The Research Of Ku-Band Receiver Front End

Mobile satellite communications system is the production which is combined by the technology of satellite communication and the technology of mobile communication technology. Because it can make real-time communication under various emergency conditions come true, therefore mobile satellite communications become a hot toptic in recent years. The receiver front-end is a key component of the mobile satellite communications system, and it can determine the receiver sensitivity of the receiving system. The study of receiver front-end system which has the characteristics of high gain and low noise is a very important work. It can not only improve the receiving sensitivity of the mobile satellite communication system, but also reduce the gain of the receiving antenna. And then we can design a antenna which has smaller size. And thus we can achieve the purpose of miniaturization of mobile satellite communications systems.This paper does some stduies about ku-band receiver front end and makes a ku-band receiver front which has the features of high gain, low noise, high receiving sensitivity and low cost.My major works for ku-band receiver front end are listed on the following:1. The second part of this paper is to make a feasible plan according to the targets of the receiving systems, make the receieving system divide a plurality of modules, and then design every module of the receieving system.2. The second part of this paper is to make a study about the working principle and design method of low-noise amplifier, and design a dual low-noise amplifier which achieves the following objectives: At the band of 12.25 GHz ~ 12.75 GHz, the noise figure of two channel amplifier is less than 0.94dB; The gain of two channel amplifier is more than 24dB; The gain flatness of two channel amplifier is less than 0.5dB; The gain difference between the two channel amplifier is less than 0.5dB; The phase difference between the two channel amplifier is less than 5o.3. The third part of this paper is to introduce the theory and method, and design two DRO based on shunt feedback structure. One of them whose oscillation frequency is 10.6GHz, and the other is 11.3GHz. The output power of all are greater than 10 dBm,and the phase moise of all are less than-100dBc/Hz@100KHz.4. The fourth part of this paper is to introduce the theory and method, and design two mixers based on the structure of drain mixer. The gain of all are greater than 6dB,the noise of all are less than 3dB, and the leakage power of local oscillator is less than-50 dBm.5. The fifth part of this paper is to make a appropriate choice of IF amplifier which can satisfy gain requirements of the receiver front-end.6. The last part of this paper is to cascade all modules which has been designed in the front, and then do some debugging and testing works to the receiving system.