SDARS Receiver Front-End (Design Review)

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SDARS Receiver Front-End(Design Review)

• Albert Kulicz
• Greg Landgren
• Advisor Prasad Shastry

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Outline

• Overview
• Goals
• Tasks for Semester
• Antenna
• LNA Network
• Fabrication
• Tentative Schedule

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What is SDARS?

• This project involves designs, simulations,
  fabrication, and testing of a patch antenna and
  low-noise amplifier (LNA) to receive SDARS
  signals by means of SIRIUS receiver.
• The inclusion of the entire active antenna
  (passive antenna impedance matching network
  LNA) will be designed to minimize physical size,
  while producing the best quality of signal.

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System Block Diagram
Incoming Circularly Polarized Satellite Signal
(-105 to -95)dbm
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Antenna Goals

• Receive signals in the frequency band from 2.32
  GHz to 2.3325 GHz (BW of 12.5 MHz)
• Left Hand Circular Polarization (LHCP)
• Match in impedance to LNA network
• (50 Ohms)
• Probe Feed Placement will determine
  polarization and impedance match

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LNA Goals

• Noise factor shall be lt 1dB
• NF F1 (F2 -1)/G1 (F3-1)/(G1G2 ) . . .
• Total gain shall be -gt 4050 dB
• Gtotal G1 G2 . . .

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Tasks for Semester

• Complete EM simulations with Momentum and
  optimize antenna design (Feb)
• Test LNA evaluation boards with NA (Feb)
• Design Impedance Matching for the LNA network
  (Feb)
• Simulate entire active antenna in Agilent ADS
  (March)
• Design Bias Circuitry for the LNAs (March)
• Outsource Fabrication of Substrates (April)
• Test Fabricated Antenna and LNA substrates (May)
• Test complete systems active antenna board with
  Sirius Receiver (May)

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3D Passive Antenna Model
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Antenna Dimension Equations

• (LW for square patch)
• Initial length L c/(2fo er(1/2))
• eeff (er1)/2 (er-1)/2112(h/L))(-1/2)
• Fringe factor, ?L0.412 h (e eff 0.3)( W/h
  0.264) / ( (e eff - 0.258)(W/h 0.8))
• New length L c/(2fo eeff(1/2)) - 2?L
• repeat iterative process
  3.69cm x 3.69 cm

1 Balanis, Constantine A, Microstrip
Antennas, in Antenna Theory, 3rd ed. John Wiley
and Sons, Inc., 2005, pp. 811-882
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PCAAD (design for 2.326ghz)
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EM Simulation / Optimization
Agilent ADS - Patch Antenna S11
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Patch Antenna Top View
Probe location x 2.6372 cm x y 2.6372 cm
(0.509 cm from center)
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EM Simulation / Optimization
Agilent ADS - Patch Antenna S11
Impedance Zo(0.978-j0.001)
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Antenna Dissected Side View
Probe Feed copper wire diameter 0.15 cm Probe
hole 0.165 cm
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Antenna - Bottom View (LNA network)
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LNA schematics
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LNA experimental Gain

• Powered by Sirius Receiver

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S11 (return loss)
Entire System (Passive Antenna LNA)
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Fabrication

• Microcircuits, Inc.
• Using Gerber files for both antenna and LNA
  layouts
• CAMtek, Inc.
• Soldering

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Tentative Schedule

• Finalize Antenna and LNA layout and send Gerber
  file to Microcircuits (Mar.9)
• Test fabricated Antenna performance (March)
• Send fabricated LNA substrate to CAMtek for
  soldering (March)
• Assembly of completed boards, solder probe,
  mount to a Plexiglas or plastic encasing (April)

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Conclusion

• Finalized patch antenna dimensions and probe
  location
• LNA network gain will not meet proposed goal, but
  will suffice for our purposes
• Simulations show respectable return loss at
  desired bandwidth
• Fabrication and Assembly to be completed

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References

• 1 Zomchek, Greg and Zeliasz, Erik. SDARS
  Front-End Receiver Senior Capstone Project
• Report. Bradley University, Spring, 2001.
• 2 Lockwood, Kevin. SDARS Front-End Receiver
  Senior Capstone Project Report.
• Bradley University, Spring, 2011.
• 3 Balanis, Constantine A., Microstrip
  Antennas, in Antenna Theory, 3rd ed. John Wiley
• and Sons, Inc., 2005, pp.811-882
• 4 Pozar, David M. and Schaubert, Daniel H. A
  Review of Bandwidth Enhancement
• Techniques for Microstrip Antennas, in
  Microstrip Antennas the analysis and design of
• microstrip antennas and arrays Institute of
  Electrical and Electronics Engineers, Inc., 1995,
• pp.157-165