CAE Software【Femtet】Murata Software Co., Ltd.
The characteristics of a spiral antenna connected to impedance-matching components are analyzed.
The impedance characteristics and radiation patterns are obtained.
Unless specified in the list below, the default conditions will be applied.
[How to Reduce the Calculation Time]
Item |
Settings |
Analysis Space |
3D |
Model unit |
mm |
Item |
Settings |
Solvers |
Electromagnetic Analysis [Hertz] |
Analysis Type |
Harmonic analysis |
Options |
Select “Ignore the influence of face/edge electrode thickness” * |
* This is the default setting. There are no face electrodes with this model. Therefore it is irrelevant to select it or not.
Mesh tab, Harmonic analysis tab and Open boundary tab are set as follows.
Tabs |
Setting Item |
Settings |
Mesh Tab |
Element type |
2nd-order element |
Multigrid/Adaptive Mesh Method |
Select [Use the adaptive mesh method]. |
|
Frequency-Dependent Meshing |
Reference frequency: 1.5×10^9[Hz] Select “The conductor bodies thicker than the skin depth constitute the boundary condition.” |
|
Harmonic analysis |
Frequency |
Minimum: 1×10^9[Hz] Maximum: 2×10^9[Hz] |
Sweep Type |
Select “Linear step” Division number: 100 |
|
Sweep Setting |
Select Fast sweep S-parameters variation: 1×10^-3 |
|
Input |
1.0[W] |
|
Open boundary |
Type |
Absorbing boundary |
Order of Absorbing Boundary |
1st degree |
The spiral antenna is formed with a conductive strip wound around the alumina (ANTENNA) . It is mounted on a substrate (SUB) made of glass epoxy. A port (P1) is set at the feeding point of the spiral antenna.
Two inductors are inserted as impedance-matching components near the feeding point. The air (AIR) encloses the substrate and the antenna entirely.
The open boundary condition is set on the surface of “AIR”.
“Conductor wall” is set on antenna and substrate electrodes (EC) as boundary condition. Inductors are set with “Lumped constant” boundary condition.
Body Number/Type |
Body Attribute Name |
Material Name |
0/Solid |
ANTENNA |
001_Alumina * |
1/Solid |
SUB |
006_Glass_epoxy * |
9/Solid |
AIR |
000_Air(*) |
* Available from the Material DB
Boundary Condition Name/Topology |
Tab |
Boundary Condition Type |
Settings |
PORT/Face |
Electric |
I/O Port |
Reference Impedance: Select “Specify” Number of Modes Number of precalculated modes: 5 Number of modes used in the actual analysis: 1 Select modes: none |
L1/Face |
Electric |
Lumped constant |
2.0×10^-9[H] |
L2/Face |
Electric |
Lumped constant |
4.0×10^-9[H] |
EC |
Electric |
Conductor wall |
Conductivity: 1.0×10^7[S/m] |
Outer Boundary Condition |
Electric |
Open boundary |
The calculated impedance characteristics of this antenna is shown below.
The radiation pattern of this antenna is plotted with the polar graph below. The unit is [dB].
To calculate this radiation pattern, the following conditions have been applied.
* Frequency: 1.5×109[Hz] (Single frequency)
* Deselect “Fast sweep”.
See [Exercise 7: Dipole Antenna].
See also [Electromagnetic Waves Directivity].
φ=90[deg], θ=0-360[deg], 60 steps