超高頻帶寬頻壓控振盪器之研製

Abstract

本論文成功地完成一套UHF寬頻壓控振盪器之系統化設計程序,對元件的選 取及寄生效應均有詳細之考,按此設計程序,寬頻壓控振盪器可以被非常有 效率地設計,在現有的SMT元件與混成電路製作技術而言,可以獲得最大的 可調頻寬.本文採用Colpitts振盪器,量測到的可調頻寬涵蓋677MHz(控制 電壓為1V時)與1210MHz(控制電壓為25V時).輸出功率(大於7dBm)的變動量 在正負1.5dB之間.二階諧波失真介於-8dBc與-28dBc之間,相位雜訊是由RF 頻譜儀直接做量測而得到的,在離載波頻率100KHz之下,其相位雜訊介於 -100 dBc/Hz與-112dBc/Hz之間.對於寬頻壓控振盪器之可調頻寬比率,提 出理論分析與及MDS模擬結果,對元件的寄生.傳輸線效應與接地效應均有 詳細的考慮,其結果是三者相當吻合,顯示預測值(理論分析與電腦模擬皆 然)與實驗值的一致性. A systemetic design procedure of UHF broadband VCO has been developed in this paper. Theparasitic effects of device and layout are both taken into account. With this efficient approach, the tuning bandwidth of VCO can be maximized under the specific devices and circuit configeration. The circuit configeration in this paper is the Colpitts oscillator. The measured tuning bandwidth of the VCO covers from 677MHz(at 1V reversed bias) to 1210MHz(at 25V reversed bias). The variation of output power(>7dBm) is less than 1.5dBm. The second harmonic distortion is between -8dBc and -28dBc. The phase noise measured directly from RF spectrum analyzer is between -100dBc/ Hz and -112dBc/Hz at offset freqency 100KHz. Theoretic analysis and MDS CAD simulation for the tuning bandwidth are presented and compared to the experiment result. The three results match to each one. This shows the great agreement between between the predicted values and experiment resuly with a careful examination of device parasitic, transmission line effect and nonideal grounding.