Search

A harmonically driven bio-radar based on the technique of a multiport interferometer (six-port) technique is proposed and studied in order to improve the performance of vital signs monitoring. The feasibility of estimating cardiopulmonary parametric signatures by deploying a harmonic multiport interferometer radar is presented. This scheme is helpful to reduce the noise floor and the effects of undesirable parasitic harmonics of breathing and intermodulation. A theoretical analysis is developed to explain why a better heart-beat detection using the proposed harmonic six-port radar architecture can be achieved. The well-known null point problem usually encountered in such radar detections of heart-beating signs is alleviated by the insertion of a fixed 45° phase shift between the two different frequencies in the six-port discriminator without an actual phase-shifter. Simulations are carried out to investigate detection accuracy and sensitivity issues for monitoring the vital signs by cancelling the breathing harmonics and intermodulation products. The concept is then validated by the measured results of an experimental prototype using the proposed harmonic six-port radar platform operating at 12 GHz (fundamental) and 24 GHz (harmonic). [ABSTRACT FROM AUTHOR]

This study presents a compact circularly polarised array using tapered slot antenna fed by a substrate integrated waveguide (SIW) power divider. With the proposed topology, broadband circularly polarised property is achieved and total gain can be increased by controlling the element length, conserving the same footprint area. The different 2 × 2 cell configurations are investigated. Simple and integrated series-parallel SIW feed for the choose cell is presented. A 2 × 2 antenna array is designed and fabricated using SIW E-plane power divider. The measured 10 dB return loss and 3 dB axial ratio bandwidths are 35.65 and 32.3%, respectively. The measured antenna gain is 14.4 dBi at 35 GHz. [ABSTRACT FROM AUTHOR]