新型微波雙向放大器及其應用

Abstract

本論文提出一種全新之雙向放大器電路架構，主要應用於主動式廣角回波天線陣列。此雙向放大器由2個反射式放大器與1個分支線耦合器組合而成；反射式放大器在與其他電路整合時，會因為負載端頻寬的問題，容易有震盪情形發生，需要設計窄頻反射式放大器，此論文所設計之窄頻反射式放大器在5.6GHz~7GHz反射增益大於0dB，在6.26GHz反射增益有8.1dB。根據此架構所設計之雙向放大器在5.76GHz~6.88GHz雙向功率增益大於0dB，在6.04GHz雙向功率增益有9.1dB。 在設計廣角回波天線陣列時，為了避免金屬反射板的干擾問題，採用在end fire 方向輻射的Yagi天線，除此之外，Yagi天線的頻寬較一般天線大，可降低對窄頻反射式放大器頻寬的要求。結合雙向放大器之主動式廣角回波陣列天線單元只有傳統廣角回波陣列的一半，回波強度卻增加5dB以上。

The thesis proposes a novel bidirectional amplifier which can be used in active retrodirective antenna array. The bidirectional amplifier combine two reflection-type amplifiers with one branch-line coupler. When the reflection-type amplifier is integrated with other circuits, the insufficient bandwidth of terminating load may cause the whole circuits oscillation. We need to design a narrow band reflection-type amplifier.The narrow band reflection-type amplifier presented in this thesis possess a return gain greater than 0dB between 5.6GHz~7GHz, and 8.1dB at 6.26GHz. The bidirectional amplifier possess a bidirectional power gain greater than 0dB between 5.76GHz~6.88GHz, and 9.1dB at 6.04GHz. To avoid the ground metal scattering effect, Yagi antenna with end-fire radiation pattern is adopted in designing retrodirective antenna array. Besides, Yagi antenna with greater bandwidth can reduce the bandwidth requirement of narrow band reflection-type amplifier. The designed active retrodirective antenna array possess not only one half antenna elements but 5dB higher reflected power gain than traditional ones.