Integrated Radio Frequency Variable Gain Amplifier

• Main Authors: Bing-Jiun Lai, 賴炳均
• Other Authors: Janne-Wha Wu
• Format: Others
• Language: en_US
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/79487323239286597680

碩士 === 國立中正大學 === 電機工程所 === 96 === The first stage of a receiver is typically a low noise amplifier, whose main features are to provide enough gain and minimize the influence to subsequent stages due to the noise generated in itself. In general, variable gain amplifier is employed for automatic gain control, which is used for automatically adjusting gain of the receiver path, so that the received RF signal can be easily processed by subsequent circuits. The requirements for the tuner front-ends are low power consumption, dB-linear, dynamic range, linearity and gain performance. The first part of this thesis is devoted itself abut the variable gain amplifier which was manufactured by the TSMC 0.18 μm CMOS process. It is applied to WiMAX system. The first one is the variable gain low noise amplifier in which the differential topology being used due to its inherent feature of low interference. The second is the variable gain amplifier, which is addressed on the high tunable gain range. It can be use in the transmitter just before the power amplifier or used in receiver after the low noise amplifier. The second part of this thesis is the wideband variable gain low noise amplifier which was fabricated by a standard TSMC 0.35 μm SiGe BiCMOS technology. In order to improve the bandwidth, two types of feedback are employed, and then using the Darlington pair to double the cutoff frequency.