Mysteries of DRA Modes Unresolved Issues for the Future

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1 Mysteries of DRA Modes Unresolved Issues for the Future Debatosh Guha Institute of Radio Physics and Electronics, University of Calcutta, India University College of Science and Technology

2 On the World Map KOLKATA

3 Our Teachers C V Raman NL 193 R. N. Tagore NL 1913 S N Bose S K Mitra M N Saha

4 Our Heritage Demonstrated a mechanical operation using WIRELESS at 2.5 GHz transmitting Horn receiving Horn

5 Bose s Pyramidal Horn Rest is History

6 Today s Presentation Unknown Mode in Known DRA

7 31 Years ago

8 Cylindrical-DRA IEEE MTT Dec m e m HEM 11δ TM 1δ TE 1δ

9 Mode Nomenclature TE n p+δ TM n p+δ HEM m n p+δ m: number of full-period variations of fields along the azimuth n: half-wave variation along radius (field between center and the periphery) p+δ : half-wave variation along z-axis of the cylinder

10 HEM 11δ Isolated Resonator 1

11 TM 1δ E H Isolated Resonator 11

12 Theoretical HEM 12δ Mode Does it Radiate? It should Isolated Resonator Boundary condition does not allow any ground plane

13 Address the Challange y x Boundary Condition demands Horizontal current in place metal New approach to realize a current ribbon?? z x Non-resonant Microstrip Patch working as a current ribbon grounded substrate circular patch Probe current 13

14 First Examination Kajfez s Sample + our Technique 11.5 mm -5-1 S 11 (db) GHz 4.6 mm ε r = Gain at 7.24 GHz Frequency(GHz) co-polarized Directivity(dBi) E Plane H Plane cross-polarized Theta(degree) 14

15 experiments DRA when the feed is alone -1-2 meas simu S 11 (db) -3 NMP -4 front back DRA: ε r,d = 1, a = 1 mm, h = 1 mm. NMP r = 5 mm, ε r,s = 2.33, t=1.575mm; Frequency (GHz) S 11 (db) -2-3 measured simulated Frequency (GHz)

16 Radiations after 3 decades f = 7.4 GHz 1 meas simu co-polarized 1 meas simu Directivity (dbi) -1-2 cross-polarized Directivity (dbi) -1-2 cross-polarized co-polarized Angle (degree) E-plane Angle (degree) H-plane D. Guha, et al. IEEE AP Transactions, January,

17 Design Limitations? Unknown Mysteries Any limitation in DRA diameter? Any limitation in DRA height? Any limitation imposed by the DRA material? zinc tungstate composite D. Guha, et al. IEEE AP Mag. August 214

18 Any other Technique? Fully planar should be most advantageous; should it be like this? No, not so straight forward. Mysteries lie in Current Ribbon with matching; solution needs a different approach. D. Guha, et al. IEEE AP-S Memphis, 214

19 Yet any Other Technique? YES! Much Easier and Robust Technique has been developed recently and reported Excitation Mechanism? Completely NEW Feed is conventional using vertical Probe. Ground plane (GP) is a metal sheet. Boundary condition of GP has been modified favorably which can support HEM 12δ mode. Probe-Pin Ground Plane Rect Trough

20 Role of Embedded Truough ground plane with trough

21 The Results TROUGH causes R A D I A T E S R A D I A T E S D. Guha, et al. IEEE AWPL, 214

22 Yet Any Other? Definitely YES An Open Book to YOU Two Different Techniques have been Explored Recently 1 Composite Aperture to realize equivalent Magnetic & Electric Dipoles as new Feed 2 Under investigation

23 Suitable Aperture Aperture Coupled Why? Aperture introduces no metal. Favors required boundary condition for HEM 12δ mode. Suitable for HEM 11δ mode too.

24 Aperture-Feed Explored HEM 12δ + HEM 11δ 2mm Feed 1 Feed 2 ε r = 1 1mm S 11 (db) -1-2 Feed1 Feed 2 Feed 3 Feed Freq.(GHz)

25 Impedance vs Feed -1 S 11 (db) HEM 11δ HEM 12δ Freq.(GHz)

26 Characterize the Feed 1.j.5j 2.j 1.2j 5.j j -.5j RL Co-Cross Isolation Gain Choose the Right Feed for Higher Mode j -2.j -5.j Feed#1 Feed#2 Feed#3 Feed# Feed1 Feed2 Feed3 Feed4

27 What about Dominant Mode? 1.j 1.5j 2.j.2j 5.j 2 -.2j j Feed#1 Feed#2 Feed#3 Feed#4 -.5j -2.j 3-1.j 4

28 Select the Optimum One RL Co-Cross Isolation Gain (db/dbi) Feed#1 Feed#2 Feed#3 Feed#4 HEM 12δ HEM 11δ

29 Radiation Patterns E-Plane Gain (dbi) Co-pol Cross-pol HEM 11δ Feed1 Feed2 Feed3 Feed Angle(degree) E-Plane Gain (dbi) Co-pol HEM 12δ Feed1 Feed2 Feed3 Feed4 Cross-pol Angle(degree) H-Plane Gain(dBi) -1-2 Co-pol Cross-pol Feed1 Feed2 Feed3 Feed4 H-Plane Gain (dbi) -1-2 Co-pol Cross-pol Feed1 Feed2 Feed3 Feed Angle (degree) Angle(degree)

30 Optimized Aperture

31 Optimized Feed Line

32 Optimum Parameters b Frequency (f) Wavelength (λ) a b 3.85GHz(f 1 ) 78mm (λ 1 ) 7.35GHz (f 2 ) 41mm(λ 2 ) a b q Table of Parameters Parameters Optimized Value In Terms of λ (mm) a 1.13λ 1 (.24λ 2 ) l l p q w w k b 2.3λ 1 (.5λ 2 ) w 3.6.5λ 1 (.9λ 2 ) l 39.5λ 1 (.95λ 2 ) p 9.12λ 1 (.22λ 2 ) q λ 1 (.1λ 2 ) K λ 1 (.28λ 2 )

33 The Prototype

34 Viewed from Feed-line side

mode measured simulated HEM 11d mode -3 3 4 5

35 Measured Results S 11 (db) -1-2 measured simulated HEM 12d mode S 11 (db) -1-2 HEM 11d mode measured simulated HEM 11d mode Freq(GHz) -3 HEM 12d mode Freq (GHz)

36 Measured Radiations E-Plane Gain(dBi) co pol measured simulated cross pol H-Plane Gain (dbi) co pol measured simulated cross pol Angle(degree)? Angle(degree) E-Plane Gain (dbi) -1-2 co pol cross pol measured simulated H-Plane Gain (dbi) -1-2 co pol cross pol measured simulated Angle(degree) Angle(degree)

37 Interesting Observation a i r f i l m Air-film Thickness~ (.2-.4)mm

38 Closely Follow HEM 12δ E-Plane Gain (dbi) -1-2 co pol cross pol measured Simulated (with airfilm) H-Plane Gain (dbi) -1-2 co pol cross pol measured simulated (with airfilm) Angle(degree) Angle(degree) E-Plane Gain (dbi) -1-2 co pol cross pol measured simulated (with airfilm) H-Plane Gain (dbi) -1-2 co pol cross pol measured simulated (with airfilm) Angle Theta (degree) Angle(degree)

39 Effect of the air-film HEM 12δ Radiation over the Operating Band HEM 11δ

40 Location on the spectrum Frequency(GHz)

Is Interesting it a Strawberry Features?

41 Is Interesting it a Strawberry Features? New feed for CDRA with HEM 11δ & HEM 12δ modes simultaneously. Both the modes with comparable Bandwidth, Gain and Patterns. Dual mode dual-band antenna with identical radiations Unavoidable air-gap is a new finding, which adds a new feature. Unconventional Pattern providing larger Beamwidth

42 Known Modes in Unknown Structures

43 TM 1δ mode after a decade Mongia et al Elect. Lett. 29(17) ,

44 Marriage of two Monopoles Lapierre, Antar, Ittipiboon, Petosa, IEEE MWCL, Jan. 25. BW 2.9:1-5 S 11 (db) -1 Ittipiboon, Petosa, Thirakoune, Bandwidth enhancement of a monopole using dielectric antenna resonator loading, ANTEM, Canada, Aug US patent no Frequency (GHz) Sept. 25

45 Problem bestowed upon

46 Mystery of BW? Inside the Modes Return Loss (db) DRR :l= 4.4 mm monopole:l=1 mm DRR+monopole:l=1 mm? reduced length monopole.6l = λ 2 / Frequency (GHz)

47 Design Becomes Easy Guha, Antar, Ittipiboon, Petosa, Lee, IEEE AWPL, vol. 5, 26. a) Design Frequency first resonances:f 1, third resonances : f 3 are related as f H 2.5 f L. b) Monopole Parameters : Length : l = λ L /4 Radius : s r s/2 (c) DRA Parameters : Spacing s is important for second and third resonances and it is optimum when.16 λ L s.13λ L and b = r + s, a = b/.3,.5 l h.4l. Finally, ε r value is extracted from the TM 1 resonance formula

48 Verification Paper design as per Design Guideline Design Freq. GHz λ L mm Antenna Parameters l mm s mm r mm -5 b mm a mm h mm ε r -1 # S 11 (db) -2 # # #1 #2 #3 S 11 (db) -25 measured simulation Frequency (GHz) Frequency (GHz)

49 Improved Bandwidth? Definitely Yes! If we can add identical mode(s) How? Adding resonators? or Resonances? Let s examine the primary resonator if it can help! GHz 2 GHz Gain (dbi) Angle Theta (degree)

50 How to accommodate that mode? By shaping the DRA 29-12

51 What s New? -1 DRR radius = 4.2 mm DRR height = 4.4 mm inner cut rad=1.3 mm ε r =1 MP height=1 mm MP rad=.65 mm S 11 (db) Frequency (GHz)

52 Radiations over the Band 1 Directivity (dbi) f=6.8 GHz 13 GHz 16 GHz 2 Ghz Angle theta (degree) 52

The Physical Insight UWB? -1-1 -1 S 11 (db) S 11 (db) S 11 (db) -2-2 -2-3 -3-3 -4-4 -4-5 -5-5 a=5.

53 The Physical Insight UWB? S 11 (db) S 11 (db) S 11 (db) a=5.1 mm HDRR Alone Only MP MP-DRA (Hybrid) Frequency 15 (GHz) 2 25 Frequency (GHz)

54 Newer Detailed Modes? Studies and wider Bandwidth? D. Guha, et al, IEEE AWPL, vol. 5, 26. Yes, Possible D. Guha, B. Gupta and Y. M. M. Antar, IEEE AWPL, vol. 8, 29 D. Guha, B. Gupta and Y. M. M. Antar, IEEE AP Transactions, Jan., S 11 (db) S 11 (db) f (GHz) BW 148.4% Frequency GHz BW 177.5% 54

55 Composite DRA Structure Monopole-like Pattern D. Guha and Y. Antar: IEEE AP Transactions Oct. 26 D. Guha and Y. Antar: IEEE AP Transactions, Dec

56 New Approach New Configurations Central Dielectric Cylinder A A Cylindrical DRA Coaxial Probe 3% Bandwidth.1λ by.6 λ rad = 1 mm, height= 1 mm ε r = 1 central cylinder: rad = mm, height= 1 mm ε r = 12 probe length = 9.2 mm, radius =.55 mm. 56

57 The Resonances Return Loss (db) Measured Simulation Frequency (GHz) by DRA Probe as monopole HEM 11d mode 57

58 Half of a Hemisphere Half of a Hemisphere Electromagnetically coupled two Half- Hemispherical DRAs

59 Composite DRA -1 4% Bandwidth with 4.8 dbi peak gain. Return Loss (db) Frequency (GHz) measured

60 Radiation Patterns GHz Gain (dbi) -1-2 simulated measured Gain (dbi) -1-2 simulated measured Angle θ (degree) Angle θ (degree) GHz Gain (dbi) φ = o simulated measured Angle θ (degree) Gain (dbi) simulated measured Angle θ (degree) φ = 9 o 6

61 Symmetric Patterns? how to obtain Need Modal Symmetry Structural Symmetry Hemispherical DRA HDRA Half-HDRA h-hdra Quarter-HDRA q-hdra 61

62 Quarter and Composite Introduces Modal Symmetry

63 Are they Different Modes? -1 S 11 (db) -2 HEM 11δ -like mode -3 1 mm 11 mm 12 mm 13 mm Frequency (GHz) TM 11 mode 63

64 Perfect Symmetry simu meas S 11 (db) Frequency (GHz) 64

65 Radiation Patterns Gain (db) simu meas Cross-polarized Co-polarized 3.1 GHz Gain (dbi) simu meas Cross-polarized Co-polarized Angle theta (degree) Angle theta (degree) Φ= deg Φ=45 deg 1 simu meas Co-polarized 3.51 GHz 1 simu meas Co-polarized Gain (dbi) -1-2 Cross-polarized Gain (dbi) -1-2 Cross-polarized Angle theta (degree) Angle theta (degree) 65

66 Compare 5 Frequency=3.3 GHz 5 Frequency=3.3 GHz Gain (dbi) -5 Gain (dbi) Φ= Angle theta (degree) Frequency=3.7 GHz Angle theta (degree) Frequency=3.7 GHz Φ=9 Gain(dBi) -5 Gain (dbi) Angle theta (degree) Angle theta (degree) 66

67 Concluding Remarks DRA is still an Open Book; Not event its 3% Explored. DRA researchers should have more insight and serious attention Resonator, Material, and Antenna need to be addressed together Next Breakthrough Awaiting New Dielectric Materials I hope to come with new information for you shortly : Mode filtering technique as a potential tool for DRA engineers. Newer Feed to resolve major DRA issues in integrated platform - which is supposed to be very hard task. 67

68 Related Books Dielectric Resonator Antennas: K. M. Luk & K. W. Leung Dielectric Resonator Antenna Handbook: A. Petosa Antenna Engineering Handbook: J. L. Volakis Ed. Dielectric Materials for Wireless Comm: M. T. Sebastian 22 Research Studies Press 27Artech House 27 McGraw Hill 28 Elsevier

69 Remarks Behind this small contribution This approach can be extended to other DRA geometries. New Lights for future applications

Project: IEEE P Working Group for Wireless Personal Area Networks (WPANs)

Project: IEEE P Working Group for Wireless Personal Area Networks (WPANs) Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Title: Channel Model for Intra-Device Communications Date Submitted: 15 January 2016 Source: Alexander Fricke, Thomas Kürner,