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Type: Posts; User: eirp

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1. ## Thread: Focal fields of dish antenna

by eirp
Replies
8
Views
2,446

### Closed: Re: Focal fields of dish antenna

Happy I was right !

Thank you..
2. ## Thread: Focal fields of dish antenna

by eirp
Replies
8
Views
2,446

### Closed: Re: Focal fields of dish antenna

Thanks! It's very old story, now finished... this was not primarily satellite antenna, rather theoretical work on this topic.
Anyway, I'm corrent you have articles in "Slaboproudy obzor"?
3. ## Thread: Focal fields of dish antenna

by eirp
Replies
8
Views
2,446

### Closed: Re: Focal fields of dish antenna

Thanks very much, that looks very reasonable! Just a remark - if we're not in far field then we have to use Fresnel transform, does the phase change significantly?

E.
4. ## Thread: Focal fields of dish antenna

by eirp
Replies
8
Views
2,446

### Closed: Focal fields of dish antenna

Hello,

I'm currently facing following problem:

We have slightly disturbed offset dish, trying to find its focus.
Dish's surface was scanned and physical optics was used to get E field in XY...
5. ## Thread: method of moment to calculate current distribution

by eirp
Replies
6
Views
1,863

### Closed: Re: method of moment to calculate current distribution

I probably didn't catch what you need exactly. In that code (+there exists nice book too) you'll find a lot of working examples, even showing current distribution on antennas
best
e
6. ## Thread: method of moment to calculate current distribution

by eirp
Replies
6
Views
1,863

### Closed: Re: method of moment to calculate current distribution

Hi, I got nice results with Makarov's code which could be freely obtained here:
http://ece.wpi.edu/mom/

Good luck :)
7. ## Thread: MoM matrix is very dense and ill conidtioned

by eirp
Replies
37
Views
6,228

### Closed: Re: a MoM question

I finally made the theory working! :D
8. ## Thread: Can CST MWS 2006 Work on Core Duo?

by eirp
Replies
6
Views
2,313

### Closed: Re: Can CST MWS 2006 Work on Core Duo?

I have also 2processor machine (2x Opteron).
The load is usually around 60-70 percents for both processors. CST recommends to run 2 simulations together to utilize processors on 100%
9. ## Thread: Can CST MWS 2006 Work on Core Duo?

by eirp
Replies
6
Views
2,313

Cheers
e

by eirp
Replies
5
Views
2,160

### Closed: Re: How to get broadband gain in CST MWS?

There's no other way. Why it's not straightforward? I think it is..
Of course it cost time, farfield is superposition of near field.
11. ## Thread: microstrip antenna gain range?

by eirp
Replies
6
Views
2,086

### Closed: Re: microstrip antenna gain range?

Rect. patch working at fundamental mode has directivity ~ 8dBi.
Simple estimation is following:

- you have 2 magnetic dipoles at radiating edges (2dBi + 3 dB)
- ground plane acts as mirror --> +...
12. ## Thread: co-polarization and cross-polalization pattern

by eirp
Replies
14
Views
14,323

### Closed: what does cross pol mean?

Dear Costox,

Arrays arent my main interest but for most of my design Im happy with spherical and ludwig3. How the BW differs in your design?

Please could you describe in details what you mean...

by eirp
Replies
5
Views
2,160

### Closed: Re: How to get broadband gain in CST MWS?

Hi, you mean this?

Macros - Farfield - Broadband FF monitor
..
Results - Template based postprocessing - Farfield (broadband)

e
14. ## Thread: co-polarization and cross-polalization pattern

by eirp
Replies
14
Views
14,323

### Closed: co polarized antenna

Polarization of antenna is given by E field distribution or electric currents (they produce E field in the same direction as the surface current dir.).
Visualizing currents on ms patches is thus...
15. ## Thread: IE3D - Dielectric cells and near field calculations

by eirp
Replies
1
Views
985

### Closed: IE3D - Dielectric cells and near field calculations

Dear all,

I was trying to calculate near E field of structure consisting of dipole illuminating lossy dielectric brick with high er.

Result is very strange, the E field (cut inside the brick)...
16. ## Thread: MoM matrix is very dense and ill conidtioned

by eirp
Replies
37
Views
6,228

### Closed: Re: a MoM question

Hi,

matrix averaging is clever idea. Unfortunately, the results (eigenvalue behavior with frequency) are better for particular cases only and for few first eigenvalues only. In general, this...
17. ## Thread: MoM matrix is very dense and ill conidtioned

by eirp
Replies
37
Views
6,228

### Closed: Re: a MoM question

Latest progress:

I'm 99% sure that problem is in [Z] matrix symmetry. I've modified [Z] matrix to be symmetric using a little stupid trick - by mirroring the lower matrix triangle part over the...
18. ## Thread: MoM matrix is very dense and ill conidtioned

by eirp
Replies
37
Views
6,228

### Closed: Re: a MoM question

Hello, Loucy,

Yes, I mean "Antenna and EM modeling with Matlab" codes as they are very powerful (importing meshes from FEMLAB) and easy to use in terms that...
19. ## Thread: MoM matrix is very dense and ill conidtioned

by eirp
Replies
37
Views
6,228

### Closed: Re: a MoM question

1) I can't prove my approach until the matrix [R] will be "healthy" for the theory, i.e. positive semidefinite (with all eigenvalues >=0) - as written...
20. ## Thread: MoM matrix is very dense and ill conidtioned

by eirp
Replies
37
Views
6,228

### Closed: Re: a MoM question

Hello, Irfan

I'm quite sure that the matrix is OK. Studying the papers, I've got strong notion that the problem lies in real(Z) which should be positive...
21. ## Thread: MoM matrix is very dense and ill conidtioned

by eirp
Replies
37
Views
6,228

### Closed: Re: a MoM question

Dear MoM professionals,

I'm currently working to have "Theory of Characteristic Modes" running. Few papers on that are attached,
it's also described a little in Harrington's book "Field...
22. ## Thread: An antenna radiates ....how can this be explained physically

by eirp
Replies
16
Views
17,670

### Closed: how an antenna radiates

Hi!

I'm usually using the attached picture.
Imagine 2 E-field lines a-b, c-d (2 other arrows is the H field, but it's not important now).
lines are travelling within the waveguide (for example 2...
23. ## Thread: Near Field Region for Wire Antennas - ?

by eirp
Replies
6
Views
1,923

### Closed: Re: Near Field Region for Wire Antennas - ?

Hi,

there was a great paper on one of the latest AP-magazine (2-3 month ago), discussing near fields of wire antennas. Check it...

If I remember, they were talking about much bigger distances...
24. ## Thread: How to simulate a conformal antenna?

by eirp
Replies
6
Views
1,940

### Closed: Re: How to simulate a conformal antenna?

"critical cells" warning means that conformal fit algorhitm wasn't be able to treat curved surface withing the cell. In result, given cell is now modelled as a "brick", like when classical staircase...
25. ## Thread: Calculating Q of slot resonators

by eirp
Replies
3
Views
1,554

### Closed: Re: Calculating Q of slot resonators

Hi!

What comes in my mind...
The Q will be dominantly given by radiation Q (I think we can ommit dielectric losses - the slot is filled by air and conductor losses).