Layne A Berge Michael T Reich Masud A Aziz Benjamin D Braaten NORTH DAKOTA STATE UNIVERSITY APPLIED ELECTROMAGNETICS LAB Department of Electrical and Computer Engineering North Dakota State University ID: 739685
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Slide1
Tuning a Dual-Band Bow-tie Slot Antenna with Parabolic Radiating Slots for the 900 MHz and 2400 MHz Bands
Layne A. BergeMichael T. ReichMasud A. AzizBenjamin D. Braaten
NORTH DAKOTA STATE UNIVERSITY
APPLIED ELECTROMAGNETICS LAB
Department of Electrical and Computer Engineering
North Dakota State University
Fargo, ND, USASlide2
Introduction and background information
Purpose of researchSimulated and measured resultsDiscussionConclusion
NORTH DAKOTA STATE UNIVERSITY
APPLIED ELECTROMAGNETICS LABOverviewSlide3
Introduction
NORTH DAKOTA STATE UNIVERSITY
APPLIED ELECTROMAGNETICS LAB
M. Miao, B. Ooi, and P. Kooi, “Broadband CPW-fed wide slot antenna,”Microwave and Optical Technology Letters, vol. 25, no. 3, pp. 206–211,2000.
Planar, bow-tie, CPW fed, slot antenna
Original design maintained broadband operation between 3 and 5 GHzSlide4
Background
NORTH DAKOTA STATE UNIVERSITY
APPLIED ELECTROMAGNETICS LAB
Planar antennas are simple to fabricate in-houseCPW (coplanar waveguide) feed allows balanced excitation
Bow-tie antenna design has a dipole like gain patternSlide5
Purpose of Research
NORTH DAKOTA STATE UNIVERSITY
APPLIED ELECTROMAGNETICS LAB
Create an antenna design using a lower permittivity substrate (original ɛr = 10.1)Dual-band operation at lower, consumer-band frequencies900 MHz
2400 MHzSlide6
Design
NORTH DAKOTA STATE UNIVERSITY
APPLIED ELECTROMAGNETICS LAB
H = 140 mmW = 240 mm, Bw = 100.2 mmBi = 8 mmBo = 70.3 mmg= 0.4 mmd = 4.6 mm
S = 7.5 mmSlide7
Design
NORTH DAKOTA STATE UNIVERSITY
APPLIED ELECTROMAGNETICS LAB
Rogers 4003CƐr = 3.55
Thickness = 1.6 mmSlide8
Design
NORTH DAKOTA STATE UNIVERSITY
APPLIED ELECTROMAGNETICS LAB
Parabolic curves emulate a Vivaldi antenna designBroadbandGreater slot perimeter = longer path taken by currents
J. Mandeep and M. Nicholas, “Design An X-Band Vivaldi Antenna,” Microwaves & RF, vol. 47, no. 8, 2008.Slide9
Measurement and Simulation Results
NORTH DAKOTA STATE UNIVERSITY
APPLIED ELECTROMAGNETICS LAB
Compared both Method of Moments and Finite-Element MethodGood correlation between simulated and measured resultsDual-band operation at 900 MHz and 2400 MHzSlide10
Measurement and Simulation Results
NORTH DAKOTA STATE UNIVERSITY
APPLIED ELECTROMAGNETICS LAB
Gain at 900 MHz in the y-z plane (left) and x-z plane (right)Gain pattern similar to a dipole antennaSimulated gain excursion caused by ideal assumptions (infinite substrate layer)Slide11
Measurement and Simulation Results
NORTH DAKOTA STATE UNIVERSITY
APPLIED ELECTROMAGNETICS LAB
Gain at 2400 MHz in the y-z plane (left) and x-z plane (right)Gain pattern deviates from that of a dipole at high frequenciesCaused by too large of a slot (electrically large dipole antenna → favors side-lobes)Slide12
Measurement and Simulation Results
NORTH DAKOTA STATE UNIVERSITY
APPLIED ELECTROMAGNETICS LAB
Surface currents at 900 MHz (left) and 2400 MHz (right)Too large of slot evident in “odd” surface currents in 2400 MHz plot (right)Slide13
Measurement and Simulation Results
NORTH DAKOTA STATE UNIVERSITY
APPLIED ELECTROMAGNETICS LAB
Field strength at 900 MHz in the y-z plane (left) and x-z plane (right)Low cross-polarization in both plotsCorrelates well with gain plotsSlide14
Measurement and Simulation Results
NORTH DAKOTA STATE UNIVERSITY
APPLIED ELECTROMAGNETICS LAB
Field strength at 2400 MHz in the y-z plane (left) and x-z plane (right)Non-negligible cross-polarization evident in each plotReinforces distorted gain patternsSlide15
Discussion
Deviation from simulated and measured gain results at 900 MHz occurred because of ideal assumption by software (infinite substrate)Poor gain plots at 2400 MHzAsymmetries partly caused by radiation losses through the substrateMain cause was found to be the slot width being near 1.5λLarge slot results in prominent side lobesSimilar to results for electrically long dipole antennas
NORTH DAKOTA STATE UNIVERSITY
APPLIED ELECTROMAGNETICS LABSlide16
Discussion
Maintained large bandwidth at both operating frequencies (Return Loss > 10 dB)602 MHz bandwidth at 900 MHz229 MHz bandwidth at 2400 MHzUsed a lower permittivity substrateLess lossCurved slot sides presented a longer path to currents than a comparable straight side
NORTH DAKOTA STATE UNIVERSITY
APPLIED ELECTROMAGNETICS LABSlide17
Conclusion
Created a dual-band bow-tie slot antenna operating at 900 MHz and 2400 MHzUsed a lower permittivity substrate than previous designsUsed curved slot sides in order to reduce size of antennaGain pattern at 2400 MHz was distortedSlot width too wide
NORTH DAKOTA STATE UNIVERSITY
APPLIED ELECTROMAGNETICS LABSlide18
Questions
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NORTH DAKOTA STATE UNIVERSITY
APPLIED ELECTROMAGNETICS LABThank you for listening!