Radio Waves
Electromagnetic waves ranging in frequencies between 3 KHz and 1 GHz are
normally called radio waves.
Radio waves are omnidirectional. When an antenna transmits radio waves,
they are propagated in all directions. This means that the sending and
receiving antennas do not have to be aligned. A sending antenna send waves
that can be received by any receiving antenna. The omnidirectional property
has disadvantage, too. The radio waves transmitted by one antenna are
susceptible to interference by another antenna that may send signal using the
same frequency or band.
Radio waves, particularly with those of low and medium frequencies, can
penetrate walls. This characteristic can be both an advantage and a
disadvantage. It is an advantage because, an AM radio can receive signals
inside a building. It is a disadvantage because we cannot isolate a
communication to just inside or outside a building.
Micro Waves
Electromagnetic waves having frequencies between 1 and 300 GHz are called
micro waves. Micro waves are unidirectional. When an antenna transmits
microwaves, they can be narrowly focused. This means that the sending and
receiving antennas need to be aligned. The unidirectional property has an
obvious advantage. A pair of antennas can be aligned without interfering with
another pair of aligned antennas.
The following describes some characteristics of microwaves propagation:
- Microwave propagation is line-of-sight. Since the towers with the
mounted antennas need to be in direct sight of each other, towers
that are far apart need to be very tall.
- Very high-frequency microwaves cannot penetrate walls. This
characteristic can be a disadvantage if receivers are inside the
building.
- The microwave band is relatively wide, almost 299 GHz. Therefore ,
wider sub-bands can be assigned and a high date rate is possible.
Electromagnetic waves ranging in frequencies between 3 KHz and 1 GHz are
normally called radio waves.
Radio waves are omnidirectional. When an antenna transmits radio waves,
they are propagated in all directions. This means that the sending and
receiving antennas do not have to be aligned. A sending antenna send waves
that can be received by any receiving antenna. The omnidirectional property
has disadvantage, too. The radio waves transmitted by one antenna are
susceptible to interference by another antenna that may send signal using the
same frequency or band.
Radio waves, particularly with those of low and medium frequencies, can
penetrate walls. This characteristic can be both an advantage and a
disadvantage. It is an advantage because, an AM radio can receive signals
inside a building. It is a disadvantage because we cannot isolate a
communication to just inside or outside a building.
Micro Waves
Electromagnetic waves having frequencies between 1 and 300 GHz are called
micro waves. Micro waves are unidirectional. When an antenna transmits
microwaves, they can be narrowly focused. This means that the sending and
receiving antennas need to be aligned. The unidirectional property has an
obvious advantage. A pair of antennas can be aligned without interfering with
another pair of aligned antennas.
The following describes some characteristics of microwaves propagation:
- Microwave propagation is line-of-sight. Since the towers with the
mounted antennas need to be in direct sight of each other, towers
that are far apart need to be very tall.
- Very high-frequency microwaves cannot penetrate walls. This
characteristic can be a disadvantage if receivers are inside the
building.
- The microwave band is relatively wide, almost 299 GHz. Therefore ,
wider sub-bands can be assigned and a high date rate is possible.
