Design and analysis of low-profile dual-band circularly polarized antenna using CMA for wearable applications
摘要
A low-profile dual-band circularly polarized antenna for wearable applications in the GPS and 2.4 GHz Wi-Fi/BT bands is studied in this article. The structure consists of simple concentric patches for dual-band operation and two stubs to realize CP radiation. The CP generation mechanism at the two operating bands is analyzed using characteristic mode theory. When placed 3 mm above the human wrist phantom model, the proposed antenna prototype has low SAR values of 0.7 W/Kg in the GPS band and 2.3 W/Kg in the Wi-Fi/BT band. The simulated on-wrist efficiencies are 30.3% and 41.9% at GPS and Wi-Fi/BT bands, respectively. The − 10 dB impedance bandwidths are 90 MHz (1.535–1.625 GHz) and 145 MHz (2.395–2.54 GHz) at GPS and Wi-Fi/BT bands, respectively. The 3 dB axial ratio bandwidths are 13 MHz (1.565–1.578 GHz) and 40 MHz (2.46–2.5 GHz) at GPS and Wi-Fi/BT bands, respectively. The proposed antenna has an overall size of 46 mm × 46 mm × 1.6 mm (0.24