A1-Electromagnetic signals

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⌘TOC on A1-Electromagnetic signals

Building .... Networks
History, Now and Future
Pioneers: Maxwell, Hertz,...
1G, 2G,... 5G networks
Frequencies and Standards
Future Challenges
A-Basics of Communication
Electromagnetic Signals
Radio Communication Principles
Digital communication: Signal/Noise Ratio
Signal strength and Capacity: Shannon
B-Antennas and Propagation
Free Space Propagation
Antennas, Gain, Radiation Pattern
Multipath Propagation, Reflection, Diffraction
Attenuation, Scattering
Interference and Fading (Rayleigh, Rician, …)
Mobile Communication dependencies
C-Propagation models
Environments (indoor, outdoor to indoor, vehicular)
Outdoor (Lee, Okumura, Hata, COST231 models)
Indoor (One-slope, multiwall, linear attenuation)
D-System Comparison
Proximity: RFID, NFC
Short Range: ZigBee, Bluetooth, ANT+,...
Mobile Network mobility
IP mobility
F-Network Building
5G and Future Networks
5G Heterogeneous Networks
Basic Internet
Video Distribution Networks
Coverage simulations
Coverage simulations
Traffic simulations
Network Capacity simulations
Building .... Networks

⌘ Wave Propagation Parameters

Can also be called "Propagation constant". Somewhat misleading, as the propagation usually varies strongly.

Alternative names:

  • Transmission parameters
  • Propagation parameters
  • Propagation coefficients
  • Transmission constants
  • Secondary coefficients

Propagation constant, symbol γ, is defined by the ratio between the amplitude at the source, and the amplitude at some distance x. Is a complex quantity, so we use α (attenuation constant) and β (phase constant) to define it. Attenuation constant, is the loss of signal, or attenuation of an electromagnetic wave travelling through a medium. Phase constant is the change in phase per meter, along the path travelled.

⌘Wave propagation and absorption mechanisms

Wave propagation and absorption mechanism
Band Frequency Wavelength Propagation via
Very low frequency, VLF 3-30 kHz 100 - 10 km Guided between the earth and the ionosphere.
Low frequency, LF 30 - 300 kHz 10 - 1 km Guided between the earth and the D layer of the ionosphere. Surface waves.
Medium frequency, MF 300 - 3000 kHz 1000 - 100 m Surface waves.E, F layer ionospheric refraction at night, when D layer absorption weakens.
High frequency, HF (short wave) 3-30 MHz 100-10 m E layer ionospheric refraction. F1, F2 layer ionospheric refraction.
Very high frequency, VHF 30-300 MHz 10-1 m Sporadic E propagation Extremely rare F1,F2 layer ionospheric refraction during high sunspot activity up to 80 MHz. Generally direct wave.
Ultra high frequency, UHF 300-3000 MHz 100-10 cm Line-of-sight propagation. Sometimes tropospheric ducting.
Super high frequency, SHF 3-30 GHz 10-1 cm Direct wave.
Extremely high frequency, EHF 30-300 GHz 10-1 mm Direct wave limited by absorption.

The frequencies which we use for mobile communications are ranging from 450 MHz (ICE), the old TV bands, 800-900 MHz (GSM), 1800 (GSM), 1900, 2100 MHz (UMTS), 2400 MHz (Wifi), 2650 MHz (LTE), and 5100 MHz (IEEE802.11a..). While previously frequency band were used for a specific technology, refarming started in 2012 to open for communication technologies in other bands. Examples of such refarming are LTE1800 indicating an operation of LTE in the 1800 band. Back in 2013 Apple surprised the European operators, as the iPhone came with LTE only in the 1800 band, and not, as usual in Europe, in the 2600 band.


⌘ Further readings

⌘ What will we learn today

  • basics of radio communication
  • sampling theorem
  • typical radio transmission
  • what effects the signal strengths

⌘ Heinrich Hertz - Radiowave propagation

Basics of wave propagation:
  • The variation of an electrical field creates a magnetic field
  • The variation of a magnetic field creates an electrical field

⌘ Electromagnetic signals

* Prerequisite: Ohm's law, current, dielectric constant , conductivity
    • "Pappa, what is voltage?"
  • Alternating electric and magnetic field
  • Direction of wave from "right-hand rule"

[Source: Wikipedia]

Note: Depending on the convention, either [A m] or are used to indicate the magnetic field. In UNIK4700 and this compendium we use the notation of



Keywords used:

  • wireless electromagnetic propagation
  • wireless electromagnetic propagation parameter
  • wireless electromagnetic propagation fading
  • wireless propagation refraction
  • wireless wave attenuation constant