Research On Material Applied On The Increase Of The Isolation Between Coplanar Antennas

With the application of integrated RF technology on the ship,the ship antennas will be array antenna through the mainstream active phased array technology or composite antenna technology,and the superstructure and the ship(or mast)will be conformal arrangement.Compared with the traditional discrete antennas,the increasing of coplanar antennas amount have changed the electromagnetic characteristics of superstructures.The coupling energy form between antennas has changed from traditional direct coupling to direct coupling and surface wave coupling.This change brings new challenges to the design of electromagnetic compatibility between warship antennas.This paper mainly studied the method of energy isolation,and applies radar absorbing material,metal baffle and EBG structure on the coupling paths of ship coplanar antennas to increase the isolation between antennas.In this paper,the electromagnetic wave propagation model of coplanar antenna was established.The coupling form of coplanar antennas and the principle of material suppression for the coupling energy were theoretically analyzed.Then the effectiveness of the material was studied by experiment or simulation.In view of the absorbing material and metal baffle,the isolation performance of the material was verified by the experiment.The experiments were carried out on the darkroom and the ship model platform respectively.The improvement of the isolation range of the absorbing material on the coplanar antenna with fixed spacing was studied.The absorbing materials had certain effect in 1GHz-18 GHz,and the 4.5GHz-6GHz isolation increased by 10 dB.In the 10GHz-18 GHz band,the increase of the isolation is 15dB-20 dB,and the effect was more obvious.Then the improvement of coplanar antenna isolation when metal baffle height and layers changes was studied,results show that the electrical length of the baffle height from 0 to 1.6 changes,the isolation is more significant improvement,reaching 6dB/?,when the electrical length increases to 4?,the isolation is increased by 10 dB.when the height of baffle is further increasing,isolation change is not obvious.Aiming at the structure of EBG,the simulation method was applied to the S band coplanar antenna isolation as an application case.The design method of S band EBG band gap structure was studied,and the influence of the size parameters of EBG structure on the surface wave band gap range and attenuation ability was studied by related methods.Finally,the simulation results show that the sidelobe suppression of S band horn antenna is applied before and after the application of EBG structure.The results show that the sidelobe of the horn antenna decreases 10 dB after installing EBG structure,which indirectly proves the effectiveness of the EBG structure to improve the isolation of the coplanar antenna.