Design of high-gain lens antenna based on phase gradient metasurface

A high-gain and low-profile lens antenna is designed using phase-gradient metasurface (PGMS). The PGMS is a planar structure and is composed of many PGMS units. By changing the size of the metal patch on the unit gradually, we can obtain a transmission phase-shifting range of about 360 degrees. Based on the principle of the phase compensation of the optical lens, the PGMS is designed. Since this phase-gradient metasurface can focus an incident plane wave, therefore, we placed an X-band patch antenna at the focal point of the PGMS as a feed source. In this way, the PGMS and the patch antenna constitutes the entire antenna system together. Then this antenna system is studied using computer simulation. Results show that the designed planar PGMS lens is not only very thin but also can effectively reduce the main beam width and thus enhance the gain of the source antennas. The gain reached 18.7 dB and high directivity was achieved.