Search

In this paper, a method to estimate the characteristics of ultra-wideband (UWB) pulse scattered from metal planar objects in far-field is proposed. When the object is in near-field, the transition of the scattered pulse shape is studied. In addition, we define a frequency averaged radar cross section (RCS) of the metal planar object in terms of the effective height of the transmitting and receiving antennas, and the energy of the excitation and received pulses. We find excellent agreement between the estimated and measured scattered pulses for metal planar objects of sizes 100\times 100\ \ mm^2, 160\times 160\ \ mm^2, and 200\times 200\ \ mm^2. For the same objects, the estimated frequency averaged RCS are close to narrowband conventional RCS. The agreement validates the proposed method, allowing us to compute the scattered pulse shape and energy based on the conventional RCS of the object. [ABSTRACT FROM PUBLISHER]

In this paper, a method to characterize buried nonmagnetic objects in ground using ultra-wideband (UWB) ground penetrating radar (GPR) is proposed. In this method, UWB pulses are radiated by the radar, while scattered signals from the ground with the buried object are received. The received signals are then post-processed to estimate the depth, thickness, and electrical properties of the buried object. A constant depth and thickness is enforced at all frequencies while the signals are processed to extract the buried object characteristics, resulting in more accurate estimations and reduced processing time. In addition, path loss due to the close proximity of the radar to the ground is compensated analytically. The applicability of the proposed method is validated with several planar objects and a boulder that we typically encounter in the construction industry. The proposed method can achieve sufficient reliability in estimating the permittivity of buried objects for the purpose of material identification. Incorporating the proposed method into the GPRs enhances their existing imaging ability by adding material identification capability. [ABSTRACT FROM AUTHOR]

We propose a design for the specific class of transverse electromagnetic (TEM) horn that can effectively radiate the electromagnetic signals into soil or concrete. The designed horn antenna has the same aperture height and width, resulting in a square-shaped horn aperture. A design guideline for the horn that considers return loss and radiation performance is described in this paper. The proposed TEM horn is constructed and measured to validate the design. The constructed horn has a maximum dimension (including the balun) of 42.9\times 26.8\times 20\ cm. Simulated and measured results suggest that the proposed horn is more effective in radiating electromagnetic energy into concrete, compared with existing TEM horn designs. For free space radiation, measured operating bandwidth of the horn is 0.75–12.0 GHz, with a gain of 3–13 dBi. When radiated into a concrete block, measured operating bandwidth of the horn is 1.0–12.0 GHz. [ABSTRACT FROM AUTHOR]