Microwave Low Noise Amplifier Analysis And Study

Rapid growth of wireless data communications has increased the demand for high performance RF&Microwave circuits, Such as Microwave Low Noise Amplifiers (LNA). The LNA is one of the most important and broad components in Microwave communication system receiver, and is used to amplify the low level signal. As the first signal processing block after the antenna, the LNA determines the noise figure and input voltage SWR and greatly impacts the dynamic range.The band of 3.5GHz was used for military, in order to expand the apply of GPRS. Ministry of Information Industry put this band for civil use, so there are no many peoples in studying and designing that band' receiver. When design the receiver of the band of 3.5GHz, more designer use MMIC LNA. But MMIC LNA always use normal circle with feedback, which can get small cubage and high integration, but not supply high noise, plainness gain and VSWR performance .In order to advance the performance of receiver of 3.5GHz, this paper give an balance LNA ,which has better performance than normal LNA's.In this paper, author introduces the basic theory of LNA, and studys the theory and technology of balance LNA. The author proposes a practical method for balance LNA ,and give a high performance one. At last, the difference between normal LNA and balance LNA is discussed and analyzed theoretically, and it is testified in the experiment.