二次諧波增強式Ka波段介質共振振盪器之研製

Abstract

本論文採用微波混合積體電路的製程技術，完成20GHz 介質共振振盪 器之研製：輸出功率0.25dBm､相位雜訊在偏離載波10KHz處有-71dBc/Hz ､高低次皆在20dBc以下；以作為衛星中華一號接收系統中的本地振盪器 電路結構為串列回授型的介質共振振盪器，將主頻振盪在10GHz ，結合主 頻抑制電路，增強二次諧波訊號，以達成20GHz 的振盪。此電路的優點： 僅須單顆主動元件､製作簡單､相位雜訊低､頻率穩定度高､體積小､成 本低廉。此外，對於元件的寄生現象：源極回授的精確控制以避免寄生振 盪及閘極終端電阻和調整螺絲對相位雜訊的影響，亦有深入的探討。最後 ，提出了系統化的設計流程，可以縮短DRO 的製作時程。 20GHz Dielectric Resonator Oscillator(DRO) with output power of 0.25dBm,phase noise of -71dBc/Hz at 10KHz offset from carrier and harmonic distortion at least -20dBc as local oscillator in ROC-SAT1 receiver is fabricated using microwave hybrid integrated circuit technique. The DRO is desgned by the commercially available DR and pseudomorphic hetero-junction FET( PHJ-FET) with series feedback configuration. The 20GHz signal is obtained by suppressing the fundamental 10GHz with a quarter wavelenth open stub and two interdigital capacitors to enhance 2nd harmonics. The circuit has the advantages of only onetransistor, easy fabrication, low phase noise, high frequency stabilization, small size and low cost. In addition, the parasitic effects are controlled especially in source feedback impedance to avoid spurious oscillation and terminator resistor improvement to reduce phase noise degradation. Fianlly, a systematic design procedure with practical consderation of parasitic device is presented for DRO design above 20GHz.