eLearning

Implementations of Coherent Software-Defined Dual-Polarized Radars

Jeremy Hershberger; Thomas Pratt; Robert Kossler IEEE Transactions on Microwave Theory and Techniques, 2017

Software-defined radio (SDR) platforms represent a compelling solution for low-cost, flexible, dual-polarized radar systems. However, the phase coherency requirements of a dual-polarized radar system between the transmit ports and between the receive ports as well as between transmission and reception, are difficult to attain in popular SDRs. In this paper, we provide high-level overviews of SDR radar systems, dual-polarization radars, ...

Measurements of ocean wave spectra with vertical polarization X-band radar image sequences

Limin Cui; Yijun He 2009 IEEE International Geoscience and Remote Sensing Symposium, 2009

Ocean wave parameters, such as significant wave height, can be computed from wave spectrum. Ordinarily X-band nautical radar can produce the three dimensional wave number frequency image spectra from a time series of radar images with a 3-D FFT algorithm. The fundamental image spectrum is related to the surface wave spectrum by the modulation transfer function (MTF). To determine the ...

Automatic co-registration performance of fully polarimetric SAR images with texture relationship

Kamolratn Chureesampant; Junichi Susaki 2011 IEEE International Geoscience and Remote Sensing Symposium, 2011

This paper presents a methodology for automatic co registration of polarimetric Synthetic Aperture Radar (SAR) images obtained from similar satellites, but with differing view angles. The Scale Invariant Feature Transform (SIFT) algorithm is applied to extract candidate Ground Control Points (GCPs), where two-way keypoint matching eliminates improbable correspondence keypoints. Minimizing the Root Mean Squared Error (RMSE) also removes matching points ...

Strong plasmonic coupling in rod-dimer/ring nanostructure

Jia-Yu Lin; Chia-Yang Tsai; Pin-Tso Lin; Tse-En Hsu; Po-Tsung Lee 2015 11th Conference on Lasers and Electro-Optics Pacific Rim (CLEO-PR), 2015

A rod-dimer/ring (RDR) plasmonic nanostructure with different gap distances is investigated in both experiment and simulation. Compared to rod-dimer and ring, the localized near-field intensity of RDR can be significantly enhanced and further increased in smaller gap distance owing to stronger coupling effect.

The optimized probe light frequency detuning for Faraday-rotation cesium atomic magnetometer

Wenhao Li; Pingwei Lin; Xiang Peng; Hong Guo 2014 Conference on Lasers and Electro-Optics (CLEO) - Laser Science to Photonic Applications, 2014

We experimentally demonstrate that the sensitivity of all-optical Faraday- rotation magnetometer can be improved by tuning probe light frequency to the edge of wings of Doppler profile with cesium atoms, which coincides with the theoretical analysis.

More eLearning Resources

IEEE-USA E-Books

• Parallel Phase-Shifting Digital Holography

  Parallel phase-shifting digital holography is a technique capable of not only instantaneously measuring the three-dimensional (3D) field but also motion picture measurement of time evolution in the 3D field. The recording and reconstruction flow of this technique are described. The technique has been experimentally demonstrated by a parallel phase-shifting digital holography system using a normal-speed camera, which lead to a high-speed camera being constructed and used so that 3D motion and phase motion picture capture were demonstrated at the rate of up to 262 500 frames per second (fps). As an ultrafast phase imaging technique, a parallel phase-shifting digital holography system using a femtosecond pulsed laser has been experimentally demonstrated. A portable parallel phase-shifting digital holography system will also be introduced here. Finally some function-extended parallel phase- shifting digital holography will be mentioned for the purpose of motion picture-measurement of 3D and color, 3D and spectral characteristics, 3D and polarization characteristics, and 3D motion picture microscopy.

• The FarField Integrals, Reciprocity, Directivity

  This chapter contains sections titled: Introduction Electrostatics and Magnetostatics in Free Space The Introduction of Dielectric, Magnetic, and Conductive Materials Time-Varying Fields The Retarded Potential Functions Poynting's Theorem The Stratton-Chu Solution Conditions at Infinity Field Values in the Excluded Regions The Retarded Potential Functions: Reprise The Far Field: Type I Antennas The Schelkunoff Equivalence Principle The Far Field: Type II Antennas The Reciprocity Theorem Equivalence of the Transmitting and Receiving Patterns of an Antenna Directivity and Gain Receiving Cross Section Polarization of the Electric Field This chapter contains sections titled: References Problems

• Inverted LFL Antenna for Dual¿¿?Band Operation

  A dual¿¿?band antenna called the inverted LFL antenna (InvLFL) is made of a thin conducting film, where both the top radiation element and the ground plane lie in the same plane, that is, the InvLFL has a card antenna structure. The card structure differs from the layered antenna structure for dual¿¿?frequency operation, where the ground plane backs a radiation element. It is emphasized that the InvLFL is intended for installation in mobile equipment. In such a case, polarization purity is not required; however, an appropriate frequency response for the voltage standing wave ratio (VSWR) is important. This chapter presents the steps involved in reaching the InvLFL configuration. The analysis for the design is performed using the finite¿¿?difference time¿¿?domain method (FDTDM) based on Yee's algorithm and the antenna excitation is modeled by a delta¿¿?gap voltage source Vin(t), which is defined by a sine function modulated by a Gaussian function.

• No title

  <p>In recent years, transmitarray antennas have attracted growing interest with many antenna researchers. Transmitarrays combines both optical and antenna array theory, leading to a low profile design with high gain, high radiation efficiency, and versatile radiation performance for many wireless communication systems. In this book, comprehensive analysis, new methodologies, and novel designs of transmitarray antennas are presented.</p> <p><ul> <li>Detailed analysis for the design of planar space-fed array antennas is presented. The basics of aperture field distribution and the analysis of the array elements are described. The radiation performances (directivity and gain) are discussed using array theory approach, and the impacts of element phase errors are demonstrated.</li> <li>The performance of transmitarray design using multilayer frequency selective surfaces (M-FSS) approach is carefully studied, and the transmission phase imit which are generally independent from the selection of a specific element shape is revealed. The maximum transmission phase range is determined based on the number of layers, substrate permittivity, and the separations between layers.</li> <li>In order to reduce the transmitarray design complexity and cost, three different methods have been investigated. As a result, one design is performed using quad-layer cross-slot elements with no dielectric material and another using triple-layer spiral dipole elements. Both designs were fabricated and tested at X-Band for deep space communications. Furthermore, the radiation pattern characteristics were studied under different feed polarization conditions and oblique angles of incident field from the feed.</li> <li>New design methodologies are proposed to improve the bandwidth of transmitarray antennas through the control of the transmission phase range of the elements. These design techniques are validated th ough the fabrication and testing of two quad-layer transmitarray antennas at Ku-band.</li> <li>A single-feed quad-beam transmitarray antenna with 50 degrees elevation separation between the beams is investigated, designed, fabricated, and tested at Ku-band.</li></ul> </p> <p>In summary, various challenges in the analysis and design of transmitarray antennas are addressed in this book. New methodologies to improve the bandwidth of transmitarray antennas have been demonstrated. Several prototypes have been fabricated and tested, demonstrating the desirable features and potential new applications of transmitarray antennas.</p>

• Index

  **Introduces timed arrays and design approaches to meet the new high performance standards** The author concentrates on any aspect of an antenna array that must be viewed from a time perspective. The first chapters briefly introduce antenna arrays and explain the difference between phased and timed arrays. Since timed arrays are designed for realistic time-varying signals and scenarios, the book also reviews wideband signals, baseband and passband RF signals, polarization and signal bandwidth. Other topics covered include time domain, mutual coupling, wideband elements, and dispersion. The author also presents a number of analog and digital beamforming networks for creating and manipulating beams. The book concludes with an overview of the methods to integrate time delay into the array design and of several other adaptive arrays that prove useful in many different systems. &nbsp_place_holder; * Examines RF signal concepts such as polarization and signal bandwidth and their applications to timed antenna arrays * Covers arrays of point source, elements in timed antenna arrays, active electronically scanned array technology, and time delay in corporate fed arrays * Includes complete design examples for placing time delay in arrays _Timed Arrays: Wideband and Time Varying Antenna Arrays_ is written for practicing engineers and scientists in wireless communication, radar, and remote sensing as well as graduate students and professors interested in advanced antenna topics. ****Randy Haupt, PhD.,**** is Professor and Department Head of EECS at the Colorado School of Mines. He received his PhD from the University of Michigan and retired from the USAF as a LtCol. Dr. Haupt was an RF staff consultant at Ball Aerospace & Technologies, Corp., senior scientist and department head at the Applied Research Laboratory of Penn State, professor and department head of ECE at Utah State, professor and chair of EE at the Uni ersity of Nevada Reno, and professor of EE at the USAF Academy. Dr. Haupt is a Fellow of the IEEE and Applied Computational Electromagnetics Society (ACES).

• Development of TemperatureStable ThickFilm Dielectrics: II. MediumK Dielectric

  A temperature-stable, medium dielectric constant (K = 100) thick-film dielectric is developed for high-temperature electronic instrumentation. A theoreneal model predicts a temperature-insensitive dielectric in the glass- Bi4Ti3O12-SrTiO3 system, while experimental results suggest an optimum composition in the glass-SrTiO3-BaTiO3 system. Interfacial polarization is the major factor which causes the devlatlon. The medium-K dielectric, when properly fired, terminated, and heattreated, can work adequately from 25°C to 400°C.

• FabryPerot Laser Diodes

  This chapter contains sections titled: Introduction Rate Equations Current versus Voltage Characteristics Current versus Light Output Characteristics Polarization of Light Transverse Modes Longitudinal Modes Modulation Characteristics Noises References

• Bistatic Scattering at a Finite-Length Cylinder

  The shadow radiation is the constituent part of the physical optics (PO) field. It was noted there that this field concentrates in the vicinity of the shadow region. This chapter verifies this property by numerical investigation of the shadow radiation generated by the finite-length cylinder. The most appropriate procedure for doing this work would be the direct application of the shadow contour theorem. It presents numerical investigation of the scattered field. The chapter considers its physical structure and presents simple high-frequency asymptotics for the directivity pattern. It deals with the E-Polarization and the H-Polarization. Finally, the chapter discusses about the PO shooting-through rays and their cancellation by Fringe rays, and the refined asymptotics for the specular beam reflected from the lateral surface.

• Vector Radiative Transfer

  Chapter 2 introduces the vector radiative transfer (VRT) theory of random media. It provides the scattering, absorption and extinction coefficients and the phase matrix of non-spherical scatterers in natural media. The first-order Mueller matrix solution of VRT for vegetation canopy model is derived. Polarization indexes, eigen-analysis and entropy are presented. Statistics of multi-look SAR images and covariance matrix are also investigated.

• The Magnetostatic Field

  The methods that have been developed for the analysis of electrostatic fields apply largely to the magnetostatic field as well. Every magnetostatic field can be represented by an electrostatic field of identical structure produced by dipole distributions and fictive double layers. The equations satisfied by the magnetic vectors of a stationary field are obtained by placing the time derivatives in Maxwell's equations equal to zero. The existence of a scalar potential function associated with the electrostatic field is a direct consequence of the irrotational character of the field vector. The units and dimensions of electrostatic quantities have been commonly based on Coulomb's law. The intensity of magnetization, or polarization, includes the permanent or residual magnetization M0 if any is present. In case the body carries a current, the interior field cannot be represented by a scalar potential and the boundary-value problem must be solved in terms of a vector potential.