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Intra-Band Frequency Reconfigurable Antenna using
RF MEMS Technology
Presented by :Chandra Shekhar Patil (1AP11EC016)
1APS COLLEGE OF ENGINEERING
04/07/15 APSCE 2
Overview
Introduction RF MEMS Switch Switch layout Exist ing system Proposed system Reconfigurable Antenna Design 2-D Layout Simulation Results Radiation pattern Fabrication & Assembly Measurement & Analysis Conclusion
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INTRODUCTION
Modern radar, ships, airplanes, spacecrafts and communication systems have experienced a tremendous increase in the number of antennas can be seen.
Demands on reducing antenna size. Requirement of antennas that cover not only
multiple frequency bands but also serve different functionalities.
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Need of Reconfigurabilty Reconfigurability in terms of
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FrequencyBandwidthPolarizationRadiation Pattern
Intro(cont..)
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Schematic layout of Reconfigurable antenna
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RF MEMS SWITCH
RF MEMS has brought revolution in RF and Microwave areas.
RF MEMS technology produces the tunable components which enables the production of dynamically tuned reconfigurable structures.
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Advantages of using RF MEMS
More efficient with low insertion loss. Low power consumption.
High linearity and high performance
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2D LAYOUT
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EXISTING SYSTEM
• To reconfigure the antenna in a dynamic manner, tuneable
components such as Switches and Varactors are used.
• And Conventional microwave components such as P-i-N
diode switches, MESFET, Varactor diode etc. are used in existing system
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PROPOSED SYSTEM
• Implementation of RF MEMS switches for thedevelopment of MEMS based reconfigurable antennas.
• The antenna is designed to achieve reconfigurability within the band (S Band).
• The shift in frequency is obtained by changing the dimension of the patch with the help of stub.
RECONFIGURABLE ANTENNA DESIGN
11
• The antenna was designed to achieve frequency reconfigurability within the band i.e. intra-band.
Square patch:- 29.1 mm x 29.1 mm
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SIMULATION RESULTS• Design and simulation Carried out in Ansoft HFSS V.12.0.
Fig. Simulated results of reconfigurable antenna with different stub length
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• Variation in stub length was done without changing the Feed location, the impedance match at feed point gets disturbed (due to increase in antenna resistance) which results in decrease in return loss.
RADIATION PATTERN
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Fig : (a) Patterns with stub not connected (b) Patterns with stub connected
FABRICATION
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• The substrate used for the antenna is PCB (ARLON , εr =2.5).
• The assembly of MEMS switch die on fabricated antenna was carried out in cleanroom.
• MEMS switch was placed between patch and stub using silver conducting epoxy and cured in 120 degree Celsius for 15 min .
• Interconnections between pads of switches and patch as well as DC bias pads were made using gold wire.
Switch performance evaluation set up
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MEASUREMENT AND ANALYSIS
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• The S-Parameter of the switch for both ON and OFF conditions.
Fig. Measured S11 under switch OFF condition
Fig.Measured S11 under switch OFF condition
SUMMARY OF RESULTS
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CONCLUSION
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The RF MEMS based reconfigurable antenna wasdesigned, fabricated and measured. The hybrid approach (i.e.assembly of MEMS switch) used in this development gavesatisfactory results. Though the actuation voltage to actuatethe switch were high (67 Volts approx.), voltage upconversionfrom 5 volt to current level can be done using charge pumpand hence can be used in defence communications where itcan reduce number of antenna working at different frequencywithin the band as well as at different bands. The antennashows frequency reconfigurability while maintaining itspattern unaffected.
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