Antenna Optimization

II. Lab

IFA Optimization

Use CST Studio to find optimum values of S and L in the IFA (inverted F antenna) shown below for |S11| < -10 dB.

Use automatic optimization functionality in CST Studio. Do not use parameter sweep to get the results.

Antenna height H = 30 mm

Wire diameter d = 4

Feed gap g = 2

Optimization variables: S, L

Optimization goal: |S11| < -10 dB at 800-850 MHz

 1) Draw the antenna geometry.

(1) Make a template. Define an infinite ground plane.

File, New and Recent, New Template, Great Project Template, MICROWAVES & RF/OPTICAL, Antennas, Planar(Patch, Slot, etc,), Time Domain, Next

Frequency Min: 0.4 GHz

Frequency Max: 1.2 GHz

Monitors: check the E-field, H-field, Farfield, Power loss

Define at: 0.8 GHz, Next

Template Name: Inverted Antenna , Finish

Simulation, Boundaries, Boundary Conditions, Zmin: choose the electric(Et=0), OK

Modeling, 고리 실린더 (Cylinder) 선택, ESC 키, Name: solid1, Orientation: Z

Outer radius: 2 Inner radius: 0.0

X center: 0 Y center: 0

Z min: 0 Z max:30

Material: PEC

Modeling, 고리 실린더 (Cylinder) 선택, ESC 키, Name: solid2, Orientation: X

Outer radius: 2 Inner radius: 0.0

Y center: 0 Z center: 28

X min: -L X max: 2

Material: PEC

L=-58

Modeling, 고리 실린더 (Cylinder) 선택, ESC 키, Name: solid3, Orientation: Z

Outer radius: 2 Inner radius: 0.0

X center: -4-s Y center: 0

Z min: 2 Z max:30

(3) Make a discrete port

Modeling, Pick Points, Pick Face Center, gap 한면에 마우스 위치후 더블클릭

Modeling, Pick Points, Pick Point From Coordinates

Enter 3D point, X:-4-s, Y: 0, Z:0 OK

Simulation, Discrete Port, OK

(4) Simulate.

Simulation, Setup Solver, Start

2. Setup an Optimizer

(1) Simulation, Optimizer,

Settings, General Properties, Result storage settings, Parametric results –All

Algorithm settings, 30% of initial value

Check the s and l parameter

Click the Reset min/max

Goals, Add New Goal

Type: Mag.(dB)

Conditions:

Operator: <, Target: -15, Weiht:1.0

Range

Range min:0.8, max:0.85, ok

Ok, Close

(2) Setup the output plot.

Post-Processing, Result Templates Tools, General 1D, choose the 0D or 1D result from 1D Result (Rescale, Derivation, etc)

Ok

Evaluate All

Simulation, Optimizer,

Apply, OK

(3) Plot |S11| (dB).

1D Results, S-Parameters, S1,1

RESULT TOOLS - 1D Plot, dB

1D Results, i1_1D_ScalesAxis

I1_1D_ScaleAxis(8) is best result

Home, Logfile, Optimizer Logfile

Result 8