Research On Low Noise, High Linearity RF Front End Circuit Design With CMOS Technology

Low noise, high linearity RF front end circuit is the key of the whole RF receiver system design. Generally, low noise and high linearity can't be accomplished simultaneously because of the MOSFET physics limitations as well as the regular circuit design philosophy. But with the prevalence of more and more wireless communication applications, system designers hope to find out RF front end circuit design solutions, which could fulfill the requirements of low noise and high linearity simultaneously. This is a brand new challenge for circuit designers, which is right the focus of this dissertation. Planar spiral inductor is the most important passive component of CMOS RF integrated circuit design. This dissertation presents an optimization algorithm for Q value maximization, which is based on a lumped physical model of spiral inductor and genetic algorithm. It is proved by experiments that this algorithm is much more computational efficient than Electronic-Magnetic (EM) computation method, while its accuracy is comparable with EM method.Based on mesoscopic conductor noise model, this thesis presents a "3-Points Noise Calculation Method" for deep submicron MOSFET technology. Compared to measurement data, this method greatly improves accuracy of mesoscopic noise model. In additions, for the first time designers could get the γ equation, which describes how the thermal noise factor γ varies with device terminal voltages. With the γ equation, designers could not only predict the noise behavior of circuit precisely, but also get much more power efficient circuit, which is significant for low power RF circuit design.To resolve the dilemma of low noise and high linearity requirements, two kinds of novel circuit topology are proposed, one is called "Output Harmonics Cancellation Method" for LNA IIP3 boosting, another is called "Current Injection Method" for mixer IIP3 boosting. Through experiments, it can be shown that these two circuits could greatly improve linearity performance with ultra-low noise degradations. Finally, this dissertation gives out RF front end design, including a 2.4GHz LNA, a 5GHz LNA, a 5GHz mixer. γ equation is used to interpret the difference of measurement and simulation results. As part of this thesis is focused on 5GHz RF front end design, to the author's knowledge, it is the first time in mainland of China that designer uses CMOS technology to achieve a 5GHz RF front end design and get most measurement results.