下世代毫米波高速傳輸通訊系統之系統規劃與評估

Abstract

本文中，利用Co-simulation模擬方法，結合三維全波模擬軟體(CST)以及高速高頻協同模擬軟體(ADS)，模擬毫米波通訊系統，毫米波通訊系統包含射頻收發模組以及天線陣列，其操作頻率為38GHz。在天線陣列設計上，我們設計一組相位陣列系統，此系統包含32組次陣列天線，其中次陣列天線具有低旁波瓣(Sidelobe Level)的特性，為了確保此相位陣列天線系統可用在點對點的毫米波通訊，我們利用CST模擬軟體模擬此一維波束掃描能力。另外，透過系統的波束成型功能，形成一個指向通訊使用者接收端的高指向性輻射場型，進而提高接收端使用者的訊雜比。在射頻收發模組設計上，可以分成四個部分，包含發射模態、接收模態、4.95GHz本地振盪源以及30.65GHz本地振盪源，在發射模態(TX)中，我們使用毫米波中頻收發模組，其操作頻率為2.4GHz，再經由二次升頻(Dual Up-Convertor)系統將頻率升至38GHz，我們以頻譜、星座圖，以及眼圖來做為調變訊號品質評估之標準，從64QAM模擬結果顯示，當I/Q輸入功率為0dBm時，發射模態整體增益為20.4dBm，EVM為3.275%，其中符碼率(Symbol Rate)為250Msym/s接收模態(Rx)模擬結果顯示，輸入訊號功率在-60dBm到-10dBm，EVM小於5%。

In this thesis, the system planning and performance evaluation of a transceiver system employed in a high-speed communication system operated at millimeter-wave frequencies is carried out. The intermediate frequency (IF) is at 2.4 GHz and the bandwidth of the base-band I/Q signal is, at least, 250 MHz. The up/down converter is designed to convert the two frequencies between IF and millimeter wave. Moreover, the electrical properties of the components, circuits and modules are evaluated by the co-simulation approach incorporating the behavior model of active components and electromagnetic field calculation for the transmission line, array antennas, and filters. The parametric study for the link budget of the millimeter wave system is also included in this research work. Additionally, 64 QAM (Quadrature Amplitude Modulation) constellation was simulated for the receiver to evaluate its EVM (Error Vector Magnitude), as well as the system SNR (Signal to Noise Ratio).