Effect of depth and soil moisture on buried ultra‐wideband antenna

Abstract

Ultra-wideband (UWB) wireless underground sensor networks consist of wirelessly connected underground sensor nodes that communicate through the soil. Performances of buried antennas and of the communication link depend on the soil dielectric characteristics. The effects of soil moisture and depth, in the frequency band of 3.1-10.6 GHz, on an UWB antenna return loss and bandwidth are presented. The measurements are conducted in two different types of soil: sandy soil and railway pebbles. The experimental results show that burying antenna shifts down its bandwidth. This phenomenon is accentuated by the increase of soil moisture and not impacted by the burial depth variations. In a dry sandy soil, the shift of the bandwidth low-end is of 0.75 GHz, while it is 1 and 1.5 GHz at 5 and 20% soil moisture, respectively. This fact has allowed us to further miniaturise the used antenna.

Radio frequency identification in internet of underground things using a soil dielectric attenuator and microstrip antenna as tag sensor

“…This result indicates that the impedance of the antenna was not altered by the soil moisture. The encapsulation eliminated direct antenna contact with the soil, and thus also eliminated the input impedance variations that occur in buried antennas, as shown in Reference 13.…”

A Non-Destructive Testing Method in Industrial Processes to Determine the Complex Refractive Index Using Ultra-Wide Band Radio

“…For the data in Fig. 11 (c), the root mean square of the errors are 3.37 pe, 2.36 pe and 2.34 pe, using (12), (13), and (14), respectively. Thus, using NFCC gives an improvement in standard deviations from above 5 pe to approximately 2 pe.…”

“…In [13], to inspect the moisture content and the quality of concrete blocks, an electromagnetic sensor (EM sensor) was buried inside the concrete, and the correlation between scattering parameter's (S11 or S-parameter) amplitude and moisture content was observed. Further, the effect of soilwater content on the buried EM sensor was presented in [14], in which the experimental results showed that burying the EM sensor causes a shift in the operating frequencies to lower frequencies and that moisture in the soil degrades the buried sensor impedance matching (i.e., introduces near-field coupling with the moist soil). Similar results were shown in [15], wherein the EM sensors were buried in snow and as a result, due to coupling the transmission band of the EM sensor shifted slightly towards lower frequencies.…”

UWB Vivaldi Antenna Array Lower Band Improvement for Ground Penetrating Radar Applications

“…The shift scale depends on the index level of the medium considered. Such approximation was already used in [13] for the measurement of WUB underground antenna. Figure 16 confirms our approach with the measurements of the previous antenna notched in the epoxy (thickness: 4 mass side / 1 mm feeding side).…”