The Theory of Matrices. By F R. Gantmacher. Two volumes, pp. 374 and 276. 1959. (Translated from the Russian by K. A. Hirsch; Chelsea Publishing Company, New York)

Introduction. UWB Channel Models. Modulation Schemes. Receiver Structures. Integrated Circuit Topologies. UWB Antennas. Medium Access Control. Positioning.

UWB theory and applications

The singularity expansion method (SEM) for quantifying the transient electromagnetic (EM) scattering from targets illuminated by pulsed EM radiation is reviewed. SEM representations for both induced currents and scattered fields are presented. Natural-resonance-based target identification schemes, based upon the SEM, are described. Various techniques for the extraction of natural-resonance modes from measured transient response waveforms are reviewed. Particular attention is given to the aspect-independent (extinction) E-pulse and (single-mode) S-pulse discriminant waveforms which, when convolved with the late-time pulse response of a matched target, produce null or mono-mode responses, respectively, through natural-mode annihilation. Extensive experiment results for practical target models are included to validate the E-pulse target discrimination technique. Finally, anticipated future extensions and areas requiring additional research are identified. >

The singularity expansion method and its application to target identification

A new threat to civil society has recently emerged. It is known as intentional electromagnetic interference (IEMI) and covers the threat of intense electromagnetic disturbances that may be applied to the sophisticated electronic systems that are so important to our daily lives. This paper provides a brief background for the threat, defines important terms, describes the different types of electromagnetic threats, explores the importance of topological concepts, summarizes the current understanding of equipment susceptibility, provides an overview of protection concepts, and summarizes the ongoing work in international standardization. This paper also serves as the introduction to the IEMI papers in this special issue.

Introduction to the special issue on high-power electromagnetics (HPEM) and intentional electromagnetic interference (IEMI)

A theory for a complete far-field transmit-receive system characterization of short-pulse antennas is derived in the time domain. The transmit-receive antenna system is characterized by a set of cascaded operators, which transform the source waveform and power into similar quantities at the receiving antenna terminals. Two such sets are defined. The first one is phrased in terms of the wave-type "time-dependent effective-height" operator, while the second one is defined in terms of the energy-type "gain operator". Both definitions fit within a complete transmit-receive system description, the latter being equivalent to the frequency-domain Friis equation. However, these operators are derived entirely in the context of the time-domain field equation. The starting point in the time-domain analysis of the effective height is the slant stack transform (SST) of the time-dependent current distribution in a manner equivalent to the spatial Fourier transform used in the frequency domain. The vector autocorrelation of the transmitting effective height is then used to define the time-dependent gain operator under impulsive source excitation. Time-domain reciprocity leads to the definitions of antenna parameters under receiving conditions and the corresponding equivalent circuit. The parameters defined in this way fit within a consistent transmit-receive convolution operator, operating on the autocorrelation of the input signal. This independent time-domain representation is thus similar to the frequency-domain representation. However, unlike the conventional frequency-domain circuit parameters, which relate voltage and current amplitudes, the time-domain circuit representation is based on incident and reflected wave-type constituents. In addition, the use of appropriate norms facilitates the transformation of our operators to stand-alone figures of merits. The general concepts developed are demonstrated for a short dipole antenna.

Antenna characterization in the time domain

Experimental studies of plasma membrane permeabilization, caused by single, intense, submicrosecond square wave pulses, indicate that the product of electric field amplitude and pulse duration (the electrical impulse) can be considered a similarity or scaling factor. A model based on the hypothesis that the intensity of membrane permeabilization effects is linearly dependent on the electric charge transferred through the permeabilized membrane, provides results, which are consistent with the empirical observations. For multiple pulses, bioelectric effects caused by ultrashort pulses were found to scale with the square root of the pulse number. This square root dependence on the pulse number points to a statistical motion of cells between pulses with respect to the applied electric field, and can be explained using an extension of the random walk statistical results to random rotations. Besides membrane permeabilization, the scaling law has also been shown to hold for secondary bioelectric effects, which are caused by permeability changes in the plasma membrane or subcellular membranes.

A scaling law for membrane permeabilization with nanopulses

[1] This paper develops some analytical approximations for the transient focal waveform produced at the second focus of a prolate-spheroidal reflector due to a pulse TEM wave launched from the first focus. This is extended to consider the spot size of the peak field near the second focus.

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2006RS003556

Focal waveform of a prolate‐spheroidal impulse‐radiating antenna

In this continuation of our paper in the last conference proceedings1, we consider further developments in the area of Impulse Radiating Antennas (IRAs). First, we consider definitions of gain in the time domain, which are important for optimizing the performance of IRAs. A reasonable definition of gain must be equally valid in transmission as in reception. Such a definition leads naturally to a transient radar equation, which we discuss. Next, we consider how to optimize the feed impedance in a reflector IRA. If we use our simple model of IRA performance, the gain of an IRA is always better at lower impedances. But this implies larger feeds with more aperture blockage. To resolve this, we refine our simple model to account for feed blockage. We also consider the radiation pattern of IRAs, and we provide simple calculations. Finally, we provide a sample experiment which confirms our theory of IRA operation.

/pdf/impulse-radiating-antennas-part-ii-4m4eyt6s8h.pdf

Impulse Radiating Antennas, Part II

A prolate-spheroidal reflector antenna focusing subnanosecond pulsed electromagnetic radiation in the near field is studied. This antenna reflector is fed by a pair of balanced, conical-plate transmission lines and the radiated pulse consists of a prepulse, an impulse, and a postpulse. Whereas the prepulse amplitude decreases inversely with distance, the impulse is maximum near the geometric focus, and its power density distribution has a full-width at half-maximum (FWHM) width of 32 cm in the axial direction and 10 cm in the lateral direction.

A Reflector Antenna for Focusing Subnanosecond Pulses in the Near Field

This paper briefly reviews the design of a prolate-spheroidal impulse-radiating hyperband antenna system to launch and focus fast (100 ps) high-voltage ( >; 100 kV) pulses onto biological targets. Design and experiments on a graded five-layer dielectric lens, designed to match the pulses into the target medium, are outlined. The design and numerical simulations of a switch system to launch high-voltage spherical TEM pulses are also presented.

Carl E. Baum

Papers

A scaling law for membrane permeabilization with nanopulses

Focal waveform of a prolate‐spheroidal impulse‐radiating antenna

Impulse Radiating Antennas, Part II

A Reflector Antenna for Focusing Subnanosecond Pulses in the Near Field

A Hyperband Antenna to Launch and Focus Fast High-Voltage Pulses Onto Biological Targets