This powerpoint presentation is focused on microwave range engineering. More over their is a video in between whose link is in description>>> https://www.youtube.com/watch?v=ZFY0VWGGFtM&t=1s

1. RADAR CROSS SECTION(RCS)
ISSUES IN ANTENNA AND WAVEGUIDE
Presented By:
Kush Singla
Roll No. 192606

2. CONTENTS
 Introduction & Meaning
 Importance of Topic
 Technical Background
 Application
 Recent Work
 References

3. INTRODUCTION & MEANING
 Antenna: Defined as “usually a metallic device (as a rod or a
wire) for radiating and receiving radio waves.” as per
Webster’s Dictionary.
The IEEE Standard Definitions of Terms for Antennas defines
antenna as “a means for radiating or receiving radio waves.”
 Radar Cross Section (RCS): It is defined as a measure of
how detectable an object is in a radar.
We can also say that it is the area of the target which depicts
how much radiation the object can absorb and reflect.
In general, objects with more RCS are easily detectable and
vice versa.

5. FACTORS AFFECTING RCS OF AN OBJECT
 Size: Larger the object, stronger is its radar reflection and thus the
greater is its RCS.
 Material: Generally less reflective materials are preferred for
manufacturing of the object.
 Radar absorbent paint: This is a special type of paint which
reduces the reflectivity of the object to a greater extent by being used on
the objects surface. Generally stealth aircrafts were painted with a
special “iron ball paint” that consisted of small metallic coated balls, here
the radar energy is converted into heat rather than reflected back.
 Shape, Directivity and Orientation: These three parameters
are arranged in any object according to its application. And wrong choice
of any of the three parameters can lead to stronger reflected signal to the
radar station.
 Smooth Surfaces: Smooth Surfaces are preferred one’s for the
object because if not then the surface could contain indentations that act
as corner reflectors which would increase RCS in any orientation.

6. Importance of Radar Cross Section
•In early times when RCS was a electromagnetic theory related
concept. Radar cross section specialists were only included in the final
stages of design in prototype not in the early stages of the concept
definition.
•With the increasing need of weapons and aircrafts electromagnetic
properties were also taken into consideration at initial stages too. This
led to an increase in the need to take RCS also an important measure.
•Nowadays, RCS is taken as a prominent consideration, more likely at
initial stage in stealth aircrafts and in defence activities.
•With the increase in consideration RCS is always a measure which
we reduce in every system for the better working of the same.
•In case of antennas various techniques and precise generalised
parameters calculation are available to reduce the content of RCS in it.
Almost all types of antenna face this measure like wire antenna,
microstrip antenna, aperture antennas etc.

7. RADAR CROSS SECTION OF AN ANTENNA
Generally in an antenna RCS is divided in two separate
components. These two components of RCS relates to the two
scattering phenomena that takes place at the antenna. Types
are as-
 Structural Mode RCS: When an electromagnetic signal falls
on an antenna surface, some part of the electromagnetic
energy is scattered back into the space, this type of scattering
is termed as Structural Mode RCS.
 Antenna Mode RCS : After the occurrence of structural mode
RCS, remaining part of the energy is absorbed by antenna
due to the antenna effect. Some part of the absorbed energy if
is again scattered back into the space due to the impedance
mismatches, this type of scattering is termed as Antenna
mode RCS.

8. STRUCTURAL MODE RCS
Consideration of reducing structural mode RCS of
an antenna simply returns to the RCS reduction
applied to any body. Things to be considered are:
 Shaping to prevent scatter into the threat regions.
 Secondly, using Radar Absorbing Material (RAM)
selectively to take care of trouble spots.

9. ANTENNA MODE RCS
Antenna Mode RCS is the phenomenon which
distinguishes antennas from other structures. For
the reduction of antenna mode RCS we take
measures as:
 Antennas should be designed to have transmission
lines matched to the antenna impedance and load
in the operating band.
 Secondly, choice of component for antenna design
should be given careful consideration so as to have
low antenna mode RCS.

10. APPLICATIONS
 Antenna scattering phenomenon has been used extensively in
many passive radio frequency Identification [RFID] devices,
where the scattering properties of an antenna are defined by
the radar cross section parameters. It is also generally used
as a small scatter communication.

11. RECENT WORK
 “A method to measure Radar Cross Section
parameters of antenna” by Sudhir Shrestha et all.
In this paper a new method to measure radar cross section
parameters of antenna are presented. The method relies on
an equation derived for the received signal power which is
represented as the superposition of structural mode scattered,
antenna mode scattered and leakage signals. The method
also measures relative phase and provides the effect of the
load connected to the antenna.

12. REFERENCES
 https://www.youtube.com/watch?v=Ydvi0MiWmHI&t=48s
 https://www.youtube.com/watch?v=ZFY0VWGGFtM
 https://en.wikipedia.org/wiki/Radar_cross-section
 https://ieeexplore.ieee.org/document/4685914