Improvement of UWB Patch Transducer Properties Applicable for Fetal Monitoring System

摘要

The great potential application of wireless bodyudnetwork (WBN) to improve the quality of healthcare service toudpeople was evaluated to incorporate the ultra wide band (UWB)udtechnology to obtain the better performance of WBN stuffudfunctionality. One of the very challenging WBN device developedudis specifically applied for fetal monitoring. The designed fetaludmonitoring was intended for specifically applied to suitableudutilized by the risk pregnant woman who has the difficult accessudto the hospital. Despite the many risk factors existed during theudpregnancy the constructed UWB fetal monitoring system isuddesigned to capable for sensing the fetus heart rate variability,udthe fetus growth and its contraction. The numerical evaluationudperformed was mainly focused to assess the electrical propertiesudof the designed UWB transducer to meet the technicaludspecification required. In practice, the transducer is in the formudof patch antenna structure. The antenna was designed using theudbasic structure of dielectric/ substrate which consists of FR4-udEpoxy material, top conducting radiator and ground. Thisudantenna is connected by edge feeding technique that set SMAudconnector on the side of the dielectric material. A number ofudsignificant electrical properties improvements of the designedudUWB patch transducer were found during the numericaludcomputing stage including the radiator/transducer pattern, theudS11, VSWR, and the gain. Through the numerical assessment it isudclearly shown that the return loss (S11) is very excellent to reachudthe value of approximately -35 dB. Considering the S11 boundaryudof -10 dB value the constructed RF-waves radiating transducer isudworking well at the frequency range from 1.3 GHz up to 4.1 GHzud(equal to the bandwidth 2.8 GHz). The best VSWR valueudobtained during the RF transducer numerical design isudapproximately 1.12. The gain achieved is 2.61 dB. The advancedudfetal monitoring development will also utilizes the incorporationudof the robust image processing technique to plot the womanudpregnancy indicators on the display unit