antanna
I would just like to ask a simple question. I can't find the formula for calculating antenna directivity from two radiation patterns. Both polarizations are measured from -180:180 degrees, step 1 degree. So basically I have 360 numbers for each polarization.
So if anyone can help me how to compute directivity from this numbers, it would be very much appreciated. I have matlab, but if there is any other software or some other way to do this, it is also great.
Thank you in advance.
Hi,
I′m not sure, if I understand you exactly, so you want calculate directivity or radiation patterns ? and "...directivity from two radiation patterns..." you think, that you have two polarization or two antenna ? and "360 numbers" are what ? Axes X is degrees, and axes Y is what ? U,I, E ... ? Directivity is only maximum. Can you more specify your requirements ?
Sure.
I have two radiation patterns. One in E plane and one in H plane. Each radiation pattern consists of 360 numbers (for each degree one number). So I have 360 numbers for E plane and 360 numbers for H plane. So my question is which formula should I use for computing directivity from both radiation patterns (E-plane, H-plane). I hope it is more clear now.
OK,
so radiation pattern E plane and H plane is not same as "two polarization". Do you now, what is directivity ? Directivity is usually max radiation pattern. And the max is the same in E plane as H plane. So you must find only max in E (or H) and you have directivity. But do you know what is "number" ? "each degree one unumber", number is Voltage or Current or E ... or what ?
hmm...
E-plane, H-plane (vertical and horizontal polarization)=2 polarizations..
Directivity:
It measures the power density an actual antenna radiates in the direction of its strongest emission, relative to the power density radiated by an ideal isotropic radiator antenna radiating the same amount of total power.
It is definitely not so simple..
"Numbers" are P(received) [dBm]...
OK,
yes, definition directivity is absolutly correct, so it is only one number, it will be the same in E plane and H plane. You must only find direction with strongest emission, and there is number - in dBm, so you can calculate directivity from Friis transmission equation (http://en.wikipedia.org/wiki/Friis_t...ssion_equation), exactly Gain, but Gain is nD where n is efficiency of antenna and D is directivity. Are you understand me ? it is easy :)
And polarization is not the same as radiation pattern in E plane and H plane, radiation pattern in E and H are only cut 3D radiation pattern! Has nothing in common with polarization. You can measure co-polar in E and H plane and cross-polar in E and H plane, are you understand ?
Added after 1 hours 10 minutes:
So I hope, that I helped you, If yes, click on "Helped me" :)
You still don't understand... Yes I know this, but this equation has two unknown variables..(Gt,Gs).. also I don't have distance...
What I am asking is how to calculate directivity from E and H plane of the radiation patterns. I know it is integral of both planes...
hi friend, please see this link
https://www.edaboard.com/viewtopic.p...130710#1130710
Aya2002 MANY THANKS! This is exactly what I was looking for!
Just one little think I don't understand:
How can I insert my numbers into U.m file? I don't have any function..just numbers?
Thanks.
in which chapter you faced this, may be (may be) i can help u
chapter 2 - Directivity..
your numbers will represents the variable (y) in the subprogram U.m.
Hence,
y=your numbers;
thats it
hmm..I don't quite understand.. I have two radiation patterns:
1)Phi=0, Theta=0:360
2)Phi=90, Theta=0:360
for each radiation pattern there are 360 numbers. "y" is only one variable, so how can I insert two planes simultaneously?
Or if I insert numbers just for one at one time than which angels should I use for theta and phi:
1)Phi=0, Theta=0:360:
TL=0, TU=360, PL=0, PU=0 ?
2)Phi=90, Theta=0:360
TL=0, TU=360, PL=90, PU=90 ?
my friend,
As i see, there must be a relationship between theta and phi so that by this relationship you can put your data in the variable y.
Added after 4 minutes:
my friend, do not forget that i am poor in this field. I am interest in the digital communications
Added after 1 minutes:
you must have this relationship:
F(THETA, PHI): the radiation intensity function
c **Note:
c The radiation intensity function F must be provided for a given
c antenna, and should be inserted into the subprogram U.
dear friend, i really appreciate your help!
I don't quite understand what you mean.. Is it possible to calculate the radiation intensity function F(THETA, PHI) from two radiation patterns which I have?
see the attached file
now the relationship is equation 2-12a
Added after 2 minutes:
please friend do not forgive me. This is what i see and as i tolled you that i am not interest in this field
OK, sorry :)
I was thinking about it this morning and I rememberd what do you think :) But so I want to write it, but Aya2002 was faster, and certainly better. I was thinking about it in "practical mode" and you need "mathematical mode" , sorry :)
Yes, once upon a time I did similar m-file.... but it is long time :)
and https://www.edaboard.com/viewtopic.p...130710#1130710 is it correct ? It think, that was cleaned :(
Added after 5 minutes:
And I rememberd, there is very good source for antenna and so on
http://www.ece.rutgers.edu/~orfanidi/ewa/
for you is ch15, there is matlab code also
i can send it by a private email cos i downloaded it before it to be cleaned.
The post has been cleaned, but here is the same topic, where you can download this programs that we discuss:
https://www.edaboard.com/ftopic157671.html
mauloftin: do you still have this m file, or do you remember how this think worked?
I still haven't figured out how to insert my data to program...