Wireless Network Transmission Through Brick Wall

In summary, the conversation discusses the transmission of data through a wireless computer network using a 2.45GHz carrier signal that can pass through a 100mm thick brick wall. The dielectric function and relative permeability of the brick are given and used to calculate the percentage of energy that is reflected and transmitted when the signal passes through the brick. The conversation also mentions the use of Fresnel's equations and the consideration of multiple reflections. The main question being discussed is whether the assumption that epsilon is approximately equal to epsilon(real) is still valid for part b of the problem and how to deal with the negative reflection coefficient when calculating the percentage of transmitted energy. In summary, the conversation addresses the calculation of energy reflection and transmission in a wireless computer
  • #1
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Homework Statement



A wireless computer network transmits data across the space between nodes as a modulation of a 2.45GHz (microwave) carrier signal. The signal is able to pass through a brick wall that is 100mm thick. Measurements have determined that the dielectric function at microwave frequencies for the material of a typical building brick is epsilon=epsilon(real) +i epsilon(imaginary)=5.86+0.68i, and the relative permeability is unity.

a) show that about 17 percent of the energy that strikes a brick surface at normal incidence is reflected. (since epsilon(real)>>epsilon(imaginary), it is satisfactory at the interface to suppose that epsilon is approximately epsilon(real).
b) show that in passing perpendicularly through 100mm of brick only about 16 percent of the incident energy emerges. (Multiple reflections can be ignored but transmission across both interfaces must be taken into account.)

The Attempt at a Solution



a) I've done this question. by (r_parallel)^2=R

and using the Fresnel relation. I just wondered though, if epsilon is approximately epsilon(real) should still be assumed for part b).

for part b):

I tried n=1, n'=sqrt(5.86) and substituting in those values into the equation for t_parallel, I get

air to brick:

t_parallel=0.585

brick to air

t_parallel=1.415

I don't know how to deal with the fact that t>> 1 for glass to air.

(0.585^2)*(1.415)^2 does not equal 16 percent.

I then tried to think about this logically.

100-17 percent is transmitted from air to glass.

but if I look at the reflection coefficient, it is negative from brick to air and I don't know how to deal with this. Please help.
 
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  • #2


Can I say that T(brick to air)=1-T(air to brick)

because if I can, then I get the right answer to the question.

Is this just a coincidence.

If I can say that T(brick to air)=1-T(air to brick), then why is this allowed? If I try to work out T the usual way, T(air to brick)=T(brick to air), giving not the correct answer
 

Related to Wireless Network Transmission Through Brick Wall

1. How does wireless network transmission through a brick wall work?

The wireless network transmits radio waves through the air, and these waves can pass through most materials including brick walls. These radio waves are received by a wireless router or access point, which then decodes the information and sends it to the connected devices.

2. Is it possible to get a strong wireless signal through a brick wall?

The strength of the wireless signal through a brick wall depends on various factors such as the distance between the router and the wall, the thickness of the wall, and the type of construction materials used. In general, the signal strength will decrease when passing through a brick wall, but it is still possible to get a strong signal if the distance is short and there are no major obstructions.

3. How can I improve the wireless signal through a brick wall?

There are a few things you can do to improve the wireless signal through a brick wall. You can try moving the router closer to the wall, using a wireless range extender, or using a higher frequency band such as 5GHz instead of 2.4GHz. You can also try adjusting the antenna positions on both the router and the device to find the best reception.

4. Are there any materials that can block wireless signals more than a brick wall?

Yes, there are materials that can block wireless signals more effectively than a brick wall. These include concrete, metal, and thick stone walls. These materials can significantly decrease the strength of the wireless signal or even block it completely.

5. Can multiple brick walls affect the wireless signal?

Yes, multiple brick walls can affect the wireless signal. The more walls the signal has to pass through, the weaker it will become. It is important to consider the placement of the router and the distance from the walls when setting up a wireless network in a building with multiple brick walls.

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