Design of a low-SAR, high-gain multiband patch antenna with quad-band AMC for off-body communication applications

The proliferation of wireless communication technologies has led to a surge in the need for multiband antennas. This study introduces an innovative multiband antenna design that incorporates a 4 x 4 Artificial Magnetic Conductor (AMC) surface to achieve reduced Specific Absorption Rate (SAR), high gain, and improved Front to Back Ratio (FBR). The multiband antenna design presented in this study spans a wide range of wireless frequency bands, including ISM, WLAN, WiMAX, Wi-Fi 6E, and 7. The antenna offers comprehensive coverage for various wireless communication applications with resonating frequencies at 2.4 GHz, 3.2 GHz, 5.5 GHz, 7.5 GHz, and 10 GHz. The AMC unit cell generates four zero-degree reflection phases with Double Negative (DNG) properties at 2.5 GHz, 3.8 GHz, 5.5 GHz, and 7.5 GHz. The compact design measures 29 x 37 x 1.6mm(3) and is placed 13 mm above an AMC surface of size 64 x 64 x 1.6mm(3). The proposed antenna design achieves an increase in gain of up to 8.55dBi at 6.01 GHz and a notable improvement of 31.5 dB in FBR at 4.5 GHz. The proposed antenna design achieves a -10 dB impedance bandwidth for a range of frequencies, including 2.34-2.43 GHz (3.77%), 2.81-3.83 GHz (30.72%), 4.82-6.21 GHz (25.20%), 7-7.65 GHz (8.87%), and 8.06-10.31 GHz (24.5%). An average percentage reduction in SAR at these frequencies with the AMC structure is 96.11%. The antenna sample was successfully fabricated, and the experimental results have been found to match well with the simulation results. Consequently, this design offers a promising solution for wearable off-body communication devices that require low-SAR, high-gain, and multiband functionality.