This document summarizes a project studying the parameters of a probe feed microstrip antenna with an operating frequency of 2.4GHz. A group of 3 students designed the antenna in HFSS with a rectangular patch on a dielectric substrate with a ground plane. They calculated the patch dimensions and studied how changing the length and width affected the resonance frequency. Their results showed that increasing the length or width decreased the resonance frequency as both dimensions are inversely related to frequency. The antenna could be used for applications such as wireless LANs, GPS, and RFID.

1. ANTENNA THEORY AND DESIGN(ET323)
PROJECT TITLE:-
PROBE FEED MICROSTRIP ANTENNA’S PARAMETER
STUDY HAVING FREQUENCY 2.4GHZ.
GROUP MEMBERS:-
ABHISHEK SAINKAR (TETB104)
AKASH NIMBALKAR (TETB106)
NITESH MANDAL (TETB108)

2. MICROSTRIP ANTENNA
 In its most basic form, a Microstrip patch antenna consists of a radiating patch on one side of a
dielectric substrate which has a ground plane on the other side Structure of a Microstrip Patch
Antenna
 For good antenna performance, a thick dielectric substrate having a low dielectric constant is
desirable since this provides better efficiency, larger bandwidth and better radiation .
 In general Micro strip antennas are also known as “ PRINTED ANTENNAS ”.
 These are mostly used at microwave frequencies.
 Because the size of the antenna is directly tied the wavelength at the resonant frequency
 Micro strip antennas are easy to fabricate and comfortable on curved surface
 Micro strip patch antennas patches are in variety of shapes , such as rectangular , square ,
triangular and circulator

3. ADVANTAGE OF PROBE FEED OVER OTHERS
Feed can be placed at any desired location inside the patch in order to
match with its input impedance.
It does not lead to cross polar polarization like other feeding technique
Matching impedance can be easily found in these technique
Easy to design.
Less complexity
High bandwidth.

4. Design Parameter for Calculation
Step 1: Calculation of the
Width (W) -
Step 2: Calculation of the Effective Dielectric Constant. This
is based on the height, dielectric constant of the dielectric and
the calculated width of the patch antenna.
Step 3: Calculation of the Effective length
Step 4: Calculation of the length extension ΔL
Step 5: Calculation of actual length of the patch
Where the following parameters are used
f0 is the Resonance Frequency
W is the Width of the Patch
L is the Length of the Patch
h is the thickness
εr is the relative Permittivity of the dielectric substrate
c is the Speed of light: 3 x 108

5. Antenna dimensions and operating frequency
Dimension of Ground ,Substrate and Patch:
Substrate RT Duroid : height =1.6 mm
Dielectric Constant : εr=2.2
Fr= 2.4 GHz
Width of patch (Wp): 50mm
Length of patch(Lp) : 42 mm

6. Length and width of substrate
Ws= Wp + 6h
Ws= 60 mm
Ls= Lp + 6h
Ls= 52 mm
Location of Feed point
X= 15 mm
Y= 12 mm

7. HFSS design

8. Results
For F=2.4 GHz
S11 and Return Loss

9. Radiation Pattern 2DBW calculation

10. VSWR
Gain 3D polar

11. Antenna Parameters

12. Parametric study
a) Varying L and W more than original value and observe
b)Varying L and W less than original value and observe

13. Results (L greater than calculated value)
S11 plot
 (observation: as the length and frequency are inversely proportional hence
the resonance frequency decreases)

14. Results L less than calculated value)
S11 plot
 (observation: as the length and frequency are inversely proportional hence
the resonance frequency increases)

15. Results (W greater than calculated value)
S11 plot
 (observation: as the Width and frequency are inversely proptional hence the
resonance frequency decreases)

16. Results (W less than calculated value)
S11 plot
 (observation: as the width and frequency are inversely proptional hence the
resonance frequency increases)

17.  Used in mobile satellite communication system.
 Direct broad cast television(DBS).
 Wire less LAN’S.
 Feed elements in coaxial system.
 GPS system.
 Radio Frequency Identification.(RFID)
 Missiles and telemetry.
 UHF Patch Antennas for Space

18. References
1] http://www.antenna-theory.com/antennas/patches/patch3.php
2] EM-TALK Patch and Line Calculator
3] http://www.ece.uprm.edu/~rafaelr/inel6068/HFSS/GSG_HFSS_Probe_Feed_Patch_Antenna.pdf
4] http://eem.eskisehir.edu.tr/cozzaim/EEM%20413/icerik/patch_coax_fed.pdf
5] https://www.researchgate.net/publication/321718725_Design_and_Performance_Analysis_of_Coaxial_Probe-
fed_Rectangular_Microstrip_Patch_Antenna_RMPA_for_IEEE_80211p_Standard_IUBAT_Review_A_Multidiscip
linary_Academic_Journal