Post on 15-Aug-2020
Compact 3D-printed Variable-infill Antenna for Snow Cover Monitoring
P. F. Espin-Lopez1, M. Pasian1
1 Dept. of Electrical, Computer and Biomedical Engineering, University of Pavia, Pavia, Italy,pedrofidel.espinlopez01@universitadipavia.it
marco.pasian@unipv.it
Alpine Regions
Motivation
Affected by snow avalanches
100 millions tons of goods
20 millions tourists
22 millions residents
avg. 100 deaths per year
Structural defense > 100 M€/y
Damage (y. 1999) ≈ 1000 M€
Source: Centre for Climate Adaptation, www.climateadaptation.eu EU FP5 SATSIE, Avalanche studies and model validation in Europe
Avalanche Forecasting
Information about the Snowpack
Manual Stratigraphy
Compact 3D-printed Variable-infill Antenna For Snow Cover Monitoring - P.F Espin-Lopez and M. Pasian - EuCAP 2018
Motivation
Manual Snow Stratigraphy
Avalanches: Instability at the interface between different snow layers.Snow stratigraphy crucial for avalanche forecasting and risk-managementManual stratigraphy is widely accepted as forecasting method
no real time – 7d/15d repetition timerarely on steep slopes – logistic and safety
problemsexpensive – time consuming, 2/3 profiles per
dayno during adverse weather – impossible,
dangerous
Not available when and where MOST NEEDED
Microwave Radar
Systems for Snowpack Monitoring
[1]-[5][1] Marshall, 2008[2] Atayants, 2014[3] Schmid, 2014[4] Frey, 2015[5] Rekioua, 2015
Compact 3D-printed Variable-infill Antenna For Snow Cover Monitoring - P.F Espin-Lopez and M. Pasian - EuCAP 2018
Antenna Specifications
Microwave FMCW Radar System presented in [*]
D ⁓ 1-2 m in Alpine Regions
S ⁓ 0.3-1 m for Optimization [*]
Snow Density (kg/m3)
LWC (%)
[*]
ε ' ε ''
dry 90 – 450 ~ 0 1.2 –1.8 ~ 0
wet 400 –700
3 –12
2.1 –4.3
0.03 –0.21
Ice 800 –900 ~ 0 ~ 0
For microwave radars aimed at snowpack monitoring, low frequencies are preferred to provide an adequate penetration depth, even in the presence of moderately wet snow [*]
Up to C band
Snow density, Liquid Water Content (LWC) and dielectric permittivity at 1 GHz for typical alpine snow [**]
*P. F. Espin-Lopez, M. Pasian, M. Barbolini, and F. Dell’Acqua, “Optimization of a multi-receiver FMCW radar for snow cover monitoring”, 12th European Conference on Antennas and Propagation (EuCAP 2018), London, UK, 9-13 April 2018.**M. T. Hallikainen, F. T. Ulaby, and M. Abdelrazik, “Dielectric properties of snow in the 3 to 37 GHz range,” IEEE Transactions on Antennas and Propagation, Vol. 34, No. 11, pp. 1329–1340, November 1986.
Ground or Air
Ground or Air
2.9
Compact 3D-printed Variable-infill Antenna For Snow Cover Monitoring - P.F Espin-Lopez and M. Pasian - EuCAP 2018
Antenna Specifications
D ⁓ 1-2 m in Alpine Regions
S ⁓ 0.3-1 m for Optimization
Radar Resolution
𝜁𝜁 =𝑣𝑣2𝐵𝐵
v = wave speed into the mediumB= radar bandwidth
⁓5 cm layers
Bandwidth > 3 GHz
Wide BeamwidthSnowpack
Compact 3D-printed Variable-infill Antenna For Snow Cover Monitoring - P.F Espin-Lopez and M. Pasian - EuCAP 2018
Antenna Specifications
D ⁓ 1-2 m in Alpine Regions
S ⁓ 0.3-1 m for Optimization
Radar Resolution
𝜁𝜁 =𝑣𝑣2𝐵𝐵
v = wave speed into the mediumB= radar bandwidth
⁓5 cm layers
Bandwidth > 3 GHz
Wide BeamwidthSnowpack
-Frequency band up to C band-Bandwidth > 3 GHz-Wide Beamwidth Antenna-Reduced volume and weight
In Summary
Compact 3D-printed Variable-infill Antenna For Snow Cover Monitoring - P.F Espin-Lopez and M. Pasian - EuCAP 2018
Premix Preperm® 3D ABS
-Special 3D filament -2.85 mm Ø-Based on ABS thermoplastic polymer-ε’r = 4.5 @1GHz-tan δ = 0.004 @1GHz-Can be printed with a FDM machine
Compact 3D-printed Variable-infill Antenna For Snow Cover Monitoring - P.F Espin-Lopez and M. Pasian - EuCAP 2018
Premix Preperm® 3D ABS
-Special 3D filament -2.85 mm Ø-Based on ABS thermoplastic polymer-ε’r = 4.5 @1GHz-tan δ = 0.004 @1GHz-Can be printed with a FDM machine
Very Low Losses!!&
Design freedom
Compact 3D-printed Variable-infill Antenna For Snow Cover Monitoring - P.F Espin-Lopez and M. Pasian - EuCAP 2018
DRW Antenna Design
- Double Ridge Waveguide Open-ended Antenna- 3D printed using Premix Preperm 3D ABS- 5.16 x 2.40 x 6.78 cm- SMA connector- Variable infill- Tapered ridges
Compact 3D-printed Variable-infill Antenna For Snow Cover Monitoring - P.F Espin-Lopez and M. Pasian - EuCAP 2018
DRW Antenna Design
Simulated input matching of the proposed antenna with variable infill (solid curve) and with constant infill (dashed curve).
Inpu
t Mat
chin
g (d
B)
Compact 3D-printed Variable-infill Antenna For Snow Cover Monitoring - P.F Espin-Lopez and M. Pasian - EuCAP 2018
DRW Antenna Design
Simulated input matching for the proposed DRW antenna fordifferent snow conditions (ε' = 1.2–4.3).
Inpu
t Mat
chin
g (d
B)
Compact 3D-printed Variable-infill Antenna For Snow Cover Monitoring - P.F Espin-Lopez and M. Pasian - EuCAP 2018
Antenna Realization
3D printed antenna (Premix Preperm)
Conductive silver-based paint
Copper electrodeposition
Fabrication Process
Compact 3D-printed Variable-infill Antenna For Snow Cover Monitoring - P.F Espin-Lopez and M. Pasian - EuCAP 2018
Antenna Realization
Input matching: simulated (solid curve) and measured (dots).Keysight N9928A Virtual Network Analyzer in anechoic chamber and a standard certified probe antenna
Inpu
t Mat
chin
g (d
B)
Compact 3D-printed Variable-infill Antenna For Snow Cover Monitoring - P.F Espin-Lopez and M. Pasian - EuCAP 2018
Antenna Realization
Normalized radiation patterns: (top) H-plane (bottom) E-plane at the central frequency of 4.15 GHz. Simulated co-polarization (solid line) and crosspolarization (dashed line), along with measured co-polarization (dots) are reported.
Normalized radiation patterns: (top) H-plane (bottom) E-plane at 2.48 GHz (solid black line), 3 GHz (solid dark grey line), 4 GHz (solid light grey line), 5 GHz (dashed black line), and 6 GHz (dashed light grey line).
Compact 3D-printed Variable-infill Antenna For Snow Cover Monitoring - P.F Espin-Lopez and M. Pasian - EuCAP 2018
Antenna Realization
Simulated (solid curve) and measured (dots) for the peak gain.
Keysight N9928A Virtual Network Analyzer in anechoic chamber and a standard certified probe antenna
Immagine Camera
Compact 3D-printed Variable-infill Antenna For Snow Cover Monitoring - P.F Espin-Lopez and M. Pasian - EuCAP 2018
Antenna Realization
Summary- Input matching better than -6 dB from
2.3 GHz to 6 GHz (BW-6dB=3.7 GHz).- Gain of 5 dBi at the central
frequencies.- 5.16 x 2.40 x 6.78 cm3 for 100 g of
mass, robust design and durable materials.
Compact 3D-printed Variable-infill Antenna For Snow Cover Monitoring - P.F Espin-Lopez and M. Pasian - EuCAP 2018
Conclusions
- A novel Double Ridge Waveguide Antenna suitable for snowpack monitoring was designed, fabricated and measured.
- Intended both for portable and permanent applications.
- Realized with 3D printed techniques using the ultra low loss filament Premix Preperm 3D ABS.
- The antenna will be tested on the field in the next days and seasons.
Compact 3D-printed Variable-infill Antenna For Snow Cover Monitoring - P.F Espin-Lopez and M. Pasian - EuCAP 2018
References
[1] H.-P. Marshall and G. Koh, “FMCW Radars for snow research,” Cold Regions Science and Technology, Vol. 52, pp. 118–131, 2008.[2] B. A. Atayants et al., Precision FMCW short-range radar for industrial applications, Artech House, 2014.[3] L.Schmid, et al., “Continuous snowpack monitoring using upwardlooking ground-penetrating radar technology,” Journal of Glaciology, Vol. 60, No. 221, pp. 509–525, 2014.[4] O. Frey, C. L. Werner, and A. Wiesmann, “Tomographic profiling of the structure of a snow pack at X-/Ku-Band using SnowScat in SAR mode,” 2015 European Microwave Conference, Paris, France, September 6–11, 2015.[5] B. Rekioua, M. Davy, and L. Ferro-Famil, “Snowpack characterization using SAR tomography – experimental results of the AlpSAR campaign,” 2015 European Radar Conference, Paris, France, September 6–11, 2015.
Compact 3D-printed Variable-infill Antenna For Snow Cover Monitoring - P.F Espin-Lopez and M. Pasian - EuCAP 2018
THANKS!
Compact 3D-printed Variable-infill Antenna For Snow Cover Monitoring - P.F Espin-Lopez and M. Pasian - EuCAP 2018
Appendix I