how to calculate phi component

dear all,

if we have e-total or e-theta component for an antenna then how to calculate e-phi component? say if e-total = -1 db at phi=90 degree then what is e-phi and e-theta?

or otherwise how to measure e-phi components alone separately?


with thanks in advance,

kbmani

assuming you talk about farfield measurements, the total field is the vectorial summation between etheta and ephi. The two vectors lay in the plane perpendicular to the direction of propagation.
On principal planes for linear vertical polarization, in the azimuth plane ephi is copolar and etheta is crosspolar. In the elevation is the other way around

assuming you talk about calcs, you need to take the integral of your field distribution to calculate the far field.

The formulas are in any basic antenna book. the easiest is for aperture antennas

Hi, Kbmanick:

Yes. E-total is a vector summation of E-theta and E-phi.

E-total = E-theta + Ephi

Please note that E-total is a vector and its compoents are complex values. You can't find its phase and direction in general because they can be changing.

Most of the time, we only provide the absolute value of E-total or |E-total. When you get E-total and E-theta, you can find E-phi = E-total - E-theta. However, if you only get |E-total| and E-theta, you can't find E-phi from them because you still miss some information.

Regards.

dear jian,

in my case i am getting same e theta and e total values ( in terms of db). e phi is very less.

how to calculate with db values?

with thanks,
kbmani