THz醫學影像系統及元件---子計畫三：THz CMOS信號源設計(I)

Abstract

近年來，THz 電磁波 (300 GHz- 3THz，T-射線) 在科學與工程上之應用已引起廣 泛之研究。相較於 X-射線 (X-ray) 而言，T-射線為非離子化幅射光源 (non-ionization radiation) ，適合進行生物組織之非侵入式偵測而較無輻射疑慮。因此其被公認為下世 代醫學影系統之重大關鍵技術。此外，其具備穿透衣服及其他非金屬化材質之特性，因 此可廣泛應用在安檢系統之影像監測、化學與生物物質偵測，腫瘤、蛀牙之醫學攝影等。 同時在短距離雷達及超高速無線資料安全傳輸等應用，也深具潛力。 依據 ITRS 之預測 [3]， CMOS 之fT 及 fmax 在 2015 年以前將高達 0.5 THz。此 一重大技術進展開啟了矽製程在 THz 系統應用之序幕，同時對於降低THz 系統成本之 可行度大為增加。本子計畫(子計畫3)之具體目標為發展用於醫學影像系統之 THz 信號 產生器。其將結合微機電波導及天線結構 (子計畫5) 組成THz 光源發射機，同時在感 測器端(子計畫4)將提供做為積體化接收機陣列之本地振盪器使用。 為達到此一目標，本計畫第一年將研發THz ( 300 GHz+)基頻模式之振盪器設計。 相 較於文獻現有藉由相位合成技術實現之振盪器，其將具備較高之功率轉移效益，且提高 功率合成之可行性。此外為強化輸出功率達到實用價值，THz 鎖相系統及其相關之子電 路將進行研發，以期最終藉由波束成型 (Beam-forming) 達到功率加乘之目的。第二年 將研發數位式 THz 振盪器陣列之校正與功率加乘技術。同時完成THz 鎖相迴路系統， 並與子計畫2 進行功率及頻譜測試。第三年將利用開發完成之 THz 信號產生器與其他 子計劃 (1-5) 共同建構影像偵測系統，充分應用在發射端與偵測器之感應陣列。 本計畫第一階段將採用 MATLAB進行系統之行為層級模擬，以有效評估架構之可 行性。第二階段將針對第一階段所開發之系統架構，使用HSPICE、ADS、Spectre RF 及Ansoft Desinger/HFSS 做電磁及電晶體層級的模擬，再利用Cadence軟體進行佈局。 第三階段將藉由 CIC 及台積電 65nm/45 nm 之製程計畫進行晶片製作並完成量測驗 證。 其成果將進一步與其他子計畫成果整合，以作為THz 醫學影像系統之信號源。

THz wave (300GHz–3THz, T-ray) applications in scientific and engineering applications have drawn tremendous research efforts recently. In contrast to X-ray, it is a non-ionized light source for non-invasive detection of biological tissues without the concern of much radiation exposure. Thus it is believed as an emerging technology for next generation medical imaging system. Additionally, T-ray is capable to penetrate clothing and many (non-metallic) packaging materials. It opens up unique screening possibilities for detection of concealed weapons, chemicals and biological agents, tumors, cavities, and also opportunities for short range radars and secured high data rate wireless communications. As projected by ITRS, the fT and fmax of CMOS (Complementary Metal Oxide Silicon) integrated circuits (IC’s) technologies will reach the regime of 0.5 THz by 2015. The great advancements have enabled silicon technology as an alternative means for realization of economical THz systems. The objective goal of this sub-project (3) is to develop THz signal generators for medical imaging system. In the transmitter side, it incorporates micro-electromechanical system (MEMS) based guiding wave structure (sub-project 5) and antenna array to realize THz light source. In the detector side, the THz signal generator also serves as local oscillators for receiver array integrated system (sub-project 4). To achieve the design goal, in the first year, THz (300 GHz+) fundamental mode oscillator in CMOS technology will be investigated and developed. In contrast to the existing technologies using phase combinations or push-push technology, it is expected to provide higher power efficiency and also facilitates power combination. To further enhance transmitted power, THz phase locking systems and their building blocks will be explored to implement phase array transmitter with beam forming. In the second year, digital intensive techniques will be developed for the T-Hz generator array calibration and power combination. Also, a THz phase locking system will be demonstrated, whose spectrum and power level will be studied in collaboration with sub-project 2. In the third year, the developed THz signal generator will be adopted as the light source for image screening as well as local oscillators for detector array integrated system (sub-project 1-5). During the first phase of this project, system behaviors of the THz signal generator will be investigated using MATLAB to evaluate the effectiveness of the sub-system architecture. In the second phase, all the circuit blocks will be designed using HSPICE, ADS or Spectre RF, Ansoft Desinger/HFSS for transistor-level simulation, and then laid-out using Cadence tools.In the third phase, the designed chips will be fabricated through CIC as well as TSMC 65nm/45nm university shuttle program, and integrated with other sub-projects (1-5) to realize a medical imaging system.