Satellite Digital Audio
Radio Service
Receiver Front-End
(SDARS)
Albert Kulicz
Greg Landgren
Advisor: Dr. Prasad Shastry
SDARS
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What is SDARS
Overall System Block Diagram
Patch Antenna
Low Noise Amplifiers (LNA)
Equipment and Parts List
Tasks for Next Semester
What is SDARS?
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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.
System Block Diagram
Active Antenna on PCB
F1
Incoming Circularly
Polarized Satellite
Signal (-105 to -95)dbm
Passive Antenna
F2
Impedance
Matching Network
SIRIUS Radio
Receiver
G2
G1
Low Noise Cascaded Amplifier Network
Antenna and LNA physical board design
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Compared to past SDARS projects, our design
will contain the entire active antenna on a single
“board” consisting of two substrates as seen
below.
Patch Antenna
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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
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 <2 or S11<-10 dB , fo = 2.326 GHz , 12.5MHz BW
Antenna Impedance Bandwidth
.012
%BW = BW/fo = (12.5M Hz/2.326 GHz) * 100% = 0.537%
Antenna High Frequency
Substrate - Rogers RO3003
Antenna Dimension Equations
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(L=W for square patch)
Initial length L = c/(2fo* εr^(1/2))
εeff= (εr+1)/2 + (εr-1)/2*[1+12(h/L))^(-1/2)
Fringe factor, ΔL=0.412 h (ε eff + 0.3)( W/h +
0.264) / ( (ε eff - 0.258)(W/h + 0.8))
New length L = c/(2fo* εeff^(1/2)) - 2ΔL
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
LHCP and Probe Feed
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SDARS signal from satellite is LHCP so the antenna
must also be LHCP to receive the signal
LHCP Probe Feed on Patch Antenna
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Using CPPATCH program we determined the distance from the
center to edge (along diagonal) to be 0.382 cm
Low Noise Amplifers (LNA)
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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
LNA Requirements
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Noise factor shall be <= 1dB
NF = F1 + (F2 -1)/G1 + (F3-1)/(G1*G2 )+ . . .
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Total gain shall be -> 40~50 dB
Gtotal = G1 + G2 + . . .
Hittite LNAs
Second stage Higher Gain
First stage NF <.9dB
Total Noise Factor = 0.77
Total Gain = 45 dB
Parts and Equipment
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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
Tasks for Next Semester
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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)
QUESTIONS
???