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A Compound Reconfigurable Microstrip Parasitic Array

Mentee: Jacob BlockMentor: Jake Adams

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Why Compound Reconfigurable?

Reconfigurable antenna properties can be changed dynamically by external control

Compound reconfigurability

– Multiple Radiation Patterns– Receive signals from multiple directions

– Multiple Operating Frequencies– Antennas are designed for specific operating frequencies– WiMAX (3.5 GHz)– WiFi (2.4 GHz)

M. Slater, “A compound reconfigurable antenna,” M.S. thesis, University of Illinois, Urbana, IL, 2008.

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Microstrip Parasitic Array

Antenna (substrate, ground, patch) Switches on parasitic elements change pattern/frequency

M. Slater, “A compound reconfigurable antenna,” M.S. thesis, University of Illinois, Urbana, IL, 2008.

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Radiation Patterns

Length of Reflector > Length of Driven > Length of Directors

Yagi-Uda Antenna (dipole cylinders) Directional radiation pattern

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Operating Frequency of Antenna

Frequency Dependent Length of arms

– Switches– Varactor (variable capacitor)

Spacing between arms – Averaging

Yagi-Uda Rules of Thumb (Numerical, not Analytic)

Length of Arms

Driven Reflector Director Separation

~ λ/2 ~ >λ/2 ~ <λ/2 ~ <λ/4

2.4 GHz 42.5mm 44mm 38mm 25mm

3.5 Ghz 25mm 27.5mm 22mm 15mm

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3.5Ghz – Right Tilt 2.4Ghz – Right Tilt

10 pF

1 pF

10 pF

1 pF

varactors

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Fun Stuff with HFSS

2.4 GHz

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Fun Stuff with HFSS

3.5 GHz

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New Design – Reduce Size, Reduce Averaging, Increase Performance

Ground Plane Resonators (slits into the ground plane)

New switching topology– Eliminate Varactors– Simplify DC bias network (less cables)– Less averaging

Mustache

Meander line

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New Switching Topology

3.5Ghz – Right Tilt 2.4Ghz – Right Tilt

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Conclusion

What I learned– HFSS– Antennas

Thanks PURE! Thanks Jake!

Questions?