FDTD Simulations on Radar Cross Sections of Metal Cone and Plasma Covered
Metal Cone
Shen Shou Max Chung1,2
1Department
of Electronics Engineering, Southern Taiwan University, Tainan, Taiwan
2Hydrology Remote Sensing Lab, Center for Space and Remote Sensing Research National Central University
*Corresponding author email: [email protected]
Abstract
Electromagnetic wave interaction with a plasma covered metal surface has been studied using the Radar Cross Section
(RCS) changes of a 10 cm diameter and 30 cm height metal cone with and without plasma coverage. A Finite-Difference-TimeDifference (FDTD) method was use to calculate the case of a cone with and without a covering of a 1 cm thick sheet plasma
for both S Band (2,3, and 4 GHz) and X Band (8, 10, and 12 GHz) frequencies. The characteristic plasma frequency was set
at 10 GHz, and electron-neutral collision frequency νen chosen to be 20 GHz. The results indicate that the metal cone has
very small RCS at head-on direction, and a large RCS looking from the back end. A Plasma covered metal cone was shown to
achieve head-on direction monostatic RCS changes between -0.47 to -7.2 dBm2 from 2-4 GHz, and -11 to -3.2 dBm2 RCS
changes from 8-12 GHz, but at the back end the RCS increases between 2.2 to 2.6 dBm2 from 2-4 GHz, and varies between 0.9 to 0 dBm2 from 8-12 GHz. In the two frequency bands investigated, maximum RCS reduction of -15 dBm2 occurs at 8 GHz
at the same direction as the incident electromagnetic wave polarization. Plasma stealth offers advantages like frequency
tunability, but the challenge is establishing an adaptive feedback mechanism that can main a constant plasma density and thus
a constant RCS by adjusting the power supplied to plasma generator while monitoring the changes in air speed, altitude, and
humidity.
I . Introduction
Stealth technology has became the most decisive factor in military airplane design. Traditional stealth technology relies on
shape morphing, radar absorption material, sensor integration, and remote electronic support. Plasma stealth uses ionized gas
to reduce the radar cross-section, it provides hope for existing fighters a method to decrease their RCS without substantial
alterations in their shapes. Plasma stealth offers advantages like frequency tunability, instant on-off, and changes of threat
reduction direction coincident with external air flows, which are not possible with Radar Absorption Material (RAM). Here we try
to evaluate numerically, for the first time, the effects of plasma layer on the RCS of a metal cone.
II. Description of Simulation Parameters
We use a commercial FDTD code GEMS to simulate the RCS of a
metal cone of 10 cm diameter at the base and 30 cm in height. The
characteristic plasma frequency was set at 10 GHz, and electronneutral collision frequency νen chosen to be 20 GHz. Figure 1(L). The
metal (cupper) cone and Huygens box (plane wave box) in the
simulation. Radar signal is coming in from the Z axis. The red arrow
indicated the electric field is polarized in X direction. Figure 1(R).
Illustration of a metal cone (bottom) surround by a plasma sheet 10 mm
thick (semi-transparent red region on top of the cone).
III. Results
(A)RCS of metal cone in S-band
(B)RCS of plasma covered metal cone in S-band
IV. Conclusion
Plasma coating achieves head-on direction monostatic RCS changes between -0.47 to -7.2 dBm2 from 2-4 GHz, and -11 to 3.2 dBm2 RCS changes from 8-12 GHz, but at the back end the RCS increases between 2.2 to 2.6 dBm2 from 2-4 GHz, and
varies between -0.9 to 0 dBm2 from 8-12 GHz.
V. References
Shen Shou Max Chung, “
FDTD Simulations on Radar Cross Sections of Metal Cone and Plasma Covered Metal Cone”
,
Vacuum, vol. 86, no. 7, pp. 970-984, Feb. 2012. (SCI: 1.048) [Most downloaded paper of Vacuum in the past 90 days, 201209,
http://www.journals.elsevier.com/vacuum/most-downloadedarticles/?utm_source=ESJ001&utm_campaign=&utm_content=&utm_medium=email&bid=0FIGT6F:2TOUW4F) ).
2012 NCHC HPC