Satellite Digital Audio Radio Service Receiver Front End SDARS by alicejenny


									Satellite Digital Audio
    Radio Service
 Receiver Front-End
         Albert Kulicz
         Greg Landgren
   Advisor: Dr. Prasad Shastry
   What is SDARS
   Overall System Block Diagram
   Patch Antenna
   Low Noise Amplifiers (LNA)
   Equipment and Parts List
   Tasks for Next Semester
                 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.
                          System Block Diagram

                                                 Active Antenna on PCB

                                                                           F1                    F2
Incoming Circularly                             Impedance                                                SIRIUS Radio
                            Passive Antenna
Polarized Satellite                           Matching Network                                             Receiver
                                                                           G1                    G2
Signal (-105 to -95)dbm
                                                                  Low Noise Cascaded Amplifier Network
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
               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
        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
 Antenna Requirements Cont…

Desired: VSWR <2 or S11<-10 dB , fo = 2.326 GHz , 12.5MHz BW
Antenna Impedance Bandwidth

   %BW = BW/fo = (12.5M Hz/2.326 GHz) * 100% = 0.537%
 Antenna High Frequency
Substrate - Rogers RO3003
    Antenna Dimension Equations
                    (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
   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
      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
   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
   Noise factor shall be <= 1dB

    NF = F1 + (F2 -1)/G1 + (F3-1)/(G1*G2 )+ . . .

   Total gain shall be -> 40~50 dB
    Gtotal = G1 + G2 + . . .
                  Hittite LNAs

First stage NF <.9dB                        Second stage Higher Gain

                       Total Noise Factor = 0.77

                       Total Gain = 45 dB
          Parts and Equipment
   RO3003 substrate         EM Simulation
                              Software (Sonnet /
   Sirius Radio Receiver
   LNA substrate - tbd      PCAAD
   HMC548LP3 LNA            Agilent ADS
   HMC667LP2 LNA            CPPATCH
   MCL15542 DC              Network Analyzer
    Blocking Capacitor       Spectrum Analyzer
                             Frequency Generator
                             Power Supplies
        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)


To top