Study On The Problems Of Large Transmitting Array Antennas For Space Solar Power Satellite

Space solar power satellite(SSPS)is a tremendous green energy system that collects and converts solar power to electric power in the outer space,and then,transmits the electric power to earth through microwave.This thesis is mainly concerned with the design of aperture field distribution of the transmitting antenna of the SSPS,the subarray partition design method for transmitting arrays,the effect of random errors on the electric performance of the system,and the concept design of the SSPS.The author's major contribution on these subjects can be summarized as follows:1.The design method of the stepped amplitude distribution taper for microwave power transmission for space solar power satellite is proposed.First,the idea of the stepped amplitude distribution is presented.Then,the optimization model of the stepped amplitude distribution is established based on the effect of the transmitting antenna aperture field distribution on the microwave power transmission efficiency.The optimization model can deal with the security of the receiving region.The simulation results indicate that,higher beam collection efficiency(BCE)can be obtained with the stepped amplitude distribution,and the BCE can be even higher than that of the 10-d B Gaussian one when the number of steps increases.It should be noted that with the stepped amplitude distribution,the construction cost and the complexity of the transmitting arrays can be greatly reduced.2.The application of uniformly excited unequally spaced arrays for microwave power transmission is performed.First,the effect of the element positions on the beam collection efficiency of the uniformly excited array is derived,and then the optimization model concerning the maximization of the BCE is established,which is solved using the chaotic particle swarm optimization method.And here the multiple optimization constrains include the maximum sidelobe level outside the receiving region,and the minimum element spacing.The simulation results indicate that,through this method,higher beam collection efficiency and lower sidelobe level can be obtained with the uniformly excited array.3.The subarray partition design method for large array antennas for microwave power transmission is proposed.First,the relationship between the subarray partition and the microwave power transmission efficiency is clarified,and then the subarray partition optimization model on the maximization of the BCE is established.The optimal subarray configuration can be obtained by the k-means algorithm.The simulation results show that,higher beam collection can be obtained with proper subarray partition,and due to high efficiency and robustness of the k-means algorithm,this method is especially suitable for the subarray partition of ultra large arrays.4.The impact mechanism of random errors of array antennas on the microwave power transmission efficiency is investigated.Errors are inevitable for large active phased array antennas due to calibration,installation,and the change of the working environment.On account of these factors,the element position errors and the excitation phase errors exist.These errors are not deterministic,and will deteriorate the antenna electromagnetic performance,such as resulting beam pointing error and the shape deformation of the radiating beam pattern,which will finally cause the reduction of the microwave power transmission efficiency.Towards this end,the effect of the element position errors and the excitation phase errors on the beam collection efficiency is derived according to the rules of probability method.The simulation results show that,the random errors will enhance the sidelobe level and then reduce the beam collection efficiency.5.A new space solar power satellite concept based on epsilon-near-zero metamaterial is proposed.This concept is consisted of a spherical condenser,hemispherical PV arrays,power management and distribution system,two conductive rotating joints,and a microwave transmitting antenna.With the combination of the epsilon-near-zero metamaterial and the spherical condenser,the common oblique incidence phenomenon that exists in other SSPS concepts can be avoided.Indeed,this new concept has several advantages:(1)constant and stable solar energy can be collected with higher efficiency;(2)complex structural control strategies can be avoided;(3)heat dissipation problem can be greatly released...