This document describes a circularly polarized fractal antenna with an arc-slot geometry. It discusses how fractal antennas can provide multiband or wideband operation to meet modern wireless communication needs. The design procedure is outlined, beginning with a basic circular patch that is divided into quadrants and bisected at angles, with arc slots added using a generator at progressively smaller scales to create the fractal pattern over iterations. Experimental results showed the antenna achieved left-hand circular polarization with a 3dB axial ratio bandwidth of 7.9MHz and return loss bandwidth of 38MHz, matching simulated results. Potential applications include mobile communications, GPS, and military networks.

1. Circular Polarized Fractal Antenna
PRESENTED BY:-
TILAK PATEL (140013111009)
GUIDED BY:-
DR. P. R. PRAJAPATI

2. Introduction
 CIRCULARLY POLARIZED (CP) ANTENNAS ARE A TYPE OF ANTENNA
HAVING CIRCULAR POLARIZATION CHARACTERISTICS. BECAUSE OF THE
ATTRACTIVE FEATURES OF CIRCULAR POLARIZATION
 CP ANTENNAS HAVE SEVERAL IMPORTANT ADVANTAGES COMPARED TO
LINEAR POLARIZED (LP) ANTENNAS.
 FRACTALS ARE CLASSIFIED INTO TWO CATEGORIES: MASS AND BOUNDARY
FRACTALS
 MASS AND FRACTALS HAVE BEEN USED FOR THE REALIZATION OF
MULTIBAND OR WIDEBAND OPERATION

3. Why there is need of fractal antenna??
 Today’s wireless and satellite communication and advance military
systems, required antennas of higher performance, higher gain, wider
bandwidth, multiband support, low cost and conventionally smaller design
dimensions. To fulfil all these requirements researchers looking for more
advanced antenna designs. One such field of advanced antenna design is
fractal antennas.

4. Fractal Boundary Generation Procedure
 The generation procedure of design of Arc-slot fractal antenna is
shown in fig 1
 Step:1 As per frequency of interest, calculate the radius of the circular
patch refer fig 1(a)
 Step:2 Select a generator, which is an arc (e × d), refer Fig.2(a).
 Step:3 Divide the given circular patch into four quadrants, and each
quadrant is bisected at an angle a = 45◦ and arc slot is created with the
help of generator, which results in iteration one fractal antenna as shown
in Fig. 1(b). The arc slot dimensions for generation of the proposed
antenna is demonstrated in Fig. 2(b) by taking only the first quadrant for
an easy understanding

5.  Step:4 Again choose Arc-slot size reduced by a scale of 50% to the
previous one at an angle of reduced scale of 50% to the previous angle, i.e.
we encounter two such locations in each quadrant to create slots
 Step:5 Repeat step 4 to generate iteration 3 as shown in Fig.1(d). Here, in
iteration 3 we encounter four locations in each quadrant to create slots

6. (a) Basic circular disc
microstrip antenna
(b) 1st iteration
(c) 2nd iteration (d) 3rd iteration
Fig. 1: Generation procedure of circular patch with Arc-slot
fractal geometry.

7. (a) Arc-slot fractal generator (b) Circular patch first quadrant
d
Fig.2 : Design geometry of circular patch arc-slot fractal geometry and its first quadrant demonstration in 3rd iteration, dimensions :
a = 45◦ , b = a/2, c = a/4, r = 40 mm, d = 6.05 mm, e = f = d/2, g = e/2, h = d/4, I = e/4.

8. EXPERIMENTAL RESULTS AND
DISCUSSIONS
 A laboratory prototype structure was fabricated to validate the simulated
results. The antenna was fitted with the standard 50Ω sub-miniature type-
A (SMA) connector having a center pin diameter of 1.2 mm.
 An anechoic chamber was used for measurement of the radiation
properties of the fabricated antenna.
 The measurement setup to measure return loss and radiation pattern are
shown in Figs. 3(a) and 3(b) respectively.

9. (a) (b)
Fig.3: Measurement setup (a) return loss measurement with VNA, (b) AR measurement in the
anechoic chamber.

10.  The simulated and return loss and AR characteristics and simulated 3D far
field radiation pattern are shown in Figs.4 and 5 respectively.
 The minimum AR of 1.17 dB is achieved at 1.7 GHz.
 the return loss bandwidth of 38 MHz (1.68 - 1.718 GHz) and 3-dB AR
bandwidth of 7.9 MHz, ranging from 1.696-1.7039 GHz is obtained

11. Fig. 4: Simulated S11 and AR of the proposed antenna.

12. Fig. 5: Farfield radiation pattern of the proposed antenna.

13.  The simulated and measured radiation patterns in the E and H-planes for
left hand circular polarization (LHCP) are drawn Fig. 6.
 The measured return loss and the AR characteristics is shown in Fig. 7.
 The AR is 1.71 dB at 1.66 GHz with a bandwidth of 13 MHz and the
impedance bandwidth is 40 MHz at center frequency 1.65 GHz obtained in
measurement.

14. Fig. 6: Simulated and the measured radiation pattern of the
proposed antenna at 1.7 GHz (Sim) and 1.657 GHz (Meas.)
frequency.

15. Fig. 7: Measured return loss and AR of the proposed antenna

16. Application
 Use in mobile communication
 Use in armature radio
 Use in military network
 Use in GPS System

17. CONCLUSION
 It is observed that the simulated and measured results are nearly
matching. The proposed antenna find applications in Mobile
communication networks, Global Position System (GPS), military network
systems like telemetry, and amateur radio, etc.

18. Reference
 IEEE Research Paper “Realization of Circular Polarized Microstrip Antenna
with Arc-Slot Fractal Geometry” By: (Dr. Pravin R. Prajapati.)

19. THANK YOU