The Research And Realization Of Active Omni Directional Small Loops Loaded Ferrite Core

With the communication technology growth in application of navigation, system requires receiving antenna ability more and more high , low outline,omni directional,anti-interference strong ability antenna becomes the hot focus on studying.The project is to come into being under such background. The paper analyses ground electric wave propagation method and it's main radiation characteristic property from the system transmitting antenna firstly:depending on the floor character,surface feature and the general configuration of the earth's surface mainly.I calculates ground wave parameters about the magnetism antenna limit working space inner field, and carried out radio noise detailedly on atmosphere.According to the navigation system characteristic and the demand and concrete technology targets, the magnetism antennas are originally systematic receiving antenna. And have suggested that orthogonality space fixes architectural loaded the low noise amplifier and the phase shifter design plan according to magnetism antenna shortcoming and virtue. The plan completely carries out the problem which the whip antenna wire volume is so large and the lonely core magnetism antenna exists directionality, and have testified the feasibility about the antenna.The syntony circuit is magnetism antenna's important component. The paper analysed the ferrite core character, ascertained magnetism antenna syntony circuit iron core type and the coil parameter according to the system main needs; and have introduced method that we make the coil winding, verifying the syntony circuit capability to the request.Finally the paper designed magnetism antenna amplification circuit. Through the scheme and systematic corresponding request , brought forward the concrete index about the circuit. According to the minimum noise designs principle , adopting highly dynamic range FET to design out low noise amplifier. Applied the ADS software to carry out the corresponding optimization on low noise amplifier index simulating; The need according to the omni directional antenna, adopted bridge type phase shifter to be in progress to two road orthogonality signals moving the software applying a relevance each other , at present simulating testifying design reaching the request; have applied the ADS software to design the band pass filter directly , have analysed and in the process of wave filter design what needs to pay attention about the problem.