Physical Optics Analysis Of Radome Pointing Error

For missile,either strategical or tractical ,the most important thing is to attack the target accurately.This depends upon the accurate location of the larget by the missile radar.For protecting radar antenna from external environment and for air-dynamical requirement,a radome is used to enclose the antenna.But the radome interferes in the orientation of the antenna,degradaties its perfor- mance,decreases the power reaching the target,and most importantly,it produces so called boresight error(BSE) that is,makes the antenna shows a slightly different direction of the target from its true direction,The boresight error is define as the angle shifted,and the boresight error slope(BSES) is defined as the ratio of angle shift to the tracing angle of the radar antenna .To predict the boresight error and boresight error slope is an unavoiding chief task in designing radome and in its operation.We present a calculation program in this paper,based on the physical optical theory(PO) theary to predict BSE and BSES for a conical type of radome.The PO theory is used to determine the ficticius currents electrical and magnetic on the inner face of the radome,which is illuminated directly by the radar antenna ,And then use the transmission matrix mothod to determine the outer surface ficticion currents ,The radiated from the antenna through radome is considered as the radiation field of these ficticion current. The radiation patterns with and whitout radome are calculated,and the angle difference in the maximum field point of their main clot show the BSE of the radome ,The BSE from -15 degree to 15 degree inθdirection,that been calculated and compared with the excited experimented data shows they coincide quite well .The result of this theory is useful for design and application radome.