A Self-Structuring 2-Port Network

A. K. G. Temme*1 C. H. (Jay) Lee2 E. J. Rothwell1

B. J. Greetis1 R. O. Ouedraogo1 S. Y. Chen2

1Department of Electrical and Computer Engineering, Michigan State University,East Lansing, MI, United States

2National Taiwan University, Taipei, Taiwan

2009 APS/URSI SymposiumFriday, June 5, 2009

Session 503.3 Ballroom C2, 8:40

Motivation Background Simulation Experiment Conc.

Overview1 Motivation2 Background3 Simulation Results4 Experimental Setup and Results

DesignRandom Search Results

5 ConclusionSummaryFuture WorkAcknowledgementsReferences

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Motivation Background Simulation Experiment Conc.

Project History

Project was started in 2007 by Jay Lee while visiting MichiganState University

Mr. Lee was responsible for simulations, design and initialconstruction of two port network

Currently supported by an IEEE AP-S UndergraduateResearch Award for 2008-2009

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Motivation Background Simulation Experiment Conc.

Motivation

Goal: To create a self structuring two port network

This two port network would be capable of adapting its structurein order to achieve a set of desired S-parameters

Figure: A basic two port network

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Motivation Background Simulation Experiment Conc.

Motivation

Goal: To create a self structuring two port network

This two port network would be capable of adapting its structurein order to achieve a set of desired S-parameters

Figure: Constructed Self-Structuring 2-Port Prototype

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Motivation Background Simulation Experiment Conc.

Motivation

Potential Uses

Filter

Attenuator

Phase Shifter

Matching network

Figure: Constructed Self-Structuring 2-Port Prototype

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Motivation Background Simulation Experiment Conc.

Self Structuring Antennae

Inspiration

The ideas of self structuring antennae served as stimuli for aself structuring two port network

Design modeled after a self structuring patch antenna[2] usingswitched pins and shorting pins

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Motivation Background Simulation Experiment Conc.

Self Structuring Antennae

Definition

An antenna array consisting of multiple elements connected byswitches allowing for the antenna to adjust its electrical shape inresponse to changes in its environment[1]

Figure: Possible self structuring antenna layout[1]

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Motivation Background Simulation Experiment Conc.

Self Structuring Antennae

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Motivation Background Simulation Experiment Conc.

Self Structuring Antennae

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Motivation Background Simulation Experiment Conc.

Simulations

In 2007 and 2008 Jay Lee studied design aspects including:

Board size and thickness

Pin placement

Feed method

Frequency tunability

Figure: Simulations of board design.Above 3D view. Right Plan viewshowing pin locations

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Motivation Background Simulation Experiment Conc.

Simulations

In 2007 and 2008 Jay Lee studied design aspects including:

Board size and thickness

Pin placement

Feed method

Frequency tunability

Simulations carried out in Feko

Genetic algorithm (GA) using GA-Feko

GA used to investigate filtering characteristics

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Motivation Background Simulation Experiment Conc.

GA Optimized Results

Figure: Band-pass optimized S-parameters centered at f0 ≈ 5.005GHzMSU Electromagnetics Research Group A Self-Structuring 2-Port Network 10/24

Motivation Background Simulation Experiment Conc.

Frequency Tunability

Figure: Results from multiple optimization runs showing the frequencytunability of the 2 Port Network

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Motivation Background Simulation Experiment Conc. Design Random Search Results

Test Board Layout

Ribbon Cable

Port 1Port 2

Figure: 2-Port network manufacturing layout

Specifications

Taconic TLY-5double sided board

42x27x0.5(cm)

3cm grid spacing

32 Coto 5V reedrelay switchescontrolling pins

232 =4, 294, 967, 296possible states

38 Perimetershorting pins

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Motivation Background Simulation Experiment Conc. Design Random Search Results

Test Board Layout

Figure: Switchable pin pad layout

Specifications

Taconic TLY-5double sided board

42x27x0.5(cm)

3cm grid spacing

32 Coto 5V reedrelay switchescontrolling pins

232 =4, 294, 967, 296possible states

38 Perimetershorting pins

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Motivation Background Simulation Experiment Conc. Design Random Search Results

Test Board Layout

Figure 4.4. Photograph of one of the switches on the self-structuring patch antenna.

83

Figure: Mounted switch setup (image frompatch antenna[2])

Specifications

Taconic TLY-5double sided board

42x27x0.5(cm)

3cm grid spacing

32 Coto 5V reedrelay switchescontrolling pins

232 =4, 294, 967, 296possible states

38 Perimetershorting pins

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Motivation Background Simulation Experiment Conc. Design Random Search Results

Test Board Layout

Figure: Perimeter shorting pins locations

Specifications

Taconic TLY-5double sided board

42x27x0.5(cm)

3cm grid spacing

32 Coto 5V reedrelay switchescontrolling pins

232 =4, 294, 967, 296possible states

38 Perimetershorting pins

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Motivation Background Simulation Experiment Conc. Design Random Search Results

Constructed Test Board

Figure: Constructed test board

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Motivation Background Simulation Experiment Conc. Design Random Search Results

Experimental Run Configurations

Currently a random search, will move to genetic algorithm

100,000 random switch state pool (NIST generated)

LabView data acquisition and search software

HP 8753D Network Analyzer

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Motivation Background Simulation Experiment Conc. Design Random Search Results

Random Search

Parameters

Frequency Range 700MHz − 1.5GHzStates 30, 000 ≈ 0.0007% of possible states

Number of Points 26 ⇒ 32MHz stepsSwitch Settle Time 30ms

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Motivation Background Simulation Experiment Conc. Design Random Search Results

S21 Characteristics

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Motivation Background Simulation Experiment Conc. Design Random Search Results

S21 Characteristics

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Motivation Background Simulation Experiment Conc. Design Random Search Results

Matching Network

Parameters

Frequency Range 700MHz − 1.5GHzStates 100, 034 ≈ 0.0023% of possible statesa

Number of Points 26 ⇒ 32MHz stepsSwitch Settle Time 30ms

aAll switches open, all switches closed, each switch individually (32), and100,000 random states % of total

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Motivation Background Simulation Experiment Conc. Design Random Search Results

SWR - Matched (blue) and Unmatched (red)

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Motivation Background Simulation Experiment Conc. Design Random Search Results

SWR - Matched (blue) and Unmatched (red)

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Motivation Background Simulation Experiment Conc. Summary Future Work Acknowledgements References

Summary

Just beginning to investigate the Self-Structuring 2-PortNetworkCurrently using a random searchLess than 1% of possible states exploredSimulations and experimental results

Summary of Characteristics

Frequency tunability of characteristics in simulation|S21| is almost continuous from −10dB to −40dB∠S21 is almost continuous from −180◦ to +180◦

Resolution of desired characteristic value small; however, notfully investigatedSelf structuring attenuator, phase shifter, and matchingnetwork experimentally achievableMatching network can drastically improve antennaperformance

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Motivation Background Simulation Experiment Conc. Summary Future Work Acknowledgements References

Future Work

Implementation of Genetic Algorithm

Investigation of resolution

Filtering capabilities

Size reduction

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Motivation Background Simulation Experiment Conc. Summary Future Work Acknowledgements References

Acknowledgements

Thank you to Jack Ross for supplying GA-Feko

This research and presentation has been funded in part by:

Michigan State University Honors College Conference TravelAward

IEEE Antennas and Propagation Society UndergraduateResearch Award 2008-2009

Thank You for Attending

Any Questions?

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Motivation Background Simulation Experiment Conc. Summary Future Work Acknowledgements References

References

C.M. Coleman, E.J. Rothwell, J.E. Ross, and L.L. Nagy.Self-structuring antennas.Antennas and Propagation Magazine, IEEE, 44(3):11–23, Jun2002.

L.M. Greetis and E.J. Rothwell.A self-structuring patch antenna.Antennas and Propagation Society International Symposium,2008. AP-S 2008. IEEE, pages 1–4, July 2008.

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