1. FEMTEC 2013 May 23, 2013, Las Vegas
Optimization of Electrical Properties
of Parallel Plate Antenna for EMC Testing
Zdeněk KUBÍK, Denys NIKOLAYEV, Pavel KARBAN, Jiří SKÁLA, Miroslav HROMÁDKA
University of West Bohemia
Faculty of Electrical Engineering

2. Abstract
The major application of a parallel plate antenna (also called: TEM-cell, strip line antenna, etc.) is the radiated immunity and interference testing for EMC applications.
Appropriately designed antenna represents a transmission line with TEM wave propagation and uniform electromagnetic field distribution between plates.
Device under test (DuT) is positioned within the region of uniform EM field.
In this presentation, we will discuss the optimization of electric properties of a small parallel plate antenna, which was designed for RF radiated immunity testing of telecommunication appliances.
We conducted numerical based optimization to improve TEM-cell parameters.
Results were verified by experiments.

3. Introduction Electromagnetic compatibility background
Majority of all modern devices use electronic circuits
All devices interact with surrounding—including other electronic devices and human bodies
Four types of interaction:
1. Conducted emission
2. Conducted susceptibility
3. Radiated emission
4. Radiated susceptibility

4. Introduction EMC immunity testing of electronic devices
Usually is performed in an anechoic chamber, E field is generated by a transmitting antenna
Parallel plate antenna (strip line, TEM cell, …):
Usually is performed in an anechoic chamber, E field is generated inside PPA (TEM wave)
Fig.1: Free space propagation of the EM wave

5. Introduction Microstrip line impedance
Impedance depends on height, width of a microstrip and effective permitivity
Electric field inside a microstrip

6. Introduction
Scattering parameters or S-parameters depict the electrical behaviour of a passive elements
where a denotes an incident wave and b represents reflected wave
S11 parameter (reflection coefficient )

7. RL Measurement
Return loss—RL
RL measurement

8. Problem
Goal: Optimize the electrical properties of parallel plate antena for EMC testing

9. Original Stripline Dimensions of the stripline: W = 300 mm
H = 400 mm
Impedance of the stripline:
Z0 = 141 Ω

10. 3D FEM Model Wave equation to be solved: Boundary conditions
Impedance boundary condition:
Scattering boundary condition:
Lumped ports
DoFs: ~1.2 MEG

11. Results
Dependence of RL on frequency: original PPA

12. Results
Dependence of RL on frequency: Z0 parameter

13. Improvement Stripline
Improvement: new impedance matching and terminator
SMD resistors were used
Disadvantage: low power load

14. 3D FEM Model Wave equation to be solved: Boundary conditions
1) Impedance boundary condition:
2) Scattering boundary condition:
3) Lumped ports
4) PMC for the symmetry BC
DoFs: ~1.7 MEG

15. RESULTS
Dependence of RL on frequency: optimized PPA

16. RESULTS
Dependence of RL on frequency; parameter: angle of feeding taper
Problem: distribution of E on the bend of a plate

17. RESULTS
Distribution of E on bend of plate: 15°, 30°, 45° and 60°

18. Comparison
Comparison of original and optimized PPA

19. Conclusions
3D FEM models were used for parallel plate antenna (PPA) simulations
The original PPA was optimized using FEM
RL improvement: approx. -15 dB
Analysis of RL dependence on termination impedance
Analysis of RL dependence on feeding taper angle
FEM models results were verified by measurement
Future research needs
New impedance coupling and termination
Difference between resistors impedance matching and balun (transmission line transformer)
Design of large PPA (width and height approx. 0.8 m, length approx. 2.5 m)
Simulations of S21 parameter – dependence of S21 on PPA filling (DuT)

20. Thank you for your attention
FEMTEC 2013 May 23, 2013, Las Vegas
Thank you for your attention
Optimization of Electrical Properties of Parallel Plate Antenna for EMC Testing
Zdeněk Kubík
University of West Bohemia
Univerzitni 26
306 14, Plzen
Czech Republic