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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
Electromagnetics Laboratory
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
Electromagnetics Laboratory
3.5Ghz – Right Tilt 2.4Ghz – Right Tilt
10 pF
1 pF
10 pF
1 pF
varactors
Electromagnetics Laboratory
Fun Stuff with HFSS
2.4 GHz
Electromagnetics Laboratory
Fun Stuff with HFSS
3.5 GHz
Electromagnetics Laboratory
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
Electromagnetics Laboratory
Conclusion
What I learned– HFSS– Antennas
Thanks PURE! Thanks Jake!
Questions?