Hard Surfaces to Reduce Blockage in Thick Cylinders

In this work, the problem of reducing the blockage caused by infinitely long cylinders by using rhombic cross-sectional shapes and hard surfaces is revisited for cross sections with sizes that are not electrically small. First, the concept of equivalent blockage width for characterizing invisibility is reviewed. Then, ideally hard cylinders with rhombic cross sections are analyzed separately for TE and TM polarizations. Finally, hard surfaces made with periodic narrow strips are presented as real coating solutions that reduce blockage simultaneously for TE and TM cases in cylinders with relatively large width and can, consequently, be considered as a possibility for cloaking (for one direction).