Title :
Dual-Frequency Microwave Moisture Sensor Based on Circular Microstrip Antenna
Author :
Ghretli, Mohamed Mustafa ; Khalid, Kaida ; Grozescu, Ionel Valeriu ; Sahri, Mohd Hamami ; Abbas, Zulkifly
Author_Institution :
Univ. Putra Malaysia, Serdang
Abstract :
A dual-frequency sensor was developed to measure moisture content of lossy liquids. The experiment is based on measurements of far-field reflection at two frequencies in the X-band, 8.48 and 10.69 GHz. The replacement of the conventional open horn antenna with microstrip radiating patches makes the sensor more versatile and compact. The sensor is interfaced to a notebook computer using a multipurpose data acquisition board and few custom made circuits. Data collection, errors correction and calibration modules were written using LabVIEWreg programming language. Three calibration methods were used to obtain an empirical equation, which is applied to obtain the moisture content of the rubber latex samples. Moisture content can be determined with a standard error 0.49%.
Keywords :
antenna radiation patterns; calibration; data acquisition; error correction; microstrip antennas; microwave antennas; moisture measurement; multifrequency antennas; notebook computers; programming languages; sensors; virtual instrumentation; LabVIEWreg programming language; calibration modules; circular microstrip antenna; data collection; dual-frequency microwave moisture sensor; error correction; far-field reflection measurement; lossy liquid; moisture measurement; multipurpose data acquisition board; notebook computer; rubber latex samples; Antenna measurements; Calibration; Frequency measurement; Liquids; Loss measurement; Microstrip antennas; Microwave antennas; Microwave sensors; Moisture measurement; Reflection; Dual microwave frequency sensor; microstrip antenna; moisture content; rubber latex;
Journal_Title :
Sensors Journal, IEEE
DOI :
10.1109/JSEN.2007.908920
