Frequency Reconfigurable Microstrip Patch Antenna
Final Project Presentation
Presented by: Mike Bly, Josh Rohman
Advisor: Dr. Prasad N. Shastry
Why Reconfigurable Antennas?Why Reconfigurable Antennas?
Practical Applications?Practical Applications?
Presentation Outline•Design Specifications•MEMS Switch Implementation•Linear Patch Antenna Design•Antenna Simulations•Inset Feed Matching Network
Design Specifications•Microstrip patch antenna (Rogers RO3010)•2 GPS application frequencies
24 MHz Bandwidth1.575 GHz Center Frequency (Patch 1)1.227 GHz Center Frequency (Patch 2)Linear Polarization
•Inset Feed matching networkMatched to 50Ω
•MEMS preferred for switching method
System Block Diagram
Switches?
Patch 1(1.575 GHz)
Patch 2 Connected
(1.227 GHz)
Inset Feed Matches to 50
ohm
Output to Coax Connector
On
Off
Switching Method•MEMS Switch
RMSW201, RADANT MEMS0.3dB Insertion Loss @ 2GHz35dB Isolation Loss @ 2GHz1.9mm x 1.85mm package size
RMSW201 MEMS Operation•+/- 90 VGS Actuation Voltage
RMSW201 MEMS Operation•+/- 90 VGS Actuation Voltage
Implementing MEMS•RS = RD = 100kΩ•Stability
Switching Method
+5V Supply Line
DC-DC Converter MEMS Gate
Switching Method•DC-DC Converter: +5V to -90V• R2/R1 = Vout/Vref• R2 = Vout/10uA
+5VDC
-90VDC
Switching Method•DC-DC Converter: +5V to -90V
+5VDC
-90VDC
Switching Method•DC-DC Converter: +5V to -90V
+5VDC
-90VDC
Switching Method•DC-DC Converter: +5V to -90V
+5VDC
-90VDC
DC-DC Converter Timing
Implementing MEMS•Conductive epoxy, double-stick thermal
tape•Wire bonding, gold plating
MEMS Evaluation Board
MEMS Evaluation Board
MEMS Evaluation Board
MEMS Evaluation Board
MEMS Evaluation Board
Patch Antenna Design Step 1
L = 30mm & W = 40.25mm L = 38.6mm & W = 40.25mm
ΔL = 0.412h*[(εeff + 0.3)(W/h + 0.264)]/[( εeff – 0.258)(W/h + 0.8)]W = c/(2fo*√((εr+1)/2))L = c/(2fo*√(εr)) – 2ΔL
Patch Antenna Design Step 2
L = 30mm & W = 40.25mm
<-Height = 1mm
Patch Antenna Design Step 3
L1 = 30mm & W = 40.25mm
Height = 1.9mmHeight = 1mm
1.575 GHz Patch Antenna Design
Simulations: 1.575 GHz Patch Antenna
Simulations: 1.575 GHz Patch Antenna•1 to 2 GHz Simulation
1.575 GHz Results
1.227 GHz Patch Antenna Design
Simulations: 1.227 GHz Patch Antenna
Simulations: 1.227 GHz Patch Antenna•1 to 2 GHz Simulation
1.227 GHz Results
Inset Feed Matching Network
INSET FEED
Freq Length(mm) Width(mm) Er Ereff Zo
1.227 34.06 40.25 10.2 9.818024134 47.16779462
1.575 30 40.25 10.2 9.818024134 67.47522359
Zin(real) Zin(imag) Wo(mm) Yo(mm) Pi
135.902 -14.159 0.59567 10.2 3.14159
290.732 -28.368 0.59567 10.2 3.14159
Inset Feed Design Step 1
y0 = [Cos-1(Z0/Zin)]2*(L/π)W0 = 0.6mm (50Ω microstrip line)W1 = W0
Inset Feed Design Step 2
L = 30mm & W = 40.25mm & y0 = 10.25mm
Height = 1mm
Inset Feed 1.575Ghz Simulation
Simulations: 1.575 GHz Inset
1.575 GHz Inset Results
Inset Feed 1.227Ghz Simulation
Simulations: 1.227 GHz Inset
1.227 GHz Inset Results
Antenna System Layout
Fabricated Antenna System
Questions?
Sources:• Application Note for MAX774 DC-to-DC Converter. RadantMEMS, 2007. Web. Nov. 2011.
<http://www.radantmems.com/radantmems.data/Library/MAX774%20DC-DC%20Converter_1.2.pdf>.
• Application Note for Test & Handling of SPST RF-MEMS Switches. RadantMEMS, 2007. Web. Nov. 2011. <http://www.radantmems.com/radantmems.data/Library/App_notes_1.6.pdf>.
• Balanis, Constantine A. Antenna Theory: Analysis and Design. 3rd ed. Hoboken, NJ: John Wiley, 2005. Print.
• DeSignor, Jessica A., and Jayanti Venkataraman. "Reconfigurable Dual Frequency Microstrip Patch Antenna Using RF MEMS Switches." IEEE Xplore. May 2007. Web. 20 Sept. 2011.
• Rebeiz, Gabriel M., and Jeremy B. Muldavin. "RF MEMS Switches and Switch Circuits." IEEE Xplore. Dec. 2001. Web. 20 Sept. 2011.
• SPST, High-Isolation, RF-MEMS Switch DC to 20 GHz. RadantMEMS, 2007. Web. 28 Oct. 2011. <http://www.radantmems.com/radantmems.data/Library/Radant-
Datasheet201_1.4.pdf>.• 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): 67-84. Print.