Single-Layer Dual-Frequency Planar Pattern Manipulation Surfaces Based on TM02 Mode and TM03 Mode of Patches

In this article, a novel method of designing planar pattern manipulation surfaces (PMSs) on a single-layer substrate that can simultaneously work at two different frequencies is proposed for multiband communication systems in future wireless networks. The electric field ( $E$ -field) distributions of different modes on the patch are analyzed with the help of characteristic mode analysis (CMA) to find the maximum and minimum $E$ -field distributions of different modes. TM02 mode and TM03 mode are chosen to realize the dual-frequency function. The pattern of TM02 mode is reoriented to broadside by two slots etched around the position with maximum $E$ -field of TM03 mode. To provide different reflection phases, two sets of pins are loaded to adjust the resonant frequencies of different patch elements. The relationships between the reflection coefficients and the positions of pins at two different frequencies are discussed. The mutual interference when manipulating the pattern at two different frequencies simultaneously is minimized with two different methods, choosing proper locations of shoring pins and taking the mutual interference into consideration with optimized algorithms. By properly designing the reflecting phase distributions on the entire surface, the reflected waves can be steered to desired directions at two different working frequencies. Finally, two prototypes are fabricated and measured to justify the presented design concept. Measured results agree well with the calculated and simulated ones, indicating that the proposed dual-frequency PMS is a promising candidate to create a smart radio environment in future wireless networks.