A Flexible Dual-Band Antenna with Stable Radiation Pattern for Wearable Application

This paper presents a flexible dual-band antenna for wearable applications. The proposed antenna consists of radiating patch, microstrip feedline, and ground plane. The four corners of the radiating rectangular patch are etched and circular slot is cut inside the patch to resonate in the Industrial Scientific Medical (ISM) band at 2.45 GHz and 5.8 GHz. The proposed antenna is designed on flexible material. The substrate material is cotton jean with dielectric constant of 1.7, loss tangent of 0.02, and the thickness of 1 mm. The overall size of antenna is $82\times 74\mathrm{mm}^{2}$. The radiation pattern of proposed antenna is unidirectional at both frequencies. The proposed antenna has the gain of 4.09 dBi and 3.19 dBi at 2.45 GHz and 5.8 GHz, respectively. The specific absorption rate (SAR) value which effects on human body is less than 2 W/kg according to IEEE95.3 standard. The SAR values of proposed antenna are 0. 3SSW/kg and 0. 35SW/kg at 2.45 GHz and 5. S GHz, respectively, over 1 gram of mass tissue. The simulated results confirm that the proposed antenna can be used for wearable applications.