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Keysight Technologies
Materials Measurement:
Phantoms
Application Brief
02 | Keysight | Materials Measurement: Phantoms - Application Brief
Overview Solution
Phantoms (designed objects that simulate various constants of The coaxial probe method is best for liquid phantom materials.
biological tissues) have been widely used for antenna character- A typical measurement system consists of a network analyzer or
istic evaluation and specific absorption rate (SAR) measurements an impedance analyzer, a coaxial probe and software. Keysight
for mobile handsets and other wireless communication devices. offers the whole product solution, the 85070E software with the
There are international test standards for SAR measurements dielectric probe kit (included), an Keysight network analyzer or
to protect human health and safety such as IEC 62209. The test the E4991A impedance analyzer. The system provides simple,
standards require measuring dielectric properties of the phantom convenient and non-destructive measurements. The measure-
material, such as relative permittivity and conductivity, prior to ment software guides you through setup and measurement, in-
testing SAR. stantly converting S-parameter network analyzer data into a data
format of your choice and displaying the results within seconds.
Phantoms are also increasingly required for a variety of medical Results can be charted in a variety of formats: r', r ", tan and
research purposes such as microwave imaging to detect breast Cole-Cole. The system can cover from 10 MHz to 50 GHz. The
cancers. It uses the difference of microwave reflectivity between frequency range is decided by analyzer.
normal tissue and cancer tissue due to different dielectric proper-
ties. Researchers need to verify that the dielectric properties of
phantom materials are equivalent to that of biological tissues for
getting precise test data.
Problem
The dielectric characteristics of liquid phantom tend to be
changeable by evaporation and chemical reaction over time. The
test standards require the measurement of dielectric properties
of phantom material within a certain period of time (e.g. within
24 hours) before SAR testing. For measuring dielectric proper-
ties within a short time period, an easy-to-setup, repeatable, and
stable test system is required. The required test frequency ranges
for medical research purposes are being increased up to 10 GHz
Figure 1. Typical system configuration
and higher.
You may need to monitor dielectric properties for many hours,
even for a very slight change in some cases The Keysight 85070E
software has an electronic calibration refresh feature that reca-
librates the system automatically with an ECal module. It elimi-
nates cable instability and system drift that causes measurement
errors over long periods of time.
03 | Keysight | Materials Measurement: Phantoms - Application Brief
References
1. Basics of Measuring the Dielectric Properties of Materials,
Application note, Literature number 5989-2589EN
2. Keysight 85070E Dielectric Probe Kit, Technical overview,
Literature number 5989-0222EN
3. C. Hahn and S. Noghanian, "Heterogeneous Breast Phantom
Development for Microwave Imaging Using Regression
Models," International Journal of Biomedical Imaging,
Volume 2012, Article ID 803607, 2012
4. N. Siauve and C. Lormel, "Interstitial microwave
hyperthermia treatment investigations," J. Physics,
Conference Series 395, 2012
5. M. Ostadrahimi, R. Reopelle, S. Noghanian, S. Pistorius,
A. Vahedi and F. Safari, "A heterogeneous breast phantom for
microwave breast imaging," Conf Proc IEEE EMBS, 2009
6. S. M. Salvador and G. Vecchi, "Experimental Tests of
Figure 2.ECal for calibration refresh
Microwave Breast Cancer Detection on Phantoms," IEEE
Trans. Antennas Propag., vol. 57, no. 6, pp. 1705-1712, 2009
7. K. Fukunaga, S. Watanabe, H. Asou and K. Sato, "Dielectric
Properties of Non-Toxic Tissue-Equivalent Liquids for
Radiowave Safety Tests," IEEE ICDL, 2005
8. IEC 62209-1: 2005, Human exposure to radio frequency fields
from hand-held and body-mounted wireless communication
devices - Human models, instrumentation, and procedures -
Part 1: Procedure to determine the specific absorption rate
(SAR) for hand-held devices used in close proximity to the ear
(frequency range of 300 MHz to 3 GHz)
9. IEC 62209-2: 2010, Human exposure to radio frequency fields
from hand-held and body-mounted wireless communication
devices - Human models, instrumentation, and procedures -
Part 2: Procedure to determine the specific absorption rate
(SAR) for wireless communication devices used in close
proximity to the human body (frequency range of 30 MHz to
Figure 3. Measurement result example
6 GHz)
Conclusion Web Resources
The coaxial method with a network analyzer or an impedance Visit our websites for additional product information.
analyzer is widely used for measuring the dielectric properties of
phantom materials. It is critical to maintain the dielectric prop- Materials Test Equipment:
erties of the phantom equivalent to that of biological tissue for www.keysight.com/find/materials
precise simulation. For more information, application notes and
white papers are listed under references. Network Analyzers:
www.keysight.com/find/na
Impedance Analyzers and LCR Meters:
www.keysight.com/find/impedance
04 | Keysight | Materials Measurement: Phantoms - Application Brief
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