Design Of Dual-Frequency And Dual-Circular Polarization Feeds And Research On Metamaterials In Feeds

Satellite communication plays an important role in modern society and is an important part of modern information society.As the receiving and transmitting signal device of communication equipment,the performance of antenna is related to the performance of the whole equipment.For reflector antenna,feed is the core component,especially for multi-band reflector antenna,whose performance depends heavily on the performance of feed.In order to achieve greater communication capacity,multi-band feed is often used,this paper based on the design of multi-band feed,coupled with dual polarization,so that the communication capacity is doubled,and the use of a common caliber horn form.This paper first designs a ring-focus antenna,and tests the feed of the reflector antenna,which can operate in circular polarization mode in K/Ka dual frequency band,which is 18.9GHz?19.1GHz and 28.9GHz?29.1GHz.To expand the communication capacity,this paper broadens the working frequency band to 19.7GHz?21.2GHz and 29.5GHz?31GHz on the basis of the feed index and adopts the dual-circular polarization working mode,which theoretically broadens the communication capacity by 15 times.in the process of designing dual-frequency dual-polarization feed,in order to overcome the matching problem between two frequency bands brought by dual polarization,a new OMT(Orthomode Transducer)structure is proposed.the structure adopts the form of symmetry,which reduces the influence of low-frequency band coupling structure on high frequency band,and realizes the reflection coefficient of four ports of transceiver under-15 dB.A circular polarizer with good standing wave coefficient is designed to reduce the same frequency isolation below-32 dB in order to overcome the disadvantage of low same frequency isolation due to the double circle polarization feed itself.to achieve dual-frequency co-caliber feed design in order to avoid dielectric loss,the Profiled corrugated horn is used,which can finally keep the phase stability of the transceiver band,and the 10 dB lobe width of 19.7GHz?21.2GHz and 29.5GHz?31GHz is kept within 65°?67° and 60°?63°,respectively.In addition,as a hot research object,metamaterials are widely used in the field of horn and waveguide.For the application scenario of metamaterials in feed,according to some special properties of metamaterials,this paper realizes the research of combining metamaterials with feed according to the functions that each component in feed needs to realize.this paper explores the possible application scenarios of metamaterials in the feed: using the selectivity of metamaterials to electromagnetic wave frequency,it can be used as a filter in the feed,and processing tests verify its filtering characteristics;using the selectivity of metamaterials to electromagnetic wave polarization,it can be used as a polarizer in the feed;based on the idea of transmission array and reflection array,the metamaterials are directly applied to the aperture field of the horn to realize the adjustment of the aperture field phase.