Home / Examples / Electromagnetic Analysis [Hertz] / Example 4: Horn Antenna

Example 4: Horn Antenna

General

The model is a horn antenna.
The S-parameters at the feeding port are solved.
Unless specified in the list below, the default conditions will be applied.
Obtain this session's project file. (Right-click and choose 'Save link as')
Results will vary depending on Femtet version and the PC environment.

[How to Reduce the Calculation Time]

Analysis Space

Item	Settings
Analysis Space	3D
Model Unit	mm

Analysis Conditions

Item	Settings
Solver	Electromagnetic Analysis [Hertz]
Analysis Type	Harmonic Analysis

Mesh tab, Harmonic analysis tab and Open boundary tab are set as follows.

Tab	Setting Item	Settings
Mesh Tab	Element Type	2nd-order Element
	Adaptive Meshing	Select [Apply adaptive meshing].
	Frequency-Dependent Meshing	Reference Frequency: 7.1x1010 [Hz] Select [The conductor bodies thicker than the skin depth constitute the boundary condition]. The surface of Metal is treated as the boundary condition having some loss, as Metal is thicker than the skin depth. See Effect of Mesh Size for reference.
Harmonic analysis	Sweep Type	Select [Linear Step by Number of Divisions]
	Sweep Setting	Minimum: 7.1x1010 [Hz] Maximum: 7.1x1010 [Hz] Division: 0
	Sweep Setting	Select discrete sweep
	Input	1.0 [W]
Open Boundary	Type	Absorbing Boundary
Open Boundary	Order of Absorbing Boundary	1st-order

Model

An aluminum horn antenna (Metal) is placed in the cubic air (Air).
The feeding point at the inside of the antenna (horn) is set with the port boundary condition. The open boundary condition is set to the outer surfaces of the cubic air.

Body Attributes and Materials

Body Number/Type	Body Attribute Name	Material Name	Mesh Size
50/Solid	Metal	001_Al *	0.3
51/Solid	horn	000_Air(*)	0.3
55/Solid	air	000_Air(*)

* Available from the material DB

Boundary Conditions

Boundary Condition Name/Topology

Tab

Boundary Condition Type

Settings

port1/Face

Electric

Port

Reference Impedance: Select
[Use the characteristic impedance calculated from the port structure]

Number of Modes

Number of Precalculated Modes: 5

Number of Modes Used in the Actual 3D Analysis: 1

Select Modes: None

Outer Boundary Condition

Electric

Open Boundary

Results

The radiation pattern of the horn antenna is plotted with polar graph.

The unit is [dB].

See [[Simple Mode] Electromagnetic Waves Directivity] or [[Detailed Mode] Electromagnetic Waves Directivity] for display of radiation patterns.