X-頻帶主動天線陣列

Abstract

本論文是設計,製作,量測X-頻帶的主動天線陣列,此天線陣列是以微帶 天線為輻射元件,再加上振盪器所形成的共平面主動天線陣列.通常在高頻 的情況下,一般固態元件無法產生高功率,因此有必要組合較多的元件,將 個別元件所提供的功率以準光學的方式在空氣中結合以得到高功率的要 求. 本計畫是參照加州大學洛杉磯分校 Dr. Itoh 對主動天線陣列的研究 而加以設計製作的.在此主動天線陣列中,微帶傳輸線週期性地將每個振盪 器連結起來,而藉由振盪器間的phasing locking 可達成功率合成的目的. 為了達到穩定振盪的要求,適當的電阻將置於微帶傳輸線的中點. 整個實 驗量測是建立在遠場的條件下,產生的訊號經由頻譜分析儀量測,獲得振盪 頻率為9.7GHz左右由單一單元雙單元以及四單元所產生的有效輻射功率分 別為 32mW, 226mW 以及 1102mW. Solid-state devices can not generate large power at very high frequencies,it is necessary to combine many solid-state devices to obtain high power. In this thesis, the quasi-optical X-band active antenna arrays are designed. The fabrication and measurement are also presented. The project is based on the circuit designed by Prof. Itoh's group. A planar periodic HEMT power-combining array is designed and fabricated in X-band.A microstrip transmission line is periodically connected to HEMT devices driving a linear microstrip antenna array. The power combining is achieved byphasing locking the oscillators. In order for only the desired power-combiningmode to oscillate, appropriate resistors are introduced at the midpoints of thecoupling lines between the active antennas. An experiment for the active antenna arrays has been carried out. The oscillation frequency is measured at about 9.7GHz. An effective radiation power(ERP) of 32mW, 226mW, and 1102mW is obtained for single-unit, two-unit, and four-unit active antenna array.