This letter presents a new metamaterial-based waveguide technology referred to as ridge gap waveguides. The main advantages of the ridge gap waveguides compared to hollow waveguides are that they are planar and much cheaper to manufacture, in particular at high frequencies such as for millimeter and sub- millimeter waves. The latter is due to the fact that there are no mechanical joints across which electric currents must float. The gap waveguides have lower losses than microstrip lines, and they are completely shielded by metal so no additional packaging is needed, in contrast to the severe packaging problems associated with microstrip circuits. The gap waveguides are realized in a narrow gap between two parallel metal plates by using a texture or multilayer structure on one of the surfaces. The waves follow metal ridges in the textured surface. All wave propagation in other directions is prohibited (in cutoff) by realizing a high surface impedance (ideally a perfect magnetic conductor) in the textured surface at both sides of all ridges. Thereby, cavity resonances do not appear either within the band of operation. The present letter introduces the gap waveguide and presents some initial simulated results.

Local Metamaterial-Based Waveguides in Gaps Between Parallel Metal Plates

Preface 1. Introduction 2. FDTD Method for periodic structure analysis 3. EBG Characterizations and classifications 4. Design and optimizations of EBG structures 5. Patch antennas with EBG structures 6. Low profile wire antennas on EBG surfaces 7. Surface wave antennas Appendix: EBG literature review.

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Electromagnetic Band Gap Structures in Antenna Engineering

To make transportation safer, more efficient, and less harmful to the environment, traffic telematics services are currently being intensely investigated and developed. Such services require dependable wireless vehicle-to-infrastructure and vehicle-to-vehicle communications providing robust connectivity at moderate data rates. The development of such dependable vehicular communication systems and standards requires accurate models of the propagation channel in all relevant environments and scenarios. Key characteristics of vehicular channels are shadowing by other vehicles, high Doppler shifts, and inherent nonstationarity. All have major impact on the data packet transmission reliability and latency. This paper provides an overview of the existing vehicular channel measurements in a variety of important environments, and the observed channel characteristics (such as delay spreads and Doppler spreads) therein. We briefly discuss the available vehicular channel models and their respective merits and deficiencies. Finally, we discuss the implications for wireless system design with a strong focus on IEEE 802.11p. On the road towards a dependable vehicular network, room for improvements in coverage, reliability, scalability, and delay are highlighted, calling for evolutionary improvements in the IEEE 802.11p standard. Multiple antennas at the onboard units and roadside units are recommended to exploit spatial diversity for increased diversity and reliability. Evolutionary improvements in the physical (PHY) and medium access control (MAC) layers are required to yield dependable systems. Extensive references are provided.

/pdf/vehicular-channel-characterization-and-its-implications-for-3l69uw88ht.pdf

Vehicular Channel Characterization and Its Implications for Wireless System Design and Performance

Before the emergence of ultra-wideband (UWB) radios, widely used wireless communications were based on sinusoidal carriers, and impulse technologies were employed only in specific applications (e.g. radar). In 2002, the Federal Communication Commission (FCC) allowed unlicensed operation between 3.1–10.6 GHz for UWB communication, using a wideband signal format with a low EIRP level (−41.3dBm/MHz). UWB communication systems then emerged as an alternative to narrowband systems and significant effort in this area has been invested at the regulatory, commercial, and research levels.

IEEE Transactions on Microwave Theory and Techniques and Antennas and Propagation Announce a Joint Special Issue on Ultra-Wideband (UWB) Technology

Smart world is envisioned as an era in which objects (e.g., watches, mobile phones, computers, cars, buses, and trains) can automatically and intelligently serve people in a collaborative manner. Paving the way for smart world, Internet of Things (IoT) connects everything in the smart world. Motivated by achieving a sustainable smart world, this paper discusses various technologies and issues regarding green IoT, which further reduces the energy consumption of IoT. Particularly, an overview regarding IoT and green IoT is performed first. Then, the hot green information and communications technologies (ICTs) (e.g., green radio-frequency identification, green wireless sensor network, green cloud computing, green machine to machine, and green data center) enabling green IoT are studied, and general green ICT principles are summarized. Furthermore, the latest developments and future vision about sensor cloud, which is a novel paradigm in green IoT, are reviewed and introduced, respectively. Finally, future research directions and open problems about green IoT are presented. Our work targets to be an enlightening and latest guidance for research with respect to green IoT and smart world.

Green Internet of Things for Smart World

This paper presents new topics that will be lectured in the short course Metamaterials for Antennas within the European School of Antennas in Spring 2012. These relates to new so-called gap waveguides that are advantageous for use above 30 GHz, because they are quasi-TEM over wide bandwidth, and do neither require dielectric material nor conductive joints between metal parts. The gap waveguides originate from research on soft and hard surfaces that also are forerunners for EBG surfaces (acting as isotropic soft surfaces) and metamaterial cloaks (realized first by hard surfaces). The course will contain material related to all these topics, and in addition an overview of the last years research on the gap waveguides including experimental demonstration of principles as well as working hardware components. In this presentation special emphasis will be given to electromagnetic (EM) packaging, the principle of PMC packaging and integration of MMICs.

https://publications.lib.chalmers.se/records/fulltext/143603/local_143603.pdf

The gap waveguide as a metamaterial-based electromagnetic packaging technology enabling integration of MMICs and antennas up to THz

Gap Waveguide Technology

In this contribution a new version of EBG-filter based on mushroom type resonators is proposed in inverted microstrip Gap Waveguide Technology. The resonator used consists of a metallic patch printed on the same layer as the transmission line and coupled to it, and a via shorting the patch to the top cover of a parallel plate waveguide. We compare results for the ideal Perfect Magnetic Conductor used during the initial filter design and the real low cost surface (bed of nails made with screws) proposed for the filter. A numerical characterization of the new filter and its stop band behaviour is described in the paper showing a good performance.

New EBG-filter design in inverted microstrip gap waveguide technology

A new structure of stacked patch antennas with bandwidth performance has been studied. This structure is realized by setting the two patches of the antenna in a non-centered position. Experiments indicate that an important increase of the bandwidth is achieved as well as the possibility of dual band antennas. Finally special features have been found when radiation patterns are measured.

http://ieeexplore.ieee.org/iel5/7598/20722/00958802.pdf

Analysis of bandwidth and radiation in non-centered stacked patches

The gap waveguide technology is an advantageous way of packaging passive microstrip components. This work presents a wideband transition from a standard microstrip line packaged by using a bed of nails, to a rectangular waveguide operating in V band. The transition is designed by means of a T-shaped patch that couples the fields into a rectangular waveguide extending vertically from the microstrip circuit. The simulated results show more than 28.5% bandwidth with S 11 lower than −10 dB. This transition is intended to be used as a WR-15 port of a planar array antenna for 60 GHz applications, where the array elements are fed by microstrip distribution networks packaged by gap waveguide technology. Thereby, radiation is avoided from the distribution network itself.

http://ap-s.ei.tuat.ac.jp/isapx/2014/pdf/TH2A_01.pdf

Eva Rajo-Iglesias

Papers

The gap waveguide as a metamaterial-based electromagnetic packaging technology enabling integration of MMICs and antennas up to THz

Gap Waveguide Technology

New EBG-filter design in inverted microstrip gap waveguide technology

Analysis of bandwidth and radiation in non-centered stacked patches

Design of a transition from WR-15 to microstrip packaged by gap waveguide technology