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The Sandia Wave Reflector

Sandia National Laboratories

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Publications:

PDF Document PublicationWave Reflector SAND 2013-8893P.pdf (1,092 KB)

433 MHz antenna and wave reflector<br />
Device weighs 0.3 kg with dimensions of 21 x 43 x 320 mm.&nbsp;<br />
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433 MHz antenna and wave reflector
Device weighs 0.3 kg with dimensions of 21 x 43 x 320 mm. 

Performance Comparison: Antenna Without and With the Wave Reflector.<br />
Solid Lines for Gain; Crossed Lines for Return Loss.<br />
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Performance Comparison: Antenna Without and With the Wave Reflector.
Solid Lines for Gain; Crossed Lines for Return Loss.

Technology Marketing Summary

The Sandia wave reflector is a magnetic conductor for wireless transmissions near 433 MHz. The device reflects perpendicular electromagnetic waves in-phase and suppresses surface waves resulting in improved gain performance and effective operation regardless of physical placement.

Description

The reflector achieves gain improvement through a quarter-wave short phenomenon. The height of the ceramic rods is electrically equivalent to a quarter-wavelength near 433 MHz. The rods are able to provide this electrical delay in a small form factor due to their high dielectric constant. As an electromagnetic wave travels through the rods along their axes it receives a 1/4 period of phase delay be-fore it reaches the conductive short. The conductive backing reflects electromagnetic waves with a +180° phase, and then the waves travel back through the rods along their axes to receive another 1/4 period of phase delay. This causes the waves to arrive at the antenna surface with a +180° phase and a 1/2 period delay, creating positive interference that effectively doubles the gain of the antenna.

 

Placement-immunity is achieved in the reflector through surface wave suppression. By preventing surface waves from propagating out of the substrate (perpendicular to the main beam direction), they cannot interact with the surrounding environment and affect the antenna’s performance. Surface wave suppression is achieved through the magnetic dipole resonance of the ceramic rods. When an electromagnetic wave near 433 MHz excites the dielectric rods in the substrate with a transverse electric field polarization, the permeability of the dielectric rods skyrockets at that frequency due to the rod’s resonance. The large permeability of the rods in resonance creates a high impedance surface for the incident electric field, which causes the wave to reflect off of the rod instead of propagating through it.

Benefits
  • Improved return loss
  • Gain reinforcement
  • Placement immunity– reflector operates effectively regardless of physical placement
  • Reduces design time required for antennas needed in various environments
Applications and Industries
  • Voice Communications
  • Mobile Robots
  • Tracking Devices
  • Inventory Reconciliation
  • Security Alarms
  • Wireless Information Storage
Patents and Patent Applications
ID Number
Title and Abstract
Primary Lab
Date
Patent 9,147,931
Patent
9,147,931
Metal-free magnetic conductor substrates for placement-immune antenna assemblies
A magnetic conductor substrate produced for mounting to an antenna includes a sheet of dielectric lattice material having a length, a width and a thickness that is less than the length and less than the width. Within the sheet of dielectric lattice material is disposed an array of dielectric elements.
Sandia National Laboratories 09/29/2015
Issued
Technology Status
Technology IDDevelopment StageAvailabilityPublishedLast Updated
SD #12134Development - At 433 MHz the Sandia Wave Reflector has an estimated TRL of 8. It has been proven to work in its final form under expected conditions.Available10/15/201310/27/2016

Contact SNL About This Technology

To: <ip@sandia.gov>