耦合振盪器研究及於電子式掃瞄天線陣列之應用

Studies on Coupled Oscillators and Their Applications in Electronically Scanned Arrays

顏昇宏(Sheng-Hong Yan)

指導教授 ： 瞿大雄

國立臺灣大學/電機資訊學院/電信工程學研究所/博士(2008年)

https://doi.org/10.6342/NTU.2008.03014

摘要

針對注入鎖定及鎖相迴路兩種耦合機制之耦合振盪器陣列，本論文旨在建立控制其相位分佈的方法。於第二章敘述此兩種耦合振盪器陣列之基本架構及基本公式推導，並應用相位分佈控制方法，製作兩種電子式掃瞄天線陣列，分別敘述於第三章及第四章，並以實驗驗證相關理論。

第三章主要係分析及製作一種波束掃瞄天線陣列，使用可自調自由振盪頻率之注入鎖定耦合振盪器陣列。藉由採用耦合第二型鎖相迴路以調整振盪器自由振盪頻率，以及經外部注入信號源以穩定陣列操作頻率，此天線陣列可以透過單一控制訊號調整其主波束方向，以及確保於操作過程，其輸出頻率穩定保持在注入信號源頻率。此外，因耦合振盪器的相位誤差所引起之波束指向誤差，可以大幅減少，且其可使用之操作頻率，可以涵蓋一個頻段而非單一頻率點。本章對相位動力方程式及穩定度，有詳細的理論推導和實驗驗證，並且製作一個三單元注入鎖定耦合振盪器陣列。從實驗中得知，相位差可調範圍為 -16° 至 52°，操作頻率範圍為 2.68GHz 至 2.72GHz，操作頻率為 2.7GHz 時，其相位誤差都在 5° 以下。將此振盪器陣列連接微帶天線，經量測不同控制電壓之天線陣列輻射場型，量測結果與理論吻合。

第四章則敘述一種可切換輻射場型之波束掃瞄天線陣列，主要係使用耦合鎖相迴路陣列。經由使用第二型耦合鎖相迴路陣列及外部參考信號源，此天線陣列可以使用單一控制訊號調控其波束方向，大幅減少因耦合振盪器之相位誤差所衍生之波束指向誤差，以及確保於操作過程，其操作頻率穩定保持在參考信號源頻率。藉由控制雙刀雙擲開關及差分放大器，此天線陣列之輻射場型，可以在和輻射場型及差輻射場型之間切換。此外，於鎖相迴路中加入除頻器，可大幅加寬此天線陣列之波束掃瞄範圍；當使用全向天線時，其掃瞄範圍可以涵蓋 -90° 到 90°。本章並製作一個使用第二型鎖相迴路技術之三單元天線陣列驗證理論。

關鍵字

電子式掃瞄天線陣列 ； 耦合振盪器 ； 注入鎖定 ； 鎖相迴路

並列摘要

This dissertation presents the study results on the capability of phase control for the oscillator arrays with two coupling mechanisms, injection locking and phase-locked loop. Chapter 2 describes the basic principles and formulations of these two kinds of oscillator arrays. Being able to regulate the phase relation of the oscillator array, two applications in electronically scanned arrays are discussed in Chapter 3 and Chapter 4. Both the theory and the experiments are studied.

Chapter 3 presents analysis and experimental results of a beam-steering antenna array using an injection locked coupled oscillator array with self-tuning of oscillator free-running frequencies. With the use of coupled type-II phase locked loops for tuning oscillator free-running frequencies and an external injection signal for stabilizing the array operating frequency, this antenna array can steer its main-beam through a single control voltage and hold its output frequency at the injection signal frequency in operation. Besides, its beam-pointing error arising from phase errors in coupled oscillators can be reduced and the array works well over a certain frequency band. Phase dynamics and stability are studied and experimentally verified. Experimental results of a three-element injection locked coupled oscillator array show that its uniform phase progression ranges between -16° and 52° and the phase errors are less than 5° at 2.7GHz. The operation bandwidth is shown from 2.68GHz to 2.72GHz. Loading this oscillator array with rectangular patch antennas, the beam-steering radiation characteristics are measured at various control voltages.

In Chapter 4, analysis and experimental results of a beam-steering and -switching antenna array using coupled oscillators and phase-locked loops are presented. Utilizing a type-II coupled phase-locked loop array and an external reference signal, the antenna array can steer its beam by a single control voltage, reduce the beam-pointing error arising from the phase errors of the oscillator array, and hold its output frequency stably at the reference signal frequency in operation. Using a double-pole double-throw switch and a difference amplifier at the center element of the antenna array, one can switch the array radiation pattern between the sum pattern and the difference pattern. Moreover, the beam-scanning range is extended to ±90° by properly using frequency prescalers in the phase-locked loops. The radiation characteristics of a three-element antenna array are measured to verify the array performance.

並列關鍵字

electronically scanned array ； coupled oscillators ； injection locking ； phase-locked loop

參考文獻

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