在本論文中，我們使用Z域的方法來設計微波放大器，有別於以往傳統放大器的設計方式，Z域技術具有可程式化之優點。透過Z域技術我們能夠快速的將電晶體與其偏壓電路的散射參數以Z多項式表示，並根據所定義之頻率響應，將電晶體的Z域等效模型與適當的串、並聯傳輸線網路結合，最後利用最佳化法找出放大器電路與所定義之目標響應的最佳近似解，並且獲得電路中所有傳輸線的特性阻抗。
使用Z域技術搭配Yule-walker方程式，我們設計了一個在操作頻段內具有2.5-dB的增益差的放大器。此放大器於頻帶1.8GHz~2.15GHz具有14.5-dB的增益與2.15GHz~2.7GHz具有12-dB的增益。雙準位放大器的設計證明了z域技術和Yule-walker方案具有任意定義一個高複雜頻率響應的優點。
量測結果方面，除了S參數外，我們也量測了數個放大器特性，其中包含1-dB增益壓縮點(P1dB)、三階交調截取點(IP3)、雜訊指數(NF)與操作頻率內的群延遲(group delay).

In this study, the z domain technique was used to design microwave amplifiers. Using z domain technique in amplifier design is quite innovative and it has the advantage of being programmable. By using z domain technique, the scattering parameters of a transistor and its bias circuit are converted into z domain polynomial quickly. Then, according to the zero locations of the prototype function in z plane, the input and output matching network of the amplifier can be formed by using shunt and serial transmission lines. Finally, the S21 of the amplifier circuit is adjusted to fit the target prototype function F(z) ( or ) with optimization algorithm, so that impedances of the transmission lines of matching network can be obtained.
A z domain amplifier is a dual-level gain amplifier which is designed with the aid of Yule-walker scheme in this thesis. This amplifier shows a 2.5-dB difference in amplitude response in the operating band, which has a gain of 14.5-dB from 1.8GHz to 2.15GHz and it has a gain of 12-dB from 2.15GHz to 2.7GHz. The design of this dual-level gain amplifier demonstrates the advantages of z domain technique and Yule-walker scheme, which leads us to define complex frequency response of an amplifier arbitrarily. The amplifier characteristics including S parameters, linearity (P1dB and IP3), noise figure, and group delay are measured and discussed in the thesis.

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