COMM 603 Lecture 1

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UC (Dr. Hany Hammad) 1/24/20

OMM (603) Lecture #1

Radio Frequency Engineering

Associate Prof. Hany Hammad

Dr. Hany Hammad, German University in Cairo

Lecture #1 Contents

Introduction.

What is Radio Frequency Engineering?.

Course Contents.

Introduction to RF and microwave engineering.

Printed transmission lines.

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Introduction

Course Title:

Radio Frequency Engineering. (COMM 603)

Instructors:

Assoc. Prof. Dr. Hany Hammad.

Eng. Randa

Course Type:

Requirement for IETCommunications and Electronicsstudents.

Course Schedule:

1 lecture per week.

1 tutorial per week.


Course Contents Introduction to RF Technologies

Microwave Network Analysis

Transmission Lines

Power dividers and directional couplers

Impedance Matching and Tuning

Microwave Resonators

Lumped elements

RF Filters

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Communications System block diagram

DemodulatorBPF/IFAmp.

Demodulated

Signal-Information

(low frequency)

ModulatorModulating

Signal-Information

Transmitter

Transmission Medium(Communication Engineering)

Band PassFilter(BPF)

LOLocal

Oscillator

Up-

ConverterPowerAmplifier

Antenna

Band PassFilter(BPF)

LowNoiseAmp.

LOReceiver


Evolution of RF applications

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RF for Smart Homes

RFID System


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RFID System



RF Filters

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Dividers & Combiners


Couplers & Hybrids

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Microwave amplifier


Planar Transmission Lines

Microstrip.

Slot Line.

Coplanar waveguide.

Coplanar lines.

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Advantages of Using planar TLs

They are planar (A planar configuration implies that thecharacteristics of the element can be determined by the

dimensions in a single plane).

They can be fabricated by photolithographic and photoetching processes.

Easily integrated with other passive and active devices.


Type of planar transmission lines

Microstrip Line Parallel Strips Line

Slot LineCoplanar Waveguide

Coplanar Strips

Conductor

Dielectric

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Microstrip Transmission Lines

Conductor(Signal)

Conductor(ground)

Dielectric

(substrate)

H-Fields

E-Fields


H-Fields

E-Fields


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SubstrateThickness d

MicrostripThickness

Microstrip

Width

Substrate

DielectricConstant



Other configurations for microstrip TL

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1r

rr

effr

reff 1

eff

p

cv

effok

eff Is function of the dielectric constant, width W, and thickness (d)

Effective Dielectric constant (eff)


Formulas for Microstrip transmission lines

rr

r

A

A

BBB

e

e

d

W

61.039.0)1ln(

2

1)12ln(1

2

2

8

2

2

d

W

2d

W

rr

rroZA

11.023.0

1

1

2

1

60 roZB

2

377

Given

W

Zo,r & d

Find

W

d

rreeff

121

1

2

1

2

1

444.1ln667.0393.1

120

4

8ln

60

d

W

d

W

d

W

W

d

Z

e

e

o

1d

W

1d

W

Given

W, d, r

Zo& eff

Find

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Example

Calculate the width and length of a microstrip line for a 50

characteristic impedance and a 90ophase shift at 2.5 GHz. The

substrate thickness is d=0.127 cm, with r=2.20.

1591.1)2.2(

11.023.0

1)2.2(

1)2.2(

2

1)2.2(

60

)50(

A 985.7

)2.2()50(2

377

B

Answer

051.3

126.3

d

W 2

2cmd 127.0 cmW 387.0

87.1)328.0(121

1

2

12.2

2

12.2

e

2103

105.2287.1

2

8

9

l

lklclvloee

cmml 19.20219.0


Losses in Microstrip Lines

Two types of losses:

Dielectric losses.

Conductor losses.

Np/mk

re

erod

)1(2

tan)1(

Np/mWZ

Ro

sc

2

o

sR Surface resistivity

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Conductivities of Some Materials


Dielectric constants & loss tangents of some materials

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Losses in Microstrip Lines


Dielectric constants & loss tangents of some materials

Commercial Materials come in standard dielectric constantsand thicknesses.

For example:

RogersCorporation provide RT/Duroids.

(http://www.rogerscorporation.com/).

CoorsTechnology (http://www.coorstek.com/)
http://www.rogerscorporation.com/http://www.coorstek.com/http://www.coorstek.com/http://www.coorstek.com/http://www.coorstek.com/http://www.coorstek.com/http://www.coorstek.com/http://www.coorstek.com/http://www.coorstek.com/http://www.rogerscorporation.com/

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Power Handling Capability

Power handling capability of a microstrip is limited by:

Heating caused because of Ohmic and dielectric losses

Limits the average power of the microstrip line.

Dielectric breakdown.

Limits the peak power.

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COMM 603 Lecture 1

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