THz影像系統---總計畫暨子計畫二：THz CMOS 波束成形發射機

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 代影像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。本計畫 (總計畫) 具體目標為發展THz 3D 影像系統，同時建構 THz CMOS 電路設計、頻譜量測、及系統構裝之能力。本計畫延攬多方面領域之教授， 涵蓋光學影像系統到電路與微機電封裝。其下統合四項子計畫，分別為(1) 微小化THz CMOS 影像系統之3D 影像重建技術 (2) THz CMOS 波束成形發射機 (3) 微小化THz CMOS 主動式射頻照影接收器陣列系統晶片 (4) THz CMOS 被動式影像接收器。各分 項計畫之重點工作項目分述如下。子計畫一利用電磁逆散射法(Electromagnetic Inverse Scattering Method) 進行 THz 3D 影像重建，並將定義系統規格予各子計畫參考。子計 畫二將開發完成 THz 信號源，並結合天線陣列，實現波束成形毫米波發射機，其可 作為影像掃描之光源信號與THz 偵測器感應陣列之本地振盪器。子計畫三將發展主動 式射頻照影接收器陣列系統晶片的開發，作為THz 3D 影像感應器。子計畫四將發展 THz SoP 異質晶片整合技術，整合CMOS 功率偵測器模組(包括鎖相放大器)晶片、高 增益THz 天線陣列晶片及THz 透鏡(Lens)晶片於單一載具上，以實現低成本、體積小、 高整合性之THz 影像系統。 在 THz CMOS 波束成形發射機之研究方面，預計將採用本研究群所提出之接收機 式鎖相迴路為系統核心，結合基頻模式 (fundamental mode) 之振盪器與倍頻器技術開 發， 透過串聯式鎖相迴路架構實現振盪器陣列與波束成形發射機。此外，並研發多頻 帶 THz 信號源，同時結合數位校準技術，以拓展分子層級檢測之應用。 在各子計畫通力合作之下，所開發之電路將採用 40 nm 以下之CMOS 先進製程設 計與製作，同時進一步整合以驗證系統之性能。此外，參加之研究群將共用軟硬體研 究資源及實驗環境。本計劃之終極目標除追求前瞻之學術研究外，亦將為台灣未來工 業技術之發展培育多樣化之頂尖人才。

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 the 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 project is to build up THz 3D imaging system through the developing of THz CMOS circuit and system packaging techniques as well as establishing the measurement capabilities of THz spectrum. This project leverages efforts and experts from aspects of optical imaging system to circuits and system packaging. It incorporates 4 sub-projects including (1) 3D imaging reconstruction technology for a miniaturized THz CMOS imaging system (2) THz CMOS beam forming transmitter (3) Miniaturized THz CMOS active RF imaging receiver array integrated system (4) THz CMOS passive imaging receiver. The action items are briefly described as follows. Sub-project (1) will setup the 3D imaging system through electromagnetic inverse scattering method and define system specifications for other subprojects. Sub-project (2) focuses on the development of CMOS THz beam forming transmitter based on array signal generators for both the imaging screening and local oscillators for THz detectors. Sub-project (3) targets at CMOS RF active imaging receiver array integrated system for 3D tomographic images. Sub-project (4) develops THz SoP technology to integrate CMOS power detector (including locking in amplifier), high gain THz antenna, and THz lens on a single carrier, so as to accomplish a low cost, small form factor, and highly integrated THz imaging system. The development of CMOS beam forming transmitter will be based on our previous research accomplishment. A receiver based-PLL will be adopted as the transmitter core. Combing with fundamental mode oscillator and frequency doubler, a THz high precision phase shifter and beam former will be realized through cascaded phase-locked loops. Additionally, multi-band THz signal generators will also be explored for molecular detection and electronic nose application. In collaboration with all the sub-projects, all integrated circuits will be designed and fabricated using a 40nm (or more advanced) CMOS process. The developed core devices will be further integrated for system verifications. Most important of all, the participated groups will share all the research resources, including hardware, software, and common facilities. In addition to pursue technology excellence, this project also aims at cultivating talents with varieties of expertise to enable the advancement of Taiwan industry.