Research And Design Of Satellite Broadband Active Receiving Antenna

Spaceborne antenna is the antenna which is loaded on satellite. Spaceborne antenna is the input and output of satellite signals. Satellite communication is achieved by the mutual transmission of electromagnetic waves between spaceborne antenna and earth station antenna.With the development of satellite communication technology, the requirement of the spaceborne antenna is increasing,and the technical performance requirements of the spaceborne antenna need to be improved a higher level. In view of this phenomenon,this paper designs a satellite broadband active receiving antenna based on non-foster impedance transform. The design has characteristics of small size,light weight,wide frequency band, etc to meet the requirements of satellite communication of receiving antenna.Firstly, this paper introduces the advantages of the active receiving antenna, application background and development history and analyzes the basic parameters of the antenna and the principle of achieving the requirement of miniaturization and broadband of active antenna.After the introduction of the principle of non-foster impedance converter,the paper analyzes the stability and sensitivity of the active antenna based on the non-foster impedance transform.Compared with the traditional active antenna, active antenna based on non-foster impedance transform has better sensitivity.On the basis of the research on the noise and nonlinearity of the active network and its effect on the overall performance of the antenna, I use non-forster matching method to design a monopole active antenna. Compared with the existing monopole active antenna, it can get the equivalent input negative capacitance at the input end of the active network, and then get the equivalent input gain. According to the technical index,the CST software is used to simulate the monopole antenna in the working frequency between 30MHz and 160MHz. Get the directivity and the input impedance from simulation, and then I design active network which matched it. In the design of active network, the high speed and low noise operational amplifier is chosen as the core component of the negative impedance converter. After the negative impedance conversion circuit,the low-pass filter is added to filter out the high frequency interference. It can match with the input of the receiver well by the impedance matching circuit.This paper designs a monopole active antenna based on the method of non-foster matching. And through the simulation, comparison and improvement to improve the design.From the simulation results we can know that: the gain is about 12dB, the noise figure is less than 3dB, the second-order intermodulation attenuation is equal or greater than 60dB, the third order intermodulation attenuation is equal or greater than 90dB. All of them satisfy the technical index requirements.