higher level of system integration. In this work, the design of BPF with complex load is applied to the matching network design of an LNA so as to achieve LNA with BPF-like response. In order to verify the effectiveness of proposed design equations and procedure, several bandpass LNAs with bandwidth from 2.3~2.5 GHz are fabricated on microwave laminate. The selectivity and stopband rejection of bandpass LNAs are achieved by bandpass matching network with transmission zeros. Optimum circuit layout is investigated through the comparison of lumped and distributed designs. Specifically, the two-stage cascade distributed bandpass LNA with passband from 2.3 to 2.5 GHz has a noise figure of 1.6±0.14 dB and small signal gain of 25.2±0.7 dB. In addition, the stopband rejection below 1.81 GHz and from 3.12 to 20 GHz are all better than 40 dB. Compared to related previous works, the proposed bandpass LNAs indeed demonstrate features of low noise figure, flat gain and high selectivity. Single chip design of K-Band bandpass LNA is also implemented with GaAs PHEMT process. It can be used for reducing module size of FMCW automobile radar system module by higher level of system integration. The proposed bandpass LNA features simple and explicit design flows. From the measurement results of bandpass LNAs with bandwidth from 2.3~2.5 GHz, design goals are successfully achieved. Although measurement results of K-Band bandpass LNAs using GaAs PHEMT process aren’t in good agreement with simulation results, the possible cause has been found out, which can be applied to the design revision of bandpass LNAs in the future.
