Testing elements in a fast communication channel 100GB/s

Testing elements in a fast communication channel 100GB/s

Final PresentationSpring 2010

Developers: Hanna Alam and Yousef BadranProject supervised by: Yossi Hipsh

Technion - Israel Institute of Technology

Agenda Brief IntroductionProject GoalsTransmitter and Receiver SchematicDesigning the Microstrip LineLosses ConsiderationsTesting the Microstrip LineComponents and Suitable DevicesConclusions and next steps

Introduction

• The Fast evolving high-speed digital systems in today’s technology and in daily life

• Using tools and technologies which we currently possess in order to create a more advanced design

• A method for breaching the 100 GB/s barrier is through channels with lower frequencies

Goals

• The ability to transfer information in a single 100GB/s rate channel between two units located on the same printed board

• Designing and characterizing the microstrip line

• Suggest theoretical and practical way to test the microstrip line in terms of signal integrity and internal losses

General Schematic

Unit1– Transmitter’s side

Sharpening the signal Reducing

tr/tf

Reducing the bit time

to 10ps

Adding Different delay to

each channel

Buffer

Sigma: Adding all of the 4 narrow signals

25GB/s100GB/s

Unit1– Transmitter’s side

• Sharpening the signal to reduce rise and fall time:

• Problem : finding a suitable buffer • In lower frequencies we use step recovery diodes, in higher frequencies the issue requires further researching

Unit1– Transmitter’s side

• Reducing the bit time is achieved by a mixer and a power divider• Delay is required in order to achieve the desired result

• Also requires additional researching

Unit2– Receiver’s side

Equalizer Splitting into 4 channels

Filtering Data Buffers Monostable

100GB/s25GB/s

Unit2– Receiver’s side

• The attenuation of the microstrip line is not uniform. The higher the frequencies the greater are the losses

• Equalizer - to compensate on the different losses preserving SI

• Monostable - to increase the bit time back to the original 40ps state

The µstrip Line

• primary objective is designing a microstrip line on a printed circuit board

• Our focus will be on a 15 cm long microstrip line.

• How to begin our design ?

Designing the µstrip

• First step is finding a suitable dielectric material for high frequency as 100 GHz

• Next, calculating and choosing microstrip line parameters considering technological constrains

• Additional possible modification that can be added

Duroid 5580

RT/duroid 5880 Properties(typical Values)

2.2 Dielectric constant -

0.0009 Dissipation factor -

Isotropic

Uniform over volume

• Duroid 5580 manufactured by Rogers Corporation

r

tan

Modeling the µstrip line

The demand for Uniform EM field in the H«λ µstrip line

“H” is the dielectric height, What is λ?

0 0

0 0

max

1 1 1c

100

0.2 «

r r r r r

c c

f GHzc cm Hf

We chose H=0.127mm = 5 mil

Modeling the µstrip line

• What about conductor’s width, W?

• W is determined by the requirement for a standard resistance of 50Ω

• As shown in the booklet we acquire that: W=15.5 mil

Basic µstrip line

• Summing up basic µstrip line parameters:

Line modification

• Shielded microstrip line:

+ Reduces cross-talk + Significantly improves energy advancement

through the µstrip line

Line modification

• Suspended microstrip

+ Foam-like material dielectric layer+ dielectric constant close to unity + Much lower losses approximately 1:5 ratio

- complicates manufacturing process

Losses Considerations

• Accurate losses equations are complicated, they’re explained in chapter 3 in the booklet

• Approximation:Typical Duroid loss = 0.3 dB/λMicrostrip length = 15 cmλ(min) = 0.2 cmExpected total losses = 22.5 dB

• This graph can be verified by SI simulations

Inte

rnal

Lo

ss

f[GHz]

Testing the µstrip line• We need to measure the losses in the

microstrip line in order to configure the equalizer or the pre-emphasis unit

• 100GHz pulses are hard to create, therefore we can calculate the Fourier series and deal with several lower frequencies individually

• This can be easily created using a simple signal generator

Testing the µstrip line

• A pulse signal can be split to a sum of sinusoidal signals in different frequencies by calculating its Fourier series

example:

Testing the µstrip line

• Multiplying the signal to reach 100GHz frequency

• Running it through the microstrip line• Using a mixer we decrease the frequency to

a measuring level • We repeat the process for additional various

frequencies• Enough points can give the losses vs.

frequencies graph

Testing the µstrip lineFirst schematic for 100GHz components :

Source-1Eva-ADF4350

MultiplierX2

MiteqMAX2M080160

4.16GHz 8.33GHz

MultiplierX12

MillitecAMC-08-RFH00

100GB/s information rate MicrostripWaveguide-microstrip adaptor

Waveguide-microstrip adaptor

100GHz

LecroyOscilloscope

Buffer

Waveguide

100GHz

Ducommun Balanced Mixers

FDB-10-01

12GHz

Source-2Eva-ADF4350

MultiplierX3

Hittite HMC916LP3E 11GHz

MultiplierX8

Millitech AMC-12-RFH00

Buffer

3.667GHz

88GHz

RFLO

IF

Testing the µstrip lineSecond schematic for 50GHz components :

Source-1Eva-ADF4350

MultiplierX4

MiteqMAX4M160169

4.16GHz 16.667GHz

MultiplierX3

Millitech MUT-19

100GB/s information rate MicrostripWaveguide-microstrip adaptor

Waveguide-microstrip adaptor

50GHz

LecroyOscilloscope

(or simple oscilloscope)

Buffer

Waveguide

50GHz

Ducommun Balanced Mixers

FDB-10-01

6GHz

Source-2Eva-ADF4350

MultiplierX4

Hittite HMC370LP4 14.67GHz

MultiplierX3

Millitech MUT-22

Buffer

3.667GHz

44GHz

RFLO

IF

Testing the µstrip lineThird schematic for 25GHz components :

Source-1Eva-ADF4350

MultiplierX3

Hittite HMC916LP3E 4.167GHz 12.5GHz

MultiplierX2

Hittite HMC576LC3B

100GB/s information rate MicrostripWaveguide-microstrip adaptor

Waveguide-microstrip adaptor

25GHz

LecroyOscilloscope

(or simple oscilloscope)

Buffer

Waveguide

25GHz

Ducommun Balanced Mixers –

FDB-42-01

1GHz

Source-2Eva-ADF4350

MultiplierX3

Hittite HMC916LP3E 12GHz

MultiplierX2

Hittite HMC576LC3B

Buffer

4GHz

24GHz

RFLO

IF

Suitable Components• EVA-ADF4350 is the supposed unit to

generate a stable 0.5:4.4 GHz signal for the testing environment

• We deal with this unit as a black box with given parameters

• Other components can be found in our booklet

appendix B

Conclusions & Next Steps• Researching devices to sharpening the signal in

unit-1, and additional units presented in the booklet

• Simulating the microstrip line using 3D simulation software such as “CST”

• Fabricating the design and testing it

• We’ve found various suitable devices that can operate in 100GHz frequency and more

• We have presented a HF medium in addition to testing environment

thank you …

Questions?