reconfigurable antennas

Electromagnetics Laboratory

A Compound Reconfigurable Microstrip Parasitic Array

Mentee: Jacob BlockMentor: Jake Adams

Electromagnetics Laboratory

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.

Electromagnetics Laboratory

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.

Electromagnetics Laboratory

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

Electromagnetics Laboratory

Electromagnetics Laboratory

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?