1. Fundamentals of Transmission channels
Introduction to Microwave
Introduction to Mobile Radio Channels
Large-scale path loss
Small-scale fading and multipath
Introduction to Mobile Radio Channels (Weeks 6-9)
 Basic concepts - Introduction to mobile radio channel, basic concepts and typical types of radio channels.
 Learning outcome
Sound understanding of free space propagation model, relating power to electric field and radio channel types.
 Tutorial examples
Tutorial examples sheet will be handed out at the end of formal teaching of this study area.
Large-scale path loss – basic theory of Large-scale path loss, three basic propagation mechanisms: reflection, diffraction and scattering. Modelling of outdoor and indoor propagations.
Develop a sound understanding of mobile wave propagation for large-scale path loss.
Small-scale fading and multipath – small-scale multipath propagation, parameters of mobile multipath channels, types of small-scale fading, statistical models for multipath fading channels.
Sound understanding of mobile wave propagation for small-scale fading and multipath using various empiric models.
by Ya Bao, FTC

2. Introduction to Microwave
All electronic communications systems send information from one point to another by transmitting electromagnetic energy from the sender to the intended receiver.
This electromagnetic energy can travel in various modes,
as a voltage or current through wires, as radio emissions through air or the vacuum of space, or as light.
by Ya Bao, FTC

3. Velocity, Frequency, and Wavelength
Velocity of an electromagnetic (EM) wave in free space (vacuum)
where μ0 is the permeability of free space and ε0 is the permittivity of free space. They are the distributed values of L and C of free space.

4. where εr is the relative permittivity (dielectric constant).
Absolute permittivity of a medium is noted as ε and is given by ε= εr ε0
where εr is the relative permittivity (dielectric constant).
Absolute permeability of a medium is noted as μ and is given by μ= μr μ0
where μr is the relative permeability, equaling to 1 for a vacuum and most nonmagnetic metals. Thus, μr equals 1 for most purposes.
If the wave travels through a medium of εr, the new velocity is vr = C/ εr1/2
where c = 3.0x108 m/s is the velocity of light in vacuum.
Example 1: What is the velocity of an EM wave when εr = 2.00?
Solution: vr = C/ εr1/2=3*108/21/2 = 2.12*108 m/s
The propagation velocity is less in any medium other than vacuum. In air, the propagation velocity of electromagnetic energy is about 95 to 98% of the value in vacuum. In wire, it is anywhere from 60 to 85% of c, depending on wire type, construction, and insulation. For example, a common type of cable used for cable TV has a propagation factor of 75% of c. The actual velocity of the electromagnetic energy in this cable is .
by Ya Bao, FTC

5. Frequency and Wavelength
Frequency f is the number of cycles per second a signal contains.
Signal (wave) period T is the time of one complete cycle, i.e. T= 1/f
Wavelength λ of an EM wave is the physical distance the wave travels in one cycle,
i.e., λ = c/f (in free space)
Example 2: caculate the wavelength λ for an EM wave f=50GHz where εr=3.0.
Solution: λ=c/f εr1/2 = 3*108 /(50*109 )*31/2 =3.5 mm
1 kilohertz (kHz)= 1,000 Hz
1 megahertz (MHz)=1,000,000 Hz = 1,000 kHz = 1*106 Hz
1 gigahertz (GHz)= Hz = 1000 MHz = 1*109 Hz
1012 , terahertz (THz); , petahertz (PHz); , exahertz (EHz);
by Ya Bao, FTC

6. The Electromagnetic Spectrum
The total span of frequencies and corresponding wavelengths used in communications systems is called the electromagnetic spectrum. The overall useful electromagnetic spectrum extends from about 10,000Hz to several billion hertz.

7. Microwaves
Microwaves are electromagnetic radiation of frequencies from several hundred MHz to several hundred GHz.
Microwaves, by virtue of their high frequency, have extremely short wavelengths, thus the word "micro" in the name. Available frequency spectrum
by Ya Bao, FTC