Microstrip antenna loaded with focusing metasurface for high-gain dual-polarization and bidirectional radiation

Abstract

In this paper, we propose a microstrip antenna that incorporates a dual-polarization and bidirectional focusing metasurface (MS) for achieving high-gain transmission in circular polarization (CP) and reflection in linear polarization (LP) radiation, respectively. Initially, we design a MS that enables independent manipulation of the transmitted CP wave at a lower frequency of 8.2 GHz and the reflected LP wave at a higher frequency of 16.2 GHz, respectively. The unit-cell of the MS comprises a combination of an outer bilayered split-ring resonator, along with inner arc-shaped and disk resonators, all separated by a dielectric substrate. Subsequently, a coaxial-fed laminated microstrip antenna is designed that is capable of realizing CP radiation with a gain of approximately 4.9 dBic at 8.2 GHz and LP radiation at 16.2 GHz with a gain of 4.8 dBi, respectively. To improve the radiation performance, we construct a coaxial-fed laminated microstrip antenna integrated with a dual-polarization and bidirectional focusing MS. This configuration enables the antenna to achieve high-gain CP radiation in transmission at 8.2 GHz with a peak gain of 13.1 dBic and high-gain LP radiation in reflection with a peak gain of 14.6 dBi at 16.2 GHz, respectively. The relative bandwidth of the MS antenna is 6.79% (at 8.2 GHz) of the transmitted CP wave and 13.54% (at 16.2 GHz) of the reflective LP wave, respectively. To evaluate the practicality of our proposed design, we fabricated and measured a coaxial-fed laminated microstrip antenna, both with and without the MS. The results obtained from these measurements closely align with our simulations, thereby validating the effectiveness of our proposed dual-polarization and bidirectional MS antenna. This antenna provides a practical solution for achieving dual-polarization radiation and facilitating high-speed information transmission in communication systems.