【实例简介】

详细介绍周期性结构的色散曲线仿真，基于CST，但HFSS设置基本相同

smr.razavizadeh @ieee.org

Dispersion diagram: CST Microwave Studio

flow and Pierce Impedance can be seen in the folder ID Resulls In parameter sweep window,

select"Edit" to view or modify the source code

taex0e-red wacc 0r parameter sweep

He, inrTtring

Result match

二he水

A-c result of a perameter sweep of the rhese between the periodic bourdery-wall.

:: pOwer =l0w, axa. electIc -LEld amol1-ud

Start

It ig recommeded to perform a aweer with phaae atena

tEgel

New seg.

Dete

Fig. 5 the user-defined vba codes of the important reports of the simulation as dispersion

curve, phase group velocity and pierce impedance

But I preferred that the following method for setting the dispersion diagram

Post processing:

The dispersion diagram, which is a graph based on"frequency"VS spatial phase variations of

the predefined parameter of phase", could obtained by the following step by step process

1)Recall the tbp and choose the 2D and 3D Field Results>3D Eigenmode result

学[p水P中n

Temp ate Based Postprocessing

General Resuts

Geneal Res Its

30FmR(3)

aD and 2) Fald Souto

Result Temo

Manage

Ac 3n FigenmxdrR

Resut name

Type Template nane

Fequency

equency Mode

alare Integation R mge

00

A Eval=Le A

VIno renge

crider o :r y icty bexa-lnotused

Setings. DeeteCuplcate Evauace i Daete Al EralLate All

Lancel Hap

Lotte.

□oco9Hp

Fig. 6 the outline of defining the postprocessing setup of dispersion plot in CSt

MWS

2) For obtaining the dispersion data of the modes start one by one from the first mode, then

after finishing simulation operation export the data in"Lxi format(available in "Table

folder in Navigation tree) for our future postprocessing in Matlab environment

3)Evaluate

Solver Setup

Whenever the Eigenmode Solveris started, a specific number of the lowest resonance

frequencies of the structure are calculated. Since only the fundamental mode is of interest, the

number of modes is reduced to"I'", and the JDM eigenmode solver is chosen, which is faster for

e given cxample

smr. razavizadeh @ieee. org

Dispersion diagram: CST Microwave Studio

上 enmod= Solver parameters

Mesh type(1) Hexahedral mesh

JDM

Choose number of modes

tomatically(0….1CG2)

o Frequencies above

Simplify Model.

F Store all result data in cache

F Calculate externa Q-facior

□ Consider

Adaptive mesh refinement

D Adaptive meshrefinement Properties

Fig 7 Eigenmode Solver setting for calculating the dispersion characteristics of the proposed

periodic structure

After the parameter sweep has been selected from the Eigenmode Solver's dialog, a new

sequence is added, and the parameter "phase" is chosen to be swept from 0 to 180 degrees in 19

steps for an equal ster

daimler

Sequences

Result wach

Check

-l sequence 1

Userdefined

Start

Parameter Sweep Paramete

Resi lt TemplatE

Name:pnase

Acceration,u.

V SwEep

180

ew Par. Edit…

Fig 8 Parametric sweep setup for pha

parameter of"pha

the

Start.

If you set lower sweep limit at zero, the machine temporary would interrupt the process and

alert we the parameter is zero, dont care about it and click Ok to continue the operation

≈

rometer Phese

Fig10

4

smr.razavizadeh @ieee.org

Dispersion diagram: CST Microwave Studio

Results

During the run process the real time dispersion results is accessible from the Table folder, as

plot based on frequency vs phase parameter, as following

Freyuellcy(Mude 1)

A Anchor Pants

F Excitaior Signas

0

4k Volage and Curer Monitors

20

I Mash Corro

ldse

Tables(or Results \Frequency(Mode 1) Parameter View Kjh

LA 2D/3D R:suts

层 TLM Res_ts

Paraneter LIst

I:/value Descrnigtid Tvpe

helix2cst

8 numbe of None

回68%

A Fequercv Mede 1)

Leng.h

Eigenmode Aralysis Solver setup ( /21

Langh

9%[x[n画

Undefined

冫hei2*

Propagation Cons ant beza/m

路凵 unwed Veneris

Mode 1

Votage and Cument Monit=rs

0.511.522.533.544.555.5

SD Schenafc 1D Result Dispersion Dagan Wode 1x Parameter View Bs

N:Value Deaciotiof Trpe-Reheixzct

修 TLM Resuts

回7%区x

s Table

phaee.50 phase ahM None

igenmoce Analysis: Salver setup(2/2.

Fmquenry Moda 1)

9%×[町A31

Undcfndd

essages Progress

Fig. ll The dispersion diagram based on(a) TBP result template, and (b)vba

userdefined

As shown in Fig. Il, all the data are the same but in Fig. I l(a) the horizontal axis is the phase

Export the data of the mode "1

ResH Yev

1) Plot Praperties.

Pbt type:

Abscissa

Crve set parameter:

Table Properties

ProPerties.

Parameter

sele-ted vaue

Copy vicwto Clipbord

Copy

Ctrl+C

E TLN Fests

OBject nformation

E Apy Haaieiei scluys lu all LumiA iLle abl=s

U29pupu烂

ADot CanceSmthchart.Ccrcex. To Currert

smr. razavizadeh @ieee. org

Dispersion diagram: CST Microwave Studio

S Export Plot Data

varc n.

OIL H

File rame.

Save

Save as type: Datatiles(ht)

Cancel

Model

Fig. 12 extraction of table dispersion data

Open via excel

Open a new Excel file and open from it your txt file of"Model. txt:

一

Import Wirord deploy

The Text wizard has detemned thet your deta is Fxee width

If tr s is conect. choose Nect, cr coos the data t/pa that best desaias you data

ECpe

b比HNW,

t Libres

I heal

startimortat row:1 a Fle ncn: 437: CE4Jntad states

Preview c fle D: wyLactreEoftwere CSTCST Exaroie ExEmples'M1520 L3 Bo2m. Model.txt

心 Homego

ACcepter

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filename Wod 1

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disko te cesred pceibon,

eric ales to numbes, date values to dates, and al

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general

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1phase Frequency(Model)

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smr. razavizadeh @ieee. org

Dispersion diagram: CST Microwave Studio

py cr the

●●“ buenmede,TET+Sicw Ws

Organie. Aewfolcer

dHl Eel wrwk.

Nusic

Exel Maao-Lnable

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mecro-enabled file fc

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pE h a topr of the workbook as t PF o

save as type

Omer Formats

lags Add a tag

box to selct trom

日4时 fgt Hide Folde

To□ SeveRance

Fig, 13 The preparation of the dispersion text data file for producing the

compatible * .csv file

We should keep just the phase and value column and eliminate others, then edit the title of the

value column as Frequency(Model), finally save as a Csv file format, as shown in Fig. 13. We

should repeat the simulation for remained modes frequencies as presented in Fig. 14, and extract

the favorite data for updating the previous"model. csv?"data file

Reault woth

Solve se: tings

Template Based Postprocessing

Method: DM

dAnd 3D Rel beans

Modes

velAte.

thoose number of modes

automatically (Dm 10 CHe

Resa nere (2)

Resut aus.

Adaotive mesh refirement

(3)

Volage Integretion nange

Setings Delete Dupicae Evaluate 0B[

Sensitity amalysis

口 Lse sensivity anays Prcoertes

ICK [Cancel][Help CRawPore Logie

Fig. 15 How we can update the calculation for the higher mode

Lumet

Paye aytuL Formulas Dale Review

Deveiuyi

回△征围,A

styler

omat,∠

Anent Nunber p

Frequency( Model) Frequen y Mode2) Frequency mode) Frecuency Mod

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Fig. 16 all the dispersion data gathered in one csv file for plotting the final

dispersion diagram for first forth modes of the proposed 1 D-periodic structure

smr. razavizadeh @ieee. org

Dispersion diagram: CST Microwave Studio

Mtalab Code for plotting the dispersion diagram

For publishing all of your plot result, especially in ieEE publications, we should import our

data into matlab environment, as a perfect engineering tool to sketch various plots in a unique plot

in a high resolution view. Here we present a brief quick guide about it

IRun matlab

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2)import the dispersion csv file

Lock in: Sow Wave

errs●5

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4)disable the header and text box

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o Create variables matching preview

u2Hwtd出W

O Create vectors from each co l m n uan g column

回包必AL

o Create vectors ftom each row using aw names

Ianahles ir D: My rcurelSotwarr lSTsCST-FiamplrFxamp exMwSa1 Figenmnd-t TE Slow Wve niprrsior c

)Run the plot m file(see the appendix)

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smr.razavizadeh @ieee.org

Dispersion diagram: CST Microwave Studio

na resu

20

Mode 1

18

Mode2

16

Mode3

下14

Mode4

TE

12

10

BAND GAP

LL 6

RL

20406080100120140160180

Phase(Deg

Fig. the final sketch of the dispersion diagram obtained by a matlab plotting

program(Appendix)

smr. razavizadeh @ieee. org

Dispersion diagram: CST Microwave Studio

Example2 2D-periodic structure dispersion diagram

In this section, dispersion characterization of surface waves propagating on a mushroom-like

periodic structure is investigated using CST MWS

Mushroom-like Ebg structures

Wavenumber k is an important parameter to describe the propagation property of

electromagnetic waves In a lossless case, the phase constant is B=k

Usually, B is a function of frequency o. Once the phase constant is obtained, the phase velocity

(vp) and group velocity(vg) can be derived

nd v

dB

Furthermore. the field distribution can also be determined such as the field variation in a

transverse direction. For a plane wave in free space, the relation between B and w is a linear

function

6(0)=k=0yoE

(2-2)

For surface waves propagating in an EBG structure, it is usually difficult to give an explicit

expression for the wavenumber k. One has to either solve an eigen-value equation or perform a full

wave simulation to determine the wavenumber. It is important to point out that the solution of an

eigen-value equation may not be unique.

In another words, there may exist several different propagation constants at the same

frequency. Each one is known as a specific mode with its own phase velocity, group velocity, and

field distribution. The relation between B and o is often plotted out and referred to as the

dispersion diagram

For a periodic structure such as the EBG, the field distribution of a surface wave is also

periodic with a proper phase delay determined by the wavenumber k (orB) and periodicity p

Thus, each surface wave mode can be decomposed into an infinite series of space harmonic waves

E(x,y,)=∑+(y,2)e-1nx,月n(a)=B2(a)+n

Here, we assume the periodic and propagation direction is the x direction. Although these space

harmonics have different phase velocities, they share the same group velocity. Furthermore, these

space harmonics cannot exist individually because each single harmonic does not satisfy the

boundary conditions of the periodic structure. Only their summation satisfies the boundary

conditions. Thus, they are considered to be the same mode

【实例截图】

【核心代码】