DESIGN OF MICROSTRIP PATCH ANTENNA FOR IEEE 802.16-2004 APPLICATIONS EHAB ESAM DAWOOD Department Of Electronic Faculty of Electronics Engineering University of Mosul Contact me: [email protected]
Jul 18, 2015
DESIGN OF MICROSTRIP PATCH
ANTENNA FOR IEEE 802.16-2004 APPLICATIONS
EHAB ESAM DAWOOD
Department Of Electronic
Faculty of Electronics Engineering
University of Mosul
Contact me:[email protected]
The IEEE 802 LAN/MAN Standards Committee develops Local Area Network standards and Metropolitan Area Network standards.
The most widely used standards are for the Ethernet family, Token Ring, Wireless LAN, Wireless PAN, Wireless MAN, Bridging and Virtual Bridged LANs. An individual Working Group provides the focus for each area.
The number 802 was simply the next free number IEEE could assign, though “802” is sometimes associated with the date the first meeting was held in February 1980.
IEEE 802
IEEE 802.16 version
IEEE 802.16 version
wireless communication means to transfer information overlong or short distance without using any wires
An antenna is defined a usually metallic device (as a rodor wire) for radiating or receiving radio waves.
the antenna is the transitional structure between free-space and a guiding device
it is used to transport electromagnetic energy from thetransmitting source to the antenna or from the antenna tothe receiver, the antenna can be in a form of microstrip.
INTRODUCTION
Microstrip: is a type of electrical transmission line which can befabricated using printed circuit board used to convey microwavefrequency signals.
Microstrip Patch Antennas (MPA): These antenna comprises ofplanar layers including a radiating element, an intermediate dielectriclaye r, and a ground plane layer.
Microstrip antenna
INTRODUCTION
6
The radiating element may be square, rectangular,triangular, or circular and is separated from theground plane layer
Representative shapes of microstrip patch elements
INTRODUCTION
TERM MEANING??
Surface waves are guided waves captured within the substrate and partially radiated and reflected back at the substrate edges.
The ground plane of a printed antenna is always is finite in size, surface waves propagates until they reach an edge or corner.
The diffracted waves take up apart of energy of the signal thus decreasing the desired signal amplitude and contributing to deterioration in the antenna efficiency as well as increasing both side lobe and cross polarization
Surface Waves
The material of Printed Circuit Board (PCB) used in mydesign is FR4 utilize as substrate.
where "FR" means Flame Retardant, and Type "4" indicateswoven glass reinforced epoxy resin.
Dielectric constant typically in the range (4.3-5.2),depends on glass resin ratio.
popular material and cost effective compared with otherPCB material that make this PCB is preferred.
FR4 Substrate Material
The main drawback of microstrip patch antenna is suffer from narrow BandWidth. Antenna BandWidth (BW) can be improved by increasing the substrate thickness. The thickness of substrate increases surface waves, surface waves pass through the substrate and scattered at bends of the radiating patch which caused degrade the antenna performance.
To overcome this problem, the technique of air-gap that represents substrate layer which has the dielectric constant is 1, by using air substrate, the surface waves is not excited easily.
Problem Statements:
surface waves
0
To increase the efficiency of the microstrip patch antennaby decreasing the loss of the reflection, it is executed byusing air-gap as a substrate in microstrip patch antenna.
To reduce the cost in the fabrication of the antenna byusing the cheap and popular FR4 material. The resonantfrequency can adjusted without requiring new design by justvarying the height of the air-gap also as well as the FR4material this made the fabrications very cost effective.
Project Objectives:
1
To improve the BandWidth (BW) by increasing the thickness of dielectric substrate and dielectric constant with lower value.
To reduce the energy loss due to surface wave, the surface waves consume apart of energy of the signal thus decreasing the desired signal amplitude and contributing to deterioration in the antenna efficiency that weaken the microstrip antenna’s performance.
Project Objectives:
2
Use the resonant frequency 3.5 GHz for WiMax application, theresonant frequency is chosen from IEEE 802.16-2004 span of 2-11GHz.
Choose the air as dielectric substrates that have the value of dielectricconstant 1 in order to reduce the surface wave excisions.
Use the transmission Line model for calculation of patch Dimension. It’s the simplest of all and gives good physical insight.
Simulate and Verify antenna design performance by applying Computer Simulation Technology Software (CST) to design MPA.
Use AutoCAD software to open the DXF file that exported from CST software simulation.
Project Scopes:
FEEDING METHOD
Microstrip Line Feed : A conducting strip directly connected to the patch which is smaller in dimension as compare to patch. It is very easy to fabricate, very simple in modeling and match with characteristic impedance 50Ω or 75Ω. This type of feeding was not successful when using with air-gap substrate.
Coaxial Feed: Feed the inner conductor of coaxial extends through the dielectric and is soldered to the radiating patch, while the outer conductor is connected to ground plane, it is easy to fabricate and match. It has low spurious radiation, and it has narrow bandwidth.
Coaxial FeedMicrostrip Line Feed
Feeding method:
Aperture Coupled Feed: is more complex and more difficult to fabricateas compare to others, High dielectric material is used for bottom substrate andthick and low dielectric constant material for the top substrate .
Proximity coupled Feed: Its fabrication is not easy as compare to otherfeed techniques, the advantage is eliminates spurious radiation and provides highbandwidth (as high as 13%), due to overall increase in the thickness of themicrostrip patch antenna.
Proximity coupled FeedAperture Coupled Feed
Feeding method:
MICROSTRIP PATCH ANTENNA
DESIGN
Resonant frequency: The Resonant frequency was used in MPA for IEEE802.16-2004 is 3.5 GHz, and take the span (3 - 4) GHz used in reflection loss and BW calculations.
Dielectric Substrate: FR4 PCB material is used as a substrate. Reflection loss and BW are calculated when using singleFR4 PCB. Subsequently, air is used as the substrate between two PCB FR4 substrates that improves the BW as well as reduce the loss of the reflection. These are compared with the data when using singleFR4 PCB.
Thickness of Substrate: The thickness of Air substrate was designed and fabricated by using 2mm spacer, the thickness of the FR4 substrate is 1.6mm.
Many factors were determined before begin the design
FR4 Substrate Dimension:
λ » λ = 85.71 mm,
The width and the length of substrate is λ/2,
FR4 substrate dimensions:
SIDE VIEW
TOP VIEW
The effective dielectric constant is a function of a frequency.
Effective Patch Width (W)
Frings factor (ΔL)
Transmission line model formula:
Effective length (Leff):
Length:
The patch is actually a bit larger electrically than its physicaldimensions due to the fringing fields and the difference betweenelectrical and physical size is mainly dependent on the PC boardthickness and dielectric constant of the substrate.
Transmission line model formula(continued) :
The design and fabrication process
included two case
SECOND CASEAir-gap TECHNIQUE
First CaseSINGLE FR4 Board
1 2
First CaseSINGLE FR4 Board Using As Substrate
Material
Effective Dielectric Constant (εreff) is
W=26.33 mm
= 3.90
First Case (Single PCB-FR4 Only) as Substrate Material:
Calculations for Patch Antenna Dimension:
Width of the Patch (W) is
resonant frequency f° =3.5 GHz, dielectric constant for FR4 substrate isεr= 4.3, height of substrate for Fr4 PCB is h=1.6 is the principleparameters must be decided.
ΔL = 0.74 mm
L = 20.22 mm
Length of the patch is:
Fringing Field Length Extension (ΔL) is:
Length of the patch is:
(13.16, 3.41) mmLocation of the feed
Design location of the coax line feed
x
SECOND CASEAir-gap
TECHNIQUE
By using the same formula for case 1, and substitute f° =3.5 GHz, εr = 1, Air h= 2mm Will get
W=42 mm
ΔL = 1.41mm L =40 mm
Second Case (Air-gap with two PCB-FR4) as Substrate Material
W=42 mm
ΔL = 1.41mm
Edge Impedance = 120.11Position of the feed (21, 8.93)
Second Case (Air-gap with two PCB-FR4) as Substrate Material
Design structure&
Simulation Resultwith
Single patch antennaUsing
CST Software
The ground plane is made of copper have thickness 0.07 for the patch
Structure of Design single patch antenna
Design, Simulation, Fabrication and Measurement Result
61
Structure design simulation of single FR4 board
Structure design of Single patch antenna using CST software
(Operating frequency and S11) Simulation of single patch antenna
S11 for single Patch Antenna Without air-gap
1D Results:
At resonant frequency 3.5 GHz is exhibit S11 equal (-10.38 dB) simulated by CST, the BandWidth (BW), the simulated BW is exhibit 36 MHz that become clear when using FR4 only without Air-gap have narrow BW.
Bandwidth Simulation of single patch antenna
Bandwidth Simulation of Single Patch Antenna without air-gap
The plot displays some important properties of the coaxial mode such as TEM mode type, line impedance.
Input impedance simulation with single patch antenna
2D Results:
Design, Simulation, Fabrication and Measurement Result
Design structure&
Simulation Resultwith
Air-gap TechniqueUsing
CST Software
The ground plane is made of copper have thickness 0.07 for the patch
Structure Design with Air-gap technique
Design, Simulation, Fabrication and Measurement Result
2
Structure design simulation with air-gap technique
Structure design of Single patch antenna using CST software
(Operating frequency and S11) Simulation with air-gap technique
2D Results:
Simulation Result for Patch Antenna with Air-gap
At resonant frequency 3.499 GHz is display S11 equal (-42.87 dB) simulated by CST, The BW that getting by using Air-gap that have value is 96 MHz
Bandwidth Simulation with air-gap technique
Bandwidth Simulation with air-gap technique
Input Impedance simulation with air-gap technique
2D Results:
Design, Fabrication, Measurement and Result
Fabrication Measurement
MPA with air-gap technique
MPA With air-gap Technique
81
S11 Measurement
Reflection Loss of Fabrication 7
Resonant frequency 3.5 GHz is exhibit reflection loss (-27.650 dB) measured by VNA. The BW for MPA with Air-gap fabrication is (158 MHz), calculation is achieved by subtract the value 3.589 GHz of M3 from M2 that have value 3.431GHz.
measured microstrip patch antenna with air-gap results
Measurement
Parameter Measured MPA Results
Resonant Frequency (fo GHz) 3.5 GHz
Reflection loss (S11 dB) -27.650 dB
Input Impedance, (Zin ohm) 54.270 ohm
BandWidth (BW MHz) 158 MHz
Smith Chart
Smith chart
Smith Chart display the resonant frequency 3.5 GHz and it exhibit impedance matching is 54.270 ohm which is actually closer to the 50ohm.
The Smith Chart Parameter
Smith chart parameter
The parameter
measurement
Resonant Frequency
(M 1)
Frequency measured 3.5 GHz
Input Impedance measured 54.27 ohm
Analysis Result
Compare between Measurement and Simulations with Air-gap and without air-gap
Analysis Result1 3
Exel
Comparison between the Simulated Result of the MPA without Air-gap and simulated as well as measured results of MPA with Air-gap
Comparison Table of Simulated and Measured Results:
Parameter
Microstrip Patch
Antenna without
Air-gap
Microstrip Patch Antenna with
Air-gap
Simulated Simulated Measured
Resonant Frequency (fo GHz) 3.5 3.5 3.5
Reflection loss (S11 dB) -10.38 -42.87 -27.650
Input Impedance (Zin ohm) 46.16 45.63 54.270
BandWidth (BW MHz)36
(1.02 %)
96
(2.74 %)
158
(4.51 %)
3
Fabrication process
Fabrications process
Flow chart for fabrication process
Fabrications process
Dry film printed
Fixing dry film on PCB
1
2
UV exposure process
3
4
The FR4 PCB after exposed
to UV light
5
UV exposure machine
Removing the
transparent layer
Developing process
7
6Developing machine
FR4 after developing
process
Etching process
8
9 10
Etching machine
Etching process
11
Ground
Front Face
Stripping process
12
13
Stripping machine
The FR4 board after
stripping process
Dry Process
14
15
The FR4 board after
stripping and Dry process
Dry machine
PCB Cutter Machine
16
17
PCB Cutter machine
18
The FR4 board after
stripping and dry process
Drilling Machine
19
20
PCB Cutter machine
21
Make hole for location of probe
The spacer between two FR4 boards is cylinder wood material; the diameter for the standing is 6mm.
Spacer between the Substrate Layers
Spacer
FR4 Substrate Material: The joining between the Fr4 substrate layers with spacing is doing by
SUPA GLUE implement at 10 seconds.
Supa Glue
Stick
Technique design with air-gap, use two FR4 PCB substrate each layer have thickness is 1.6mm, the first board is consist of FR4 substrate have radiating patch but it strip from ground plane, the second board is consist of radiating patch and ground plane separated by FR4 substrate, the separation between two layers is air-gap.
FR4 Substrate with Air gap Separation
MPA with Air-gap technique
CST Simulations
CST Microwave Studio: Computer Simulation Technology (CST) develops and markets
software tools for the numerical simulation of electromagnetic fields. CST was founded in 1992 in Darmstadt, Germany.
Select Template Create a new CST microwave studio project after open CST design
environment.
CST Microwave Studio
CST Microwave Studio:
Antenna Template
CST Microwave Studio
CST Microwave Studio:
Draw the Substrate Brick
Creation Brick
CST Microwave Studio
CST Microwave Studio: continue with the same thing by drawing the air-gap and second layer for
substrate-2, but only change the material in air-gap substrate to air from material library list
The Air-gap with Two Layers Substrate
CST Microwave Studio
CST Microwave Studio: Draw the ground plane, this perform by choose the pick face and clicking
to the surface of substrate FR4-2 and pick to the surface of substrate
CST Microwave Studio
CST Microwave Studio: By using extrude tool to create the ground plane for the second layer of
FR4 substrate.
Ground PlaneExtrude
Face
CST Microwave Studio
Ground PlaneExtrude
Face
CST Microwave Studio
CST Microwave Studio: Construct the dual patch first is stacked patch antenna and the second
is the probe fed patch,
stacked patch antenna probe fed patch antenna
CST Microwave Studio
CST Microwave Studio:
Model the Coaxial Feed
Outer InnerFeed Feed
,
CST Microwave Studio
CST Microwave Studio:
Common Solver Setting: Define Waveguide Port
Wave guide port consist of add the excitation port
Solve →Waveguide Ports
Waveguide Port Excite Port
CST Microwave Studio
CST Microwave Studio:
Define the Frequency Range and Boundary Conditions
+
Frequency Range Boundary Conditions
CST Microwave Studio
CST Microwave Studio:
Define Farfield Monitor
Farfield Monitor
CST Microwave Studio
Network Analyzer
Network analyzer 4
The VNA device is divided into two parts, the first isscreen and the second is control button. The screenis used for display the graph, this graph representthe S11and BW that will be measured and analysed.The control button consists of seven sectionsarranged from top to bottom and from left to right is(TRACE, NAVIGATION, CHANNEL, SUPPORT,DISPLAY, DATA ENTRY, SYSTEM). The start ofthe frequency range and the stop span on VNAdevice, its accomplished by selecting CHANNELsection from control button. Then, checking theresonant frequency and it was 3.5 GHz, and thespan 1 GHz.
Network analyzer
4
Calibration of VNA
Calibration of VNA
MPA connect with VNA 41
MPA with Air-gap Measurement 7
Related Slide
Air gap technique
0
VNA 4
Improvement of bandwidth 2
Single patch antenna simulation Air–gap technique simulation
Coax line feed
Coax line feed location
x