A Dual-Polarized Meandered Ring-Slot Antenna for Wireless Capsule Endoscope Systems

In this letter, a novel dual-polarized capsule antenna is designed. The antenna is printed on a circular substrate with a superstrate to miniaturize the antenna, and is located at the upper end of the capsule. The dual-polarization capability is achieved by exciting a pair of degenerate modes of a meandered ring-slot antenna using two inductive coupling elements. The antenna is designed for use in the Industrial, Scientific, and Medical (ISM) band at 2.45 GHz. Since the antenna adopts a pair of orthogonal degenerate modes, there is relatively high isolation between the two ports. To verify the proposed design, measurements of S-parameters and far-field parameters were performed on the fabricated antenna prototype. The numerical simulation and the experimental results essentially agree. In addition, the robustness of the antenna is checked, its specific absorption rate is evaluated, and its link margin is analyzed.