A novel planar LHM radome for microstrip antenna

The designed LHM unit cell can indeed achieve gain improvement. It is easy and cheap to fabricate our planar LHM structure by using FR-4 slab. Our results show that a two-layer structure of LHM radome can achieve gain improvement by 3 dB. The gain can be further improved by increasing the number of layers. The number of layers can be determined from the requirement of particular gains for different applications. However, more than 12 layers of LHM will produce little further gain enhancement in this structure. Since the LHM radome is placed very close to the antenna and the radome only covers the area of the radiation patch, the extra volume of the LHM is limited. In addition, the LHM structure has lower sensitivity to the S11 besides gain improvement, even at small spacing between radome and antenna. These advantages together make it feasible to apply the LHM radome to the existing antennas in a wireless system.