Low-profile and wideband gain enhanced Fabry-Perot cavity antenna using gradient PRS and AMC

Low-profile and wideband gain enhancement Fabry-Perot cavity antennas (FPCA) is proposed using gradient Partially Reflective Surface (PRS) and gradient Artificial Magnetic Conductor (AMC). A wideband source antenna is designed with a -10 dB impedance bandwidth of 58.1% (6.1-11.1 GHz). The PRS is constructed by a complementary frequency-Selective Surfaces (FSS) with a square hole and four small patches in a unit, which realizes phase increasing with frequency. The PRS and the AMC are gradient alone x-direction to achieve wideband phase compensation. While they are uniform in y-direction to realize better gain enhancement. Compared with the source antenna, the gain enhancement of the proposed FPCA is about 4-7 dBi. Moreover, the simulated and measured 3-dB gain bandwidths are 7.26-10.33 GHz (34.8%) and 6.8-10.8 GHz (46%), respectively. The gain enhanced bandwidth is about 52.3% (6.5-11.1 GHz). The impedance bandwidth is 6-11.1 GHz (59.65%). By using the gradient size AMC, the profile of the FPCA is reduced from 0.5 lambda(0) to 0.2 lambda(0), where lambda(0) is the wavelength of 8.5 GHz. The proposed FPCA has the characteristics of wide impedance bandwidth, wide 3-dB gain bandwidth, wide gain enhanced bandwidth and low-profile.