Electromagnetic Performance Analysis Of Antenna Radome Based On PO Method

Antenna radome is a shell structure,which protects enclosed antennas or antenna array from erosion of complex natural environment outside.It provides physical isolation of base station antennas,airborne antennas,satellite communication antennas,and other antenna systems from complex natural environments.To a certain extent,it extends the antenna life.Besides,for antennas,radome can play a hidden role in the case of the use of camouflage coating.The role of modern radomes is not only to protect the antenna structure,but also to solve many special problems.For electromagnetic waves out of the operating frequency band of the antenna,a radome diffuses the incident plane wave to the non-incoming wave direction or other direction,reducing the echo in the incoming direction.Wideband stealth airborne radome,which cooperates with airborne active phased array,reduces the RCS of antennas and effectively avoids the ground and airborne early warning radar network interception.After a specially enhanced design of the radome,and even anti-bombing function,the nuclear war environment clock can make the equipment from or less heat radiation,radiation damage directly.Radome itself can also be made into beautiful handicrafts.Landscaping radome is designed as trees,street lamps and other objects,and makes the surrounding environment harmony to ease the residents of the installation of base station antenna resistance.Antenna Radome technically has many contradictions.It requires not only in the shape to maintain aerodynamic performance and to meet the structural strength and stiffness,but also to meet the need of electromagnetic performance.In this thesis,electromagnetic performances of antenna radome are analyzed by using the physical optics method.Taking a rectangular dipole array-a single-layer hemispherical radome and a pyramidal horn antenna-a sandwich semi-ellipsoidal radome,parameters of electromagnetic performances of antenna radome are calculated,such as power transmission coefficient,boresight error,reflection lobe,etc.The main research work is as follows.Firstly,near field of dipole array is calculated using induced electromotive force to obtain incident filed on the inner of hemispherical radome.And then,transmission coefficient and reflective coefficient of dielectric radome are calculated,which taking tangential phase into consideration and coincides with formula of multiple reflection.Incident wave can be decomposed into horizontal and vertical components to gain transmitted field on the outer and reflected field on the inner.For transmitted field,radome enclosed far field pattern,direct lobe,is obtained by solving surface integral according to equivalent principle.For reflected field,a second incident field and reflected field are obtained by solving aperture integral.And pattern is gained in far zone.Total reflective lobe can be solved based on multiple iterative method.Gain pattern of radome enclosed planar dipole array and pyramidal horn antenna is consistent with FEKO,an electromagnetic simulation software,to prove the correctness of the algorithm.Then,effect of mesh size on convergence is discussed.Sampling criteria are satisfied when the face size is less than a quarter wavelength.Finally,effect of interactive number,scanning angel and height of horn aperture on reflective lobe are analyzed.It shows that When the iteration is more than twice,the total reflection lobe converges and the calculation accuracy is higher.When the scanning angle of the antenna increases,the peak value of the reflection valve power level increases.When the distance between the antenna and the radome becomes smaller,the reflection lobe is enhanced,resulting in the depression of the main lobe of the total lobe and the decrease in transmission efficiency.