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Rough Terrain GPR Antennae made of flexible hose are dragged along small trails to image near surface geology in field areas with dense vegetation and rugged topography. For accurate antenna midpoint coordinates between transmitter and receiver two miniature GPS receivers are attached to such a snake-like 50 MHz GPR antenna. During a three day field test on a Pleistocene highstand reef complex in...
The bicone antenna is known for its wideband applications. Past publications and development of this type of antenna concentrate on radiating into the air. For GPR use the antenna needs to radiate into the ground. In this work the effect of dielectric loading of the antenna to produce a better match to the ground is investigated. This is developed for both traditional GPR schemes where transmit and...
The design of a linear Vivaldi antenna array for water leaks detection is presented. We show the 3D antenna design with the bandwidth of interest between 250–2000 MHz, which is necessary for sufficient depth penetration and high resolution imaging and characterization. New modifications on features with respect to the traditional Vivaldi antenna design are discussed. The radiation patterns show that...
The focusing capabilities for one dimensional (1D-CR MIMO) and two dimensional circularly rotating multiple input multiple output (2D-CR-MIMO) arrays in different media are investigated. Impact of the position of the focusing point on the beamwidth and sidelobe structure is investigated. Impact of the medium (dielectric permittivity and ohmic losses) on the focusing capabilities is studied. For focusing...
This paper describes a new broadband ground coupled antenna array for step-frequency GPR operating continuously over the frequency range from 200 MHz – 3 GHz. The broad frequency range makes the array suitable both for high resolution shallow imaging and deeper investigations where efficient coupling of energy into the ground is crucial. A method for estimating penetration depth based on signal variance...
A new resistively loaded bow-tie antenna which can operate from 300 MHz to more than 3 GHz bandwidth is proposed. The proposed antenna employs a metamaterial lens to improve the forward gain and front-to-back ratio. The antenna radiates pulses with minimal late-time ringing and high peak amplitude. A stable radiation pattern obtained from 300 MHz to 2 GHz, makes it suitable for time domain as well...
In a well-controlled experimental setup, a very high precision for studying soil water dynamics can be achieved with Ground-Penetrating Radar (GPR). However, accessing detailed hydraulic information for a field scale 2D subsurface structure requires the usage of multiple antennas. As each antenna is a unique instrument, the evaluation of signals recorded with different antennas under otherwise identical...
This paper presents an investigation of the radiation characteristics and sensitivity of a high-frequency Ground-Penetrating Radar (GPR) antenna using radiation patterns obtained from both physical measurements and a three-dimensional (3D) Finite-Difference Time-Domain (FDTD) numerical model. The aim was to develop an understanding of how electromagnetic energy is radiated and received by a real GPR...
The performance of ground penetrating radar (GPR) for subsurface target depth measurement can be directly related to the ability to accurately measure the signal time-of-flight. For impulse GPR systems that utilize the successive sampling technique to acquire radar data, the presence of deterministic timing jitter in the sampling electronics will warp traces along the time axis in a nonlinear manner...
Full-wave inverse modeling of low-frequency, near-field ground-penetrating radar (GPR) data was used for simultaneously reconstructing both the electric permittivity and conductivity of the soil. Low GPR frequencies provide a significant sensitivity of the reflection coefficient to electrical conductivity and are less affected by soil roughness and local heterogeneities. Based on the near-field model,...
Forward looking imaging system with data acquisition over 2D aperture is studied. Theoretical analysis for polar sampling at the aperture is performed and the sampling constraints based on polar Fourier transform are determined. From the analysis, it can be seen that polar sampling requires equi-arc-length and uniform samplings respectively in azimuthal and radial directions to avoid the spatial spectra...
Corrosion of reinforced concrete structures is the most significant issue for its safety and lifetime. During the structural assessment of lifetime evaluation of structures, destructive tests might increase the damage size of the structure. This investigation attempts to identify the corrosion effect of the reinforcement in concrete and chloride contamination of the concrete using Ground Penetrating...
We discuss complex permittivity spectra of two lossy soils measured from 6 kHz to 6 GHz using time domain reflectometry, in which Maxwell-Wagner relaxation (MWR) is present but also unwanted electrode polarization EP, mainly below 1 MHz, is strong. The soils are mostly quartz, with one having lesser calcite and the other lesser gypsum. Volumetric water contents ranged from 8.5–30.9%. We use a simple...
We measured the broadband (40 Hz–20 GHz) relative dielectric permittivity of sieved surficial samples of an arid-zone soil. The soil samples were equilibrated at 25 °C with relative humidities of 43, 54, 84, and 97 %. Debye-like Maxwell-Wagner-Sillars (MWS) polarization relaxation times of 309, 227, and 73 ns were calculated for the soil samples equilibrated at relative humidities of 43, 54, and 84...
Many cemeteries have limited space and can often contain unmarked and undocumented graves. Encountering unmarked burials, or establishing locations free from burials, can be a problem. This case study reports an investigation of the area around a family burial plot in the cemetery of a church in rural Derbyshire, England, where a number of burials have taken place but where detailed records of the...
The study is focused on the characterization of a pre-Trajan wall structure, decorated with mosaics. The wall is located below the Crvptoporticus of the “Baths of Trajan” complex, at Rome historical centre. The surveyed wall is 15 m large and 0.9 m wide, with an height ranging from 3 to 5 m. GPR survey was planned with the aim to reconstruct the inner geometry, characterizing materials constituting...
GPR studies were carried out in the Całowanie Fen, a large peatland in the Masovia region (Central Poland) for the identification of the peatland stratigraphy and to create a three-dimensional model for the central and eastern part of the fen. The Całowanie Fen is located within the Masovian Landscape Park on the overflood terrace in the Middle Vistula River Valley. Fen covers an area of about 15...
Ground-penetrating radar (GPR) is a well-established technique for investigating the sub-surface stratigraphy in sandy coastal environments. GPR is most commonly applied in sandy coastal settings to determine the environmental evolution of an area. Several studies have used GPR to investigate the impact of storms through the identification of erosional scarps and very few have used GPR to investigate...
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