UBC Theses and Dissertations
On the design of wideband CMOS low-noise amplifiers Molavi, Reza
Integrated wideband low-noise amplifiers (LNAs) are used in communication applications in which either the signal bandwidth is large or multiple narrowband signals are processed simultaneously. An example of the former case is the recently popular ultra wideband (UWB) wireless technology that can be used for high-data-rate low-power short-range wireless communications. A multi-mode multi-standard wireless system is an example of the latter case. Providing large enough gain while introducing as little noise as possible over a wide frequency band is a challenging design task, in particular if the LNA is designed in CMOS. In this work, a methodology for designing wideband CMOS LNAs is presented. The core of the design is the inductively degenerated LNA which is a popular architecture in narrow-band applications due to its superior noise and input matching properties as well as low power consumption. Wideband performance of inductively degenerated LNA is explored both at the circuit and system level. Trade-offs among different design requirements and their impacts on circuit parameters is discussed in detail. To demonstrate the effectiveness of the design technique, two wideband LNAs are designed and simulated in a 0.18μm CMOS technology. The first LNA is intended for a multi-standard system with the frequency range of 1.4 to 2.5GHz. The frequency band of the second LNA is from 3 to 5GHz which covers the lower band of UWB technology.
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