Book

Description

This book presents a triangular-notched wideband antenna for wearable wireless body area networks (WBAN) and Global Positioning System (GPS) applications. The compact antenna (0.487λ0 × 0.581λ0 ) is fabricated on a low-cost jeans substrate and features a broad rectangular slot for improved gain and compressed reduced ground for a wide operating bandwidth (1.47-2.68 GHz). The triangular notches in the patch increase the electrical length of the patch and the resulting fundamental mode TM10 (1.51 GHz), and control impedance matching. The antenna achieves bidirectional radiation patterns a 6.20 dBi peak gain, and 98% efficiency. When a large slot (Lslot ×Wslot ) is cut in a patch, it interrupts the standard TM current distribution and creates its resonance at 2.51 GHz, which overlaps the higher order mode of the patch (slot resonance mode TM02 ) and resulting in a “wideband effect” (1.47-2.68 GHz bandwidth). The antenna bending exhibited stable S11  and gains. The human body phantom results ON-body and OFF-body Specific Absorption Rate (SAR) values of 1.24 W/kg (wrist) and 1.06 W/kg (chest) at 100 mW input power, within IEEE/IEC limits of 2 W/kg for 10 g tissue. The performance parameters were validated using SMA 1075X and an anechoic chamber. The antenna had an average efficiency of 88% and a peak gain of 6.20 dBi. The proposed approach introduces an antenna size-reduction method. At 2.45 GHz, the antenna was 8.96% smaller than a typical antenna. The same antenna can be used for boy-centric medical applications if the specific absorption rate (SAR) and bending impact are carefully measured.The antenna demonstrated the stability of the effectiveness parameter against bending. Compared to the IEEE standard SAR value of 2 W/kg, the antenna's averaged SAR value with 10 g tissues on the human body, wrist, and chest was 0.979 W/kg, 1.02 W/kg, and 1.26 W/kg, respectively. By modifying the input power levels in the future, the SAR value at the thigh, which is slightly higher than the standard value, could be reduced. The proposed antenna is an ideal solution for low-power MMIC/MIC transmitters and receivers in Wi-Fi, WLAN, WiMAX, Bluetooth, and energy-harvesting.