modeling

Thanks for all inputs. As a conclusion, if the simulator can perform the drawing the hexical, it can use to simulate this type antenna. But no one have indicated the correctness of the model for such complex model compared to dipole, monopole, etc.

Addition to your conclusion: Some software can import the CAD model and do the simulation. In other words, you draw the helix in some geometrical modeller, and the EM simulator read the geometry and then simulate it.

If you want a good starting point for what to model, this program will design a helical antenna for you.

I worked with helical under CST.
Without coil form all OK!
But with PTFE coil form I had very many problems.

you can use the HFSS to draw this kind of structure and use it for simulation

HFSS certainly can be used to simulate a helical antenna, but I do not know how accurate that will be.
There is no command or tool to draw it, but you can draw it in AutoCad or
similar program, save it as a *.dxf file and than import into HFSS.
8)

My expirience with WIPL-D for simulation of helical antennas is very positive, even when only 4 segment per turn and effective radius are used. I use full version of the software with embedded generation of helicoidal structures and don't believe that currently available student versions have such possibility. However, even not ideal models can give usable results.

you may like to use feko...or xfdtd.

Hi all,

the to be released CST Microwave studio v5 will be a good candidate for helix em simulation. There is already a macro which you can use to draw the helix quite quickly. Presently in v4.3, you cannot use sub-gridding which makes designing a helix filled with dielectric a real pain but new version out sometime in Jan 2005 will include this fantastic feature which will make thing much easier. The mesh required for the structure will be a lot lesser for good accuracy which might mean you don't have to sit and wait ages for a simulation to run :D

Hope this helps.

HFSS has the problem of building the structure as well as the usual radiation result questions. The patterns may come close to measured but don't try and use it for tuning the axial ratio the generated outputs are not correct. For a quicker look at the helix and a fairly good first on the geometry you can use SuperNec, Wipl and Antenna Optimizer if it's still available (do a search for Brian Beezley). 8)

who can offer the softcopy of the book: "antenna and em modeling with matlab".... thks,

Sure, I have used HFSS 9 to simulate a helix. Although slower than HFSS 8.5, simulations are accurate with respect measurements. The only problem is the high number of thetaedres, which results in a lot of simulation time

hi ie3d use in simulation of helical antenna at all here example of it

helical antennas are fairly simple structures and are well defined in literature. the rules for designing the style helix you would like (axial/normal) are straightfoward and easy to implement. assuming you have a constant pitch and diameter.

i think you will find having a nec code, wipld or even matlab if you prefer to right your own will suffice. you will also find the initial design you create with formulas straight out of a textbook will conform quite well to your first simulation.

although cst, fidelity and hfss are great programs in their own right they maybe overkill for your application.

good luck :)
gb

hi all,
Who has a helical antenna design in MWS, please share in this forum!
Thanks!

anyone tried agilent 3D tools (AMDS, EMDS) for Antenna applications?

Hi

Ive done a dozen helical antenna simulations with CST MICROWAVE STUDIO, completely parameterized - it works ok, but the user has to be careful with the meshing. Mine had a high dielectric core in the middle, and it was not very easy to model and mesh.

There are no drawbacks with the PBA (Perfect Boundary Approximation), that is used in the CST mesh. Its just a mathematical trick which allows the use of more than one material in a single cell. If someone is interested go to IEEE Explore and type in Partial Filled Cells, its the name literature gives to it. As a matter of fact, only CST managed to get it implemented in a 3D solver.