2010 APS_ Broadband Characteristics of A Dome Dipole Antenna

1,611 views
1,551 views

Published on

0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total views
1,611
On SlideShare
0
From Embeds
0
Number of Embeds
212
Actions
Shares
0
Downloads
9
Comments
0
Likes
0
Embeds 0
No embeds

No notes for slide

2010 APS_ Broadband Characteristics of A Dome Dipole Antenna

  1. 1. Broadband Characteristics of a Dome-Dipole Antenna Jing Zhao, Chi-Chih Chen, Dimitris Psychoudakis, and John L. Volakis ElectroScience Laboratory Department of Electrical and Computer Engineering The Ohio State University Columbus, Ohio 43212 {zhao.189,chen.118,psychoudakis.1,volakis.1}@osu.edu July 15, 2010
  2. 2. Outline Body-of-Revolution Dome-Dipole Antenna Motivation Numerical Formulations and Antenna Description Calculation Results and Experimental Validations Optimization of Inverted-Hat Antenna Using Genetic Algorithm Concluding Remarks z t=N BOR N N −1 z N −2 ˆ t ˆ t φ Ei y S φ ρ x 3 2 1 t=0 Broadband Characteristics of a Dome-Dipole Antenna IEEE APS/URSI Symposium, July 2010, Toronto 2/19
  3. 3. Motivation UWB Antenna of 100:1 Bandwidth Broadband Characteristics of a Dome-Dipole Antenna IEEE APS/URSI Symposium, July 2010, Toronto 3/19
  4. 4. Motivation UWB Antenna of 100:1 Bandwidth UWB operation from low VHF band up to several GHz Commercial services: WLAN, UMTS (up to 5 GHz) Military communications: JTRS, SINGARS, UHF SATCOM, and EPLRS (30-3000 MHz) Broadband Characteristics of a Dome-Dipole Antenna IEEE APS/URSI Symposium, July 2010, Toronto 3/19
  5. 5. Motivation UWB Antenna of 100:1 Bandwidth UWB operation from low VHF band up to several GHz Commercial services: WLAN, UMTS (up to 5 GHz) Military communications: JTRS, SINGARS, UHF SATCOM, and EPLRS (30-3000 MHz) Limitations of conventional designs Several radiators of various sizes and shapes Protruding for low frequency operation Sidelobes dominate radiation patterns at high frequencies Broadband Characteristics of a Dome-Dipole Antenna IEEE APS/URSI Symposium, July 2010, Toronto 3/19
  6. 6. Motivation UWB Antenna of 100:1 Bandwidth UWB operation from low VHF band up to several GHz Commercial services: WLAN, UMTS (up to 5 GHz) Military communications: JTRS, SINGARS, UHF SATCOM, and EPLRS (30-3000 MHz) Limitations of conventional designs Several radiators of various sizes and shapes Protruding for low frequency operation Sidelobes dominate radiation patterns at high frequencies Dome-dipole antenna A single aperture (24” wide and 20” tall) generates VP radiation and provides consistent dipole-like pattern over 100:1 bandwidth. Broadband Characteristics of a Dome-Dipole Antenna IEEE APS/URSI Symposium, July 2010, Toronto 3/19
  7. 7. Motivation Body-of-Revolution (BoR) Antenna Fast Analysis Broadband Characteristics of a Dome-Dipole Antenna IEEE APS/URSI Symposium, July 2010, Toronto 4/19
  8. 8. Motivation Body-of-Revolution (BoR) Antenna Fast Analysis Limitations of commercial MoM solvers 3-D meshing: memory-demanding & time-consuming for electrically large structure 3-D mesh (FEKO) Broadband Characteristics of a Dome-Dipole Antenna IEEE APS/URSI Symposium, July 2010, Toronto 4/19
  9. 9. Motivation Body-of-Revolution (BoR) Antenna Fast Analysis Limitations of commercial MoM solvers 3-D meshing: memory-demanding & time-consuming for electrically large structure BoR antenna solver Using BoR principle (3-D ⇒ 2-D + Fourier modes analysis) to efficiently evaluate axi-symmetry antenna performance. 10 5 z (in) 0 −5 −10 −12 −8 −4 0 4 8 12 ρ (in) 3-D mesh (FEKO) 2-D mesh (BoR) Broadband Characteristics of a Dome-Dipole Antenna IEEE APS/URSI Symposium, July 2010, Toronto 4/19
  10. 10. Numerical Formulations and Antenna Description Basis Function Expansion Surface currents on a BoR [1]: Longitudinal direction (ˆ) : piecewise linear (triangle) t ˆ a finte Fourier series Azimuthal direction (φ): z ∞ N t=N t t φ φ BOR N J(r ) = [aαn Jαn (r ) + aαn Jαn (r )] N −1 α=−∞ n=1 z N −2 ˆ t ˆ t φ Jαn (r ) = ˆ(r )fn (t)e jαφ t t Ei y φ ˆ Jαn (r ) = φ(r )fn (t)e jαφ S φ ρ t φ x Unknowns: aαn & aαn for mode α and 3 2 basis function n. 1 t=0 [1] J. R. Mautz and R.F. Harrington, “Radiation and scattering from bodies of revolution,” Appl. Sci. Res. vol. 20, Jun 1969. Broadband Characteristics of a Dome-Dipole Antenna IEEE APS/URSI Symposium, July 2010, Toronto 5/19
  11. 11. Numerical Formulations and Antenna Description Excitation The antenna feed is modelded by a delta gap source: V0 ˆ △z z : r =0 E i (r ) = 0 : else φ-independent excitation: α = 0 mode only + No coupling between the t-directed currents and the φ-directed currents ∆z I O E i V0 in aαn = 0 (Iφ = 0) φ 0 z V0 - Antenna input impedance: Zin = Iin x y Broadband Characteristics of a Dome-Dipole Antenna IEEE APS/URSI Symposium, July 2010, Toronto 6/19
  12. 12. Numerical Formulations and Antenna Description Matrix System Employing Galerkin’s method in conjuction with BoR principle, the matrix system for each mode α is given by tφ Ztt α Zα It α t Vα = . Zφt α Zφφ α Iφ α φ Vα Utilizing the property of vertically polarized feed, the above equation finally reduces to Ztt · It = V0 . 0 0 t Solve for It to determine surface currents J(r ) and far-zone radiated 0 electric field via jωµ e −jkr ′ E (r ) = − J(r ′ )e jkˆ·r d r ′ . r 4π r V Broadband Characteristics of a Dome-Dipole Antenna IEEE APS/URSI Symposium, July 2010, Toronto 7/19
  13. 13. Numerical Formulations and Antenna Description 24” wide and 20” tall BoR Dome-Dipole Antenna 3-D version of the flare dipole Exponentially tapered outer surface for constant impedance z = 1.7(e 0.161y − 1) Small electrical separation between the upper and bottom surfaces for uniform radiation pattern z x y Broadband Characteristics of a Dome-Dipole Antenna IEEE APS/URSI Symposium, July 2010, Toronto 8/19
  14. 14. Calculation Results and Experimental Validation Electrical Performance of the 24”×20” Dome-Dipole Antenna (30 MHz-2 GHz) Calculations and measurements are in reasonably good agreement VSWR<3 from 180 MHz to 2 GHz (fed to 50 Ω coaxial cable) Stable realized gain (θ = 90◦ ) at high frequencies 8 10 Simulation (FEKO) 7 Simulation (BOR) 5 Measurement 6 0 Realized Gain, dBi 5 −5 VSWR 4 −10 3 −15 2 −20 Simulation (FEKO) 1 −25 Simulation (BOR) Measurement 0 −30 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 Frequency, GHz Frequency, GHz VSWR Realized Gain (θ = 90◦ ) Broadband Characteristics of a Dome-Dipole Antenna IEEE APS/URSI Symposium, July 2010, Toronto 9/19
  15. 15. Calculation Results and Experimental Validation Computational Efficiency Improvement Computing platform Intel R CoreTM 2 Duo Processor with 3 GHz and 4 GB RAM Moderate size problem (30 MHz-2 GHz) Frequency sweep: 41 equally spaced sampling points FEKO: 1,116s v.s. BoR: 155s 7.2 times efficiency improvement Electrically large problem (6 GHz, i.e. 12λ × 10λ) Solver # of unknowns CPU time (s) FEKO 101,310 5,306 BoR 249 56 Unknowns reduction: 400 times & CPU time reduction: 100 times! Broadband Characteristics of a Dome-Dipole Antenna IEEE APS/URSI Symposium, July 2010, Toronto 10/19
  16. 16. Calculation Results and Experimental Validation Elevation Plane Patterns (Single Main Lobe) 0o 0o 0o 0o 330o 30o 330o 30o 330o 30o 330o 30o o o o o o o o 300 60 300 60 300 60 300 60o 270 o −30 −20 −10 90o 270 o −30 −20 −10 90o 270 o −30 −20 −10 90o 270 o −30 −20 −10 90o dB dB dB dB 240 o 120o 240 o 120o 240 o 120o 240 o 120o o o o o 210o 150 210o 150 210o 150 210o 150 180o 180o 180o 180o f = 100 MHz f = 2 GHz f = 4 GHz f = 6 GHz 0o 0o 0o 0o 330o 30o 330o 30o 330o 30o 330o 30o 300o 60o 300o 60o 300o 60o 300o 60o 270 o −30 −20 −10 90o 270 o −30 −20 −10 90o 270 o −30 −20 −10 90o 270 o −30 −20 −10 90o dB dB dB dB 240o 120o 240o 120o 240o 120o 240o 120o o o o o 210o o 150 210o o 150 210o o 150 210o o 150 180 180 180 180 f = 8 GHz f = 10 GHz f = 12 GHz f = 14 GHz Broadband Characteristics of a Dome-Dipole Antenna IEEE APS/URSI Symposium, July 2010, Toronto 11/19
  17. 17. Calculation Results and Experimental Validation Measured Gain along the Horizon (2 GHz-14 GHz) Measured realized gain at θ = 90◦ is almost greater than 0 dB from 2 GHz to 14 GHz, increasing to 4 dB 10 Measurement 0 dB 5 Realzied Gain, dBi 0 −5 −10 −15 −20 2 3 4 5 6 7 8 9 10 11 12 13 14 Frequency, GHz Broadband Characteristics of a Dome-Dipole Antenna IEEE APS/URSI Symposium, July 2010, Toronto 12/19
  18. 18. Optimization of Inverted-Hat Antenna Using Genetic Algorithm Optimization of Inverted-Hat Antenna Inverted-Hat Antenna (IHA) A novel compact frequency-scaled structure for broadband operation with properly designed outer surface growth profile [2]. [2] J. Zhao, C.-C. Chen and J. L. Volakis, “Frequency-Scaled UWB Inverted-Hat Antenna,” IEEE Trans. Antennas Propagat., vol. 58, no. 7, pp. 2447-2451, Jul, 2010. Broadband Characteristics of a Dome-Dipole Antenna IEEE APS/URSI Symposium, July 2010, Toronto 13/19
  19. 19. Optimization of Inverted-Hat Antenna Using Genetic Algorithm Optimization of Inverted-Hat Antenna Inverted-Hat Antenna (IHA) A novel compact frequency-scaled structure for broadband operation with properly designed outer surface growth profile [2]. Goal: constant gain, constant impedance and uniform radiation pattern across a large BW Approach: genetic algorithm (GA) Design Parameters: width, global profile, curvature and # of elliptical segments [2] J. Zhao, C.-C. Chen and J. L. Volakis, “Frequency-Scaled UWB Inverted-Hat Antenna,” IEEE Trans. Antennas Propagat., vol. 58, no. 7, pp. 2447-2451, Jul, 2010. Broadband Characteristics of a Dome-Dipole Antenna IEEE APS/URSI Symposium, July 2010, Toronto 13/19
  20. 20. Optimization of Inverted-Hat Antenna Using Genetic Algorithm Optimization of Inverted-Hat Antenna Inverted-Hat Antenna (IHA) A novel compact frequency-scaled structure for broadband operation with properly designed outer surface growth profile [2]. Goal: constant gain, constant impedance and uniform radiation pattern across a large BW Approach: genetic algorithm (GA) Design Parameters: width, global profile, curvature and # of elliptical segments [2] J. Zhao, C.-C. Chen and J. L. Volakis, “Frequency-Scaled UWB Inverted-Hat Antenna,” IEEE Trans. Antennas Propagat., vol. 58, no. 7, pp. 2447-2451, Jul, 2010. Broadband Characteristics of a Dome-Dipole Antenna IEEE APS/URSI Symposium, July 2010, Toronto 13/19
  21. 21. Optimization of Inverted-Hat Antenna Using Genetic Algorithm Optimization of Inverted-Hat Antenna Inverted-Hat Antenna (IHA) A novel compact frequency-scaled structure for broadband operation with properly designed outer surface growth profile [2]. Goal: constant gain, constant impedance and uniform radiation pattern across a large BW Approach: genetic algorithm (GA) Design Parameters: width, global profile, curvature and # of elliptical segments [2] J. Zhao, C.-C. Chen and J. L. Volakis, “Frequency-Scaled UWB Inverted-Hat Antenna,” IEEE Trans. Antennas Propagat., vol. 58, no. 7, pp. 2447-2451, Jul, 2010. Broadband Characteristics of a Dome-Dipole Antenna IEEE APS/URSI Symposium, July 2010, Toronto 13/19
  22. 22. Optimization of Inverted-Hat Antenna Using Genetic Algorithm Cost Function COST = αreal Preal + αimag Pimag + αdir Pdir + αripple Pripple Broadband Characteristics of a Dome-Dipole Antenna IEEE APS/URSI Symposium, July 2010, Toronto 14/19
  23. 23. Optimization of Inverted-Hat Antenna Using Genetic Algorithm Cost Function COST = αreal Preal + αimag Pimag + αdir Pdir + αripple Pripple Preal : Resistance (R) ⇒ constant 1 Preal = |R(f ) − avg (R(f ))|2 , αreal = 0.5 Nf Nf Nf : total number of discrete frequencies Broadband Characteristics of a Dome-Dipole Antenna IEEE APS/URSI Symposium, July 2010, Toronto 14/19
  24. 24. Optimization of Inverted-Hat Antenna Using Genetic Algorithm Cost Function COST = αreal Preal + αimag Pimag + αdir Pdir + αripple Pripple Pimag : Reactance (X) ⇒ 0 1 Pimag = |X (f )|, αimag = 0.5 Nf Nf Nf : total number of discrete frequencies Broadband Characteristics of a Dome-Dipole Antenna IEEE APS/URSI Symposium, July 2010, Toronto 14/19
  25. 25. Optimization of Inverted-Hat Antenna Using Genetic Algorithm Cost Function COST = αreal Preal + αimag Pimag + αdir Pdir + αripple Pripple Preal : Resistance (R) ⇒ constant 1 Preal = |R(f ) − avg (R(f ))|2 , αreal = 0.5 Nf Nf Pimag : Reactance (X) ⇒ 0 1 Pimag = |X (f )|, αimag = 0.5 Nf Nf Nf : total number of discrete frequencies Broadband Characteristics of a Dome-Dipole Antenna IEEE APS/URSI Symposium, July 2010, Toronto 14/19
  26. 26. Optimization of Inverted-Hat Antenna Using Genetic Algorithm Cost Function (cont’d) COST = αreal Preal + αimag Pimag + αdir Pdir + αripple Pripple Broadband Characteristics of a Dome-Dipole Antenna IEEE APS/URSI Symposium, July 2010, Toronto 15/19
  27. 27. Optimization of Inverted-Hat Antenna Using Genetic Algorithm Cost Function (cont’d) COST = αreal Preal + αimag Pimag + αdir Pdir + αripple Pripple Pdir : Maximation of directivity gain (Prefer 5 dB) 1 G (f ) : if G (f ) < 5 dB Pdir = − Pdir (f ), Pdir = Nf 5 dB : else Nf αdir = 0.8 Nf : total number of discrete frequencies Broadband Characteristics of a Dome-Dipole Antenna IEEE APS/URSI Symposium, July 2010, Toronto 15/19
  28. 28. Optimization of Inverted-Hat Antenna Using Genetic Algorithm Cost Function (cont’d) COST = αreal Preal + αimag Pimag + αdir Pdir + αripple Pripple Pripple : Minimization of gain ripples across the band 1 Pripple = |G (f ) − avg (G (f ))|2 , αripple = 10 Nf Nf Nf : total number of discrete frequencies Broadband Characteristics of a Dome-Dipole Antenna IEEE APS/URSI Symposium, July 2010, Toronto 15/19
  29. 29. Optimization of Inverted-Hat Antenna Using Genetic Algorithm Cost Function (cont’d) COST = αreal Preal + αimag Pimag + αdir Pdir + αripple Pripple Pdir : Maximation of directivity gain (Prefer 5 dB) 1 G (f ) : if G (f ) < 5 dB Pdir = − Pdir (f ), Pdir = Nf 5 dB : else Nf αdir = 0.8 Pripple : Minimization of gain ripples across the band 1 Pripple = |G (f ) − avg (G (f ))|2 , αripple = 10 Nf Nf Nf : total number of discrete frequencies Broadband Characteristics of a Dome-Dipole Antenna IEEE APS/URSI Symposium, July 2010, Toronto 15/19
  30. 30. Optimization of Inverted-Hat Antenna Using Genetic Algorithm Optimization of 6” tall IHA on Infinite Ground Plane GA program setup Population size: 16 Selection: Tournament Crossover: Uniform Mutation rate: 0.05 Maximum # of generation : 20 IHA parameter coding # of bits in a chromosome: 13 Width 10”, 12”, 14”, ..., 36”, 38”, 40”, 4 bits Global Profile convex/concave, 1 bit Curvature 0.1, 0.2, ..., 0.9, 1, 1.5, 2, 2.5, 3, 4, 5, 4 bits # of Ellipse 3, 5, 7, ..., 29, 31, 33 4 bits Broadband Characteristics of a Dome-Dipole Antenna IEEE APS/URSI Symposium, July 2010, Toronto 16/19
  31. 31. Optimization of Inverted-Hat Antenna Using Genetic Algorithm 6” tall IHA Optimization (200 MHz - 2 GHz) Optimized IHA using GA for constant gain and impedance Profile of 6" tall IHA 10 Optimized IHA using GA 8 IHA Published by Zhao, etc. [2] Width Global Profile Curvature # of Ellipse 6 H, in 12” convex 0.1 33 4 2 0 −16 −12 −8 −4 0 4 8 12 16 W, in 15 150 Optimized IHA using GA Resistance − Optimized IHA using GA IHA Published by Zhao, etc. [2] 125 Reactance − Optimized IHA using GA Resistance − IHA Published by Zhao, etc. [2] Reactance − IHA Published by Zhao, etc. [2] 10 100 Impedance (Ω) Directivity (dB) 75 5 50 25 0 0 −25 −5 −50 0 0.5 1 1.5 2 0 0.5 1 1.5 2 Frequency (GHz) Frequency (GHz) Broadband Characteristics of a Dome-Dipole Antenna IEEE APS/URSI Symposium, July 2010, Toronto 17/19
  32. 32. Optimization of Inverted-Hat Antenna Using Genetic Algorithm 6” tall IHA Optimization (1 GHz - 6 GHz) Optimized IHA using GA for constant gain and impedance Profile of 6" tall IHA 10 Optimized IHA using GA 8 IHA Published by Zhao, etc. [2] Width Global Profile Curvature # of Ellipse 6 H, in 28” convex 0.8 31 4 2 0 −16 −12 −8 −4 0 4 8 12 16 W, in 15 175 Optimized IHA using GA Resistance − Optimized IHA using GA IHA Published by Zhao, etc. [2] 150 Reactance − Optimized IHA using GA 125 Resistance − IHA Published by Zhao, etc. [2] Reactance − IHA Published by Zhao, etc. [2] 10 100 Impedance (Ω) 75 Directivity (dB) 50 5 25 0 0 −25 −50 −75 −5 −100 1 2 3 4 5 6 1 2 3 4 5 6 Frequency (GHz) Frequency (GHz) Broadband Characteristics of a Dome-Dipole Antenna IEEE APS/URSI Symposium, July 2010, Toronto 18/19
  33. 33. Concluding Remarks Summary Broadband Characteristics of a Dome-Dipole Antenna IEEE APS/URSI Symposium, July 2010, Toronto 19/19
  34. 34. Concluding Remarks Summary A dome-dipole antenna is designed, fabricated and validated to provide consistent dipole-like pattern over 100:1 bandwidth using 24”×20” aperture. It is rugged and simple for ground vehicle communication systems Broadband Characteristics of a Dome-Dipole Antenna IEEE APS/URSI Symposium, July 2010, Toronto 19/19
  35. 35. Concluding Remarks Summary A dome-dipole antenna is designed, fabricated and validated to provide consistent dipole-like pattern over 100:1 bandwidth using 24”×20” aperture. It is rugged and simple for ground vehicle communication systems Utilizing body-of-revolution (BoR) principle, compared to the commercial 3-D MoM solver FEKO, the computational efficiency is improved by a factor of 100 when evaluating the performance of an electrically large dome-dipole antenna (12λ × 10λ) Broadband Characteristics of a Dome-Dipole Antenna IEEE APS/URSI Symposium, July 2010, Toronto 19/19
  36. 36. Concluding Remarks Summary A dome-dipole antenna is designed, fabricated and validated to provide consistent dipole-like pattern over 100:1 bandwidth using 24”×20” aperture. It is rugged and simple for ground vehicle communication systems Utilizing body-of-revolution (BoR) principle, compared to the commercial 3-D MoM solver FEKO, the computational efficiency is improved by a factor of 100 when evaluating the performance of an electrically large dome-dipole antenna (12λ × 10λ) Incorporating BoR method and genetic algorithm (GA), a 6” tall inverted-hat antenna (IHA) is optimized for constant impedance and gain performance Broadband Characteristics of a Dome-Dipole Antenna IEEE APS/URSI Symposium, July 2010, Toronto 19/19

×