Multifunctional Partially Reflective Surface for Smart Blocks

In general, a partially reflective surface (PRS) is mainly used to increase the gain of an antenna; some metallic objects placed on the PRS degrades the antenna performance because the objects change the periodic structure of the PRS. Herein, we propose a multifunctional PRS for smart block application. When a passenger passes over a smart block, the fare can be simultaneously collected and presented through the LED display. This requires high gain antenna with LED structure. The high gain characteristic helps the antenna identify passengers only when they pass over the block. The multifunctional PRS has a structure in which an LED can be placed in the horizontal direction while increasing the antenna gain. We used the antenna’s polarization characteristics to prevent performance deterioration when LED lines are placed in the PRS. We built the proposed antenna and measured its performance: At 2.41 GHz, the efficiency was 81.4%, and the antenna gain was 18.3 dBi. Furthermore, the half-power beamwidth was 18°, confirming a directional radiation pattern.

Compact and Robust Fabry-Perot Cavity Antenna with PEC Wall

In this paper, a novel Fabry-Perot cavity (FPC) antenna with a perfect electric conductor (PEC) wall is proposed to design a structurally compact and robust high-gain antenna. Generally, the FPC antenna comprising a PEC ground and a partially reflective dielectric surface (PRDS) is required to have a half-wavelength height to satisfy the resonance condition. If a perfect magnetic conductor (PMC) is substituted for the PEC ground, the height of the FPC antenna can be reduced to a quarter wavelength. The PRDS of the proposed FPC antenna is located on the PEC ground to obtain the effect of a PMC. Moreover, PEC walls are employed to block leakage by a guided mode inside the PRDS. As a result, the proposed FPC antenna can be designed as a compact high-gain antenna although it is composed of PEC ground and PRDS. To verify its feasibility, we simulated and measured the performance of the proposed antenna regarding the reflection coefficient, peak gain, and far-field radiation pattern. Finally, the height of the proposed antenna was reduced by approximately 50% compared with the conventional antenna, while the peak gain is more than equal to that of the conventional antenna.