FINAL REPORT FOR ENGINEERING 485L

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2 Νοε 2013 (πριν από 3 χρόνια και 11 μήνες)

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1






FINAL REPORT FOR ENGINEERING 485L

















Design Project: Reconfigurable Micro
-
strip Antenna











12/
7
/11











Gabriel Lee


Jesse A. Palao

2



Table of Contents


i.

Abstract









P.

3

ii.

Function (purpose of project)







P.

4

iii.

Specifications









P.

5

iv.

Diagrams









P.

8

v.

Programming Codes








P.

12

vi.

Cost










P.

14

vii.

Time Table (timeframe of tasks done)





P.

15

viii.

Estimate Life Cycle








P.

16

ix.

Customers









P.

17

x.

Impact (environmental, social, economic, ethnic and

safety)



P.

18

xi.

Matlab Comparison Results







P. 19

xii.

Conclusion









P.

21

xiii.

Bibliography

and Appendix







P.

22










3



ABSTRACT

The following proposed project presents the design of a frequency reconfigurable micro
-
strip
antenna. The micro
-
strip
antenna will be composed of three layers: the patch, a substrate which
is a Rogers RT/duroid 5880 with a dielectric constant of 2.2, and an infinite ground plane. They
will be placed, respectively, from top to bottom. The reconfiguration will be done by us
ing a
stepper motor which will give the rotation for the antenna patch in order to obtain the three
frequencies initially proposed in this project. The patch that is going to be used will be made out
of copper. A ring
-
shaped form composed of four different

shapes will be used for the rotating
part of the antenna. The antenna will transmit different frequencies depending on the
configuration and the rotation. A simulation will be done first in order to confirm the ring
-
shaped
form as well as to confirm the s
pecific frequencies to be obtained. The target frequencies for the
proposed proje
ct are from 2
-
10 GHz.

































4


FUNCTION

The purpose of this project is to simulate and design a reconfigurable micro
-
strip antenna.

The
antenna’s configurations will transmit different frequencies, as mentioned in the

Abstract. In
order to make the configurations possible without the use of manual labor, an Arduino Uno
microcontroller was used along with a stepper motor to perform the

rotation. The rotation will be
set at 90 degrees for each configuration by the microcontroller
, up to 270 degrees and rotate back
to its original position
. The momentary switch controls the rotation by pressing it once. The
stepper motor will be attached
underneath the rotating part of the antenna to do the
configurations in order to obtain the desired frequencies.






































5


SPECIFICATIONS

The following
list below lists all items

that were used during the simulation and the design
process of the reconfigurable micro
-
strip antenna:




Arduino Uno microcontroller





Microcontroller

ATmega328

Operating Voltage

5V

Input Voltage (recommended)

7
-
12V

Input Voltage (limits)

6
-
20V

Digital I/O Pins

14 (of which 6 provide PWM output)

Analog Input Pins

6

DC Current per I/O Pin

40 mA

DC Current for 3.3V Pin

50 mA

Flash Memory

32 KB (ATmega328) of which 0.5 KB used by bootloader

SRAM

2 KB (ATmega328)

EEPROM

1 KB (ATmega328)

Clock
Speed

16 MHz








6




Bipolar
Stepper Motor





Size

35 mm square x 26 mm, not including the shaft

Weight

130 g (4.5 oz)

Shaft diameter

5 mm

Steps per revolution

200

Current rating

280 mA per coil

Voltage rating

7.4 V

Resistance

26 Ohm per coil

Holding torque

650 g
-
cm (9 oz
-
in)

Inductance

19.2 mH per coil

Lead length

12 in

















7




Stepper Motor
Driver








Ansoft HFSS v. 13.0



Momentary Switch



Capacitors



Resistors



Reconfigurable m
icro
-
strip antenna prototype

model












8


DIAGRAMS

Wiring Diagram





9


Circuit Diagram























10


Pictures





11












12


PROGRAMMING CODES

The following code is used for the Arduino Uno microcontroller
, which controls

the stepper
motor’s rotation
. One

moment
ary switch is used to
control the rotation by 90 degrees in
increments.


#define DIR_PIN 2

#define STEP_PIN 3


const int buttonPin = 4; // the number of the pushbutton pin

const int ledPin = 2; // the number of the LED pin



// Variables will change:


int ledState

= HIGH; // the current state of the output pin


int buttonState; // the current reading from the input pin


int lastButtonState = LOW; // the previous reading from the input pin


int c = 0; // counter starts at 0



// the following variables are long's because the time, measured in miliseconds,

// will quickly become a bigger number than can be stored in an int.


long lastDebounceTime = 0; // the last time the output pin was toggled


long debounceDelay = 50; // t
he debounce time; increase if the output flickers



void setup() {


pinMode(buttonPin, INPUT);


pinMode(ledPin, OUTPUT);


pinMode(DIR_PIN, OUTPUT);


pinMode(STEP_PIN, OUTPUT);

}



void loop() {


// read the state of the switch into a local variab
le:


int reading = digitalRead(buttonPin);




// check to see if you just pressed the button


// (i.e. the input went from LOW to HIGH), and you've waited


// long enough since the last press to ignore any noise:




// If the switch changed, due to noise or pressing:


if (reading != lastButtonState) {


if (c < 3){


rotateDeg(
-
90, 0.1);


// reset the debouncing timer


lastDebounceTime = millis();


c = c + 1;


if ((millis()
-

lastDeb
ounceTime) > debounceDelay) {


// whatever the reading is at, it's been there for longer

13



// than the debounce delay, so take it as the actual current state:


lastButtonState = reading;


}


}




else{


rotateDeg(2
70, 0.1);


// reset the debouncing timer


lastDebounceTime = millis();


c = 0;


if ((millis()
-

lastDebounceTime) > debounceDelay) {


// whatever the reading is at, it's been there for longer


// than the debounce del
ay, so take it as the actual current state:


buttonState = reading;


}


digitalWrite(ledPin, buttonState);


lastButtonState = reading;


}


}


}


void rotateDeg(float deg, float speed){


//rotate a specific number of degrees (
negitive for reverse movement)


//speed is any number from .01
-
> 1 with 1 being fastest
-

Slower is stronger


int dir = (deg > 0)? HIGH:LOW;


digitalWrite(DIR_PIN,dir);



int steps = abs(deg)*(1/0.225);


float usDelay = (1/speed) * 70;



for(int i=
0; i < steps; i++){


digitalWrite(STEP_PIN, HIGH);


delayMicroseconds(usDelay);



digitalWrite(STEP_PIN, LOW);


delayMicroseconds(usDelay);


}

}









14


COST

The following items list items

that were purchased
, which were required for the
project,

and how
much each item cost:


Arduino Board $
30

Stepper Motor Driver $18.51

Bipolar Stepper Motor $17.90

Proto
-
Board $23.65

9V Battery $0.50

Momentary Switch $0.67

10K Resistor $0.10




































15


TIME TABLE

The following
lists things/tasks that were accomplished since the start of the project along with
an estimated date that it was completed.



First sample
patch
antenna
simulation
using HFSS v. 13.0


Week of September 5
th



Dr. Costantine’s published antenna design using HF
SS v. 13.0


Week of

September 26
th



Debouncer Circuit built


Week of October 24
th




Finishing design simulation to obtain fabricated prototype


Week of November 7
th




Arduino Code obtained and completed


Week of November 28
th




Completed p
roto board
soldering of entire design


Week of

December 4
th







































16


ESTIMATED LIFE CYCLE

The following items listed, which were used for the overall project design, have a certain life
expectancy until it is no longer useable.



RT/duroid

5880



can be stored indefinitely at (65
-
85 degrees F
ahrenheit; 18
-
30 degrees
Celsiu
s) and at humidity levels.

If the ambient temperature is above or below the desired
ambient temperature, its lifetime is reduced.



Capacitor
-

depending on how it will be
used and

depending on

the temperatures to
consider from the capacitor and its surrounding ambience, the following equation is used
to calculate its lifetime:





















Where



is the load life rating,



is the max voltage rating,



is the initial voltage,



is
th
e maximum

temperature rating of a capacitor, and



is the ambient temperature. It has
been estimated that the lifetime of capacitors range between 20
-
40 years due to how often
it is used, heat dissipation and the a
mbience.



Resistor



the resistors used are mainly composed of carbon, and

the half
-
life of decay for
carbon has been confirmed to be about 5,730 years. The resistor’s life expectancy is
based on the amount of current and voltage being applied, heat dissipa
tion and how often
it is used.



Copper



without any form of corrosion

to consider from weather, ambience, etc. copper
can p
otentially
be usable for
more than 100 years.


























17


CUSTOMERS

There are many potential customers when it comes to
antennas and their useful applications. For
this particular antenna design and for the frequencies that were obtained, there can be some
potential customers who may be interested in this type of antenna

depending on the type of
application
t
he consumer is
looking for
.

For the 3.5
-
3.65 GHz band, applications within this
range include IEEE 802.16e applications, WiMAX, Mobile WiMAX, and SOFDM. For the 5.15
-
5.96GHz band, applications includes unlicensed European 5.4 GHz band applications, WiFi
systems, WiMAX te
chnology, IEEE 802.11a wireless LAN, Wireless video systems, and UNII
and ISM applications. Based on the frequencies for our design, potential customers will be
interested based on preference of applications. For the 4GHz band, frequency is reserved for
go
vernment authorities and military institutions, making them an additional potential customer
for their projects.



































18


IMPACT

The antenna design can make an impact based on each of the following:



Environmental Impact


If an
antenna is able to do many functions, then the more useful
it will be. An antenna can transmit and/or receive wireless signals over a certain area as
well as transmit and/or receive wireless signals from one distant area to the other.



Social Impact


Wireless and mobile communications will be much faster over the old
-
fashioned form of sending and receiving messages

by means of using paper
. This
includes text messages through cellular phones, sending messages by e
-
mail,
using
Wi
-
Fi
, and so on.



Economic
Impact


By optimizing a prototype design, the improved version of the design
will see a reduced cost in terms of reducing the dimensions, fewer components used,
improving the programming code, and better and smaller components.



Eth
ic
al

Impact


By making
astute and ethical decisions into what the antenna’s functions
should be, how big or small it should be and determining the cost of the antenna, then the
final product will be seen as very useful and practical.

For this design, the applications
that it has

are very useful and practical.



Safety Impact


The design is indeed very safe, with very minimal concerns. In
accordance with the wave length spectrum, with frequencies that are very small in terms
of going through material, one is unaffected by such pene
trating frequencies.




























19


MATLAB COMPARISON RESULTS



20






21


CONCLUSION

In conclusion, the design of the reconfigurable micro
-
strip patch antenna was indeed a
challenging process
in terms of the duration

of time
, the amount of

information that had to be

researched and learned
, overcoming many problems, and performing simulation for the antenna
with decent process which took about approximately an hour depending on how complicated the
antenna design. Due to being introduced to a

design project that was never learned before and
unable to take the class, one had to consider taking the easy route in terms of time. The Arduino
Uno microcontroller was considered easy to use for the programming aspect. The type of stepper
motor we used

in conjunction with the microcontroller ensu
red that it was not very difficult to
work with. Using HFSS was the most important ingredient in the design process since the
simulation helped in determining the type of antenna it was going to be as well as at
tempting to
obtain the target frequencies for the antenna. It required a large amount of time in terms of
figuring out how to optimize the design, figuring out how to obtain the target frequencies,
overcoming poor convergence, and so on. A lot of obstacles

surfaced very quickly and solutions
needed to be found. Overall, it was an overwhelming experience all on its own and very
rewarding when everything was completed.































22


BIBLIOGRAPHY AND APPENDIX

[1]

J. Costantine

“A Reconfigurable Multi
-
Band Microstrip Antenna based on open ended
microstrip lines.” Antenna and Propagation, 2009, EuCAP 2009, p 792
-
795, 2009
.

[2]

J. Costantine “A Frequency Reconfigurable Rotatable Microstrip Antenna Design”

Antennas
and Propagation Society International Symposium (APSURSI), 2010 IEEE, p. 1
-
4, 2010.

[3]

“Ansoft HFSS User Guide” p. 5.3
-
1


5.3
-
19, ANSYS, Inc. 2009.

[4]

“Handout on Microstrip Antennas” p. 722
-
752

[5]

Stepper Motor: Bipolar, 200 Steps/Rev, 35x26mm, 7.4V, 280mA

http://www.pololu.com/catalog/product/1207

[6] “Arduino

Uno”

http://arduino.cc/en/Main/ArduinoBoardUno

[7] “Easy Driver Stepper Motor Driver”
http://schmalzhaus.com/EasyDriver/

[8
] “Use the Easy Driver Stepper Motor Driver”
http://bildr.org/2011/06/easydriver/
, 2001