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Journal of Microwaves, Optoelectronics and Electromagnetic Applications

On-line version ISSN 2179-1074

J. Microw. Optoelectron. Electromagn. Appl. vol.17 no.4 São Caetano do Sul Oct./Dec. 2018

http://dx.doi.org/10.1590/2179-10742018v17i41363 

Article

Validation of RKAS Soil Dielectric Model at C and X-Band Microwave Frequencies

Rajeev Kumar1 

Arvind Sharma2 

Anupamdeep Sharma3 

1IKG Punjab Technical University, Jalandhar, Punjab, India, rajivandphysics@rediffmail.com

2Anupamdeep Sharma, National Institute of Pharmaceutical Education and Research, Raiberraily (UP), India arvindkamalsharma@gmail.com

3Arvind Sharma, Chandigarh Engineering College, Landran, Mohali, India, dr.anupamdeep@yahoo. com

Abstract

In the present study an attempt is made to validate soil dielectric model which was formed to estimate the values of dielectric constant of dry and moist soil at various volumetric moisture contents at C and X-Band microwave frequencies. Eight Soil samples are collected from various parts of Haryana. Dielectric constants are measured using waveguide cell technique at C and X-Band microwave frequencies at varying volumetric moisture contents and then compared with estimated values obtained from model. The model has good accuracy and practicality.

Index Terms Dielectric Constant; Haryana; Soil Dielectric Model

I. INTRODUCTION

In the present era of technology, microwave remote sensing is a major tool to understand and analyze natural resources like soil. The soil has physical properties like porosity, bulk density, texture, grain size, color etc; Chemical properties like pH, organic matter, nutrients available, inorganic matter etc; Electrical properties like permeability, dielectric constant, dielectric loss, electrical conductivity etc. In microwave remote sensing of soil, its electrical parameters play important role as it depends on soil moisture, texture of soil and frequency at which measurements are made. Dielectric constant is a function that depends on texture of soil, moisture content and frequency at which observations are made [1]-[8] and play very important role to understand and analyze soil.

For the estimation of value of dielectric constant of soil from its physical constituents and volumetric moisture content present in it, a mathematical model was formed which is named as RKAS model [9]. In our previous study [9], the model is formed using results of six soil samples from Hisar, Ramgarh, Rohtak, Siswal, Balsmand and Naraingarh at various moisture contents and compared with Hallikainen et al. Model [10]. In the present paper, an attempt is made to validate the mathematical model for soil samples from eight different locations of Haryana with different textured soil. These eight locations are Kaithal, Rewari, Jind, Panipat, Sonipat, Jhajjar, and Mahendargarh and Sirsa districts of Haryana.

Testing of validation of the model is done in two steps:

  1. Comparison of modeled results of dielectric constant at various volumetric moisture contents with measured results at different frequencies.

  2. Comparison of modeled results of dielectric constant at various volumetric moisture contents with other available model at different frequencies.

II. EXPERIMENTAL DETAILS

Soil samples are collected from eight different locations of Haryana - Kaithal, Rewari, Jind, Panipat, Sonipat, Jhajjar, Mahendargarh and Sirsa. Texture of these eight samples are given in Table 1.

Table I TEXTURE OF SOIL SAMPLES ON WHICH TESTING OF VALIDATION IS DONE 

Area Sand (%) Silt (%) Clay (%) Texture
Rewari 82 12 6 Loamy Sand
Mahendragarh 80 13 7 Loamy Sand
Jind 66 18 16 Sandy Loam
Panipat 61 22 17 Sandy Loam
Jhajjar 68 18 14 Sandy Loam
Sirsa 72 16 12 Sandy Loam
Kaithal 51 31 18 Loamy
Sonipat 66 19 15 Sandy Loam

The samples of soil collected first sieved and coarse particles are removed. The texture structure of four samples is presented in Table 1 for which measurements are made. The fine particles obtained are then oven dried for several hours to remove moisture completely and make it dry. Now to prepare moist soil samples measured quantity of distilled water is added to dried soil. The gravimetric soil moisture content in percentage term is calculated using the following relation [11]:

wo(%)=wwwdwd×100

Where ww. is the weight of wet soil and wd is the weight of dry soil.

A. Measurement of dielectric constant of soil

In the present work, technique used for the measurement constant is waveguide cell technique [12]. A microwave bench operating at C-Band is used at 5.3 GHz in TE10 mode with Gunn source at room temperature and another microwave bench operating at X-Band is used at 12 GHz in TE10 mode with reflex Klystron as microwave source were used for measurements. The microwaves are allowed to be incident on the sample. A part of incident signal reflects and superimpose with incident signal to give rise to standing wave pattern. The dielectric constant is measured by using the shift in minima of standing wave pattern that takes place due to the change in guide wavelength on the introduction of sample in the waveguide. Dielectric constant can be calculated using the following relation:

=g+[λgs2a]21+[λgs2a]2

where g is real part of admittance, λgs is wavelength in air filled guide, a = inner width of rectangular waveguide.

Fig. 1 Block Diagram of Experimental Set up of Microwave Bench. 

III. RESULTS AND DISCUSSION

The plots showing variations of dielectric constant of soil of Kaithal, Rewari, Jind, Panipat, Sonipat, Jhajjar, Mahendargarh and Sirsa for 5.3 GHz are shown in Figs. 2 (a) to 2 (h) respectively. The observed values of dielectric constant of these soils at different volumetric moisture contents are compared with RKAS Model and Hallikainen model. Table II shows maximum and minimum errors in measurements for each sample. It is seen that the percentage error in the model are within allowable range. The percentage errors in the measurements of dielectric constant of soil are lesser in case RKAS model than Hallikainen model in six out of eight samples. In remaining two samples of soil, the differences in errors are not much significant and in can be neglected.

Fig. 2 Dielectric constant of soils. 

Table 2 Comparison of modeled and observed values of dielectric constant at C-Band 

Area f = 5.3 GHz
Percentage error
RKAS Model Hallikainen model
Minimum Maximum Minimum Maximum
Rewari 0.03 8.16 0.69 10.97
Mahendragarh 0.25 7.71 0.22 11.43
Jind 1.62 10.78 1.65 13.72
Panipat 0.67 20.43 1.54 27.47
Jhajjar 1.62 13.21 0.18 9.27
Sirsa 1.01 13.50 0.37 14.05
Kaithal 0.04 17.49 0.87 18.26
Sonipat 1.66 9.02 1.27 10.60

The plots showing variations of dielectric constant of soil of Kaithal, Rewari, Jind, Panipat, Sonipat, Jhajjar, Mahendargarh and Sirsa for 12 GHz are shown in Figure 2 (i) to 2 (p) respectively. The observed values of dielectric constant of these soils at different volumetric moisture contents are compared with RKAS Model and Hallikainen model. Table III shows maximum and minimum errors in measurements for each sample. It is seen that the percentage error in the model are within allowable range. The percentage errors in the measurements of dielectric constant of soil are lesser in case RKAS model than Hallikainen model in four out of eight samples. In remaining four samples of soil, the differences in errors are not much significant and in can be neglected.

Table III Comparison of modeled and observed values of dielectric constant at X-Band 

Area f = 12 GHz
Percentage error
RKAS Model Hallikainen model
Minimum Maximum Minimum Maximum
Rewari 0.70 23.99 0.22 23.40
Mahendragarh 2.32 29.72 1.64 24.53
Jind 0.68 16.40 1.13 22.02
Panipat 0.60 23.14 0.41 20.59
Jhajjar 0.28 22.96 1.57 27.73
Sirsa 0.70 25.09 2.74 25.61
Kaithal 0.79 28.53 0.40 21.81
Sonipat 0.06 23.40 0.60 25.01

IV. CONCLUSION

From the study on the variation of dielectric constant of soil with volumetric moisture content, it is found that dielectric constant is strongly depend on volumetric moisture content. Table 2 and Table 3 shows the variations of dielectric constant of soil of Kaithal, Rewari, Jind, Panipat, Sonipat, Jhajjar, Mahendargarh and Sirsa with volumetric moisture content at 5 GHz and 12 GHz. Values obtained under laboratory conditions and modeled values are presented here. The values obtained experimentally are compared with RKAS model as well as with Hallikainen model. It is seen that the values obtained from RKAS model are accurate and the percentage error is in allowable range.

REFERENCES

1. [1] O. P. N. Calla et al., “Estimation of dielectric constant of soil from given texture at microwave frequency,” Indian Journal of Radio & Space Physics, vol. 33, pp 196-200, 2004. [ Links ]

2. [2] O. P. N. Calla et al., “Study of the properties of dry and wet loamy sand soil at microwave frequencies,” Indian Journal of Radio and Space Physics, vol. 28, pp. 109-112, 1999. [ Links ]

3. [3] J. F. Parr et al., “Soil quality: Attributes and relationship to alternative and sustainable agriculture,” American Journal of Alternative Agriculture, vol. 7.1-2 pp. 5-11, 1992. [ Links ]

4. [4] P. R. Chaudhari et al., “Soil bulk density as related to soil texture, organic matter content and available total nutrients of Coimbatore soil,” International Journal of Scientific and Research Publications vol.3, no.2, pp. 1-8, 2013. [ Links ]

5. [5] D. Gadani et al., “Dielectric mixing model for the estimation of complex permittivity of wet soils at C and X band microwave frequencies.” Indian Journal of Pure & Applied Physics (IJPAP), vol.53, pp. 190-198, 2015. [ Links ]

6. [6] L. K. Dospatliev et. al., “Determining the relationship between the dielectric properties and the basic physical and chemical parameters of the air-dry soil,” International Journal of Scientific and Research Publications, vol.4, no.7, pp. 1-7, 2014. [ Links ]

7. [7] K. Rajeev and A. Sharma, “Dielectric properties of soil of Indo-Gangetic region of Haryana at C-Band microwave frequency,” Advanced Materials and Radiation Physics (AMRP-2015): 4th National Conference on Advanced Materials and Radiation Physics, 1675, AIP Publishing, 2015. [ Links ]

8. [8] K. Rajeev and A. Sharma, “Dielectric properties of soil of Indo-Gangetic region of Haryana at X-Band microwave frequency, ” Journal of Chemical, Biological and Physical Sciences, vol. 6 no. 3, pp 631-638, 2016. [ Links ]

9. [9] K. Rajeev, A. Sharma, A. Sharma, “Mathematical Modeling For The Estimation Of Dielectric Constant Of Dry And Moist Soil At C And X Band Microwave Frequencies,” International Journal for Research in Applied Science and Engineering Technology, vol. 5, no. IX, pp. 1646-1655, 2017. [ Links ]

10. [10] M. T. Hallikainen et al., “Microwave dielectric behavior of wet soil-part 1: empirical models and experimental observations,”, IEEE Transactions on Geoscience and Remote Sensing, vol. GE-23, no. 1, pp.25-34, 1985. [ Links ]

11. [11] J. R. Wang and T. J. Schmugge, “An empirical model for complex dielectric permittivity of soils as a function of water content,” in IEEE Transactions on Geoscience and Remote Sensing (USA), vol. 18, pp. 288-295, 1980. [ Links ]

12. [12] M. Sucher and J. Fox, The handbook of microwave measurements, Vol II (John Wiley, New York, 1963). [ Links ]

Received: July 03, 2018; Revised: July 31, 2018; Accepted: September 27, 2018

Creative Commons License This is an Open Access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.