Microwave Low Noise Amplifier Design

As one of microwave receiving system modules, Low Noise Amplifier plays a decisive role on the entire system performance. The Low Noise Amplifier is widely used in Microwave Communications, Radars, Electronic Countermeasures, Telemetry and Remote Mapping, Radio Astronomy, Geodetic, etc. The basic requirements of LNA are reliability, low noise, enough gain, sufficient bandwidth and wide dynamic range. In addition, their volumes, power consumptions, etc. may be required under the different applications. At present, the LNA is developed towards to the directions of the higher frequency, lower noise, wider bandwidth, higher linearity, more integration and standardization.This paper has introduced the basis theoretical of microwave low Noise Amplifier firstly, and then researched the design of the Low Noise Amplifier which includes the calculating of the noise figure, the choosing of the matching circuit and the improving method of the stability of LNA, etc. A Limited Low Noise Amplifier which has a frequency range of 2.0GHz to 2.4GHz and a Low Noise Amplifier which has a frequency range of 5.6GHz to 6.8GHz were designed by using the microwave circuit simulation software Advanced Design System. And the 2.0GHz to 2.4GHz Limited Low Noise Amplifier used lumped parameters and distributed parameters hybrid matched. Which used source-level series negative feedback to improve the stability of the amplifier? And the Performance are shown as follows: the noise figure is less than 1dB, the gain is more than 30dB, the fluctuation is less than 1dB, the input and output VSWR is less than 1.5, and the output 1dB gain compression point is better than 15dBm. The limiter designed by MA-COM Company's limited diode could operate perfectly when the input pulse power is up to 400W, and less than 0.3dB insertion loss. This limiter has a simple structure, stable performance, strong limiting ability, low insertion loss etc. the 5.6GHz to 6.8GHz Limited Low Noise Amplifier used microstrip impedance jump style matched, With a simple structure, easy to debug easy processing characteristics. Used EM electromagnetic hybrid simulation of the ADS Momentum three-dimensional simulator, and full account the impact of distributed parameter and the package of the devices, Improve the simulation accuracy. The Performance are shown as follows: the noise figure is less than 1.2dB, the gain is more than 40dB, the fluctuation is less than 1dB, the input and output VSWR is less than 1.5.