| After several decades of rapid development, radio frequency (RF) wireless communication technology has been widely used in various fields of modern society with its advantages such as convenience, efficiency. At the same time, the demand for market requires a higher performance index of RF wireless communication system. For example, the circuit can operate with lower voltage and having the lower power consumption, a smaller size and a wider work bandwidth. In the RF front-end circuit, low noise amplifier (LNA) is one of the most important modules. The degree of LNA’s performance has a decisive influence to the receiver noise coefficient and sensitivity performance. Hence, the study on high performance LNA design has important theoretical and practical significance.The main purpose of this paper is not only to research relevant theories and design technologies of LNA, but also to design the LNA circuit with a good performance by using CMOS technology. In order to achieve this purpose, the first work is detailed research and analysis of RF integrated circuit theory that a LNA designer needs to know, such as the theory of S-parameter theory, the theory of noise, RF integrated circuit devices, besides, the current reuse technique and the noise eliminate technology. Based on the theoretical research, the paper had completed the design and simulation of the following three kinds of LNA:(1) A 2.4GHz narrowband LNA is designed by using the Cascode structure and current reuse technology, and the pre-simulation is carried out. The gain on the 2.4GHz is 23.5dB. The input and output reflection coefficient both are less than-16dB. The noise coefficient is 0.72dB. The LNA1 can operate at 1.5V supply voltage. The power consumption is 4.9mw. The input third-order intercept point is-1.6dBm.(2)By using the forward body bias and fold-Cascode structure to optimize the power supply voltage and power consumption, a 2.4GHz narrowband LNA is designed in this paper. The pre-simulation results show that the LNA can operate at 0.5V supply voltage and the power consumption is 1.8mw. At 2.4GHz the gain is 23.8dB and the noise coefficient is 0.62db. The input reflection coefficient is -28.2dB and output reflection coefficient is -24.8dB.(3)Based on the studying on relevant theories of broadband LNA, for the optimization design of noise performance and gain performance, the paper designs a 2-5GHz wideband LNA with two-stage resistive feedback current reuse structure and noise elimination technique. The LNA has taken out the pre-simulation, layout design and post-simulation. The results of the LNA’s post-simulation show that the LNA2 can operate in 2-5 GHz, under 1.5V supply voltage. The power consumption is 9.03 mW. The noise coefficient is less than 2.75 dB. The highest gain reaches 20.5 dB. The input and output reflection coefficient both are less than -10 dB. The reverse gain is below -38 dB. Input third-order intercept point is -4.98 dBm at 3GHz. |
