Results of HFSS Simulator

Initial SMA Launch Results

Michael’s Work on the SMA Launch

as of 1/26/2009

Table of Contents

• Initial Model– This will contain many pictures of the model and

explanation of what things are. Many questions results from this…

• Results– Results from the initial simulation.

• I show transmission and reflection (as these are obviously important)

• I show power efficiency (to make sure that the S-Matrix is approximately lossless)

• I show phase because we want to make sure that phase doesn’t have such a large slope that it could vary a lot with small differences with machining, etc.

Initial Model

These are a few views of the model that was given to us from Michael Enders. The only difference would be a change in the pin-

length (I cut it for my model)

Shown here is what was done first – I added the stackup to the model. The top and bottom layers are the Rogers3003 dielectric and the middle is the layer of Arlon. I added thru-holes so that the legs of the connector could go through. Those thru-holes are three

dimensional objects defined as ‘copper’ because on the actual board they will be filled with some sort of conductive material (I didn’t know what to use at the time). The center

pin of the connector was cut to coincide with the top layer of dielectric.

Initial Model

Next I added a 50 ohm transmission line – just for something to have there for now. It is placed a little farther than the center pin to ensure 100% connection (as was shown in the

PDF from Michael Enders). It is placed within the arlon as can be seen from the insert.

Initial Model

TOP DIELECTRIC

ARLON50 OHM LINE

BOTTOM DIELECTRIC

CENTER PIN

Initial Model

I show three new objects here. I first placed the ‘dielectric block’ (which is actually a cylinder) in the bottom layer of dielectric. I chose to fill this with the epoxy that had an 3.62 for epislon_r. I then added the center pin’s thru-hole. This is also a filled thru-hole that is defined as copper. It

touches the copper trace on top and extends down to the epoxy filled ‘dielectric block.’

DIELECTRIC BLOCKEPSILON = 3.62

THRU-HOLE_TOP

THRU-HOLE_BOTTOM

Initial Model

Lastly, because the signal pin cannot be shorted, I had to ‘etch’ a cylinder of air around the pin. This meant that I had to make a physical ground on the top plane (as opposed to letting the solver assign the ground plane) as well as a physical cylinder of air. Both are as thick as the signal trace (seen in red, which is 0.7mil) as was seen from the initial project

stackup information. The same ground plane could have been made on the bottom – but for now, I chose not to do so.

Initial Model

These pictures show how the model’s wave ports were defined. The first port (for the fifty ohm line) was defined as usual. The second port was defined where it was because I couldn’t define

it anywhere else! That was the only surface on the pin that HFSS allowed me to define a waveport on… maybe it’s right, maybe not. Note that there is no defined integration line for the second port. I don’t know where I would define it from… The wave ports were not normalized.

Initial Model

These show the analysis parameters for the initial simulation. I used a small amount of passes (just to get an idea of how it would work). I swept from DC to 18GHz with a fairly large step size (as this range was recommended by Michael Enders a while back). I began

with a fast sweep.

Results

These show how well the simulation went. The delta S is large-ish, but this was expected with so few adaptive passes. Note the results for Port Impedance at

11GHz, though – only 7.7131 ohms… I’m pretty sure it is a 50 ohm connector, so I show my results for Port 2 not normalized (as it was originally set) and normalized to 50 ohms.

ResultsPort 2 Not Normalized

These are the S-Parameters for the un-normalized Port 2. Blue is transmission and the red are return loss. It is a weird curve with spikes from higher order modes. Not good

at all (for seemingly ALL frequencies…)

0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 18.00Freq [GHz]

-20.00

-10.00

0.00

Y1

Ansoft Corporation 59646-0001S Parameters

m1

m2m3

m4

Curve Info

dB(S(1,1))

Setup1 : Sw eep1

dB(S(1,2))

Setup1 : Sw eep1

dB(S(2,1))

Setup1 : Sw eep1

dB(S(2,2))

Setup1 : Sw eep1

Name X Y

m1 10.0000 -0.9254

m2 12.0000 -3.1842

m3 12.0000 -2.9213

m4 10.0000 -7.6180


This is the power efficiency of the un-normalized Port 2. It is pretty okay (except for where the higher order modes propagate)

0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 18.00Freq [GHz]

0.60

0.65

0.70

0.75

0.80

0.85

0.90

0.95

1.00

1.05

ma

g(S

(1,1

))^2

+m

ag

(S(2

,1))

^2

Ansoft Corporation 59646-0001Power Efficiency

m1

m2

Curve Info

mag(S(1,1))^2+mag(S(2,1))^2

Setup1 : Sw eep1

Name X Y

m1 10.0000 0.9811

m2 12.0000 0.9710


Phase for the un-normalized Port 2. May be a useless graph…

0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 18.00Freq [GHz]

-500.00

-400.00

-300.00

-200.00

-100.00

-0.00

100.00

200.00

ca

ng

_d

eg

(S(1

,2))

[d

eg

]

Ansoft Corporation 59646-0001Phase Difference

Curve Info

cang_deg(S(1,2))

Setup1 : Sw eep1

ResultsPort 2 Normalized

These are the S-Parameters for the normalized Port 2. Blue is transmission and the red are return loss. This makes a bit more sense – but isn’t as happy a graph as we would like. Michael Ender’s said that this connector has been used for lower frequencies (3-4GHz) – which can kinda

make sense from this graph…however, results are not good for our frequency range.

0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 18.00Freq [GHz]

-40.00

-30.00

-20.00

-10.00

0.00

Y1

Ansoft Corporation 59646-0001S Parameters

m1m2

m3

m4

Curve Info

dB(S(1,1))

Setup1 : Sw eep1

dB(S(1,2))

Setup1 : Sw eep1

dB(S(2,1))

Setup1 : Sw eep1

dB(S(2,2))

Setup1 : Sw eep1

Name X Y

m1 10.0000 -1.1429

m2 12.0000 -1.8707

m3 12.0000 -4.7384

m4 10.0000 -6.6421


Power Efficiency for the normalized Port 2 doesn’t change much from the un-normalized version. Still very little power is lost.

0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 18.00Freq [GHz]

0.90

0.92

0.94

0.96

0.98

1.00

1.02

1.04

ma

g(S

(1,1

))^2

+m

ag

(S(2

,1))

^2

Ansoft Corporation 59646-0001Power Efficiency

m1

m2

Curve Info

mag(S(1,1))^2+mag(S(2,1))^2

Setup1 : Sw eep1

Name X Y

m1 10.0000 0.9853

m2 12.0000 0.9801


This is the phase for the normalized Port 2. Not much difference from the un-normalized – still probably not of much use.

0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 18.00Freq [GHz]

-600.00

-500.00

-400.00

-300.00

-200.00

-100.00

0.00

100.00

200.00

ca

ng

_d

eg

(S(1

,2))

[d

eg

]

Ansoft Corporation 59646-0001Phase Difference

Curve Info

cang_deg(S(1,2))

Setup1 : Sw eep1

Results of HFSS Simulator

Documents

Transcript of Results of HFSS Simulator