Precise Moisture Monitoring for Various Soil Types Using Handheld Microwave-Sensor Meter

Lee

et al. 2017

IJECE

A compact and low cost portable vector reflectometer is designed for a reliable measurement of reflection coefficient, <em>S</em><sub>11</sub>. This reflectometer focuses on return loss measurement of frequency ranges from 450 MHz to 550 MHz. The detection of magnitude and phase is based on the utilization of surface mount Analog Devices AD8302 gain/phase detector. The data acquisition is controlled by using Arduino-Nano 3.0 microcontroller, with the use of two analog to digital converter (ADC) and a digital to analog converter (DAC). One port (Open, short and matched load) calibration technique is used to eliminate systematic errors prior to data acquisition. The evaluation of the reflectometer is done by comparing the result of the measurement to that of vector network analyzer.

Section: One Port (Open Short and Load) Calibrationmentioning

confidence: 99%

Development of Compact P-Band Vector Reflectometer

Lee

et al. 2017

IJECE

“…A C-section is a coupled-line coupler with its two ends interconnected so as to form a two-port network, as shown on the left of Figure 1(a). It is an all-pass network (|S 21 (x)| 5 18x) exhibiting a frequency dependent group delay response, with its delay maxima occurring at odd-multiple of quarter-wavelength frequencies, that is, l 5(2m 1 1)k g [5,6]. Such a conventional C-section can be extended to a higher-order configuration, as proposed in [3], to form an HC coupled-line phaser, as shown in the right of Figure 1(a).…”

Section: Hybrid-cascade Coupled-line Phasers For High-resolution Radimentioning

confidence: 99%

“…Real part of permittivity, which is known as dielectric constant, ε ′ r is an important parameter in food and agricultural industries processing using microwave techniques. ε ′ r varies greatly between soil types due to different trace elements content in soils, terrain (vegetative and mountainous) , and moisture content (MC) . Measurement of MC is well‐established due to high sensitivity of water toward ε ′ r .…”

Section: Introductionmentioning

confidence: 99%

Dielectric characterization of various soil types using modified microstrip ring resonators techniques

Micro & Optical Tech Letters

Dimon

et al. 2014

Self Cite

In this article, four nondestructive sensor tool of microstrip ring resonator (MRR) with mean diameter 84.8 mm were developed to determine different soil types based on the dielectric constant, e r 0 of respective soil types using frequency-variation method. The four MRR were designed with different angles of microstrip bends (conventional sensor 5 0.98 rad, Sensor A 5 1.34 rad, Sensor B 5 1.57 rad, and Sensor C 5 1.64 rad) at the sides of each corner and each sensor was modeled in resistor-inductor-capacitor (RLC)-lumped element circuit with proper adjustment of capacitances. Seven types of soil samples were placed, respectively, on the MRR holder up to 25 mm. The S-parameters measurement was made with E5071C vector network analyzer. In this article, the measured dielectric constant using proposed Sensor B has better accuracy with smallest overall uncertainties of 2.14% against commercial dielectric probe HP85070D and 2.43% against coaxial cavity technique while its sensitivity was determined at 0.125 toward the seven soil samples and measurement resolution of 0.849. Both mentioned parameters were the highest as compared to the other three proposed sensors.

“…are within ±0.02 m.c. The deviation is due to several factors such as soil-water mixture is not uniform during the preparation of samples as well as some water content has evaporated into air during experiment [2]. …”

Section: A Moisture Measurementsmentioning

confidence: 99%

“…Microwave ring sensor for soil moisture and dielectric measurement was first introduced by Kamal Saramandi [1], followed by monopole sensor [2], antenna patch [3], resonator cavity [4], , and coaxial probe [5]. Time domain reflectometry (TDR) and currently the most popular, frequency domain reflectometry (FDR) which is used in this paper are significant operating system for microwave aquametry measurement.…”

Section: Introductionmentioning

confidence: 99%

Soil moisture dielectric measurement using microwave sensor system

2014 International Symposium on Antennas and Propagation Conference Proceedings

Dimon

2014

Self Cite

A microwave sensor system has been developed to operate from 2.2 GHz to 4.4 GHz and used to determine the change of soil dielectric constant with various values of gravimetric moisture content from 0% to 26%. Soil samples are placed on a microstrip ring resonator (MRR) sensor and the respective incident and reflected voltages are measured and converted into magnitude of return loss, |S 11 |. The calculated return loss, |S 11 | is then correlated with corresponding soil moisture content obtained from oven drying method and also the soil permittivity obtained from commercial dielectric probe with vector network analyzer.