Periodic Leaky-Wave Antennas for Orbital Angular Momentum Multiplexing System Master Thesis Final Presentation

Transcription

1 Periodic Leaky-Wave Antennas for Orbital Angular Momentum Multiplexing System Master Thesis Final Presentation Amar Al-Bassam

2 Outline I. INTRODUCTION II. CONCEPT OF GENERATION III. ELECTROMAGNETIC MODELING IV. DESIGN & EXPERIMENTAL RESULTS CONCLUSIONS & QUESTIONS 2

3 I. INTRODUCTION II. CONCEPT OF GENERATION III. ELECTROMAGNETIC MODELING IV. DESIGN & EXPERIMENTAL RESULTS CONCLUSIONS & QUESTIONS 3

4 Orbital Angular Momentum Spin Angular Momentum Elliptical polarization Orbital Angular Momentum Helical phase-fronts Photons cannot have zero spin. Linear polarization is combination of RHCP and LHCP Images courtesy of physics.gla.ac.uk/optics 4

5 Magnitude & Phase of Vortex Beams 5

6 I. INTRODUCTION II. CONCEPT OF GENERATION III. ELECTROMAGNETIC MODELING IV. DESIGN & EXPERIMENTAL RESULTS CONCLUSIONS & QUESTIONS 6

7 Leaky-Wave Antenna (LWA) Types Uniform Truly Periodic Periodic Quasi -Uniform invariant along propagation axis dominant or higher mode fast-wave mode periodic along propagation axis space harmonics (SH) using fast SH ( 0 slow), -1 BWD and FWD CRLH topologically periodic, but electromagnetically uniform period << using fast SH: n = 0 7

8 Full-Space Scanning 8 Report Amar Al-Bassam

9 Vortex Beam Generation Concept 9

10 Phase Front of Linear & Circular LWA Off-broadside operation Titled phase front by Off-broadside operation Spiral phase front around propagation axis 10

11 I. INTRODUCTION II. CONCEPT OF GENERATION III. ELECTROMAGNETIC MODELING IV. DESIGN & EXPERIMENTAL RESULTS CONCLUSIONS & QUESTIONS 11

12 Surface Current Density Radial current (Shunt Mode) Azimuthal current (Series Mode) 12 *Eigenmode simulation in HFSS

13 Dyadic Green s Function Scalar Green s function Dyadic Green s function R. E. Collin, Field Theory of Guided Waves, 2 nd ed. 13

14 EM Modeling of Circular Array Circular array of radially directed electric dipoles Constant separation between elements and constant radius Propagation constant Arbitrary magnitude and phase excitation 14

15 EM Modeling of CLWA (*) S. Otto, Z. Chen, A. Al-Bassam, A. Rennings, K. Solbach and C. Caloz, Circular Polarization of Periodic Leaky-Wave Antennas with Axial Asymmetry: Theoretical Proof and Experimental Demonstration, TAP

16 Numerical Results 16

17 Example: Uniform Current 17

18 Example: Decaying Current 18

19 Example: Decaying Current with Two Points Exciation 19

20 I. INTRODUCTION II. CONCEPT OF GENERATION III. ELECTROMAGNETIC MODELING IV. DESIGN & EXPERIMENTAL RESULTS CONCLUSIONS & QUESTIONS 20

21 MIM-CRLH Unit Cell Design 21

22 Simulation Results of One Unit Cell 22

23 Two Halves CLWA 23

24 Simulation Results 24

25 Feeding Network 25

26 Simulation of the Feeding Network 26

27 Maximizing Radiation Efficiency 27

28 Prototype 28

29 29 Measurement & Simulation Comparison

30 Cylindrical Near-Field Measurement E-Field sampling on a cylindrical surface Near-field to far-field transformation Back transformation to planar near-field 30

31 Results of Near-Field Measurement 31

32 Transmission Measurement Setup 32

33 33

34 34

35 Circular Phased Array: An Alternative to CLWA Radial patch array 35

36 Simulation Results 36

37 I. INTRODUCTION II. CONCEPT OF GENERATION III. ELECTROMAGNETIC MODELING IV. DESIGN & EXPERIMENTAL RESULTS CONCLUSIONS & QUESTIONS 37

38 Conclusions EM modeling of CLWA - valid in near- and far-field - models the series and shunt modes independently - pahse & amplitude relations Experimental Validation - near-field measurement - two channels multiplexing 38

39 Thank You!