Zenneck Surface Wave Research Articles

Dispersion-free characterization of terahertz slab–waveguide modal confinement based on a metal Bragg grating structure

Photonic waveguide structures that use periodic metal grooves and periodically perforated metal slits (PPMSs) can laterally confine Sommerfeld and Zenneck surface waves of metals with the electric field accumulation among metal interspaces in the terahertz (THz) region, instead of the total internal reflection principle of dielectric slab media. For the efficiency enhancements of THz-wave coupling and slab–waveguide confinement, specific integrators with high refractive indices or specified for input angles of transverse magnetic polarized waves, such as prisms, metal blades, and waveguides, are requested to excite spoof surface plasmons in the THz region. However, the integrator-assembled slab–waveguides encounter challenges of THz pulse-wave communication in compact and low-distortion systems. A resonant waveguide grating structure based on PPMSs is experimentally demonstrated to confine THz lateral waves from the plane-wave radiation in free space. The open frame and periodic metal cavities of PPMSs can work as a slab–waveguide to transmit structural confined waveguide modes with forwarding evanescent waves of Fabry–Pérot resonance. For 0.1–1 THz waves, the short wavelengths that are both less than half the metal slit width and 3.75 times the metal thickness can lead to zero dispersion and the highest confinement factor in a slab–waveguide for PPMS-confined THz waves. This behavior is opposite to the high structural dispersion in confined THz waves of surface plasmonic devices.

Insights on electromagnetic field distribution due to a vertical electric dipole source inside an infinite steel casing

Energized vertical steel casings have been developed to excite and monitor changes in the electrical properties of resistivity anomalies associated with hydrocarbon production and [Formula: see text] injection, among other applications. Accordingly, the spatial distribution of the fields expected in the medium surrounding a casing source has received considerable attention. However, investigations of the in-borehole distribution of the fields, currents, and charges have been lacking. Such an analysis is the objective of this work. Inside the borehole, the electric field is dominantly vertical, owing to the azimuthal symmetry of the charge density induced at the inner and outer casing boundaries. At the inner surface, charges accumulate dominantly in the vicinity of the source. At the outer surface, charges distribute along the extent of the casing, driven by the vertical channeling and radial leakage of the current flow. Inductive effects arise as the source oscillates in time, effectively resulting in a vanishing flux of azimuthal magnetic field and switching of the sign of the charge density along the vertical extent of the pipe. The alternating charge distribution yields fields propagating inward and outward within the metallic medium, describing inhomogeneous Zenneck surface waves that can interfere as they propagate and superimpose up and down the borehole. In the surrounding medium, the azimuthal magnetic field is driven by the current flowing vertically along the borehole, whereas a dominantly radial electric field is driven by the charge distributed on the outer casing surface.

Zenneck surface wave interconnect with encircle routing for effective inter chip communication

Generally, copper traces are widely used to provide communication among integrated circuits (IC's) of printed circuit board (PCB). In case of high rate data transfer, systems or traces may be damaged due to trace resistivity. In order to overcome this issue, surface wave phenomenon based channel/waveguide is introduced for IC communication in this work. Here, high frequency communication is possible due to both conductivity and dielectric behaviors of surface waves. Use of Zenneck surface instead of copper traces with Encircle Routing (ER) based channel assignment helps to achieve efficient IC communication. High rate of data transfer with low channel dispersion are major benefits of ER based Zenneck surface wave communication. Matlab working platform is used for design analysis by means of attenuation, field decay, skin depth, channel dispersion, power saving rate and signal voltage gain. Also, performance analysis is taken within the frequency range of 50 to 500 GHz to explore a deterministic channel communication between the IC's as an alternate of copper traces.

Terahertz Spoof Surface Plasmonic Logic Gates.

SummaryLogic gates are important components in integrated photonic circuitry. Here, a series of logic gates to achieve fundamental logic operations based on linear interference in spoof surface plasmon polariton waveguides are demonstrated at terahertz frequencies. A metasurface-based plasmonic source is adopted to couple free-space terahertz radiation into surface waves, followed by a funnel-shaped metasurface to efficiently couple the surface waves to the waveguides built on a domino structure. A single Mach-Zehnder waveguide interferometer can work as logic gates for four logic functions: AND, NOT, OR, and XOR. By cascading two such interferometers, NAND and NOR operations can also be achieved. Experimental investigations are supported by numerical simulations, and good agreement is obtained. The logic gates have compact sizes and high intensity contrasts for the output “1” and “0” states. More complicated functions can be envisioned and will be of great value for future terahertz integrated computing.

Zenneck Waves in Decision Agriculture: An Empirical Verification and Application in EM-Based Underground Wireless Power Transfer

In this article, the results of experiments for the observation of Zenneck surface waves in sub GHz frequency range using dipole antennas are presented. Experiments are conducted over three different soils for communications distances of up to 1 m. This empirical analysis confirms the existence of Zenneck waves over the soil surface. Through the power delay profile (PDP) analysis, it has been shown that other subsurface components exhibit rapid decay as compared to the Zenneck waves. A potential application of the Zenneck waves for energy transmission in the area of decision agriculture is explored. Accordingly, a novel wireless through-the-soil power transfer application using Zenneck surface waves in electromagnetic (EM) based wireless underground communications is developed.

Analysis of Two-Media Structures Using Longitudinal Spectrum: Space, Surface, and Zenneck Waves

The longitudinal spectral expansion method is extended to simplify the electromagnetic field analysis in a two-media structure with and without ground plane. A nonconventional Riemann sheet is invoked that clarifies some important characteristics of the fields. For instance, it is straightforward to prove that in a two-media half-space, no surface wave exists for lossless media. However, if a medium is lossy, then a fast surface wave, known as a Zenneck surface wave ( ZSW ), exists that dominates within a limited radial distance.

Selective Excitation of the Microwave Sommerfeld—Zenneck Surface Wave on a Conductive Strip

Surface electromagnetic waves (SEWs) on imperfect conductors proposed by A. Sommerfeld and J. Zenneck in the early 20th century have remained unrecognized by academic science for almost a hundred years due to a regrettable misunderstanding of theorists and unsolved radio communication problems. Recognition could have come much earlier if radiophysicists had been able to apply excitation of SEWs in the centimeter range of microwaves, generation of which became possible in the first half of the 20th century with development of radar. Radiophysical experiments on excitation of surface electromagnetic waves on conductors in the centimeter range of radio waves are presented. A method for selective excitation of SEWs is described. Its essence is that the space radio wave radiation is suppressed by screening while the SEW on the conductive strip is excited by isolated currents launched through a slit in the screen.

Network-on-Chip Multicast Architectures Using Hybrid Wire and Surface-Wave Interconnects

The network-on-chip (NoC) has been introduced as an efficient communication backbone to tackle the increasing challenges of on-chip communication. Nevertheless, merely metal-based NoC implementation offers only limited performance and power scalability in terms of multicast and broadcast traffics. To meet scalability demands, this paper addresses the system-level challenges for intra-chip multicast communication in a proposed hybrid interconnects architecture. This hybrid NoC combines and utilizes both regular metal on-chip interconnects and new type of wireless-NoC (WiNoC) which is Zenneck surface wave interconnects (SWI). Moreover, this paper embeds novel multicast routing and arbitration schemes to address system-level multicast-challenges in the proposed architecture. Specifically, a design exploration of contention handling in SWI layer is considered in both centralized and decentralized manners. Consequently, the hybrid wire-SWI architecture avoids overloading the network, alleviates the formation of traffic hotspots and avoid deadlocks that are typically associated with state-of-the-art multicast handling. The evaluation is based on a cycle-accurate simulation and hardware description. It demonstrates the effectiveness of the proposed architecture in terms of power consumption (up to around $10$ x) and performance (around $22$ x) compared to regular NoCs. These results are achieved with negligible hardware overheads. This study explore promising potential of the proposed architecture for current and future NoC-based many-core processors.

On the Condition for Transformation of a Fast Surface Wave into a Slow Surface Wave

Surface plasmons (polaritons) along the boundary between vacuum and a dissipative half-space with given complex permittivity, including the case of placing an electrically thin dielectric layer (system of layers) on the boundary, are considered. Conditions for transformation of a fast gliding Zenneck surface wave (polariton) into a slow wave (slow surface plasmon) are considered. The behavior of the group velocity and the energy velocity of motion (transfer) in such structures are analyzed. The reflection coefficient of the Zenneck wave along the sea for the ice pack of a given thickness is determined. It has been shown that rigorous solution of the Sommerfeld problem by means of numerical calculation of integrals in the near zone allows obtaining the solution of the inverse problem of the structure of the surface region on the basis of redundant experimental data on components of the electromagnetic field on the surface at different ranges from the antenna.

Near-Field Surface Waves in Few-Layer MoS2

Recently emerged layered transition metal dichalcogenides have attracted great interest due to their intriguing fundamental physical properties and potential applications in optoelectronics. Using scattering-type scanning near-field optical microscope (s-SNOM) and theoretical modeling, we study propagating surface waves in the visible spectral range that are excited at sharp edges of layered transition metal dichalcogenides (TMDC) such as molybdenum disulfide and tungsten diselenide. These surface waves form fringes in s-SNOM measurements. By measuring how the fringes change when the sample is rotated with respect to the incident beam, we obtain evidence that exfoliated MoS2 on a silicon substrate supports two types of Zenneck surface waves that are predicted to exist in materials with large real and imaginary parts of the permittivity. We have compared MoS2 interference fringes with those formed on layered insulator such as hexagonal boron nitride where only leaky modes are possible due to its small permittivity. Interpretation of experimental data is supported by theoretical models. Our results could pave the way to the investigation of surface waves on TMDCs and other van der Waals materials and their novel photonics applications.

Excitation and Propagation of Sommerfeld–Zenneck Surface Waves on a Conducting Strip in the Centimeter-Wave Band

The paper presents the results of experimental studies and the analysis of the surface electromagnetic wave propagation along metal conducting strips in the centimeter-wave band, which is convenient for simulation of open waveguides for the optical and terahertz bands of electromagnetic radiation.

Grating-coupled excitation of the Uller–Zenneck surface wave in the optical regime

The excitation of the Uller-Zenneck surface wave in the optical regime was theoretically investigated for planar as well as periodically corrugated interfaces of two homogeneous, isotropic dielectric materials, with only one of the two being dissipative. A practical configuration involving the planewave illumination of a planar interface of the two partnering materials was found to be unsuitable for experimental confirmation of the existence of this surface wave. But, when the interface was periodically corrugated, the Uller-Zenneck wave was found to be excited over a wide range of the angle of incidence. Air and crystalline silicon were identified as suitable partnering materials for experiments in the visible and ultraviolet spectral regimes.

Terahertz imaging of sub-wavelength particles with Zenneck surface waves

Impact of sub-wavelength-size dielectric particles on Zenneck surface waves on planar metallic antennas is investigated at terahertz (THz) frequencies with THz near-field probe microscopy. Perturbations of the surface waves show the particle presence, despite its sub-wavelength size. The experimental configuration, which utilizes excitation of surface waves at metallic edges, is suitable for THz imaging of dielectric sub-wavelength size objects. As a proof of concept, the effects of a small strontium titanate rectangular particle and a titanium dioxide sphere on the surface field of a bow-tie antenna are experimentally detected and verified using full-wave simulations.

Hybrid wire‐surface wave interconnects for next‐generation networks‐on‐chip

Networks-on-chip (NoC) is a communication paradigm that has emerged to tackle different on-chip challenges and satisfy different demands in terms of high performance and economical interconnect implementation. However, merely metal-based NoC pursuit offers limited scalability with the relentless technology scaling especially in global communications. To meet the scalability demand, this study proposes a new hybrid architecture empowered by both metal interconnect and Zenneck surface waves interconnects (SWIs). This architecture reduces the NoC average hop count between any communication pairs, which has been reflected as a better average delay and throughput. Furthermore, SWI enables more efficient power dissipation and faster cross the chip signal propagation. The authors' initial results based on a cycle-accurate simulator demonstrate the effectiveness of the proposed system architecture, such as significant power reduction (23%), large average delay reduction (34%) and higher throughput (35%) compared with regular NoC. These results are achieved with negligible hardware and area overhead. This study explores promising potentials of SWI for future complex global communication.

How Surface Waves Reduce Through-Life Costs

This article discusses the possibility of using Zenneck surface waves on platforms in order to reduce through-life engineering costs. It is proposed that this can be achieved in two main ways: (1) replace cables with a surface wave channel to increase the flexibility of designs and reduce the cost of repairs and maintenance and (2) use of surface waves for wide area structural health monitoring to reduce service intervals and inspection times.

The Electromagnetic Wave Propagation on the Interface between Low and High Loss Dielectrics

The wave propagation on closed curved interface (a rod or ball) between low and high loss dielectrics was studied and compared with well-known wave propagation problem on flat plane interface between low loss and high loss media. We have studied the propagation of a cylindrical wave along a round dielectric rod immersed into a high loss medium and a spherical wave forming by the oscillations in a dielectric ball immersed into a high loss medium as well. These waves have surface character similar to the wave known as the Zenneck surface wave. The distinctive characteristic of such cylindrical or spherical waves: the more loss in high loss medium the greater its surface character. We showed that the wave attenuation is essentially small at enough big dissipative loss in outer medium of dielectric structures.

THz Zenneck surface wave (THz surface plasmon) propagation on a metal sheet

We present an experimental study of the propagation of the THz Zenneck surface wave on an aluminum sheet, now more commonly denoted as the THz surface plasmon (TSP). Here, the TSP pulse is generated by coupling the THz pulse from a metal parallel-plate waveguide onto the aluminum sheet; the propagated TSP pulse is detected at the output end of the sheet using a standard photoconductive dipole antenna. We separate the associated free-space THz pulse from the TSP pulse using a curved sheet. The observed weakly guided TSP propagation has the expected low group velocity dispersion, but also has anomalously high attenuation and much tighter binding to the metal surface than predicted by Zenneck theory.

The ancient and modern history of EM ground-wave propagation

Radio-wave transmission over the surface of the Earth is a subject of enquiry going back to the beginning of the century. In this review, an attempt is made to describe the ground-wave mechanism that is omni-present. We first call attention to the early analytical contributions of Zenneck and Sommerfeld, based on a flat-Earth model. The subsequent controversies, particularly with regard to the role of the Zenneck surface wave, are outlined. Further developments by other pioneers, such as van der Pol, Fock, Bremmer, Norton, and Millington, are reviewed, and an attempt is made to put these in a modern context. We also show that the trapped surface wave can be a significant contribution to the total ground-wave field, when the Earth boundary is sufficiently inductive. Mixed-path theory and confirming model tests by Ray King are described briefly, along with calculated propagation curves for twoand three-section paths. The bibliography includes references to related topics, such as tropospheric refraction and topographic influences.

Spectral analysis of a dissipative problem in electrodynamics: The sommerfeld problem

This paper contains a survey of Gilliam and Schulenberger's work entitled ‘The propagation of electromagnetic waves through, along and over a three dimensional conducting half space’. A special case of this problem was originally considered in the now classic paper by A. Sommerfeld in 1909. Since that time there have been a tremendous number of articles in engineering and physics literature on special cases of this important physical model. However, the real composition of the electromagnetic field due to general finite energy sources remained unclear. In particular, there has been considerable controversy regarding the existence and properties of the Zenneck surface wave. The extreme length and technical nature of the complete solution found in Gilliam and Schulenberger's work as well as the rich history and physical importance of this problem provide the motivation for this survey. Furthermore, the techniques used in the work provide a basis for the rigorous mathematical analysis of a great many dissipative problems in electrodynamics within a unified mathematical framework.

On the excitation of the Zenneck surface wave over the ground at 10 MHz

Using a planar earth model the infinite vertical aperture with a Zenneck wave variation is found to excite only the Zenneck wave with no radiation field. The finite vertical aperture excites a field which is similar to the Zenneck wave near the aperture but resembles the usual ground wave at large distances. Numerical results for various aperture heights are given for a frequency of 10 MHz for a homogeneous ground path.