在本論文中，我們使用z域的方式來設計微波放大器。有別於以往傳統放大器設計方式，z域技術擁有可程式化之優點。於設計之前，須挑選適合的電晶體，將此電晶體與其偏壓電路之散射參數以Z多項式表示，建立Z時域模型。設計時，首先需要定義理想的放大器設計目標響應，並根據所定義之響應，將電晶體Z域模型與適當的並聯、串聯傳輸線網路結合。最後我們利用演算法找出此放大器電路與目標響應間的最佳近似解，並且得到電路中所有傳輸線的特性阻抗。
本論文中用z域技術搭配elliptic方程式設計了一組操作頻段在1.8 GHz ~ 2.7 GHz之微波放大器。其中elliptic相對於其他方程式具有高響應斜率的優點。另外，我們也利用Yule-walker方程式實現了一組雙準位微波放大器，此放大器於頻帶1.8Ghz ~ 2.15GHz與2.15 GHz ~ 2.7 GHz內有3-dB的增益差。雙準位放大器的實現也展示了Yule-walker方程式具有可自行定義高複雜度響應的優點。
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. Before the implementation of the amplifiers, the z domain model of a transistor and its bias circuit are created in z domain polynomial by using LLS (linear least squares) algorithm. In the design phase, the prototype function F(z) of the amplifier is defined first. 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 of the amplifier circuit is adjusted to fit the target prototype function F(z) with optimization algorithm, so that impedances of the transmission lines of matching network can be obtained.
Two amplifiers designed with z domain technique are presented in this paper. The first amplifier is featured with frequency response of elliptic equation, which has the defined operating band from 1.8 GHz to 2.7 GHz. The second amplifier is a dual-level amplifier which is designed with the aid of Yule-Walker scheme. This amplifier shows a 3-dB difference in amplitude response in the operating band. The design of both amplifiers 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 parameter, 1-dB gain compression point (P1dB), noise figure (NF), and group delay are measured and discussed in the thesis.

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