Time Reversed Electromagnetic Wave Propagation as a Novel Method - PowerPoint PPT Presentation

Time Reversed Electromagnetic Wave Propagation as a Novel Method of Wireless Power Transfer Frank Cangialosi, Tyler Grover, Patrick Healey, Tim Furman, Andrew Simon, Steven M. Anlage 1

Current State of Long-Range WPT Ubiquitous WPT requires greater range than provided by near-field technologies Microwave Beaming

X Current State of Long-Range WPT Ubiquitous WPT requires greater range than provided by near-field technologies Microwave Beaming Precise Alignment Obstructions

Current State of Long-Range WPT Ubiquitous WPT requires greater range than provided by near-field technologies Microwave Beaming Precise Alignment Obstructions

Current State of Long-Range WPT Ubiquitous WPT requires greater range than provided by near-field technologies Microwave Beaming Precise Alignment Safety Hazard Obstructions

Time Reversal A signal-focusing technique 1. Time Forward Step Target requests power, source records sona Target Device T 15 Voltage (mV) 10 5 S 0 Power Source -5 -10 (Enclosed cavity with reflecting walls) -15 0 2 4 6 8 10 12 14

Time Reversal A signal-focusing technique 1. Time Forward Step Target requests power, source records sona Target Device T Gaussian Pulse (50 ns) “Sona" 15 Voltage (mV) 10 5 S 0 Power Source -5 -10 (Enclosed cavity with reflecting walls) -15 0 2 4 6 8 10 12 14

Time Reversal A signal-focusing technique 1. Time Forward Step 2. Time Reverse Step Target requests power, Source reverses and broadcasts, source records sona sona reconstructs on target 400 Target Device Voltage (mV) 300 200 100 T 0 -100 -200 -300 -400 13.45 13.46 13.47 13.48 13.49 13.5 13.51 Time( µ s) “Sona" 15 Voltage (mV) 10 5 S 0 Power Source -5 -10 (Enclosed cavity with reflecting walls) -15 0 2 4 6 8 10 12 14

Time Reversal A signal-focusing technique 1. Time Forward Step 2. Time Reverse Step Target requests power, Source reverses and broadcasts, source records sona sona reconstructs on target 400 Target Device Voltage (mV) 300 200 100 T 0 -100 -200 -300 -400 13.45 13.46 13.47 13.48 13.49 13.5 13.51 Time( µ s) “Sona" 15 15 Voltage (mV) 10 10 5 5 S 0 0 Power Source -5 -5 -10 -10 (Enclosed cavity with reflecting walls) -15 -15 0 2 4 6 8 10 12 14 14 12 10 8 6 4 2 0

Time Reversal A signal-focusing technique 1. Time Forward Step 2. Time Reverse Step Target requests power, Source reverses and broadcasts, source records sona sona reconstructs on target 400 Target Device Voltage (mV) 300 200 100 T 0 -100 -200 -300 -400 13.45 13.46 13.47 13.48 13.49 13.5 13.51 “Reconstruction” Time( µ s) pulse “Sona" 15 15 Voltage (mV) 10 10 5 5 S 0 0 Power Source -5 -5 -10 -10 (Enclosed cavity with reflecting walls) -15 -15 0 2 4 6 8 10 12 14 14 12 10 8 6 4 2 0

Time Reversal A signal-focusing technique 1. Time Forward Step 2. Time Reverse Step Target requests power, Source reverses and broadcasts, source records sona sona reconstructs on target 400 Target Device Voltage (mV) 300 200 100 T 0 -100 -200 -300 -400 13.45 13.46 13.47 13.48 13.49 13.5 13.51 “Reconstruction” Time( µ s) pulse “Sona" 15 15 Voltage (mV) 10 10 Good for rectification 5 5 S 0 0 Power Source -5 -5 -10 -10 (Enclosed cavity with reflecting walls) -15 -15 0 2 4 6 8 10 12 14 14 12 10 8 6 4 2 0

Time Reversal for WPT Requires… Provides… Spatial reciprocity Range (not limited to 1 1 of the wave equation free space drop-off) Reflective Resilience to 2 2 surfaces obstructions Ray-chaotic Power concentrated 3 3 environment at any given location 5

Experimental Setup Scattering panels Device Power Source ensure ray chaos (on MikroMove) (5Ghz, 3dBm) +35 0 (mm) -35 Wave Generation (TX) Wave Analysis (RX) PSG AWG MATLAB Oscilloscope 6

Spatial Profiling of Reconstruction +35 Target: 0 0 mm -35 Constant Velocity 0.2 mm/s 7

Spatial Profiling of Reconstruction +35 Target: 0 0 mm -35 Constant Velocity 0.2 mm/s 7

Spatial Profiling of Reconstruction +35 Target: 0 0 mm -35 Constant Velocity 0.2 mm/s 7

Spatial Profiling of Reconstruction +35 Target: 0 0 mm -35 Constant Velocity 0.2 mm/s 7

Spatial Profiling of Reconstruction � ◆� ✓ x + c � � V ( x ) = a · � + d � sinc � � b V ( x ) x 8

Spatial Profiling of Reconstruction � ◆� ✓ x + c � � V ( x ) = a · � + d � sinc � � b V ( x ) x 8

Spatial Profiling of Reconstruction � ◆� ✓ x + c � � V ( x ) = a · � + d � sinc � � b V ( x ) Background noise x 8

Spatial Profiling of Reconstruction � ◆� ✓ x + c � � V ( x ) = a · � + d � sinc � � b V ( x ) Background noise x 8

Targeting a Moving Receiver “ Refresh ” the sona before it gets stale 3.5 V(t) Peak-To-Peak Voltage (V) 3 2.5 2 1.5 1 0.5 0 0 20 40 60 80 100 120 140 Time (s) 9

Targeting a Moving Receiver “ Refresh ” the sona before it gets stale 3.5 V(t) Peak-To-Peak Voltage (V) 3 2.5 2 1.5 1 0.5 0 0 20 40 60 80 100 120 140 Time (s) 9

Targeting a Moving Receiver “ Refresh ” the sona before it gets stale 3.5 V(t) Peak-To-Peak Voltage (V) 3 2.5 2 1.5 1 0.5 0 0 20 40 60 80 100 120 140 Time (s) 9

Targeting a Moving Receiver “ Refresh ” the sona before it gets stale 3.5 V(t) Peak-To-Peak Voltage (V) 3 2.5 2 1.5 1 0.5 0 0 20 40 60 80 100 120 140 Time (s) 9

Targeting a Moving Receiver “ Refresh ” the sona before it gets stale 3.5 V(t) Peak-To-Peak Voltage (V) 3 2.5 “Dead” time 2 1.5 1 0.5 0 0 20 40 60 80 100 120 140 Time (s) 9

Targeting a Moving Receiver “ Refresh ” the sona before it gets stale 3.5 V(t) Peak-To-Peak Voltage (V) 3 2.5 “Dead” time 2 1.5 1 0.5 0 0 20 40 60 80 100 120 140 Time (s) 9

Targeting a Moving Receiver “ Refresh ” the sona before it gets stale Experimental Results 3.5 3.5 V(t) V(t) Peak-To-Peak Voltage (V) Peak-To-Peak Voltage (V) 3 3 2.5 2.5 2 2 1.5 1.5 1 1 0.5 0.5 0 0 0 0 20 20 40 40 60 60 80 80 100 100 120 120 140 140 Time (s) Time (s) 10

Potential WPT System Supplier searches for participating devices Initialization Talk Session 5 (which may or may not have charge) Friday,17:45 (Selective Collapse of Nonlinear Time Reversed Small fraction of power reflected by device, Steady State Electromagnetic Waves) allowing supplier to find new location

Limitations And Future Work Transfer efficiency Use multiple channels Environmental losses Investigate and mitigate Dead time Use dedicated hardware TX and calculate new sona simultaneously These limitations are dependent on our lab equipment, they are not fundamental limitations of the technique 12

Summary Time is a promising new basis for long-range WPT can transmit energy to receivers in motion Reversal does not require the receiver to be powered Poster Session 2 Talk Session 5 Friday,14:40 Friday,17:45 (Time Reversed Wave Propagation (Selective Collapse of Nonlinear Time as a Novel Method of WPT) Reversed Electromagnetic Waves) frank@cs.umd.edu anlage@umd.edu 13