Antenna Simulation - Information source

[Mictronics]

Just started this thread for those who are (like me) interested in antenna simulation.

Would be nice to build up a knowledge base for such simulations, optimization of existing and new designs, theoretical verification of design parameters etc.

Some PC tools for simulation:
* 4nec2 (free)
* HFSS
* CST Microwave Design Studio
* Antenna Magus

My favorite is CST for now, very powerful and, if setup properly, results will be close to reality. Though needs time to get used to it.

While setting up a model in CST I try to use as much parameters and math as possible so later on optimization can be done automatically.

I going to list some of my setups here from time to time.

The Skew-Planar-Wheel:

The results shown on the picture are no tweaked, dimensions are just set for best return loss.

[kenkos68]

I was hoping a thread like this would show up!

I have been playing with 4nec2 at home and at work. How close is 4nec2 simulations to actual? I ran OMM's CP open biquad NEC (RHCP) and got the best return loss at 1300 Mhz. Yet OMM shows it right on 1280 Mhz from his analyzer. If I add 0.5mm to section 'A', I get the best simulation return loss at 1280 Mhz where I want it. If I were to build this, which dimensions should I use? I ask because I don't have access to test equipment yet to verify.

I have also scaled down OMM's pinwheel to 5800 Mhz. I have built these and they do work well, but again, no equipment to verify where it really is.

Math isn't a problem for me. What I am teaching myself now is more antenna theory.

-Ken

[Mictronics]

Ken, since you have no test equipment I recommend to take the practical proofed values from OMM.

[sircana]

Subscribed. This guy is not an Antenna Magus, he is an Antenna Genius.

[IBCrazy]

One thing that I find very beneficial is the X/R frequency sweep analysis, not the return loss plots. The return loss only tells part of the picture. Analysis of the X/R graph has helped me design entirely new antennas. The turnstile, crosshair, and the pentalobe sphere antennas were all designed using the X/R frequency sweep as the development tool. I am working on another CP BiQuad right now using this.

Try this one: take 2 skew wheels set to 100 ohms at 1240 or 1280 MHz. This translates to: 1 at 1160MHz, the other at 1360MHz (roughly guessing here). Place them 1/2 wavelength apart with one flipped upside down underneath the other and feed them with exactly 1 wavelength of coaxial cable in a "T" connector. Now do a frequency sweep of this antenna at 1200-1320MHz. Plot the graph of this new antenna. Now change the spacin between the two antennas and watch what happens

Send me your Email address or just Email me. I will send you the source code for the Pentalobe sphere and the Crosshair antennas I have developed. I think you will really like them. Just don't share the details until I'm ready to release.

-Alex

[Mictronics]

I have setup a new antenna simulation for a so called tri-filar helical antenna.
The design is based on the following US patent: http://www.freepatentsonline.com/6738026.pdf
Unfortunately there are still some unknown factor I can't solve from the patent:

• There shall be a ground plane below the monopole structure, what size?
• Does the monopole lower end needs to be connected to ground?
• What material can be used for the dielectric?

Any ideas?

There seems to be also a IEEE article about this antenna: http://ieeexplore.ieee.org/xpl/freea...number=1220046
Is someone with IEEE access here who can may provide a copy to me?

My full parameterized model: