A repeater coil is used to extend the detection distance of a passive wireless multi-parameter sensing system. The passive wireless\nsensing system has the ability of simultaneously monitoring three parameters by using backscatter modulation together with\nchannel multiplexing. Two different repeater coils are designed and fabricated for readout distance enhancement of the sensing\nsystem: one is a PCB (printed circuit board) repeater coil, and the other is a copper wire repeater coil. Under the conditions of\nfixed voltage and adjustable voltage, the maximum readout distance of the sensing system with and without a repeater coil is\nmeasured. Experimental results show that larger power supply voltage can help further increase the readout distance. The\nmaximum readout distance of the sensing system with a PCB repeater coil has been extended 2.3 times, and the one with a\ncopper wire repeater coil has been extended 3 times. Theoretical analysis and experimental results both indicate that the high Q\nfactor repeater coil can extend the readout distance more. With the copper wire repeater coil as well as a higher power supply\nvoltage, the passive wireless multi-parameter sensing system finally achieves a maximum readout distance of 13.5 cm.
Loading....