Abstract
The wireless system is being rapidly proliferated and the growing of capacity in wireless communication requires a new type of wireless communication method which does not affect current systems. In February 2002, the FCC ruled the 7500 MHz spectrum for ultra-wideband radio and the purpose of this new standard is to provide a specification for a low cost, low complexity, low power consumption, high security and high data-rate wireless communication capabilities within the personal operating space. In this thesis, the main focus is to expand the conventional narrowband LNA design based on currently available 0.18 □m CMOS technology suitable for UWB applications. In chapter 2, the fundamental of RF receiver is presented, and the review of narrowband LNA design is introduced in the last section. In chapter 3, the design method of ultra-wideband LNA is proposed. In the first section, the basic wideband concept will be introduced. In the following sections, two ultra-wideband low noise amplifiers based on the same circuit topology but two different types of input matching networks are proposed. One is the Chebyshev band-pass filter, and the other is a simple LC high-pass filter. The comparison of measured results indicates that the adoption of a high-pass filter as the input-matching network results in a better noise performance than that of using a band-pass filter. Furthermore, the grounded-coplanar-waveguide (GCPW) configuration of the transmission line is employed in the circuit layout to minimize additional noise caused by the interconnect loss and substrate coupling. In the chapter 4, the current-reused technique is introduced, and with this technique, a 3.1－10.6 GHz ultra-wideband LNA is proposed. The measured results also demonstrate the feasibilities of achieving high power gain, low power dissipation and very low noise figure simultaneously. Moreover, in order to be suitable for low operating voltage design, an ultra-wideband LNA combining the current-reused technique and folded-cascode structure is presented, and the operating frequency focus on 3－5 GHz for low-band applications. The simulation results also demonstrate the excellent performance of large power gain, good input-matching, very low noise and moderate power consumption.