A compact reconfigurable concurrent dual-band Wilkinson power divider for noninvasive vital sign detection applications

A Compact Concurrent dual-band Reconfigurable Wilkinson power divider (WPD) for noninvasive human vital signs detection is reported in this paper. The Tuning element is incorporated into the shunt element of the dual-band impedance transformer of the concurrent dual-band WPD circuit. Design approach along with design equations is provided to enhance further design utility. Tunability of both bands (2.45/5.25 GHz) is investigated using a single varactor diode thereby resulting compact size and less cost. The performance of the WPD as a function of various tuning voltages is studied in detail. A hardware prototype is realized to work at WLAN bands and exhibiting a total tunability bandwidth of 385 MHz and 735 MHz at lower and upper frequency bands, respectively, for a varactor voltages varying from 0-15 V. The calculated and measured results are in good agreement. The measurement analysis shows that the proposed compact reconfigurable dual-band WPD can be used as a subsystem in a noninvasive multi-band RF vital sign detection system for the better detection of human vital signs such as heartbeats and respiration rate.