Near-Field Focused Phased Array and Scanning Antennas for RFID Applications

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Near-Field Focused Phased Array and Scanning
Antennas forRFID Applications

• Greg Mendolia
• Vice President, Product Strategy
• Office 443-259-0140 x 130
• Fax [phone]

Paratek Microwave, Inc. 6935 Oakland Mills Road,
Suite G Columbia, MD 21045
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Paratek Microwave, Inc.

• Founded in 1998 to develop innovative RF
  components based upon the companys proprietary
  materials technology, ParascanTM
• The Parascan materials science enabled the
  development of Parateks thin film, thick film
  and bulk material electronically tunable
  capacitors
• Electronic tunable RF components led to
  development of smart scanning antennas
• Independent, multi-beam, 360 steering
• Frequency coverage from 30MHz to 3 GHz
• Fast scanning in azimuth, elevation and frequency
• Re-configurable aperture for wide beam
  acquisition and then narrow steerable beam
• Maintain uninterrupted communications, increased
  LPI/LPD, higher capacity through frequency reuse
• Null steering for increased anti-jam
• Higher gain
• Horizontal and vertical polarization diversity
  mitigates multipath

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RFID Technology Challenges

• Accurate reading of 100 of the tags is essential

Tags inside moving payload
- - B U T - -

• Technical limitations reduce tag read rates
• Reader reception of tag data vulnerable to
  obstruction and de-tuning from metal, liquid and
  dense materials
• Conventional reader antennas do not track and
  stare at moving tags

- - I M P A C T - -

• Slow industry adoption due to technology
  shortfalls

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Paratek Solution

• Near Field Focused, Scanning Phased Array (NFA)

• Antenna power is surgically directed at and
  focused on targeted RFID tags by increasing
  power levels in the near field without polluting
  spectrum in the far field
• Antenna RF power is focused at the tag instead of
  spread over the entire area
• More signal power delivered at the tag gt more
  tags read and better ability to write to tags
• Multipath and interference problems reduced gt
  decreased tag contention
• Antenna tracks tags as they pass by
• Increased beam dwell time on tag gt longer read
  time
• Direction of tag movement can be detected
• Are items entering or leaving the area?

• KEY RESULT Dramatically improved tag read rates
  for RFID unfriendly materials

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Paratek NFA vs. Conventional Reader Antenna
Paratek Near Field Focused Phased Array Antenna
Conventional Reader Antenna Energy Distribution
Lower field intensity in near field
6dBi gain limit in far field
Higher field intensity in near field
6dBi gain limit in far field

• Near Field Focused Phased Array amplifies and
  focuses RF to increase power in the near field
• Arrays of elements are used to control energy
  focus and distribution
• RF power decays quickly so that power levels in
  the far field are comparable to standard antennas
• Compliant with FCC energy levels in far field
• Permits higher near field energy intensity at the
  tag location

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Paratek NFA vs. Conventional Phased Array Antenna
Conventional Far Field Focused Array Antenna
Paratek Near Field Focused Phased Array Antenna
6dBi gain limit in far field
Lower field intensity in near field
Higher field intensity in near field
6dBi gain limit in far field

• Conventional arrays focus energy in the
  far-field, not near field

• Paratek re-engineers the phase of each element in
  the array, focusing the energy in the near field
  where the tags are located
• The depth and direction of the focused region can
  be easily steered with standard phased array
  electronics

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Paratek NFA vs. Conventional Array Reader Antenna
Near Field EIRP
RF energy focused on tags
RF energy not where its needed
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Paratek NFA vs. Conventional Array Reader Antenna
Far Field EIRP
High far field RF energy (pollutes spectrum)
Far field RF energy dispersed
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Paratek NFA vs. Conventional Array
9 dB Improvement Over Conventional Antennas in
Near Field / Far Field Ratio
Target focus range NFA is 4.5 dB higher
NFA is 4.5dB lower
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Paratek NFA vs. Conventional Array
Comparative Statistical Read Rate (tags on
surface of cases of bottled water)
Same far-field EIRP
275 greater read rate _at_ 5
1,060 greater read rate _at_ 6
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Paratek Scanning Antenna

• Antenna Characteristics
• 862 - 928 MHz
• Passive Tx/Rx, 30 dBm max
• Gain 6.3 8.4 dBi
• Dual linear polarization V/H
• 27 dB isolation V-H ports

• Full 360 azimuth scan range
• 50 Azimuth beam (-3dB)
• 70 Elevation beam (-3dB)
• lt -10 dB Side/back lobe
• gt 12 dB Return loss, 50 ohm
• lt 1 ms Beam switch/scan

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Paratek Scanning Antenna
RFID Vertical Beam
Elevation Plane
Azimuth Plane
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Video 1
Conventional Far Field Focused Array Antenna
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Video 2
Paratek Near Field Focused Phased Array Antenna
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Summary

• Parateks Near Field Focused, Scanning Phased
  Array (NFA) antenna dramatically improves tag
  read rates under all conditions, especially RFID
  unfriendly materials, while also enhancing the
  ability to write to tags
• Electronic steering enables tracking of tags for
  increased acquisition time gt Results in
  dramatically improved read rates, as well as
  identification of direction of travel for tagged
  products
• Directed and controlled RF energy reduces tag
  contention and multipath issues
• NFA transmitted RF energy (EIRP) decays at a
  faster rate over distance gt Results in lower far
  field interference to other products or to other
  RFID systems