Spherical Wave Expansions Source (*.swef)

Spherical Wave Expansion Source (*.swef)

HFSS SBR+ Parametric Antennas of By File... type can import single- and multi-frequency spherical wave expansion (SWE) files in a commonly used format exported by several commercial antenna tools (e.g., Ticra Champ). Like current-source list (.csrc) files, and unlike antenna pattern table (.patdat) files, SWE antennas have high-order, near-field radiation properties, making them intrinsically more accurate than antennas imported in far-field pattern formats when illuminating nearby structures. For compatibility with SBR+, the file extension must be set to .swef. When you import a .swef file, the input dialogue includes a parameter area with a drop down menu:

The Parameter area includes a drop down menu to select SWE Mode Truncation. You can select None, Dynamic, or Fixed (Custom).

If you select Custom, the SWE Max N Index field is enabled.

For editing properties, placement, and visualization, file based antennas resemble parametric antennas.

For .swef files, you must insert into the header block(s) of the provided SWE file a Frequency key line, as described below. HFSS SBR+ supports both the Q-coefficients format and the older AB-coefficients format. It can also import .swef files containing multiple expansions (i.e., coefficient blocks), each one representing a different frequency sample. A multi-frequency .swef file is created by concatenating, in increasing frequency order, multiple single-frequency (.swef) files. Mixing AB and Q coefficients in the same file is not permitted.

AB Coefficients

In the case of the AB-coefficients format, the header before each coefficient block must contain the following four lines, maintaining the indicated line order and with no spaces between. Keys in bold must be included as typed.

Title
Frequency f_hz (extra line relative to SWE standard format)
MMax (integer)
MMax+1 integers for NMax coefficients

After the header, 4 real numbers on each line are used to represent the real and imaginary parts of the a_mn and b_mn coefficients, such that the coefficients follow the sequence below:

a0,1 b0,1

a0,2 b0,2

...

a0,N(0) b0,N(0)

a1,1 b1,1

a-1,1 b-1,1

a1,2 b1,2

...

a1,N(1) b1,N(1)

a-1,N(1) b-1,N(1)

...

aM,M bM,M

a-M,M b-M,M

aM,M+1 bM,M+1

...

aM,N(M) bM,N(M)

a-M,N(M) b-M,N(M)

A 2-frequency AB .swef file example is shown below.

High-efficiency Horn

Frequency 11500000000

2 2 3

0.115467E-03 0.305491E-03 -0.597125E-03 -0.174065E-03

-0.404947E-04 0.252913E-03 -0.200067E-03 0.152949E-03

0.128725E-03 0.298848E-03 0.204994E-03 0.240563E-03

0.282213E-03 -0.271228E-03 0.713716E-04 0.646115E-04

-0.181136E-03 -0.262236E-03 0.568925E-04 0.129049E-03

-0.711213E-04 0.108705E-03 0.196338E-04 -0.174016E-03

-0.912608E-04 0.378009E-04 0.121696E-04 -0.177426E-04

0.649170E-04 -0.501389E-05 0.446827E-05 0.553745E-04

0.502546E-04 0.664317E-05 -0.214199E-04 -0.201388E-04

-0.256921E-04 -0.297337E-04 0.147851E-04 0.432019E-03

High-efficiency Horn

Frequency 12000000000

2 3 3

0.233219E-04 0.609080E-04 0.312162E-03 -0.144566E-03

-0.276714E-03 -0.188706E-03 -0.467364E-03 -0.446705E-04

0.247382E-03 0.211029E-03 -0.132354E-03 0.156872E-03

0.173807E-03 -0.105876E-03 -0.807569E-04 0.175449E-03

-0.610848E-04 -0.452046E-04 0.377000E-04 -0.306724E-03

-0.508518E-04 0.126624E-04 -0.227225E-03 0.462618E-04

-0.164177E-04 0.444172E-04 0.112475E-03 0.291202E-04

0.557026E-04 0.190620E-04 0.115186E-03 -0.238145E-04

0.186932E-04 -0.565990E-04 -0.556033E-04 0.775226E-05

-0.643883E-04 0.521515E-04 0.124740E-04 0.252009E-04

0.181098E-04 -0.447097E-04 -0.396963E-04 -0.279198E-04

0.182588E-04 0.209599E-04 0.316011E-04 -0.109181E-04

The above example will not produce any meaningful SWE representation. It only serves to illustrate the file format.

Q Coefficients

Q-coefficient files have a different header than AB-coefficient files. Several header lines contain ignored text and dummy data, but all the lines in the header must be present for HFSS SBR+ to parse it correctly. As with AB-coefficient files, an extra line identifying the frequency sample must be added to the header for compatibility with HFSS SBR+ . Keys in bold must be included as typed.

Text string
Text string
4 integer control numbers, NTHE NPHI NMAX MMAX
Text string
5 real data numbers (dummy data items)
5 real data numbers (dummy data items)
Text string
Text string
Frequency f_hz (extra line relative to SWE standard format)

The only data used by HFSS SBR+ Parametric antennas are the values of NMAX and MMAX to determine the total number of coefficients to read. For each M mode from 0 to MMAX, the following block of coefficients follows the header:

M, POWERM (integer, real)
Q1MN Q2MN (4 real numbers per line)

where that M is the azimuthal mode index |m|, POWERM is the power in all coefficients +/-m, and the Q1MN and Q2MN coefficients are

for M = 0

Q101 Q201

Q102 Q202

Q103 Q203

...

Q10NMAX Q20NMAX

for M different than 0, M = m

Q1,-m,m Q2,-m,m

Q1,m,m Q2,m,m

Q1,-m,m+1 Q2,-m,m+1

Q1,m,m+1 Q2,m,m+1

...

Q1,-m,NMAX Q2,-m,NMAX

Q1,m,NMAX Q2,m,NMAX

A 2-frequency Q .swef file example is shown below.

File created by SWEP2 on 2015/ 9/24 at 7: 0:26

SWE

180 8 3 2

Rotation angles (Theta, Phi, Chi)=(0.00000, 0.00000, 0.00000)

0.0000 180.00 0.0000 359.99 0.00000

SWEP_DUMMY_FILE_NAME

Frequency 11603000000

0 3.0082396525702973E-29

-3.1915279054525894E-16 -1.2892349207803435E-16 -3.8509178493100355E-16 -1.8049288890924806E-16

-5.4172934656081795E-16 -7.3271596763214834E-16 -4.3842840686185935E-16 -8.8646620346315665E-16

1.1107004432486917E-15 4.3339505229049944E-17 1.1217237521873848E-15 1.2951602867000140E-16

1 0.4999765885681955

1.4793217033613612E-18 -3.1357721221466865E-18 1.5274090844190164E-18 4.2809100101664339E-18

-1.9252328312778913E-01 1.1651586264459781E-02 -2.0192491940241922E-01 -6.7317664009445416E-05

1.8666136540373346E-18 2.8787677569168861E-19 -3.1057427227729180E-18 3.3082674111624142E-18

9.8138549095459840E-03 -2.4230456057802729E-01 2.4936045948149160E-02 -2.5035917896031079E-01

-4.2987978961492822E-18 1.5321395932099931E-18 -1.7352837081002618E-18 -6.5033976194751674E-18

2.7508153381481415E-01 2.0893222682079500E-02 2.5940539672443474E-01 2.1630794936559665E-02

2 3.6104890168479111E-33

-1.7470258951002181E-18 -2.0774762527596600E-18 -1.8082213102957466E-19 -9.1362725841771620E-19

-1.0554789826723718E-18 -1.6897058625735897E-18 3.4220101385728232E-21 1.9132250922702059E-18

-2.9328385823772792E-18 1.7156784729134458E-19 -3.1341623772531889E-19 -1.1329591729328374E-18

-2.0100295867262535E-18 -8.8694426018338640E-19 -8.7960399314802765E-19 1.7312637664486764E-18

File created by SWEP2 on 2015/ 9/24 at 7: 0:26

SWE

180 8 3 3

Rotation angles (Theta, Phi, Chi)=(0.00000, 0.00000, 0.00000)

0.0000 180.00 0.0000 359.99 0.00000

SWEP_DUMMY_FILE_NAME

Frequency 11703000000

0 2.8820236773030870E-29

-4.9205799476449772E-16 -2.4495463494826524E-16 -5.5813128445449028E-16 -2.7073933336387207E-16

-4.3362371199214033E-16 -9.0688615665946252E-16 -3.7356502612065278E-16 -9.8376127457496648E-16

7.8526158604867005E-16 3.1041135484342719E-16 7.9694440919737040E-16 4.1316994985027605E-16

1 0.4999777050592423

-5.3472196810921811E-19 -4.3007910149543931E-18 4.1626947467127237E-19 7.5718687702418272E-18

-1.9072752874637075E-01 1.1766580158570537E-02 -1.9948262852927875E-01 1.1232179777612324E-03

2.8981563155590727E-18 3.5754557596140601E-19 -5.2146054685044776E-18 2.4253069313164503E-18

1.0945650686875724E-02 -2.4126104316529043E-01 2.4643389614931455E-02 -2.4856384063328121E-01

9.5675273891171790E-19 5.3403417546511193E-18 -5.4286022965855179E-19 -1.1503424690493544E-17

2.7311952122770955E-01 2.0597687831541416E-02 2.5840120731726490E-01 2.2084602270527109E-02

2 5.1148291304191848E-33

-6.9532898777596087E-18 6.4300740906263065E-19 3.2739851403263512E-18 5.7078571449140461E-18

-7.0053476956511754E-18 -4.3995227310233528E-19 -5.6372427909811814E-18 5.8778959090251952E-18

-3.1440268835569142E-19 -3.9850347618643944E-18 2.6093602155778856E-18 9.1764376219979173E-19

-4.5649017014803075E-19 -7.7811420149503691E-18 -3.8743135072928263E-18 -2.2314829902343887E-18

3 2.3279879002995588E-32

-1.4634393879898799E-18 -1.4073355212909901E-18 -5.4072438315811004E-18 3.2319825198116401E-19

-2.5652903303343589E-18 3.1763737384608062E-19 -2.5628199228530487E-18 3.4049505993075118E-18

Related Topics:

SBR+ Range Doppler Solution Setup