Satellite Digital Audio Radio Service Receiver Front-End (SDARS)

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Satellite Digital Audio Radio ServiceReceiver
Front-End(SDARS)

• Albert Kulicz
• Greg Landgren
• Advisor Dr. Prasad Shastry

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SDARS

• What is SDARS
• Overall System Block Diagram
• Patch Antenna
• Low Noise Amplifiers (LNA)
• Equipment and Parts List
• Tasks for Next Semester

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What is SDARS?

• The Satellite Digital Audio Radio Service is
  primarily for entertainment broadcasting from
  orbital satellites and received by modules
  commonly found on modern automobiles. (ex XM or
  Sirius Radio)
• 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 and LNA physical board design

• Compared to past SDARS projects, our design will
  contain the entire active antenna on a single
  board consisting of two substrates as seen
  below.

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Patch Antenna

• Passive portion of the active antenna
• Receives incoming signal from satellite
• Design Goal Make it smaller than previous SDARS
  attempts and stay within the specified
  requirements

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Antenna Requirements

• 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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Antenna Requirements Cont
Desired VSWR lt2 or S11lt-10 dB , fo 2.326 GHz
, 12.5MHz BW
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Antenna Impedance Bandwidth
.012
BW BW/fo (12.5M Hz/2.326 GHz) 100
0.537
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Antenna High Frequency Substrate - Rogers RO3003
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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
  3.692cm x 3.692 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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LHCP and Probe Feed

• SDARS signal from satellite is LHCP so the
  antenna must also be LHCP to receive the signal
• LHCP Probe Feed on Patch Antenna
• Using CPPATCH program we determined the distance
  from the center to edge (along diagonal) to be
  0.382 cm

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Low Noise Amplifers (LNA)

• The LNA network will take the low-power satellite
  signal and amplify it to a level where the Sirius
  receiver can reliably decode the radio channels
• A cascaded network of LNAs will allow us to
  achieve both a low total noise factor and a high
  total gain
• Two stages of amplification will suffice

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LNA Requirements

• 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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Hittite LNAs
Second stage Higher Gain
First stage NF lt.9dB
Total Noise Factor 0.77
Total Gain 45 dB
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Parts and Equipment

• RO3003 substrate
• Sirius Radio Receiver
• LNA substrate - tbd
• HMC548LP3 LNA
• HMC667LP2 LNA
• MCL15542 DC Blocking Capacitor

• EM Simulation Software (Sonnet / Momentum)
• PCAAD
• Agilent ADS
• CPPATCH
• Network Analyzer
• Spectrum Analyzer
• Frequency Generator
• Power Supplies

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Tasks for Next Semester

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

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QUESTIONS

• ???