ISAP 2018

Short Course
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• Date / Time: October 23, (Tue.), 13:00~18:00

• Place: Capri Room, Paradise Hotel Busan, Korea

Short Course 1

13:00-13:40

Stand on the Antennas and Propagation Standards

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Stand on the Antennas and Propagation Standards

Vikass Monebhurrun

Within the field of wireless communication, the IEEE 802.11 series of standards related to WiFi [1] is probably the most popular standarddeveloped by the IEEE Standards Association (IEEE-SA). This is certainly due to the fact that the IEEE 802.11 protocol is implemented in ubiquitous devices and WiFi is typically available everywhere. For many, standards development is often related to wireless communication protocols (from 2G to 5G) and to compliance assessment of the corresponding wireless communication devices. Actually, there exists a multitude of standards, recommended practices and guides for different applications and fields. In the field of electrical engineering, several international institutions develop standards which are usually enforced by regulatory bodies. And, although IEEE-SA develops voluntary standards (which could eventually be made mandatory), suchdocuments help establish harmonized engineering terminology, methods and practices elaborated through a consensus-based approach. In the field of communication, it is obvious that harmonization ensures that devices developed by different manufacturers can communicate with each other using a commonly defined and accepted protocol. Prior to the marketing of an electronic device, it is also important to ensure that it is compliant with regard to possible interference and safety which are addressed by electromagnetic compatibility standards.

The IEEE Antennas and Propagation Standards Committee (APS/SC), sponsored by the IEEE Antennas and Propagation Society (AP-S),develops and maintains standards that are within the fields of antennas and propagation. There are currently six standards that have already been developed: Std. 145 [2], Std. 211 [3], Std. 149 [4], Std. 1502 [5], Std. 1720 [6], and Std. 356 [7]. Std. 145 and Std. 211provide the standard definitions of terms for antennas and radio wave propagation, respectively. Misuse of technical terms is still frequently observed, especially in conference papers and presentations. The most common misuse is probably the term “return loss” often taken to be the synonym of “reflection coefficient” [8]. The IEEE Standard Dictionary of Electrical and Electronics Terms provides the accepted definitions of these terms [9].Std. 149, which provides the standard test procedures for antennas, is currently being revised as a recommended practice for antenna measurements [10]. Std. 1502 dedicated to the measurement of radar cross-section (RCS)is also being revised to include a section on RCS calibration. A minor revision is being undertaken for Std. 356 on the measurement of electromagnetic properties of earth media [11].

The APS/SC committee recently approved the formation of a study group on numerical modelling for antennas and propagation applications. The proposal followed the observation that commercial as well as non-commercial software packages are frequently employed to perform electromagnetic simulations but, as more and more complex configurations are tackled, it becomes difficult to assess the consistency and accuracy of the results.To demonstrate that the simulation results are reliable, they are usually compared to either known analytical solutions (when available) or results obtained using another software based on a different electromagnetic solver or measurement results. However, sometimes the simulation results are simply used to prove a design concept, for example of a novel antenna, without any demonstration that the simulation tool was properly used. Software vendors usually provide default settings in the commercial software packages for different types of applications. Typical example configurations are also provided to train the user about the software but they are not always studied.Hence, arecommended practice on electromagnetic modelling which describes the simulation procedure to be followed using typical methods such as the finite element method (FEM), the method of moments (MoM) and the finite difference time domain (FDTD) method should prove useful for the numerical modelling of problems related to the field of antennas and propagation. The recommended practice should provide the minimum requirements to ensure that the method was properly applied, benchmarks, and eventually, an accepted uncertainty budget.

The objective of the talk is to disseminate information about the standards developed for antennas and propagation applications, and to encouragetheir use.

References

• [1] IEEE Standard for Information Technology – Telecommunications and information exchange between systems local and metropolitan area networks – Specific requirements – Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications, IEEE Std. 802.11-2016.

• [2] IEEE Standard Definitions of Terms for Antennas, IEEE Std. 145-2013.

• [3] IEEE Standard Definitions of Terms for Radio Wave Propagation, IEEE Std. 211-1997.

• [4] IEEE Standard Test Procedures for Antennas, IEEE Std. 149-1979.

• [5] IEEE Recommended Practice for Radar Cross-Section, IEEE Std. 1502-2007.

• [6] IEEE Recommended Practice for Near Field Antenna Measurement, IEEE Std. 1720-2012.

• [7] IEEE Guide for Measurement of Electromagnetic Properties of Earth Media, IEEE Std. 356-2010.

• [8] Trevor S. Bird, “Definition and misuse of return loss,” IEEE Antennas and Propagation Magazine, Vol. 51, No. 2, April 2009, pp. 166-167.

• [9] IEEE Standard Dictionary of Electrical and Electronics Terms, Sixth Edition, Std. 100-1996.

• [10] Vikass Monebhurrun, “Revision of IEEE Antennas and Propagation Society Standards 149, 211, and 1502,” IEEE Antennas and Propagation Magazine, Vol. 58, No. 3, June 2016, pp. 104 & 113.

• [11] Vikass Monebhurrun, “Revision of the Guide for Measurements of Electromagnetic Properties of Earth Media,” IEEE Antennas and Propagation Magazine, Vol. 60, No. 4, August 2018, pp. 142.

Dr. Vikass Monebhurrun

(CentraleSupelec, France
Chair IEEE Antennas & Propagation Standards Committee)

Short Course 2

13:40-14:40

Artificial Electromagnetic Structures and Associated Devices based on Active ‘Negative’ Elements

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Artificial Electromagnetic Structures and Associated Devices based on Active ‘Negative’ Elements

Silvio Hrabar

More than fifteen years have passed from the introduction of the field of RF electromagnetic metamaterials. These are artificial structures, electromagnetic properties of which (permittivity and permeability) are not found in continuous, naturally occurring materials. Metamaterials have brought some novel intriguing physical phenomena such as negative refraction, sub-wavelength propagation, resolution-free imaging, just to mention a few. Unfortunately, the practical real-word engineering applications are still rather limited due to two basic problems: pronounced losses and a narrow operating bandwidth. This is the inherent drawback of all known passive metamaterials, caused by the basic background physics (energy-dispersion constraints), rather than used technology. The loss issue has been considerably softened by recent introduction of metasurfaces (the two-dimensional equivalent of metamaterials). However, achieving a large operation bandwidth is still a main obstacle in many applications, particularly in antenna technology.

A very interesting idea that might work around this inherent limitation is based on the active circuits that mimic behavior of hypothetical negative capacitors, negative inductors, and negative resistors. It is well known that negative capacitors and negative inductors have dispersion curves that are the exact inverse of the dispersion curves of ordinary ‘positive’ elements. Therefore, the dispersion of ordinary passive metamaterials can be compensated for with the ‘inverse’ dispersion of negative capacitors and inductors, resulting in extremely broadband behavior. Typical examples include RF ENZ transmission lines developed at University of Zagreb that span the bandwidths from more than four octaves (1 MHz to 40 MHz) up to 1:700 or more than 9 octaves (1MHz to 700 MHz). These structures were additionally enhanced by adding in-situ re-configurability feature. Using an external DC control signal it is possible to achieve tunableDPS-ENZ or DPS-MNZ behavior.Additionally, inclusion of negative resistors can provide gain and, therefore, compensate the unavoidable losses of passive metamaterial/metasurface structures.

Furthermore, there are some novel ideasthat go beyond dispersion compensation and make use of inherent non-linearity and instability of negative elements. The most recent example is a non-Foster radiating system thatemploys unstable non-Foster/negative-resistance-capacitance active device (a source) connected to an antenna. The internal impedance of active device is identical to the antenna self-impedance, but with the flipped sign. This system behaves as a self-oscillating antenna with theoretically infinite bandwidth with perfect matching. The performed experiments showed tuning bandwidth of one decade (1:10) in RF regime. It is envisaged that this approach could lead to perfectly-matched,tunable self-oscillating metasurfaces.

This lecturereviews the field of artificial structures based on ‘negative’ elements, presenting the basic background theory, the most important experimental resultsachieved at University of Zagreb, still unclear issues,and future research trends.

Prof. Silvio Hrabar

(University of Zagreb, Croatia)

	Short Course 3 14:40-15:40
	Antenna Design on Complex Platforms by using Characteristic Modes, Eigenmodes and Characteristic Basis Functions Prof. Raj Mittra (University of Central Florida, USA) ※ In this lecture, all the participants will be given access to a website from which can download the notes. If you would like to access the notes, please bring your own laptop.

Break Time

15:40-16:00

Short Course 4

16:00-17:00

Rectangular Coordinate Orthogonal Multiplexing Antenna System for Non-Far Region Communication

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Rectangular Coordinate Orthogonal Multiplexing Antenna System for Non-Far Region Communication.

Jiro Hirokawa

This tutorial talk deals with the rectangular coordinate orthogonal multiplexing (ROM) antenna system for non-far region communication, which would be advantageous in comparison with OAM transmission using radio waves [1]. The OAM transmissionis based on the orthogonality in the cylindrical coordinate system. For the orthogonality in the circumferential direction, phase variations are used, which have typically a narrow band. The treatments in the radial and the circumferential directions are different. The OAM transmission was proposed originally in optics [2], where the normalized frequency bandwidth is almost negligible and the narrow-band operation is acceptable. However wireless systems in microwave and millimeter-waves sometimes requires a wide bandwidth of 10-20%, where conventional narrow-band OAM transmission would cause a problem.
ROM [3] uses beam orthogonality in the rectangular coordinate system. The orthogonality is based on polarity and wideband operation is achieved by introducing the structural symmetry of the feeding elements such as magic T. The extension to two-dimensional orthogonality is easy because the treatments in the x- and the y- directions are the same. The feasibility is discussed on one system, where a corporate-feed waveguide slot array antenna and a monopulse circuit are combined. 4-multiplexing 40cm-communication using 16x16-slot arrays are confirmed experimentally in 80GHz band. Some recent advances are also explained on excitation control for maximizing transmission between the transmitting and the receiving antennas for a given distance and extension to 16-multiplexing.

References

• [1] S. M. Mohammadi, L. K. S. Daldorff, J. E. S. Bergman, R. L. Karlsson, B. Thidé, K. Forozesh, and T. D. Carozzi ” Orbital Angular Momentum in Radio — A System Study,” IEEE Trans. Ant. Propag., Vol. 58, No. 2, pp. 565-572, 2010

• [2] G. Gibson, J. Courtial, M. J. Padgett,” Free Space Information Transfer using Light Beams carrying Orbital Angular Momentum,” Optics Express, Vol. 12, No. 22, pp. 5448-5456, Nov. 2004.

• [3] K. Tekkouk, J. Hirokawa, and M. Ando, “Multiplexing Antenna System in the Non-Far Region Exploiting Two-dimensional Beam Mode Orthogonality in the Rectangular Coordinate System,” IEEE Trans. Antennas Propagat., vol. 66, no. 3, pp. 1507-1515, Mar. 2018.

Prof. Jiro Hirokawa

(Tokyo Institute of Technology, Japan)

Short Course 5

17:00-18:00

Some Research Advances in mmWave 5G

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Some Research Advances in mmWave 5G

Wei Hong

The standardization of sub-6GHz 5G mobile communications has been fixed in June, 2018, the spectrum allocation and standardization of millimeter wave 5G (mmWave 5G) is underway and is expected be finished in one or two years. Massive MIMO has been considered as one of the main enabling technologies of 5G, and multibeam array is the key technology of massive MIMO systems. In this talk, the recent research advances in multibeam arrays, ICs and systems related to mmWave 5G in the State Key Laboratory of Millimeter Waves (SKLMMW), Southeast University are reviewed.

Prof. Wei Hong

(Southeast University, China)