應用於車用雷達與點對點通訊系統之互補式金屬氧化物半導體毫米波功率放大器

Abstract

隨著製程不斷的演進，互補式金屬氧化物半導體製程的電流增益截止頻率已大於150-GHz，使得互補式金屬氧化物半導體製程上也可以實現毫米波頻段的電路；矽製程的高整合的高整合和低成本的優勢，再搭配毫米波頻段的各種特性，矽製程在毫米波系統的應用將愈來愈廣泛。但互補式金屬氧化物半導體製程具有些先天上的一些缺陷，諸如低操作電壓、低崩潰電壓與高損耗被動元件等缺點，將使得以互補式金屬氧化物半導體製程實現高效能的毫米波電路為一非常困難的課題。有鑑於此，論文中將提出電路技巧減緩此些製程缺點所造成的障礙，同時並以實際晶片之量測結果加以驗證。 功率放大器為無線收發系統中重要元件之一，功率放大器使用於傳輸機的輸出級，提供足夠的能量供天線輻射信號。本論文將探討毫米波頻段的功率放大器設計。首先論文將討論主動以及被動元件在高頻段設計時須考量的課題，並簡單介紹一些功率放大器的基本原理和設計考量。最後提出一個操作於77-GHz的之功率放大器，以65奈米互補式金屬氧化半導體製程製作。電路採用傳輸線作為其匹配電路以及採變壓器形式的功率合成器來與增進輸出功率。根據量測結果，在1.0伏特的操作偏壓，在77-GHz可達到 27.3-dB的小訊號功率增益、輸出1-dB壓縮功率值為8.5-dBm、最大輸出功率為12.9-dBm。操作偏壓在1.2伏特時，在77-GHz可達到 27.9-dB的小訊號功率增益、輸出1-dB壓縮功率值為10.2-dBm、最大輸出功率為14.6-dBm。此電路驗證互補式金屬氧化物半導體製程技術確實可實現高功率輸出之毫米波功率放大器並與矽鍺製程技術相當的性能。

With the continued scaling of silicon CMOS technology, the unity gain cut-off frequency of CMOS transistors is above 200-GHz, which provides opportunities for circuits operating at millimeter-wave band. Silicon technology has advantages such as high integration and low cost. Utilizing a variety of characteristics of millimeter-wave band, applications for millimeter-wave systems in silicon technologies will be more and more popular. Nevertheless, the CMOS technology possesses some inherent disadvantages, such as its low supply voltage, low breakdown voltage, and large loss of on-chip passive components, so it is difficult to realize the high performance CMOS circuits for the millimeter-wave applications. In this thesis, RF circuit techniques are presented to alleviate those bottlenecks and provide the experimental results to verify the functionality. Power amplifiers are one of the most critical elements in wireless transceiver nowadays. They are utilized at the output stage of a transmitter to provide sufficient power for antenna to radiate electromagnetic energy. In this thesis, we focus the on the design of millimeter-wave power amplifier. At the beginning, we discuss the design and analysis of active and passive components at higher frequencies, and briefly introduce some basic theory and design considerations for RF power amplifiers. Next, a 77-GHz power amplifier in 65-nm standard digital CMOS technology for automotive radar and point-to-point communication applications is presented. This circuit employs transmission lines as its matching networks and the transformer power combiner to improve the output saturation power. According to the experimental results, the proposed power amplifier achieves 27.3-dB small signal gain, 8.5-dBm output 1-dB compression point and 12.9-dBm saturated output power at 1.0-V operation. When it is operated at 1.2-V, it achieves 27.9-dB small signal gain, 10.2-dBm output 1-dB compression point and 14.6-dBm saturated output power. This work has demonstrated that CMOS technology is appropriate for the millimeter-wave power amplifier for high output power applications.