Microstrip transmission line for soil moisture measurement

Xuemin Chen; Jing Li; Renyue Liang; Yijie Sun; C. Richard Liu; Richard Rogers; German Claros

doi:10.1117/12.571448

8 December 2004 Microstrip transmission line for soil moisture measurement

Xuemin Chen, Jing Li, Renyue Liang, Yijie Sun, C. Richard Liu, Richard Rogers, German Claros

Proceedings Volume 5590, Sensors for Harsh Environments; (2004) https://doi.org/10.1117/12.571448
Event: Optics East, 2004, Philadelphia, Pennsylvania, United States

Abstract

Pavement life span is often affected by the amount of voids in the base and subgrade soils, especially moisture content in pavement. Most available moisture sensors are based on the capacitive sensing using planar blades. Since the planar sensor blades are fabricated on the same surface to reduce the overall size of the sensor, such structure cannot provide very high accuracy for moisture content measurement. As a consequence, a typical capacitive moisture sensor has an error in the range of 30%. A more accurate measurement is based on the time domain refelctometer (TDR) measurement. However, typical TDR system is fairly expensive equipment, very large in size, and difficult to operate, the moisture content measurement is limited. In this paper, a novel microstrip transmission line based moisture sensor is presented. This sensor uses the phase shift measurement of RF signal going through a transmission line buried in the soil to be measured. Since the amplitude of the transmission measurement is a strong function of the conductivity (loss of the media) and the imaginary part of dielectric constant, and the phase is mainly a strong function of the real part of the dielectric constant, measuring phase shift in transmission mode can directly obtain the soil moisture information. This sensor was designed and implemented. Sensor networking was devised. Both lab and field data show that this sensor is sensitive and accurate.

Citation Download Citation

Xuemin Chen, Jing Li, Renyue Liang, Yijie Sun, C. Richard Liu, Richard Rogers, and German Claros "Microstrip transmission line for soil moisture measurement", Proc. SPIE 5590, Sensors for Harsh Environments, (8 December 2004); https://doi.org/10.1117/12.571448

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available