printed yagi uda antenna

Project Title: Design, SIMULATION &

FABRICATION OF PRINTED YAGI-UDA ANTENNA

BY: AMIT GUPTA &

BAKSHI HARSHPREET SINGHB -T E C H ( S E M E S T E R V I I )

B H A R AT I V I DYA P E E T H U N I V E R S I T Y,

C O L L E G E O F E N G I N E E R I N G , P U N E

EXTERNAL GUIDE

Mr EZHARUL ANSARISC. ‘C’, DLRLHYDERABAD

INTERNAL GUIDE

PROF. BRIG (RETD.) R.M. KHAIRE

Head, Dept. of E&TCB.V.U.C.O.E,

PUNE

Outline of Presentation Overview Specifications Approach Design and Analysis Simulation Study Fabrication Results Future Roadmap Conclusion

Overview Aim of the Project: The aim of the project is to design, carry out simulation study and fabricate a PRINTED YAGI UDA ANTENNA.

SpecificationsParameter Specifications

Frequency Range 4.0 GHz - 4.4 GHzGain 6 dB

Beamwidth Min 70o in both planesReturn loss Better than 10dBPolarization Linear

Connector type SMA Tab typePhysical Dimensions 50x70 (mm)

Weight < 100g

Approach Literature survey:

Antenna fundamentals Types of Antennas Antenna Parameters

Determination of Antenna Design Parameters Modeling Simulation Optimization Fabrication Testing

Design And Analysis

DirectorsTop Radiating element

Bottom Radiating

Ground Plane or Reflector

Substrate

Top

Bottom

Design and Analysis A Dipole, is chosen, as the radiating element to obtain Linear Polarization. Three directors and one reflecting element are used, to obtain the desired gain and return loss. Rogers RT Duroid 5880 substrate board having a dielectric constant 2.2 was used in our project. This is chosen because, lower the dielectric constant, more will be the propagation of the EM Waves through the substrate. Hence a low dielectric constant substrate is chosen. Its thickness is kept to be 0.8mm and the perfect electric conductors are Copper. The feed line used is a microstrip line having a thickness of 4.8 mm, which matches the input impedance of the antenna and the feed.

Design and Analysis Calculated (Theoretical Dimensions):

PARAMETERS FORMULA CALCULATED VALUES (in mm)

Distance between Reflector and Dipole

0.2λ-0.35 λ 14.2-24.85

Distance between the successive directors

0.2 λ -0.35 λ 14.2-24.85

Width of Dipole 0.015 λ -0.025 λ 1.06-1.7

Width of Directors 0.015 λ -0.025 λ 1.06-1.7

Length of Radiating element

0.45 λ -0.49 λ 31.95-34.79

Length of directors* 0.4 λ -0.45 λ 28.4-31.95

* The successive directors were reduced in size by 85%

Simulation Study

Perfect Electric Conductors

Simulation Study

Excitation (Waveport)

Simulation Study

Radiation Box

Parameter Optimization The Optimized Parameters are listed in the table given below:

PARAMETERS FORMULA CALCULATED VALUES (in mm)

Theoretical(in mm)

Optimized(in mm)

Distance between Reflector and Dipole

0.2λ-0.35 λ 9.4-16.45 10.55

Distance between the successive directors

0.2 λ -0.35 λ 9.4-16.45 D1-D2 = 9.60D2-D3 = 8.45

Width of Dipole 0.015 λ -0.025 λ 0.7-1.1 1.5Width of Directors 0.015 λ -0.025 λ 0.7-1.1 1.5Length of Radiating

element0.45 λ -0.49 λ 21.15-23.03 30.0530

Length of directors* 0.4 λ -0.45 λ 18.8-21.15 D1=23, D2=18.2, D3=15.6

Simulation ResultsParameter Specifications Result

Frequency Range 4-4.4GHz 3.9-4.4 GHz

Bandwidth 400 MHz 500 MHzReturn loss Less than 10dB Less than 10 dB

Gain 6 dB 6.9dBBeamwidth 70o 76o

Polarization Linear LinearPhysical Dimension 50mmX70mm (max) 48.6mmx66.4mm

Weight Less than 100g -

Simulation Results

GAIN/ RADIATION PATTERN

Gain = 6.9dB

-10.00

-5.00

0.00

5.00

90

60

30

0

-30

-60

-90

-120

-150

-180

150

120

HFSSDesign1Radiation Pattern 4 ANSOFT

Curve Info

dB(GainTotal)Setup1 : LastAdaptivedir='-5.412mm' dirl='26mm' Freq='4.2GHz' Phi='0deg'

dB(GainTotal)Setup1 : LastAdaptivedir='-5.412mm' dirl='26mm' Freq='4.2GHz' Phi='90deg'

Simulation ResultsReturn loss as obtained after the Simulation Study is shown below:

RETURN LOSS

-17.68 db3.90 4.00 4.10 4.20 4.30 4.40

Freq [GHz]

2.50

3.75

5.00

6.25

7.50

8.75

10.00

dB(V

SW

R(1

))

HFSSDesign1XY Plot 2 ANSOFT

Curve Info

dB(VSWR(1))Setup1 : Sw eepdir='-5.412mm' dirl='26mm'

Simulation Results The variation in Gain and Return loss of the Antenna by the successive addition of Directors is depicted below:

Elements Gain (dB) at 4.2 GHz Return Loss

Director 1 5.736 Resonant Freq: 4.3 GHz

Peak : -17.86 dB

Director 1 and 2 6.5118 Resonant Freq: 4.2 GHz

Peak : -18 dB

Director 1, 2 and 3 6.9056 Resonant Freq: 4.2 GHz

Peak : -18.74 dB

Results of Fabricated Antenna

Results of Fabricated Antenna

Results of Fabricated Antenna

Results of Fabricated AntennaFrequency

(GHz)

Gain

(dB)

Beamwidth in HP

(degree)

Beamwidth in VP

(degree)

4 4.22 69.39 120.74

4.1 5.99 67.24 116.58

4.2 6.18 65.33 111.35

4.3 6.14 65.85 107.15

4.4 6.74 66.66 100.11

4.5 7.36 65.75 94.40

4.6 6.56 63.19 92.01

Results of Fabricated Antenna A return loss of -43.954 dB is measured, which is resonant at a frequency of 4.39GHz. Its value is below the -10 dB mark in a bandwidth of 525 MHz over the range 4.1 GHz to 4.625 GHz.

Comparison between the specifications, simulated

and measured resultsParameter Specifications Results

Simulated Realized

Frequency Range 4-4.4GHz 3.9-4.4 GHz 4.1 GHz-4.6GHz

Bandwidth 400 MHz 500 MHz 525 MHz

Return loss Less than 10dB Less than 10 dB Less than 10 dB

Gain 6 dB 6.9dB 6.18 dB

Beamwidth 70o 76o 65 o

Polarization Linear Linear Linear

Physical Dimension 50mmX70mm (max) 48.6mmx66.4mm 48.6mmx66.4mm

Weight Less than 100g Less than 100g Less than 100g

Key InferencesThe total length of the dipole determines the frequency of operation of the antenna. The length and frequency are inversely proportional.The reflector size and spacing have negligible effect on the forward gain and large affects on the backward gain and input impedance. The size and spacing of the directors has a large effect on the forward gain, backward gain and input impedance.More than one reflector provides little improvement on the directivity of the antenna. The addition of more directors will increase the gain of the antenna, although after the addition of approximately 5 directors the advantages of adding more directors decreases significantly.

Future Roadmap The Antenna may be assembled and used for its intended applications, in defence or satellite communication, if the required Gain is 6-7 dB and Return loss is below 10 dB.

Conclusion The Yagi Uda antenna for the specified parameters is successfully modelled, simulated, and fabricated to obtain the aimed specifications.