The present p a per prop oses a new g round p enetratin g radar (GPR) system for obtainin g hi g h resolution ima g es for objects buried under the surface of a g round soil.
Interferometric devices have drawn great interest in all-optical signal processing for their high-speed photonic activity. Quantum-dot semiconductor optical amplifier (QD-SOA)-based gate has added a new momentum in this field to perform all-optical logic and algebraic operations. In this paper, for the first time, a new scheme for all-optical full adder using fife QD-SOA based Mach-Zehnder interferometers is theoretically investigated and demonstrated. The proposed scheme is driven by three input data streams; two operands and a bit carried in from the next less significant stage. The proposed scheme consists of two XOR, two AND, and one OR gate. The impact of the peak data power as well as of the QD-SOAs current density, maximum modal gain, and QD-SOAs length on the ER and Q-factor of the switching outcome are explored and assessed by means of numerical simulation. The operation of the system is demonstrated with 160 Gbit/s.
A novel method for the estimation of a forest vertical structure using Polarimetric Synthetic Aperture Radar (PolSAR) data only without the need to interferometry data is proposed in the present paper. Electromagnetic (EM) simulation is used to develop the proposed method, where the SAR pulse is simulated as a plane wave incident in the direction of the side looking angle of the SAR. For this purpose, the forest canopy layer is modeled as clouds of randomly oriented thin straight dipoles which are randomly distributed within an inclined prism volume, whereas the forest soil surface is modeled as a random rough surface. The proposed method aims to estimate the average height of the canopy layer above the soil surface, the canopy layer thickness, and the roughness of the forest ground surface. The proposed method is based on the Radar Vegetation Index (RVI) and the normalized Radar Cross Section (RCS) calculated from the PolSAR data and their relevance to the parameters of the forest vertical structure. Some examples are presented to demonstrate the capability of the proposed method using some PolSAR images obtained through EM simulation of the scattering from forest regions and by applying the theorem of SAR target composition with the Multiple Component Scattering Model (MCSM). The phase differences between the components of scattering obtained from the solution of the SAR target decomposition problem are used in the estimation process. The accuracy of the proposed method is assessed by calculating the percentage error of the estimated vertical structure and ground roughness for each resolution cell of the simulated forest region. It is shown that the percentage errors of the estimated parameters are very low, which reflects the accuracy and efficiency of the proposed method.
High quality factor bandpass filters based on a number of cascaded resonators of dual-resonance mechanism are proposed in the present paper. Each resonator is constructed as two overlapped coplanar waveguide (CPW) resonant structures. The cascaded resonators mediate microwave coupling between two isolated corner-shaped CPW feeders only at the resonant frequencies leading to a bandpass filter of high quality factor. The two resonant frequencies and the separation between them can be fine-tuned by the dimensions of the structure. The effects of the dimensional parameters of the resonator and the feeding CPW regions on the resonant frequencies and the performance of the bandpass filter are investigated. The effect of the loss tangent of the dielectric substrate material on the quality factors at the two resonant frequencies is studied. Three prototypes of the proposed filter are fabricated and experimentally studied for more understanding of the underlying physical principles of operation and for verifying some of the simulation results. The experimental results show good agreement when compared with the corresponding simulation results. It is shown that, at low enough absolute temperature, the proposed structure can operate as superconducting microwave resonator when made from the appropriate materials. Also, it is shown that an optimized design of the proposed bandpass filter, based on superconducting CPWR structure, can achieve quality factors high enough to form a quantum data bus for hybrid architecture of quantum information systems.
In this paper, a simulation of ground penetrating radar "GPR" system on lossy and dispersive soil is investigated. The capability of the GPR system to detect buried targets is examined by evaluating and comparing the electromagnetic coupling between the transmitting and receiving antennas in two cases: (i) when the system is placed over an empty ground and (ii) when it is placed over a ground inside which a practical target is buried at a proper depth. Simulation software based on the finite difference time domain "XFDTD" is used for the electromagnetic simulations. The results concerning the coupling between the transmitting and receiving antennas are presented considering various practical parameters such as the operating frequency, the electric properties of the ground soil and the buried target, and the location at which the receiving element is placed. It is shown that the target detectability is strongly dependent on all of the above parameters. Also, the capability of target shape extraction and recognition are demonstrated through polarimetric ground penetrating radar.
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