1. Frequency Reconfigurable Microstrip Patch Antenna
Final Project Presentation
Presented by: Mike Bly, Josh Rohman Advisor: Dr. Prasad N. Shastry

2. Why Reconfigurable Antennas? Practical Applications?

3. Presentation Outline Design Specifications MEMS Switch Implementation
Linear Patch Antenna Design
Antenna Simulations
Inset Feed Matching Network

4. Design Specifications
Microstrip patch antenna (Rogers RO3010)
2 GPS application frequencies
24 MHz Bandwidth
1.575 GHz Center Frequency (Patch 1)
1.227 GHz Center Frequency (Patch 2)
Linear Polarization
Inset Feed matching network
Matched to 50Ω
MEMS preferred for switching method

5. System Block Diagram

6. Switching Method MEMS Switch RMSW201, RADANT MEMS
0.3dB Insertion 2GHz
35dB Isolation 2GHz
1.9mm x 1.85mm package size
SPST, DC to 20GHz, Wire Bonding, +/- 90V Gate-Source Voltage

7. RMSW201 MEMS Operation
+/- 90 VGS Actuation Voltage

8. RMSW201 MEMS Operation
+/- 90 VGS Actuation Voltage

9. Implementing MEMS
RS = RD = 100kΩ
Stability
Minimize Hot-Switching

10. Switching Method

11. Switching Method DC-DC Converter: +5V to -90V R2/R1 = Vout/Vref
R2 = Vout/10uA
+5VDC
The p-channel MOSFET Q1 switches on and off, controlling the output voltage (-90V). When the voltage across L1 exceeds 210mV, an internal voltage comparator indirectly measures the current passing through the MOSFET. This shuts off the MOSFET, discharges the inductor L1, and charges the Capacitor C4
-90VDC

12. Switching Method
DC-DC Converter: +5V to -90V
+5VDC
-90VDC

13. Switching Method
DC-DC Converter: +5V to -90V
+5VDC
-90VDC

14. Switching Method
DC-DC Converter: +5V to -90V
+5VDC
-90VDC

15. DC-DC Converter Timing
Timing in us

16. Implementing MEMS Conductive epoxy, double-stick thermal tape
Wire bonding, gold plating

17. MEMS Evaluation Board RO3010 25 mil Substrate 1.5” by 6”
Gold Plating Required
8 Coax Connectors
1.6x0.8mm SMT Resistors
Test DC-DC Converter
Measure Isolation and Insertion Losses

18. MEMS Evaluation Board RO3010 25 mil Substrate 1.5” by 6”
Gold Plating Required
8 Coax Connectors
1.6x0.8mm SMT Resistors
Test DC-DC Converter
Measure Isolation and Insertion Losses

19. MEMS Evaluation Board RO3010 25 mil Substrate 1.5” by 6”
Gold Plating Required
8 Coax Connectors
1.6x0.8mm SMT Resistors
Test DC-DC Converter
Measure Isolation and Insertion Losses Determine effects of MEMS’ ground plane

20. MEMS Evaluation Board RO3010 25 mil Substrate 1.5” by 6”
Gold Plating Required
8 Coax Connectors
1.6x0.8mm SMT Resistors
Test DC-DC Converter
Measure Isolation and Insertion Losses

21. MEMS Evaluation Board RO3010 25 mil Substrate 1.5” by 6”
Gold Plating Required
8 Coax Connectors
1.6x0.8mm SMT Resistors
Test DC-DC Converter
Measure Isolation and Insertion Losses

22. Micro-Circuits, Inc. Contact: Robert Modica (630) 628-5764

23. Patch Antenna Design Step 1
ΔL = 0.412h*[(εeff + 0.3)(W/h )]/[( εeff – 0.258)(W/h + 0.8)]
W = c/(2fo*√((εr+1)/2))
L = c/(2fo*√(εr)) – 2ΔL
L = 30mm & W = 40.25mm
L = 38.6mm & W = 40.25mm

24. Patch Antenna Design Step 2
<-Height = 1mm
L = 30mm & W = 40.25mm

25. Patch Antenna Design Step 3
Height = 1.9mm
Height = 1mm
L1 = 30mm & W = 40.25mm

26. 1.575 GHz Patch Antenna Design

27. Simulations: 1.575 GHz Patch Antenna

28. Simulations: 1.575 GHz Patch Antenna
1 to 2 GHz Simulation

29. 1.575 GHz Results

30. 1.227 GHz Patch Antenna Design

31. Simulations: 1.227 GHz Patch Antenna

32. Simulations: 1.227 GHz Patch Antenna
1 to 2 GHz Simulation

33. 1.227 GHz Results

34. Inset Feed Matching Network
Freq
Length(mm)
Width(mm) Er
Ereff Zo
1.227
34.06
40.25
10.2
1.575 30
Zin(real)
Zin(imag)
Wo(mm)
Yo(mm) Pi

35. Inset Feed Design Step 1 y0 = [Cos-1(Z0/Zin)]2*(L/π)
W0 = 0.6mm (50Ω microstrip line)
W1 = W0

36. Inset Feed Design Step 2 Height = 1mm
L = 30mm & W = 40.25mm & y0 = 10.25mm

37. Inset Feed 1.575Ghz Simulation

38. Simulations: 1.575 GHz Inset

39. 1.575 GHz Inset Results

40. Inset Feed 1.227Ghz Simulation

41. Simulations: 1.227 GHz Inset

42. 1.227 GHz Inset Results

43. Antenna System Layout

44. Fabricated Antenna System

45. Questions?

46. Sources:
Application Note for MAX774 DC-to-DC Converter. RadantMEMS, Web. Nov <
Application Note for Test & Handling of SPST RF-MEMS Switches. RadantMEMS, Web. Nov <
Balanis, Constantine A. Antenna Theory: Analysis and Design. 3rd ed. Hoboken, NJ: John Wiley, Print.
DeSignor, Jessica A., and Jayanti Venkataraman. "Reconfigurable Dual Frequency Microstrip Patch Antenna Using RF MEMS Switches." IEEE Xplore. May Web. 20 Sept
Rebeiz, Gabriel M., and Jeremy B. Muldavin. "RF MEMS Switches and Switch Circuits." IEEE Xplore. Dec Web. 20 Sept
SPST, High-Isolation, RF-MEMS Switch DC to 20 GHz. RadantMEMS, Web. 28 Oct <
Yang, Songnan, Chunna Zhang, Helen K. Pan, Aly E. Fathy, and Vijay K. Nair. "Frequency Reconfigurable Antennas for Multiradio Wireless Platforms." IEEE Microwave Magazine (2009): Print.