FPA using a three‐layer PSS for gain enhancement

For the Fabry–Perot antenna (FPA), the non‐uniform electromagnetic (EM) field phase distribution on its aperture adversely affects its gain. To uniformise the FPA's aperture phase distribution and thereby improve the gain, a three‐layer phase‐shifting structure (PSS) is proposed. By using a hybrid method combining the equivalent circuit method and the full‐wave simulation, the PSS is designed to shift the phase of EM wave within a large range of about 360°, while allowing EM wave to penetrate it smoothly. As a sample, a PSS is fabricated and applied to a cylindrical FPA working at 5.8 GHz. Simulation and measurement show that the proposed PSS successfully transforms the field phase distribution on the FPA's aperture to a much more uniform one, and achieve a significant gain enhancement of 4.76 dB (from 15.09 to 19.85 dB). The three‐layer structure causes an insertion loss of only 0.88 dB.