Intro

Question 1

Guglielmo Marconi developed the first practical radio system

Answer 1

1895

Question 2

Marconi successfully transmitted the first transatlantic signal

Answer 2

1901

Question 3

The first radio broadcast was made

Answer 3

1906

Question 4

The concept of cellular telephony was introduced

Answer 4

1947

Question 5

Martin Cooper, made the world’s first handheld cellular phone call.

Answer 5

1973

Question 6

Nordic Mobile Telephone (NMT), the first fully operational cellular network, was launched.

Answer 6

1981

Question 7

The first version of the Wi-Fi standard (802.11) was released

Answer 7

1997

Question 8

802.11g standard were introduced, offering speeds up to 54 Mbps.

Answer 8

2003

Question 9

The 802.11n standard were introduced, allowing speeds of up to 600 Mbps.

Answer 9

2009

Question 10

The introduction of 4G networks brought download speeds of up to 100 Mbps

Answer 10

2009

Question 11

The deployment of 5G networks began, promising speeds up to 10 Gbps, ultra-low latency, and enhanced capacity for a wide range of applications.

Answer 11

2018

Question 12

Radio Wave Propagation was predicted mathematically by (1) _____ in 1865 but was first demonstrated experimentally by (2)_____ in 1867.

Answer 12

1.James C. Maxwell
2.Heinrich R. Hertz

Question 13

Free-space propagation of electromagnetic waves is often called

Answer 13

radio-frequency (RF) propagation or simply radio propagation.

Question 14

are electromagnetic waves, like light, that propagates through free space in a straight line with a velocity of approximately same as speed of light.

Answer 14

Radio waves

Question 15

The energy level of the signal _____ rapidly with distance from the transmitting antenna.

Answer 15

decreases

Question 16

Once a _____ has been radiated by an antenna, it travels or propagates through space and ultimately reaches the receiving antenna.

Answer 16

radio signal

Question 17

The ____ wave is affected by objects that it encounters along the way such as trees, buildings, and other large structures

Answer 17

electromagnetic

Question 18

is an electrical energy that has escaped into free space.

Answer 18

ELECTROMAGNETIC WAVE

Question 19

as the name implies, involves the creation of electric and magnetic fields in free space or in some physical medium.

Answer 19

Electromagnetic radiation

Question 20

The waves that propagate are known as

Answer 20

transverse electromagnetic waves (TEM)

Question 21

characteristically means that the electric field, the magnetic field and the direction of propagation of the wave are all mutually perpendicular.

Answer 21

TRANSVERSE ELECTROMAGNETIC WAVE

Question 22

The essential properties of radio waves are

Answer 22

frequency, intensity, direction of travel, propagation velocity, and plane of polarization.

Question 23

The ____ of a plane electromagnetic wave is simply the orientation of the electric field vector in respect to the surface of the earth (looking at the horizon).

Answer 23

polarization

Question 24

If the polarization remains constant, it is described as

Answer 24

Linear Polarization

Question 25

If the polarization vector rotates 360° as the wave moves one wave length through space and the field strength is equal at all angles of polarization, the wave is described as having

Answer 25

Circular Polarization

Question 26

When the field strength varies with changes in polarization, this described as

Answer 26

Elliptical Polarization

Question 27

The propagation velocity is given by

Answer 27

Vp=C/√Er

Question 28

is the ratio of permittivity of the material and the permittivity of air or free space.

Answer 28

Relative permittivity (dielectric constant)

Question 29

The permittivity of air is approximately

Answer 29

8.85 x 10^-12 F/m

Question 30

would radiate equally from this source in all directions.

Answer 30

Waves

Question 31

A ____ , that is, a surface on which all the waves have the same phase, would be the surface of a sphere.

Answer 31

wavefront

Question 32

Such a source is called an

Answer 32

isotropic radiator

Question 33

There is no ____ of energy as radio waves propagate in free space, but there is attenuation due to the spreading of the waves.

Answer 33

loss

Question 34

The energy would be spread over a larger surface as the distance from the source _____

Answer 34

increased

Question 35

Since an isotropic radiator radiates equally in all directions, the ______, in watts per square meter, is simply the total power divided by the surface area of the sphere.

Answer 35

power density

Question 36

Power Density, in watts per square

Answer 36

PD = Pt/4πr^2

Question 37

As the wavefront moves further from the source, the ____ the power density.

Answer 37

smaller

Question 38

Power density is also the rate at which the energy passes through a given surface area in free space

Answer 38

PD = εΗ

Question 39

The strength of the electric field, ɛ (in volts per meter), at a distance r from a point source is given by

Answer 39

ε = (√30Pt)/r

Question 40

Power density and the electric field are related to impedance in the same way that power and voltage relate in an electric circuit.

Answer 40

PD = ε ²/Zo

Question 41

Characteristic Impedance of a lossless transmission medium is equal to

Answer 41

Zo=√(U/ε )