LOG SPIRAL ANtenna design, using HFSS software. It has brief description about the ANTENNA and the software

1. DESIGN OF MINIATURIZED ULTRA-
WIDEBAND CONICAL SPIRAL
ANTENNA USING HFSS
Under Guidance of
T Anusha Lalitha
Assistant Prof. TCE, BMSCE
By
Sandeep Kumar P 1BM11TE045
Satish Kumar T V 1BM11TE048
Sharath Chandran C K 1BM11TE406
Santosh Patil 1BM12TE409

2. Introduction
• What is an ANTENNA ???

3. Antenna Characteristics
An antenna is a device that is made to efficiently
radiate and receive radiated electromagnetic waves.
There are several important antenna characteristics
that should be considered when choosing an antenna
for your application as follows:
• Antenna radiation patterns
• Power Gain
• Directivity
• Polarization

4. Conical Spiral Antennas
High data rate and wider bandwidth requirements for
datavideo transfer and growth in number of users lead
to increase operating frequencies of these systems to
microwave and millimeter-wave frequencies.
Spiral antennas are one of frequency independent
antennas with wide bandwidth and good pattern
efficiency in compare with other antennas.
Desirable radiation characteristics can be achieved by
changing circular radius r, number of turns N and the
width of them W.

5. Types of conical spiral antenna
Log Spiral Antenna
Archimedean Spiral Antenna
Sinuous Spiral Antenna

6. ConstructionofSpiralAntenna
Creating First Arm
The second arm is constructed by
Rotating the first arm by π radians

7. Log Spiral Antenna Parameters
Where
ro = inner radius
a = Ln( ExpansionRatio)/2pi
The pitch angle Ψ related to expansion
coefficient a by
tan Ψ = r/(da/dΦ) = 1/a
the design ratio τ is defined to be less than 1 and
is given by
this is ratio of OA/OB of the figure and is the ratio of the radii for one turn of the log spiral curve.

8. ConicalArchimedean Antenna Parameters
The centerline of the antenna is defined by
ρ = aφ
The first arm, which begins along the x-axis in
this example, is defined by the edges

9. ConicalSinuousAntenna Parameters
where Φ and r are polar coordinates
p is cell number and τ is growth rate
the design parameters may be
independent of p to form a LP structure that is periodic function
of logarithm of radius r .

10. HIGH FREQUENCY STRUCTURE
SIMULATOR

11. HFSS….???
Uses Finite Element Method to solve
Electromagnetic structure
Used for antenna design and design of complex
RF electronic circuit elements including filters,
transmission lines, etc.
HFSS is essential for designing high-frequency
and/or high-speed components used in modern
electronics devices

12. Features
Powerful drawing capabilities to simplify design
entry
Computes s-parameters and 3D passive
structures
Advanced materials
Model Library-including spiral inductor
Calculate far-field patterns
Wideband fast frequency sweep
Create parameterized cross section models- 2D
models

13. HFSS Analysis Design Flowchart
Construct Geometry
(User Input)
Define Volume Conditions
(User Input)
Define Surface Conditions
(User Input)
2D Excitation Solution
(Automatic)
3D Mesh Generation
(AutomatIc)
Solve 3D Matrix
(Automatic)
View/Plot S-Parameters
(User Input)
View/Plot Fields
(User Input)
PRE-PROCESSING SOLUTION POST-PROCESSING
Define Solution
Requirements
(User Input)

14. Applications
Antennas
Microwave transitions
Waveguide components
RF filters
Three-dimensional discontinuities
Passive circuit elements

15. RESULTS

16. RETURN LOSS
LOG SPIRAL
ARCHIMEDEAN

17. INPUT IMPEDENCE
LOG SPIRAL ARCHIMEDEAN

18. Z PARAMETERS

19. 3D GAIN OF RHCP
LOG SPIRAL
ARCHIMEDEAN
SINUOUS

20. 3D GAIN OF LHCP
LOG SPIRAL
ARCHIMEDEAN SINUOUS

21. 2D GAIN OF RHCP
LOG SPIRAL
ARCHIMEDEAN

22. SINUOUS SPIRAL

23. 2D GAIN IN LHCP
LOG SPIRAL
ARCHIMEDEAN

24. SINUOUS

25. Features of Conical Spiral Antenna
• Conical spiral antennas are true frequency
independent antennas Cover the required 6.5 : 1
frequency range
• Relatively constant beam characteristics
(beamwidth, polarization, ...)
• Usefully wide beamwidth while maintaining
other desirable properties
• Low ellipticity (axial ratio)
• Good polarization purity (wide band)
• Low mutual coupling in array

26. In additionto the aboveperformance
requirements,the antennawouldbe versatile
in the followingways:
• Inexpensive
• High power levels (100 W) as sensor
• CW and Pulse Applications
• Use in confined spaces
• Provides Circular Polarization

27. Antenna characteristics with
frequency
• Nearly constant beam pattern
• Low back-lobe at all but lowest frequency
• Relatively small, smooth impedance variation
• Good axial ratio maintained
• Spiral features
1. Low mutual coupling
2. Polarisation purity
3. Good isolation

28. Applications
• Measurement of electromagnetic (EM)
Shielding Effectiveness in confined spaces.
• As facility-embedded EM sensors for
receive antennas.
• Wideband communications.
• Monitoring of the frequency spectrum.

29. Applications(contd.)
• A pair of spiral antennas are used in this
application, having identical parameters
except the polarization, which is opposite
(one is right-hand, the other left-hand
oriented).
• Spiral antennas are useful for microwave
direction-finding.

30. CONCLUSION :
The main goal is to UWB conical log spiral antenna is to
transmit data at very high data rates by sending pulses of
energy rather than using a narrow band frequency
carrier.
The main objective was to get information of the near-
and far-field characteristics and on the input impedance
for a wide range of parameters is presented in a form
suitable for use in the design of practical antennas.