Antenna and Radiation

8/10/2019 Antenna and Radiation

1/20

ECNG 6706 - Antennas and RadiationIntroduction

Sean Rocke

September 8

th

, 2014

ECNG 6706 - Antennas and Radiation 1 / 20
http://find/


2/20

Outline

1 Course Introduction

2

Dig Comms Overview

3 Course Tools

4 Conclusion

http://find/


3/20

Course Introduction

Course Administration

Lets take a look at the CourseOutline...

http://find/


4/20

Dig Comms Overview

Elements of a Digital Communications System

Lets take a look at the CommsProgramme Overview...

http://find/


5/20

Dig Comms Overview

Communications Channels

Wireline Channels

Wireless Channels

Fiber-Optic Channels

Underwater Acoustic Channels

Storage Channels

THE BODY!!!!

http://find/


6/20

Dig Comms Overview

Mathematical Models for Communications Channels

1 Additive Noise Channelr(t) = s(t) +n(t)

2 Linear Time Invariant (LTI) Filter Channel

r(t) =s(t) c(t) +n(t) =

c()s(t )d+n(t)

3 Linear Time-Variant (LTV) Fiter Channelr(t) =s(t) c(; t) +n(t) =

c(; t)s(t )d+n(t)Mobile

cellular channel example

LTV filter -c(; t) =L

k=1 k(t)( k)

Received signal -r(t) =L

k=1 k(t)s(t k) +n(t)

http://find/


7/20

Course Tools

ECNG 6706 Tools

ECNG 6706 will leverage both analytical and computeraided tools foranalysis of digital communications systems:

Analytical Tools:

Mostly B.O.M.D.A.S.+ Trigonometry . . .Circuit Theory

Electromagnetic Field TheoryProbability & Random Process TheoryLinear Algebra (i.e., Vector & Matrix Algebra)Signals and Systems Analysis (e.g., Fourier, Laplace)

Computeraided Tools:

MATLAB & Simulink (Simscape, SimRF, RF Toolbox, CommsToolbox,. . . )COMSOLSpreadsheets (seriously!) . . . :-)


C T l
http://find/http://goback/


8/20

Course Tools

Module 1 - Math Primer

Polynomial approximations - Taylor & Maclaurins Series

Sum/product of sines/cosines

Complex envelope signal representation


C T l
http://find/


9/20

Course Tools

Polynomial Approximations

Many exist (e.g., Taylor, Maclaurin,. . . )

Taylor Series:

Function representation as aninfinite seriesbased on value of

functions derivativesat a single point

f(x) =

n=0f(n)(a)

n! (x a)n =f(a) + f

(a)1! (x a) +

f(a)2! (x a)

2 +

Only works under certain conditions!!!

Ifa= 0, Taylor series= Maclaurin series


Course Tools
http://find/


10/20

Course Tools


Example 1:

Using the Taylor series expansions ata=0, prove the following:

1 ex =1 +x+ x2

2! + x3

3! + x4

4! + x5

5! +

2 cos(x) =1 x2

2! + x4

4! x6

6! + x8

8!

3 sin(x) =x x3

3! + x5

5! x7

7! + x9

9!


Course Tools
http://find/


11/20

Course Tools


Figure:sin(x) and its Taylor series approximations, up to order 13. Source:Wikipedia.

Question:

So whats the point of the Taylor series for thiscourse?!?!


Course Tools
http://find/


12/20

Course Tools

Sum/product of sines/cosines

Product Sum:cos(A)cos(B) = cos(AB)+cos(A+B)

2

sin(A)sin(B) = cos(AB)cos(A+B)2

sin(A)cos(B) = sin(A+B)+sin(AB)2

cos(A)sin(B) =

sin(A+B)sin(AB)

2Sum Product:

sin(A) sin(B) =2sinAB

2

cos

AB

2

cos(A) +cos(B) =2cosA+B

2

cos

AB

2

cos(A) cos(B) = 2sinA+B

2

sin

AB

2

Shifts:sin(A+

2) =cos(A)

cos(A+ 2) = sin(A)


Course Tools
http://find/


13/20

Course Tools

Complex Envelope

Baseband SignalSignal with frequency content only in the vicinity of DC (i.e., 0Hz)Complex envelope: x(t) =xI(t) +jxQ(t)xI(t)- In-phase component, xQ(t)- Quadrature component

Bandpass SignalSignal with frequency content not in the vicinity of DCx(t) = R[x(t)ejct]

c=2fc- Carrier frequency

Figure:Baseband vs Bandpass Spectrum. Based upon: Kolumban et al

(2012).ECNG 6706 - Antennas and Radiation 13 / 20

Course Tools
http://find/


14/20

Course Tools

Complex Envelope

Figure:Baseband Bandpass Conversion. Based upon: Kolumban et al(2012).


Course Tools
http://find/


15/20

Receiver Architecture Examples

Figure:Receiver Architecture Examples. Basedupon:Cruzetal(2010).


Course Tools
http://find/


16/20

Transmitter Architecture Examples

Figure:Receiver Architecture Examples. Based upon: Cruz et al (2010).


Course Tools
http://find/


17/20

Transceiver IC Examples

Figure:Analog Devices FMCOMMS 4 1x1 Agile RF Transceiver. Source:Analog.com.


Course Tools
http://find/


18/20

KEy Concepts Review

Baseband upconversion to bandpass can be achieved via

modulation, requiring a mixer circuitBandpass downconversion to baseband can be achieved via

demodulation, requiring a mixer circuit

Mixing can be achieved using devices with nonlinear VI

characteristics (e.g., diodes, transistors)Nonlinear characteristics produce mixing effect as seen from

Taylor series expansion of some nonlinear functions

Mixing produces output frequencies that are the sum and

difference of the input frequencies (and possible harmonics)

Filtering removes unwanted frequencies and harmonics

Many transceiver architectures exist with different strengths and

weaknesses, allowing for some choice in transceiver design for

the various communications channel types


Conclusion
http://find/


19/20

Conclusion

We covered:

Course Overview

Dig Comms Systems Overview

Course Tools

Your goals for next class:

Install and familiarize yourself with MATLAB

Review readings on Radio Architectures in prep for next class


Q & A
http://find/


20/20

Thank You

Questions????

http://find/

Antenna and Radiation

Documents