Antenna Design

Lab 10 - Inverted-L and inverted-F Antennas

 I. Simulation

1. Monopole antenna

Monopole dimensions:

Feeding: Gap-fed with a discrete port with source impedance of 50 W

Design frequency:  f ₀ = (1000 + PIN/1000) MHz=1GHz

실습조교 PIN = 0000

Monopole axis: in z direction

Reference resonant dipole length: L = 0.45 λ = 0.45 ´ 300 = 135 mm

Monopole end-to-ground plane distance:  L/2 = 0.225 λ= 68 mm

Monopole diameter: d  = (L/2)/34 = 2.0 mm

Monopole feed gap: g/2 = d/2 = 1 mm

Monopole: PEC

Frequency range: 0.5f₀ to 1.5f₀

(1) Make the Monopole

Modeling, Cylinder 아이콘 선택, ESC 키, Name: solid1, Orientation: Z

(2) Make an infinite PEC (Et = 0) ground plane on the Zmin (z = 0) boundary box.

a) Boundaries configuration

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

b) 포트설정

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

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

Modeling, Pick Points, Pick Point From Coordinates

Enter 3D point, X:0, Y: 0, Z:0 OK

Simulation, Discrete Port

Simulation, Discrete Port, OK

Simulation, Setup Solver

1) 시뮬레이션 설정

주파수 설정:

Simulation, Frequency, Min. frequency: 0.5, Max. frequency: 1.5

필드 모니터 설정:

Simulation, Field Monitor, E-field, Frequency, Frequency:1, Apply

Simulation, Field Monitor, H-field and Surface current, Frequency, Frequency:1, Apply

Simulation, Field Monitor, Far field/RCS, Frequency, Frequency:1, Apply

Simulate

Simulation, Setup Solver, Start

1-1. Plot the antenna structure

1-2. Plot |S11| (dB) at 0.5f₀ to 1.5f₀

1-3. Plot the input impedance on the Smith chart.

1D Plot, Smith Chart

1-4. On the Smith chart, mark the frequency f₀ and find the input impedance Z_in.

Add Curve marker and input frequency 1.0

Right-click, Add Marker, place the mouse pointer on the curve and double-click

1-5. Plat 3D Gabs at f₀. 

1-6. Find max(Gabs) at f₀.

(Gabs)=5.176 dBi

2. Inverted-L antenna (ILA)

L₁ = 0.3 (L/2), L₂ = 0.7 (L/2), where L, g, and d are defined in the above.

(1) Make the antenna geometry and plot it in 3D.

Vertical

Modeling, Cylinder 아이콘 선택, ESC 키, Name: solid1, Orientation: Z

Horizontal

Modeling, Cylinder 아이콘 선택, ESC 키, Name: solid1, Orientation: X

(2) Make an infinite PEC (Et = 0) ground plane on the Zmin (z = 0) boundary box.

a) Boundaries configuration

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

(3) Make a discrete port.

Modeling, Pick Points, Pick Face Center, select a face in the gap and double click.

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

Modeling, Pick Points, Pick Point From Coordinates

Enter 3D point, X:0, Y: 0, Z:0 OK

Simulation, Discrete Port

Simulation, Frequency, Min. frequency: 0.5, Max. frequency: 1.5

필드 모니터 설정:

Simulation, Field Monitor, E-field, Frequency, Frequency:1, Apply

Simulation, Field Monitor, H-field and Surface current, Frequency, Frequency:1, Apply

Simulation, Field Monitor, Far field/RCS, Frequency, Frequency:1, Apply

Simulate

Simulation, Setup Solver, Start

2-1. Plot the antenna structure.

2-2. Plot |S11| (dB) at 0.5f₀ to 2.0 f₀.

2-3. Plot the input impedance on the Smith chart.

m

2-4. On the Smith chart, mark the frequency f₀ and find the input impedance Z_in.

2-5. Plat 3D Gabs at f₀. 

2-6. Find max(Gabs) at f₀.

(Gabs)=-0.289 dBi

3. Inverted-F antenna (IFA)

L₁ = 0.3 (L/2), L₂ = 0.7 (L/2), where L, g, and d are defined in the above.

(1) Make the antenna geometry and plot it in 3D.

Vertical 1

Modeling, Cylinder 아이콘 선택, ESC 키, Name: solid1, Orientation: Z

Horizontal

Modeling, Cylinder 아이콘 선택, ESC 키, Name: solid1, Orientation: X

Vertical 2

Modeling, Cylinder 아이콘 선택, ESC 키, Name: solid1, Orientation: Z

Ok

(2) Make an infinite PEC (Et = 0) ground plane on the Zmin (z = 0) boundary box.

a) Boundaries configuration

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

(3) Make a discrete port.

Modeling, Pick Points, Pick Face Center, select a face in the gap and double click.

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

Modeling, Pick Points, Pick Point From Coordinates

Enter 3D point, X:0, Y: 0, Z:0 OK

Modeling, Pick Points, Pick Point From Coordinates

Enter 3D point, X:0, Y: 0, Z:0 OK

Simulation, Discrete Port

Simulation, Frequency, Min. frequency: 0.5, Max. frequency: 2

필드 모니터 설정:

Simulation, Field Monitor, E-field, Frequency, Frequency:1, Apply

Simulation, Field Monitor, H-field and Surface current, Frequency, Frequency:1, Apply

Simulation, Field Monitor, Far field/RCS, Frequency, Frequency:1, Apply

3-1. Plot the antenna structure.

With all other dimensions fixed, change S to the following values

S = 2d, 4d, 6d, 8d, and 10d

using the parameter sweep method in CST Studio. If necessary, repeat the parameter sweep in smaller intervals for the lowest value of min{|S11| (dB)}.

Simulation, Setup Solver, Time Domain Solver Parameters, Par. Sweep,

New Sequence, New Parameter, Parameter Sweep Parameter

close

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

Evaluate All

Simulation, Par.Sweep, Start

0D or 1D result.

1D Results, S-Parameters, S1,1

RESULT TOOLS - 1D Plot, dB

If necessary, repeat the parameter sweep in smaller intervals for the lowest value of min{|S11| (dB)}.

S = 1, 2, 3, 4,5 and 6

start

Now set S = S_optimum=3  and do the following

Change the S value (S=3)

Simulation, Field Monitor, Far field/RCS, Frequency, Frequency:1.21, Apply

Simulate

Simulation, Setup Solver, Start

3-3. Plot |S11| (dB) at 0.5f₀ to 2.0 f₀.

3-4. Plot the input impedance on the Smith chart.

3-5. On the Smith chart, mark the frequency f₀ and find the input impedance Z_in

.

3-6. Plat 3D Gabs at f₀. 

3-7. Find max(Gabs) at f₀.

(Gabs)= 3.928 dBi

Summarize your simulation in the following table.

Antenna	Frequency fC (GHz) for minimum |S11|	|S11| < -10 dB bandwidth (GHz)	Rin, Xin at fC.	Max (Gabs) at fC
Monopole	1.03	0.157	33,34-3,57 Ω	5.176 dBi
ILA	1.12	-	6.45-22.43 Ω	-0.289 dBi
IFA	1.21	0.035	70.8+26.2 Ω	3.92 dBi