應用於雷達及光通訊系統的高速電路

CMOS的技術不斷進步，元件可以操作在非常高的頻率。CMOS的發展提供了一個成本較為低廉的平台來實現這些通訊技術，並使這些產品的普及化變成可能。本論文的主要目標是利用CMOS製成來實現高速系統中的電路，並提出幾種電路設計技巧來克服實現電路所遇到的問題。在無線通訊方面，本研究把重點放在79 GHz 的車用防撞雷達。為了實現在CMOS上的雷達系統，我們設計了數個電路並驗證其特性。首先是相位偏移調變器。為了避免車用雷達被其他車輛或訊號干擾，我們可以利用編碼的技術來確定接收到的訊號是自己發射出去並反射回來的。gm-boost和source-end inductive peaking的方法被應用在這個電路中來增加電路的特性。接著是一個利用自我乘三並注入鎖定的震盪器。利用注入鎖定我們可以濾掉在乘三過程中的諧波項，並提升輸出的訊號強度。可程式化增益放大器也在這篇論文中討論。為了滿足各種雷達系統中面對的情形，如不同距離反射回來的訊號強度不同，許多參數都設計成可調整，並留下空間在未來可以使用數位訊號處理器來做控制。完整的車用防撞雷達發射端也在本研究中製作並分析。雷達發射端包含了可程式化脈波產生器、壓控震盪器、頻率調變器、驅動放大器以及平衡不平衡器。這個電路可以產生並傳送三種調變訊號，分別是開關鍵調變、二進制相移鍵控以及連續波頻率調變。在光通訊方面，由於光二極體的雜散電容會造成第一級電路的不易設計，而二極體產生的電流也必須轉成電壓來做更近一不的訊號處理。因此光通訊系統中通常都會插入一級轉阻放大器在光二極體與後級的電路之間。Regulated Cascode是一種常用的低輸入阻抗架構。針對傳統架構，我們做了一些改良。在第一個電路中我們利用插入一級共閘級放大器來降低電路所需要的操作電壓;在第二個電路中，capacitive peaking的技巧可以讓電路操作在更大的頻寬。

關鍵字

車用；雷達；光通訊；轉阻

並列摘要

As the technology improves, circuits fabricated on CMOS can have faster operation speed. This provides a great opportunity to realize high speed communication systems on CMOS. In this work we focus on circuits designed for high speed applications, and propose several techniques to conquer problems when designing these circuits. For wireless communication, this thesis is focused on 79 GHz automotive pulse radar application, and several circuit blocks are presented. First, to prevent signals from interrupting other cars' signals, coding technique is adopted, so there needs to be a BPSK modulator designed for coding function. Second, injection-locked VCO is used to solve harmonic problems resulting from original self-tripling VCO. It serves as an active filter and can provide a clean LO source. Programmable gain amplifier is also proposed in this thesis. It provides various gains when the radar echo signals have different signal strength. Complete 79 GHz automotive pulse radar transmitter is also shown in this work. It consists of a programmable pulse generator, a voltage controlled oscillator, a BPSK modulator, a driving amplifier, and a balun. It can transmit modulated signals including OOK, BPSK, and FMCW. For optical communication system, since the parasitic capacitance from the photodiode degrades bandwidth performance, the system needs a low input impedance transimpedance amplifier to relieve this parasitics' effect. Based on conventional regulated cascode (RGC) structure, we designed and analyzed two modified transimpedance amplifiers (TIA). The first transimepdance amplifier solves the voltage headroom problem caused by cascode structure while the second transimpedance amplifier employs capacitive peaking technique to enhance circuit bandwidth.

並列關鍵字

automotive ； radar

參考文獻

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[2] H. Krishnaswamy and H. Hashemi, “A 4-channel 4-beam 24-to-26GHz spatio-temporal RAKE radar transceiver in 90nm CMOS for vehicular radar applications,” in Solid-State Circuits Conference Digest of Technical Papers (ISSCC), 2010 IEEE International, pp. 214–215, 2010.

[4] R. Mailloux, “Phased array theory and technology,” NASA STI/Recon Technical Report N, p. 246, 1981.

[6] A. Oncu, B. B. M. Wasanthamala Badalawa, and M. Fujishima, “22–29 GHz Ultra-Wideband CMOS Pulse Generator for Short-Range Radar Applications,” Solid-State Circuits, IEEE Journal of, vol. 42, no. 7, pp. 1464–1471, 2007.

[7] J.-H. Tsai and T.-W. Huang, “35–65-GHz CMOS Broadband Modulator and Demodulator With Sub-Harmonic Pumping for MMW Wireless Gigabit Applications,” Microwave Theory and Techniques, IEEE Transactions on, vol. 55, no. 10, pp. 2075–2085, 2007.

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應用於雷達及光通訊系統的高速電路

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