Dual-Band Dual-Function Metasurface Unit Cells for FPC Antennas: Feasibility Analysis

Generally, the substrates used for PRS and the metal ground plane of a FPC antenna are uniform and homogeneous, allowing them to provide consistent amplitude and phase for reflection/transmission. However, for unit cells functioning as a phase-shifting metasurface, size variations are necessary to achieve phase modulation for RA at high-frequency bands. Consequently, the dimensions of the unit cells on the partially reflective surface are not entirely identical. Thus, it is crucial to examine their amplitude and phase response in the low-frequency range to assess their feasibility in realizing a FPC antenna.

In order to evaluate the impact of the phase gradient of RA function on the performance of PRS function, the amplitudes and phases of reflection/transmission at 7 GHz are plotted in Fig. 6 with the change of r1 shown in Fig. 3. The simulation results indicate that the frequency response of the unit cell remains stable as the circular patch changes. Moreover, the maximum phase differences are 0.67ﾰ and 0.45ﾰ, respectively. These findings confirm the feasibility of the Fabry-Perot cavity antenna and demonstrate that our designed dual-band dual-function metasurface unit cells can achieve independent tunability within their dual operating frequency bands.