60-GHz 緩衝放大器與低相位變異可變增益放大器之研製

Abstract

According to the progress of communication techniques and process technologies, wireless communication and high data-rate transmissions become the trend of developments. Recently, 60 GHz becomes a more important developed frequency band, since it is an unlicensed band for application of WPAN, which can provide the secure and efficient short-distant transmission. On the other hand, in process technologies, because of the advantages of high integration potential, low cost and low power in CMOS, it gradually replaces other process to become a major process to realize analog circuits. In this thesis, two amplifiers, which are buffer amplifier and variable gain amplifier (VGA), are applied in 60 GHz and realized by CMOS technology The 60 GHz buffer amplifier, which can amplify signal from prior stage to input of front-end power amplifier and guarantee the maximum output power can be delivered without saturation at prior stages, is discussed in first part. This amplifier is implemented by 65-nm CMOS process, and matched by TFMS lines. With reasonable power consumption, the amplifier achieves high gain and high output power with broadband characteristics of both small-signal and large-signal due to broadband matching technique. This buffer amplifier can achieve maximum linear-gain of 23.7 dB with 3-dB bandwidth of 14 GHz with maximum saturated output power of 10.3 dBm and maximum peak PAE of 16%. Therefore, it also can be applied as a medium power amplifier. In the second part, the 60 GHz VGA, which can be applied in receiver phase array systems, is designed and fabricated. With current-steering topology to realize variable gain, this VGA is implemented by 90-nm CMOS process, and matched TFMS lines. In addition to the characteristics of high linear-gain with good flatness and large gain variation range, the technique to compensate insertion phase is implemented in this VGA. As a result, the insertion phase variation is lower than 6.6° versus gain tuning. Low phase variation VGA can be applied in phase array systems to reduce the complexity of control systems while can enhance the quality of modulated signals in vector sum modulators.