Ultra Wideband Digital Ultra Wideband Digital Wireless LinkWireless Link

By Matthew Carrier, Nicholas Merrill, By Matthew Carrier, Nicholas Merrill, Brandon Mui, Justin BurkhartBrandon Mui, Justin Burkhart

Advisor: Professor R.W. JacksonAdvisor: Professor R.W. Jackson

What is Ultra Wide Band? What is Ultra Wide Band?

Ultra Wide Band (UWB) uses very low-powered, Ultra Wide Band (UWB) uses very low-powered, short pulsed radio signals to transfer data over a short pulsed radio signals to transfer data over a wide range of frequencieswide range of frequencies

FCC Definition:FCC Definition: Signals must occupy bandwidth >500MHzSignals must occupy bandwidth >500MHz Or, signal bandwidth is 20% of the carrier frequencyOr, signal bandwidth is 20% of the carrier frequency

Why do we need Ultra Wide Band?Why do we need Ultra Wide Band?

High-tech designs require portability, speed, & performanceHigh-tech designs require portability, speed, & performance Portability:Portability:

UWB use multiple low-powered pulses → low power consumptionUWB use multiple low-powered pulses → low power consumption UWB data rate is inversely proportional to distance (thus short UWB data rate is inversely proportional to distance (thus short

range)range)

Speed:Speed: Proposed to be between 40-600 Mb/s, and eventually up to Gb/sProposed to be between 40-600 Mb/s, and eventually up to Gb/s

Performance:Performance: Volume of information proportional to the frequency bandVolume of information proportional to the frequency band More information → better graphics, better resolution for RADAR, More information → better graphics, better resolution for RADAR,

etc.etc.

Standard TR-UWB systems are “dogged” by implementation Standard TR-UWB systems are “dogged” by implementation issuesissues The receiver requires an extremely wideband delay The receiver requires an extremely wideband delay

elementelement

As a solution, Professor Goeckel has developed theory for As a solution, Professor Goeckel has developed theory for Slightly Frequency Shifted Reference UWBSlightly Frequency Shifted Reference UWB

Transmitted Reference UWB SystemsTransmitted Reference UWB Systems

t

data

data

Reference Reference

(Transmitted Reference UWB)

Slightly Frequency Shifted UWBSlightly Frequency Shifted UWB

Rather then separating the data from the reference in time, Rather then separating the data from the reference in time, this systems separates them in frequencythis systems separates them in frequency

Data and Reference pulse Data and Reference pulse mustmust be orthogonal in frequency be orthogonal in frequency

This avoids using the extremely wideband delay element in This avoids using the extremely wideband delay element in the receiverthe receiver

Our project is to take Prof. Goeckel’s theory and prove the Our project is to take Prof. Goeckel’s theory and prove the concept through building a scaled prototypeconcept through building a scaled prototype

DeliverablesDeliverables

Transmitter/Receiver Electronics PrototypeTransmitter/Receiver Electronics Prototype

Transmitter/Receiver Antenna PrototypeTransmitter/Receiver Antenna Prototype

Packaging design is Packaging design is notnot part of project part of project

Omni antennaOmni antenna Pulse Generator has pulses with picosecond rise Pulse Generator has pulses with picosecond rise

timestimes Oscillator used for frequency shifting of the pulsesOscillator used for frequency shifting of the pulses PLD is used for buffering of dataPLD is used for buffering of data

TransmitterTransmitter

PLDInput

Pulser

Oscillator

X

X

Σ

ReceiverReceiver

Omni antennaOmni antenna Oscillator at same frequency and phase as transmitter (sync Oscillator at same frequency and phase as transmitter (sync

not yet designed)not yet designed) PLD is for out-buffering of received dataPLD is for out-buffering of received data

X

XOscillator

PLDIntegrator

What is Missing?What is Missing? Need to design circuitry to synchronize the Need to design circuitry to synchronize the

frequency shift oscillators frequency shift oscillators Need to develop/buy integrator circuitry Need to develop/buy integrator circuitry

that can be triggeredthat can be triggered Integrator and PLD sampling also have sync Integrator and PLD sampling also have sync

issues that need to be worked outissues that need to be worked out Antenna design has yet to be implementedAntenna design has yet to be implemented

An antenna in our channel has already been An antenna in our channel has already been designed by grad students here at UMASSdesigned by grad students here at UMASS

Pulse Generation: Closer LookPulse Generation: Closer Look

Create very fast pulses using Step Create very fast pulses using Step Recover Diodes (SRD)Recover Diodes (SRD)

MDR SpecificationMDR Specification Transmitter & Receiver prototype builtTransmitter & Receiver prototype built

Built using modular components connected with Built using modular components connected with coaxial cablecoaxial cable

No synchronization circuitry implementedNo synchronization circuitry implemented No antenna implementedNo antenna implemented

Antenna design & prototype builtAntenna design & prototype built Tested for gain, return loss, & radiation patternsTested for gain, return loss, & radiation patterns

Synchronization Circuitry Synchronization Circuitry Will be designed independently from the Will be designed independently from the

prototypeprototype

Questions/Suggestions?Questions/Suggestions?

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