Monday12 Group3

From School2007

By SAGBO K. A. Romaric -From Benin (IMSP)

Hi, I am SAGBO Romaric from BENIN in West Africa. We start today the second week of our School, which we wish richer in knowledge.

I would try my best to tell you about today activities.

Session 1 was given by Prof R. Struzak about Basic Antenna Theory From 9 am to 11:20 am.

In the first two session we got a good introduction to the basics of antenna theory, it was good since to complement the theory that is somehow abstract we had some interactive Java applets that provide plenty freedom to analyze the effect of the parameters like: size of antenna, distance between elements in an array, change of phases, etc.

We also review the principal parameters of antennas, parameters like gain, (which is related with the directivity), polarization, equivalent circuits, bandwidth, among others.

Finally we got an introduction to smart antennas where a clear explanation of the fundamentals and its applications took place.

This theory was very useful in order to understand what came after during the day which was the practical construction of an can-tenna.

He introduce session by antenna's function.

After this, he talk about basic antenna types. We have many information about antennas and reflectors.

We see too, radiation pattern, gain and polarization.

Prof. Struzak talk about Equivalent circuit and radiation efficiency.

We talk after this about Smart antennas and Some theory.

All this was supported by Java Applets simulations available on this site www.amanogawa.com.

This is an example of these simulations

Session 2 was given by Prof E. Pietrosemoli about Antennas for WIFi and his nice experience with Carlo From 11h20 am to 12:20 am.

The first lecture as in a general sense since we did not make any specification for particular type of antennas or bans of frequency; but, in the second lecture with professor Ermano Pietrosemoli, we could have good knowledge about antennas in the specific band of wifi and their application i a specific project that allows to he and his team to got the world record by the biggest wifi radiolink. One think that was very remarkable is that since at big distance the access protocol starts to show some problems for normal operation then there is a professor in the IIT who is making some upgrades on the access protocol, we expect to know more about it.

He talk about their long reach wifi link, theirs motivations, theirs difficulties and which is theirs next goals.

All this was very beautiful.

Session 3 was given by Prof Rob Flickenger about DIY WIFI Antennas From 14h pm to 14:45 pm.

After lunch came a hands-on session. every one of us were very interested in construct a can-antenna according to the indications provided by the lecturer, that is why we got the first can-tennas and not only that the ones that got more centered in the band on wifi.

After the first constructing process we make a interesting process to measure the impedance coupling of the can-tennas to the waveguide i.e. the reflection coefficient that we had in each antenna. This reflection coefficient was analyzed by using the spectrum analyzer an consist in feed the can-tenna with power and then measure how much of that power came back so the lower the power coming back, in the wifi band of course, the better the can-tenna; by this process we realize that our feeder pins where a little big (just a few millimeters) so made corrections to it.

Measures to build Ideal WIFI antenna

Session 4 is lab session and was given by Prof Rob Flickenger, Carlo, Marco, ... about Antenna building and Measurements on antennas From 14:45 pm to 18:30 pm.

These images talk by themselves.

Rob building an antenna.