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32nd International Union of Radio Science General Assembly & Scientific Symposium * Montreal, Canada * 19-27 August 2017 Home Page

Program
COMMISSION TUTORIALS

Commission A

Date: Thursday, August 24, 11:00 – 12:00
Room: TBA

Presenter: Judah Levine, Time and Frequency Division, NIST Boulder
Title: Distributing Time and Frequency Data: Requirements and Method
Convener: Yasuhiro Koyama

Description: There are many commercial, financial, and industrial applications that depend on accurate time and frequency information. High-frequency trading of stocks and commodities, telecommunications, and the control and synchronization of the electrical power grid are just a few examples. The level of accuracy that is required to support these applications is relatively modest from the perspective of the internal time scales of most National Metrology Institutes and timing laboratories, but satisfying the requirements becomes much more challenging when the need for extreme reliability and the limitations of many of the common distribution channels are included. I will describe the near-term future requirements and the solutions that have been proposed to satisfy them. None of the solutions is completely adequate now and all of them will have increasing difficulty in the future, and I will discuss methods that could address these limitations.

Commission B

Date: Monday, August 21, 9:40 – 10:40
Room: TBA

Presenter: Sergei Tretyakov
Title: Metasurfaces: Synthesis for Perfect Refraction and Reflection of Waves into Arbitrary Directions
Convener: Ari Sihvola

Description: Electrically thin composite layers (metasurfaces) can be used to realize extremely thin absorbers, lenses, focusing reflectors, and more. In this tutorial talk we will discuss metasurfaces optimally designed for application-required transformations of electromagnetic fields. We will explain what physical properties of metasurface unit cells are responsible for various field transformations and illustrate the potentials of this technology by several examples from our experimental work. The main focus of the lecture will be on surfaces for perfect refraction or reflection of plane waves into desired directions. Conventionally, design of transmitarrays and reflectarrays has been based on assuring the desired reflection or transmission properties at every point of the metasurface area, using the generalized laws or refraction and reflection.  However, this approach does not lead to exactly the required performance. In this talk we will explain how it is possible to create metasurfaces which function exactly as is required by the design specification and show experimental results.

Commission C

Date: Wednesday, August 23, 9:40 – 10:40
Room: TBA

Presenter: Sana Salous
Title: 5G Radio Channel Models to Standardization
Convener: Amir Zaghloul

Description: 5G radio systems will use higher frequency bands to enable high data rate applications. This tutorial will cover various aspects of 5G radio systems including deployment scenarios, propagation issues and standardization.

Commission D

Date: Wednesday, August 24, 13:40 – 14:40
Room: TBA

Presenter: J Leuthold
Title: The Path towards 100 Gbit/s Wireless Communications
Convener: Günter Steinmeyer

Description:100 Gbit/s wireless communications is emerging as a solution to overcome the access network bottleneck. Yet, capacities above 100 Gbit/s require new technologies and photonic-electronic devices that can handle sub-THz carrier frequencies that allow for fast beam steering of pencil beams and that can process novel modulation formats. This tutorial session will review recent progress in the field and highlight the impact of novel technologies such as plasmonics to overcome the technological challenges on the path to Tbit/s wireless communications.

Commission E

Date: Friday, August 25, 9:40 – 10:40
Room: TBA

Presenter: William Radasky
Title: EMC Aspects in Smart Grids
Convener: D.V. Giri

Description: Smart Grids are being contemplated and portions of them implemented in some nations. This tutorial talk deals with the EMC aspects of the smart grids.

Commission F

Date: Thursday, August 24, 11:00 – 12:00
Room: TBA

Presenter: Dr. Luca Baldini
Title: Modeling Rain Medium for Weather Radar and Propagation
Convener: Simonetta Paloscia

Description: Abstract: Modeling rain for weather radar and propagation applications is generally accomplished through modeling the drop size distribution (DSD) and its variability and drop shapes. The DSD is defined to be the number of drops per unit volume of air and per unit of drop diameter interval and often is modeled with a three-parameter gamma distribution. Instruments called ‘disdrometers' can measure the diameter distribution of drops reaching the ground, from which volume DSD are derived. On the other hand, active instruments, such as vertical profilers or weather radar can estimate DSD aloft based on different measurement principles. From measured or theoretical distribution of DSD, using electromagnetic simulation models, radar and propagation variables can be obtained. Obviously, measured distributions can be considered as more representative of the natural variability of rain in a given location than theoretically derived distributions, but are affected by different sources of errors. The mpact of DSDs, estimated by different instruments or theoretically derived, on weather radar retrievals or in predicting propagation effects will be analyzed.

Commission G

Date: Thursday, August 24, 13:40 – 14:40
Room: TBA

Presenter: Tim Fuller-Rowell
Title: Will We Ever be Able to Model and Forecast the Ionosphere Well Enough to Support the Needs of the Radio Wave Users?
Convener: Iwona Stanislawska

Description: TBA

Commission H

Date: Tuesday, August 22, 13:40 – 14:40
Room: TBA

Presenter: Prof. Craig Rodger, University of Otago, NZ
Title: Drivers, detection, and wider significance of precipitation from the radiation belts

Description:
Wave particle interactions are a fundamental physical mechanism driving change in the Van Allen radiation belts. Growing evidence indicates that cyclotron resonance between VLF whistler-mode waves and energetic electrons play crucial roles for the acceleration of electrons to relativistic energies. It has long been recognised that the same resonances also pitch-angle scatter electrons, moving them towards the loss cone and causing loss of these electrons into the atmosphere through precipitation.

Particle precipitation into the atmosphere is believed to be one significant mechanism for the loss of energetic electrons from the radiation belts. Wave-particle interactions involving ULF through to VLF waves are understood to be the most important drivers of these loss events. The majority of these waves are naturally generated, but manmade waves from large communications transmitters can also play a role, particularly in the inner radiation belt.

There is growing interest in energetic electron precipitation (EEP). This is partially because of the need to include both acceleration and loss processes in radiation belt predictive models. There is also a new focus on the impact of the energetic electron precipitation on the polar atmosphere, with increasing evidence of significant changes in upper-atmospheric chemistry, and coupling to polar-surface climate.

In this talk I will provide an overview of the fundamental processes driving precipitation, discuss the properties of observed EEP, and discuss its wider significance to the Earth's system. I will also attempt to include some open questions in this area.

Commission J

Date: Monday, August 21, 13:40 – 14:40
Room: TBA

Presenter: Lars-Ake Nyman
Title: The Atacama Large Millimeter Array (ALMA)
Convener: Willem Baan

Description: TBA

Commission K

Date: Tuesday, August 22, 11:00 – 12:00
Room: TBA

Presenter: Tahera Emilie van Deventer
Title: International EMF Project to Assess Health and Environmental Effects of Exposure to Static and Time Varying Electric and Magnetic Fields in the Frequency Range 0-300 GHz
Convener: Joe Wiart

Description: The processes for assessing health risks and developing exposure guidelines for electromagnetic fields have evolved to reflect the rigorous and systematic use of evidence as the basis for public health policies. This talk will provide an update on the activities of the World Health Organization and address the opportunities and challenges faced in analyzing the current scientific evidence and in developing standards that are useful to and applicable by regulatory authorities.