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Type: Posts; User: promach

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1. ## Thread: Derivation of Marchand Balun equations

by promach
Replies
2
Views
243

### Closed: Re: Derivation of Marchand Balun equations

Analysis and design of impedance-transforming planar Marchand baluns talks about the derivation process, but it is still not complete.

We still need to derive equation (1) of the paper.
2. ## Thread: HFSS port 'Port1' does not have a valid reference plane above or below it.

by promach
Replies
62
Views
3,968

### Closed: Re: HFSS port 'Port1' does not have a valid reference plane above or below it.

See https://github.com/promach/planar_marchand_balun

I suppose I made mistake in the width of the coupled microstrip (W=2mm) in terms of ports impedance of 50 ohm ??
...
3. ## Thread: Derivation of Marchand Balun equations

by promach
Replies
2
Views
243

### Closed: Derivation of Marchand Balun equations

Could anyone advise about derivation of Marchand Balun Equations ?

Note: Screenshot below is taken from paper :

New Design Formulas for Impedance-Transforming 3-dB Marchand Baluns

...
4. ## Thread: microstrip low pass filter design issues with sonnet

by promach
Replies
37
Views
1,862

### Closed: Re: microstrip low pass filter design issues with sonnet

Could you post the ADS linecalc window screenshot which shows 120° ?
5. ## Thread: microstrip low pass filter design issues with sonnet

by promach
Replies
37
Views
1,862

### Closed: Re: microstrip low pass filter design issues with sonnet

Someone else told me the above.

What do you think ?
6. ## Thread: microstrip low pass filter design issues with sonnet

by promach
Replies
37
Views
1,862

### Closed: Re: microstrip low pass filter design issues with sonnet

Is it possible to prove this mathematically using some microstrip expressions ?
7. ## Thread: microstrip low pass filter design issues with sonnet

by promach
Replies
37
Views
1,862

### Closed: Re: microstrip low pass filter design issues with sonnet

I am trying to understand why open-circuited stub has a better S21 response compared to stepped impedance according to the result at figure 5.4 below:

this microstrip equation for Zo does not...
8. ## Thread: microstrip low pass filter design issues with sonnet

by promach
Replies
37
Views
1,862

### Closed: Re: microstrip low pass filter design issues with sonnet

See https://github.com/promach/low_pass_filter

By the way, what is the difference between open-circuited stub and stepped-impedance ?

See 2GHz Microstrip Low Pass Filter Design with...
9. ## Thread: microstrip low pass filter design issues with sonnet

by promach
Replies
37
Views
1,862

### Closed: Re: microstrip low pass filter design issues with sonnet

I have added a polygon covering the entire box region at the GROUND layer.

However, I am not sure if I have actually added a ground metal plane.
I could not see the ground plane using 3D viewer...
10. ## Thread: microstrip low pass filter design issues with sonnet

by promach
Replies
37
Views
1,862

### Closed: Re: microstrip low pass filter design issues with sonnet

I have inserted the feedline as shown in the figure below. May I know how to generate a DXF layout file (without the extra feedline structure) for actual manufacturing purpose ?

By the way, is...
11. ## Thread: Deriving admittance matrix for shortened quarter-wavelength transmission line

by promach
Replies
2
Views
357

### Closed: Re: Deriving admittance matrix for shortened quarter-wavelength transmission line

For equation (1) , I am trying to use MATLAB y2abcd() function to convert admittance matrix to ABCD matrix.

However, I am getting mismatch between MATLAB answer and actual theoretical result.
...
12. ## Thread: Deriving admittance matrix for shortened quarter-wavelength transmission line

by promach
Replies
2
Views
357

### Closed: Deriving admittance matrix for shortened quarter-wavelength transmission line

For Reduced-size branch-line and rat-race hybrids for uniplanar MMIC's , how to derive equation (2) ?

and is the imaginary constant j needed in equation (1) ?

https://i.imgur.com/Y32GkzC.png
...
13. ## Thread: microstrip low pass filter design issues with sonnet

by promach
Replies
37
Views
1,862

### Closed: Re: microstrip low pass filter design issues with sonnet

What do you exactly mean by reference plane shift ?
14. ## Thread: microstrip low pass filter design issues with sonnet

by promach
Replies
37
Views
1,862

### Closed: Re: microstrip low pass filter design issues with sonnet

Someone told me the above with regards to the two extra rectangles nearest to the ports.

What do you guys think ?

What about in HFSS ?
15. ## Thread: microstrip low pass filter design issues with sonnet

by promach
Replies
37
Views
1,862

### Closed: Re: microstrip low pass filter design issues with sonnet

Why does Z0 of a microstrip line depends on W but not L ?

https://i.imgur.com/PBsnQTv.png
16. ## Thread: microstrip low pass filter design issues with sonnet

by promach
Replies
37
Views
1,862

### Closed: Re: microstrip low pass filter design issues with sonnet

I know, but do you notice the two extra rectangles (which do not have any designated length and width dimensions) nearest to the ports ?

https://i.imgur.com/n422Rvv.png
17. ## Thread: microstrip low pass filter design issues with sonnet

by promach
Replies
37
Views
1,862

### Closed: Re: microstrip low pass filter design issues with sonnet

For the two ports (which are allocated two rectangle patches), I know I can use PCB calculator, but how do I decide the input and output impedance of the microstrip transmission line ?

Is VNA...
18. ## Thread: Balun design gives box resonance error in Sonnet

by promach
Replies
19
Views
1,232

### Closed: Re: Balun design gives box resonance error in Sonnet

Something else is not right.

I have attached the Sonnet design file at the end of this post

https://i.imgur.com/tW4I1hh.png

https://i.imgur.com/f1upN7t.png
19. ## Thread: LNA circuit not working

by promach
Replies
33
Views
1,453

### Closed: Re: LNA circuit not working

Are you implying that I should not include any load matching resistor RL at all for all type of circuit spice analysis (.tran, .ac and .noise) ?
20. ## Thread: Balun design gives box resonance error in Sonnet

by promach
Replies
19
Views
1,232

### Closed: Re: Balun design gives box resonance error in Sonnet

See page 4 of the paper

https://i.imgur.com/qDZFCfJ.png
21. ## Thread: HFSS port 'Port1' does not have a valid reference plane above or below it.

by promach
Replies
62
Views
3,968

### Closed: Re: HFSS port 'Port1' does not have a valid reference plane above or below it.

I have imported and simulated the same layout in Sonnet

How do I unwrap the phase difference (S12-S13) such that it does not jump from +180 degree to -180 degree ?
...
22. ## Thread: HFSS port 'Port1' does not have a valid reference plane above or below it.

by promach
Replies
62
Views
3,968

### Closed: Re: HFSS port 'Port1' does not have a valid reference plane above or below it.

I managed to make the balun more matched in terms of phase difference for S12 and S13

Note: I have attached a zip containing the dxf file as well as the Ansys Neural File.
...
23. ## Thread: Balun design gives box resonance error in Sonnet

by promach
Replies
19
Views
1,232

### Closed: Re: Balun design gives box resonance error in Sonnet

Wait, why just the feed structure for this box mode test ?

I am not sure. I need to email the original authors of the paper regarding this. I will get back to this post once they reply.
...
24. ## Thread: Balun design gives box resonance error in Sonnet

by promach
Replies
19
Views
1,232

### Closed: Re: Balun design gives box resonance error in Sonnet

I downloaded your zip file but I still find that box resonance errors are still not suppressed as you had stated in post #7

Did I miss anything ?

https://i.imgur.com/2XFed11.png
25. ## Thread: Balun design gives box resonance error in Sonnet

by promach
Replies
19
Views
1,232

### Closed: Re: Balun design gives box resonance error in Sonnet

Free space as in vacuum ? then this will only work well within simulation.

I already tried to increase the Air layer height to 40mm , but I just got more box resonance errors.
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