Biblio

This manuscript prescribes the design of a four-port ultra-wideband (UWB) diversity antenna combined with 2.4 GHz ISM radio band. The denim-based wearable antenna is intended for use as a radio frequency identification (RFID) tag for tracking and security applications. The unit cells of the antenna are arranged orthogonally to each other to achieve isolation \$\textbackslashtextbackslashgt15\$ dB. The bending analysis of the proposed antenna is performed to ensure its stability. The dimensions of the unit cell and four-port MIMO antenna are \$30 \textbackslashtextbackslashtimes 17 \textbackslashtextbackslashtimes 1\$ cubic millimeter and \$55 \textbackslashtextbackslashtimes 53 \textbackslashtextbackslashtimes 1\$ cubic millimeter, respectively. The proposed antenna’s specific absorption rate (SAR) is researched in order to determine the safer SAR limit set by the Federal Communications Commission (FCC).

This paper designed a longitudinal bending coupled piezoelectric transducer. The transducer is composed of a rear metal block, a longitudinally polarized piezoelectric ceramic piece and a slotted round front cover. The longitudinal vibration of the piezoelectric oscillators drive the front cover to generate bending vibration to widen the operating frequency band while reducing the fluctuation of transmission voltage response. In this paper, the design method of this multimode coupled transducer is given, and the method is verified by numerical simulation. The results show that the analytical theory and numerical simulation results have good consistency. This longitudinal-flexural coupled vibration transducer widens the bandwidth while preserving the emission voltage response.