Electromagnetic considerations in the design of high performance large sandwich radomes

It is shown that the reduction of the scattering effect from the seams in large sandwich radomes can be obtained by minimizing the scattering level from the individual seams and optimizing the radome geometry. The scattering from an untuned seam increases with frequency and is related to the polarization current induced in the seam. This effect can be characterized by the induced field ratio (IFR) and the seam scattering pattern. The seam effect on the insertion phase delay (IPD) and the transmission losses (TLs) of the panel for vertical and horizontal polarization is shown. It is observed that for normal incidence the IPD caused by the panel is 26 degrees and the untuned seam causes an additional IPD of 13 degrees . To reduce the IPD caused by the seam, tuning techniques, such as insertion of conductive strips in the seam, are used.<>