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Radar Cross Section Reduction Short Course
by Marietta Scientific,
Inc.
Radar Cross Section Reduction (RCSR) technology is an emerging
discipline which will be considered for every future DoD system. It is a topic, which
typically is mired, in obscure mathematical detail. Marietta Scientific’s goal is to
present physical concepts suitable for personnel working in stealth disciplines. Our
course presents technical issues facing designers of low observables (LO) systems, general
signature reduction techniques available, and an overview of the measurement and
analytical tools, which can be applied.
Where & Who should attend:
The RCSR course is designed to be presented at your facility. You
may tailor the course content by selecting topics from the enclosed topic list, or you may
arrange for specialized topics which target activities at your facility. The enclosure
illustrates a typical three day course. A lecture day is comprised of six lecture hours,
and the total cost of the course is determined based on the number of lecture days
requested. In order to allow for interaction and questions during the presentation, class
size should not exceed 40 attendees.
Each attendee will receive a copy of the selected lecture material as well as
the text book, Radar Cross Section, Artech House,
Second Edition, by E. F. Knott, J. F. Shaeffer, and M. T. Tuley.
The course has been designed to emphasize physical concepts rather than
mathematics so that most topics will be easily understood. However, a few topics are
in-depth mathematical treatments best suited for your LO technical specialists.
Typical Three Day RCS Short Course:
| Hour |
Day 1 |
Day 2 |
Day 3 |
| 1 |
Course Intro and RCS LO Technology Introduction |
Design Topics I |
Materials II |
| 2 |
RADAR Fundamentals |
Design Topics II |
Materials III |
| 3 |
Electromagnetic Scattering Basics |
Design Topics II Continued |
Materials III continued |
| 4 |
RCS Data Examples Specifications & Formats |
RCS Scaling Issues |
Hip Pocket Estimation |
| 5 |
Scattering Mechanisms |
RCS Budgets & Integration Issues |
Physical Optics |
| 6 |
Surface Waves |
Materials I |
Compact Image Ranges |
A brief description of lecture topics offered is list below along with a
notation of suitable audiences for each topic: DE = design engineer,
LOT = LO technology specialist, M = manager
OVERVIEW AND BACKGROUND TOPICS:
 | RCS LO TECHNOLOGY TOPICS AND MANAGEMENT
(1 hour): An overview of RCS signature sources, RCSR approaches, overview of the required
disciplines in design, materials, analytics, test, avionics, and projects/IRAD; suggested
organization; and security issues. Suitability: DE, LOT, M
|
| RADAR FUNDAMENTALS (1 hour): An
overview of RADAR system fundamentals needed to understand RCS issues. Topics include:
frequency/wavelength/band identification; Types of RADAR; RADAR fundamentals; RADAR range
equation; definition of radar cross section; detection issues; multipath effects; typical
RADAR systems; and benefits of RCS reduction. Suitability: DE, LOT,
M
|
| ELECTROMAGNETIC SCATTERING BASICS
(1.5 hour): Electromagnetic wave fundamentals; physics of scattering and the three
size/wavelength regimes; RCS Parameters; units and measurement scales; and overview of RCS
prediction theories of physical optics, geometric optics, and method of moments.
Suitability: DE, LOT
|
| RCS DATA EXAMPLES, SPECIFICATIONS, AND DATA
REDUCTION (1 hour): Concept of scattering centers; phasor addition; non
LO RCS examples; LO RCS examples; RCS versus frequency for LO targets; typical
specifications; and data presentation and formats. Suitability: DE, LOT
|
| SCATTERING MECHANISMS (1 hour):
Scattering from complex targets; aircraft scattering mechanism overview; general aircraft
model example; everything you ever wanted to know about specular scattering: specular
point definition, planar surfaces, singly curved surfaces, doubly curved surfaces, leading
and trailing edges, rims, and multiple bounce; frequency characteristics of various
scattering mechanisms; and hierarchy of scattering mechanisms. Suitability: DE, LOT
|
| SURFACE WAVE MECHANISM (1 hour):
Surface wave definition and requirements for existence; types of surface waves: traveling,
creeping, and edge; where surface waves cause scattering; surface wave reduction
approaches. Suitability: DE, LOT
|
RADAR CROSS SECTION REDUCTION APPROACHES
| DESIGN TOPICS I (1.5 hour):
Overall approaches for RCSR; identification of scattering mechanisms for typical aircraft;
overall issues; shaping road map; threat sector concepts; elementary scattering relative
to azimuth and elevation; planform shaping; and side sector shaping. Suitability: DE, LOT
|
| DESIGN TOPICS II, PRINCIPLES
AND EVOLUTION OF PLANAR FACETING TO BLENDED SURFACE DESIGN (1.5 hours):
Review principles of planar faceted design for specular and sidelobe envelope end region
control; evolution to non planar surfaces for specular and sidelobe envelope; edge
diffraction and S curve introduction; and scattering mechanisms from canonical curved
bodies. Suitability: DE, LOT
|
| LOW FREQUENCY ISSUES (1 hour):
Low frequency radar characteristics; dominant scattering mechanisms at low frequency;
typical RCS patterns; diagnostic imaging; reduction approaches. Suitability: DE, LOT
|
| RCS SCALING ISSUES (1 hour):
Review of rigorous scaling laws; Review of high frequency scattering mechanisms;
Scattering mechanism frequency/wavelength/size relation-ships; Size independent scattering
mechanisms; Scaling relationships for size independent targets; and scaling road map.
Suitability: DE, LOT
|
| RCS BUDGET CONCEPTS AND INTEGRATION ISSUES
(1 hour): RCS Budget concepts; rationale for use; sample budget sheet; RCS numbers game;
integration issues: minimum discontinuities; crew station, high and low energy locations,
blended radomes, and surface imperfections. Suitability: DE, LOT
|
| MATERIALS I (1 hour): An
overview of the role of materials in RCSR. Topics include: materials as second approach to
RCSR; general classes of materials; phasor cancellation versus absorption; typical
airframe applications; and related test and analysis approaches. Suitability: DE, LOT
|
| MATERIALS II (1 hour):
Fundamental material electrical characterization and specular absorber types. Topics
include: EM characterization of material; fundamental concepts; EM fields near ground
plane; specular absorbers; surface wave magnetic absorbers; geometric absorbers; perimeter
treatments; and tips. Suitability: DE, LOT
|
| MATERIALS III (2 hours): Non
specular absorbers and R card design issues. Topics include: definition of non specular
scattering; review of non specular scattering mechanisms: end region, edge wave,
leading/trailing edge diffraction, and surface traveling and creeping waves; why edges are
critical; RCSR approaches for surface/creeping waves, end region current taper, perimeter
and tip treatments; bulk absorber characterization; R card and bulk edge functions;
current taper versus resistive taper; resistive profile recipe for R cards; example
results for 2-D TE and TM polarizations; end resistance considerations; and bulk edge
issues. Suitability: DE, LOT
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| INLET AND EXHAUST CAVITY ISSUES
(1 hour): Topics: scattering regimes; low frequency issues; location; waveguide below
cutoff; body influence on incident field, low energy regions; high frequency issues:
scattering mechanism, baseline ROM signature estimates, aspect ratio, and RCSR approaches;
and analytics for cavities. Suitability: DE, LOT
|
| HIP POCKET RADAR CROSS SECTION ESTIMATION
(1 hour): Sets up the approaches required to estimate major scattering mechanism cross
section. Topics include: application ground rules; estimation approaches; hip pocket
formulas; examples; and constant phase region size estimation. Suitability: DE, LOT, M
|
| ELECTROMAGNETIC REVIEW I (1
hour): Review of basic electromagnetic wave theory. Topics include: review of fundamental
mathematics, complex numbers, and vector field theory; Maxwell's equations; EM wave
characteristics; reflection of EM waves at boundaries; transmission line / EM wave
analogy; and surface current point of view. Suitability: LOT
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| ELECTROMAGNETIC REVIEW II (1
hour): Further EM review. Topics include: waves at boundaries: boundary conditions,
Snell's law, reflection (Fresnel) coefficients, and transmission coefficients; analogy to
transmission line theory; and boundary conditions as surface currents, Stratton-Chu form
of Maxwell's equations. Suitability: LOT
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| HIGH FREQUENCY METHODS I: PHYSICAL OPTICS
(1 hour): Introduction to Physical Optics. Topics include: PO assumptions; starting
magnetic field integral equation; generalized bistatic formula; flat plate example;
stationary phase; cylinder scattering; physical and geometric optics compared; and
pitfalls / problems in using PO for low observable targets. Suitability: LOT
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| HIGH FREQUENCY METHODS II: GEOMETRIC OPTICS
(1 hour): Introduction to Geometric Optics. Topics include: GO background; GO bistatic
formula; GO backscatter formula; GTD background; edge diffraction; tip diffraction; PO,
GO, & GTD summary; and multiple scattering. Suitability: LOT
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| METHOD OF MOMENTS (MOM) INTEGRAL EQUATIONS
(1 hour): A brief introduction. Topics include: definition; motivation & failings of
PO and GO; limitations; scope of problems treatable; magnetic field integral equation
(MFIE); electric field integral equation (EFIE); The unknown currents; the matrix; the
voltage vector forcing function and solution for currents; the bistatic and backscatter
fields; examples; and general considerations and future directions. Suitability: LOT
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| GROUND PLANE RANGES (1 hour): An
introduction. Topics include: rationale for outdoor measurements; theory of operation: the
ground bounce multipath, field gain; optimum antenna and target heights; target support
and mounting considerations; target support considerations. Suitability: DE, LOT
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| COMPACT IMAGE RANGES (1 hour):
An introduction. Topics include: rationale for use and data types; theory of operation:
downrange theory; down/cross range image theory; types of reflector systems; some issues
for reflector dish edges. Suitability: DE, LOT
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