C波帶電子可調式介電質共振振盪器之研製

Abstract

近年來由於衛星傳播及無線通訊的日漸普遍,因此對小體積、低相位 雜訊和高穩定度之 本地振盪源的需求日趨重要。本論文成功地利用MDS( Microwave Design System)完成一套 C波段的電子諧調式介電質共振振 盪器VTDRO[ Varactor-Tuning Dielectric ResonatorOscillator ]以供 相鎖迴路使用並發展出一套系統化設計程序,按此設計程序,吾人可以大大 縮減研發製作的時間和成本並有效利用各種傳輸線結構,增加振盪器的輸 出功率。 本文採用Colpitts振盪電路組態,以高Q值高穩定的DR當作共 振腔[ Tank Circuit ],並採用兩種不同的DR耦合結構以增加耦合的係數, 一是切線型:輸出功率為 3 dBm,頻率為5.09 GHz,離中心載波 100 KHz時 相位雜訊為 -113 dBc/Hz;二是圓弧型:輸出功率為 11 dBm,頻率為 5.05 GHz, 100 KHz相位雜訊為 -112 dBc/Hz。在小體積限制下( 38.9× 21.8×12.0 , mm ),其機械諧調( Mechanical Tuning )頻寬為 30MHz,可 調範圍 0.6％ 。C另一個電子諧調式的VTDRO,其頻率為 5.082 GHz( 0 V 控制電壓)到 5.096 GHz( 26 V控制電壓),可調頻寬 14 MHz,範圍則是 0.28 ％,相位雜訊在離載波 100 KHz時是 -103 dBc/Hz。VTDRO的可調範 圍,利用MDS預測非常接近,並發現可調頻寬主要是受到變容二極 的電容變 化和非理想的接地面。 In recent years, with the prevailing satellite and wireless communication, requirements of small size, low phase noise and high stability local oscillator are more and more demanded. In this paper,we successively utilize MDS(Microwave Design System) to accomplish the C-Band VTDRO (Varactor Tuning DRO)for PhaseLock Loop and develop a systematic design procedure in addition. According tothis procedure, fabrication time and product cost are highly reduced, and output power of the oscillator is increased by effectively applying various transmission line structure. In this paper, the Colpitts oscillation circuit mode is used. With DR of high Q and high stability as Tank Circuit, two different types of DR coupling structures are applied to increase the coupling coefficient. The first type is straight corner type: the output power is 3 dBm, central frequency is 5.09 GHz, phase noise is -113 dBc/Hz offset central frequency 100 KHz. The second type is arc type: the output power is 11 dBm, central frequency is 5.05 GHz,phase noise is -112 dBc/Hz offset central frequency 100 KHz. Under the restriction of small size (38.9×21.8×12.0,mm), the mechanical tuningbandwidth is 30 MHz, the tuning range is 0.6 ％. As for the order electronical tuning VTDRO, the central frequecny is 5.08 GHz, output power is -0.6 dBm with variation of ±0.8 dBm, tuning range is from 5.082 GHz ( 0 V control voltage)to 5.096 GHz ( 26 V control voltage), the tuning bandwidth is 14 MHz and thetuning range is 0.28 ％. The phase noise is -103 dBc/Hz offset central frequency100 KHz. The tuning range of VTDRO is highly matched to the numerical analysisand MDS prediction. It is found that the tuning frequency is mainly restricted by the capacitance variation of Varactor diode and unideal groundung.