Analysis of Compact Dual-Band Metamaterial-Based Patch Antenna Design for Wearable Application

A compact dual-band metamaterial-based planar patch antenna on a semi-flexible substrate is analyzed in this article. The design, printed on a Rogers substrate, having a thickness of 3.04 mm and the overall dimension is 70.4 × 76.14 × 3.11mm3 (0.37λ0 × 0.40λ0 × 0.016λ0), where λ0 = 190 mm at fL = 1.575 GHz. The design equations are presented for both GNSS (global navigation satellite system) L1/E1 lower band and the upper i.e., 2.45 GHz wireless local area network (WLAN) band. Furthermore, CSRR (complementary split-ring resonator) responsible for the CP (circularly polarized) behavior of the antenna at the lower band is explained using an equivalent circuit model. The proposed equivalent model contains two parallel RLC (resistor-inductor-capacitor) circuits connected in series with one capacitor. To describe its functionality in bending conditions, the antenna is simulated at different bending radii. SAR (Specific absorption rate) of the antenna is evaluated on a voxel human model to check its functionality at different distances from the model. The maximum averaged SAR is found to be 0.381 W/kg at 5 mm from the voxel model. This value is well below the International Commission on Non-Ionizing Radiation Protection (ICNIRP) limit of 2 W/kg averaged over 10 g of human tissue for European countries. The antenna is compared with the literature to show its compactness and superior performance as compared to other already reported designs.