Hi,
How to know the type of polarization of an antenna in HFSS?
Thank you.
For identifying what kind of polarization, in any software we use one term called "AXIAL RATIO". In HFSS (Go to : Create far fields report - Rectangular plot- Axial ratio)
For circular polarization, ideally the AR is 0 dB. But, generally we consider it as up to 3 dB. Some people may consider up to 6 dB.
For elliptical polarization it must higher than 0dB.
For linear polarization ideally it is infinite.
Dear researcher,
Firstly ,
To completely describe the polarization state of a radiated field, two independent components are required. HFSS supports three types of descriptions:
• Spherical / polar
• Ludwig-3
• Circular
for that, you should plot field parameters like
Axial ratio of the electric field. and Polarization ratio of the electric field
the HFSS computations are respecting the IEEE definitions and norms
have a nice day
1. Plotting rETheta and rEPhi in the far field, one can understand whether the antenna is linearly, elliptically or circularly polarized. Observe the vector components of Electric Field in the far field.
For identifying what kind of polarization, in any software we use one term called "AXIAL RATIO". In HFSS (Go to : Create far fields report - Rectangular plot- Axial ratio)
For circular polarization, ideally the AR is 0 dB. But, generally we consider it as up to 3 dB. Some people may consider up to 6 dB.
For elliptical polarization it must higher than 0dB.
For linear polarization ideally it is infinite.
For plotting the polarization, You must clear your concept for polarization. See, there are three types of polarization and each linear, circular or elliptical depends upon axial ratio of fields. So, first find out the field magnitude and calculate axial ratio, if it is infinite then linear, if it is 1 then circular and if it is something else but equal to 1 then elliptical. you can also calculate using phase of fields. One simple thing, you can directly find out the polarization by analyzing the plots of fields in HFSS or CST.
thank you for your answer but I found in the hellp :
Axial ratio is defined as the ratio of the major to the minor axis of the polarization ellipse.
1. Ex and Ey are orthogonal complex-valued field components. If either is zero, HFSS treats the field as linearly polarized. However, if neither Ex and Ey is zero:
2. Compute circular components E- and E+ from:
E- = Ex - jEy
E+ = Ex + jEy
3. If E+ = 0 or E- = 0 HFSS understands the field as perfectly circular, the axial ratio is 1. Otherwise, for the elliptical polarization case, HFSS determines the tilt angle t from:
phase(E-/E+) = 2t
- Based on elevation pattern and azimuth pattern you can find polarization. In hfss software you can find the polarization using xy plane, yz plane and zx plane..
In HFSS, you can calculate the radiated field Ephai and Etheta. If their magnitude is equal and phase difference is 90 degree, it is a circilar polarization. If their phase difference is 0 or 180 degree, or one of Ephai and Etheta value is zero, it is a linear polarization. otherwise it is a elliptic polarization.
The analytical part from radiation pattern is already explained by various experts. I add the physical observations of antenna
Non planner antenna: Orientation will decide the type of linear polarisation.
Dual feed (with phase shift of 90 degree) or dual element spaced 90 degree apart, will create circular/elliptical polarisation. Than to see the axial ratio to bifurcate from circular/elliptical
In case of micro strip, apart from the dual feed with 90 degree phase difference, the corner cut creates circular polarisation
Smrity Dwivedi maam you are writing that if it is 1 then circular and if it is something else but equal to 1 then elliptical. So for circular it is 1 and also for elliptical it is equal to 1. Please maa'm clear it to me
In ANSYS HFSS follow the following steps for LHCP or RHCP plots: 1. Right click on 'Results' -----> Create Far fields report ---> Radiation Pattern 2. Select Gain ----> GainLHCP or GainRHCP ---> Select dB as the unit 3. Click on New Report. At theta=0 deg., if GainLHCP has higher magnitude than GainRHCP, then your antenna is LHCP polarized and vice-versa if GainRHCP has higher magnitude than GainLHCP (as shown in Fig. 11 of R. Xu, J. Li, Y. Qi, Y. Guangwei and J. Yang, "A Design of Triple-Wideband Triple-Sense Circularly Polarized Square Slot Antenna," in IEEE Antennas and Wireless Propagation Letters, vol. 16, pp. 1763-1766, 2017.)
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