ngVLAThe Next Generation Very Large Array
NATIONAL RADIO ASTRONOMY OBSERVATORY
DesignandDevelopmentofultrawideband8-50GHzLNA
AndrewJanzen,EzraLong,LoreneSamoska,SteveMontanez,JoseVelasco,JimBowen
The Next Generation Very Large Array
Outline
• Motivation• Modeling• MMICmeasurements• LNAmeasurementresults• MMICdesigniteration
The Next Generation Very Large Array
Motivation
• IncreaseDSNdownlinkdatarateby10xatXandKAbands• DecreasesystemcostofNGVLA• Opendoorsforwidebandscience• Challengeolddesignassumptions
The Next Generation Very Large Array
DC– 50GHzProbestation
Probestation MMICundermicroscope
The Next Generation Very Large Array
TransistorsunderTestOMMICTransistors NGCTransistors
The Next Generation Very Large Array
The Next Generation Very Large Array
The Next Generation Very Large Array
HowbettermodelseffectLNApredictions
Solid- NGCDashed- JPL
The Next Generation Very Large Array
0.01 5 10 15 20 25 30 35 40 45 50Frequency (GHz)
OMMIC MMIC probe measurements
-40-35-30-25-20-15-10
-505
10152025303540
35.9 GHz35.87 dB
0.6872 GHz28.48 dB
DB(|S(1,1)|)NAA_11_28_chip_high_bias_15K
DB(|S(2,1)|)NAA_11_28_chip_high_bias_15K
DB(|S(1,2)|)NAA_11_28_chip_high_bias_15K
DB(|S(2,2)|)NAA_11_28_chip_high_bias_15K
DB(|S(1,1)|)NAA_13_16_chip_high_bias_15K
DB(|S(2,1)|)NAA_13_16_chip_high_bias_15K
DB(|S(1,2)|)NAA_13_16_chip_high_bias_15K
DB(|S(2,2)|)NAA_13_16_chip_high_bias_15K
DB(|S(1,1)|)NAA_13_16_chip_low_bias_15K
DB(|S(2,1)|)NAA_13_16_chip_low_bias_15K
DB(|S(1,2)|)NAA_13_16_chip_low_bias_15K
DB(|S(2,2)|)NAA_13_16_chip_low_bias_15K
DB(|S(1,1)|)NAA_11_28_chip_low_bias_15K
DB(|S(2,1)|)NAA_11_28_chip_low_bias_15K
DB(|S(1,2)|)NAA_11_28_chip_low_bias_15K
DB(|S(2,2)|)NAA_11_28_chip_low_bias_15K
The Next Generation Very Large Array
50GHzLNAModuleDevelopment
The Next Generation Very Large Array
LNAassembly- OMMICLNAlayout ZoominonMMIC
The Next Generation Very Large Array
50GHzTestbedEnablesHot/cold,noisesource,Sparametersto50GHz
The Next Generation Very Large Array
0.01 5 10 15 20 25 30 35 40 45 50Frequency (GHz)
OMMIC MMIC probe measurement 300K and 15K
-40
-20
0
20
40 33.76 GHz32.81 dB
0.3537 GHz29.82 dB
DB(|S(1,1)|)NAA_13_16_chip_high_bias_15K
DB(|S(2,1)|)NAA_13_16_chip_high_bias_15K
DB(|S(1,2)|)NAA_13_16_chip_high_bias_15K
DB(|S(2,2)|)NAA_13_16_chip_high_bias_15K
DB(|S(1,1)|)NAA_i3_16_chip_high_bias
DB(|S(2,1)|)NAA_i3_16_chip_high_bias
DB(|S(1,2)|)NAA_i3_16_chip_high_bias
DB(|S(2,2)|)NAA_i3_16_chip_high_bias
The Next Generation Very Large Array
0.01 5 10 15 20 25 30 35 40 45 50Frequency (GHz)
LNA SN002 300K vs 5K comparison
-40-35-30-25-20-15-10-505
10152025303540
DB(|S(1,1)|)NAA_SN002_300K_in_dewar_n35dBm
DB(|S(2,1)|)NAA_SN002_300K_in_dewar_n35dBm
DB(|S(1,2)|)NAA_SN002_300K_in_dewar_n35dBm
DB(|S(2,2)|)NAA_SN002_300K_in_dewar_n35dBm
DB(|S(1,1)|)NAA_SN002_5K_in_dewar_n35dBm
DB(|S(2,1)|)NAA_SN002_5K_in_dewar_n35dBm
DB(|S(1,2)|)NAA_SN002_5K_in_dewar_n35dBm
DB(|S(2,2)|)NAA_SN002_5K_in_dewar_n35dBm
The Next Generation Very Large Array
-15
-10
-5
0
0 10 20 30 40 50
Loss(d
B)
Frequency(GHz)
Ommic WidebandLNAHousing#002ThruMeasurementwithinductorandbiasnetwork
S11 S21 S12 S22
The Next Generation Very Large Array
Designiteration
• NGCMMICredesign• Usedfourfingerdeviceonfirststage• Changeddevicesizes• Decoupledfirststagebiasnetworkfromsubsequentstages• Removedinputbiasnetworkonfirststage
The Next Generation Very Large Array
50LN2N2- AhmedAkgiray OriginalDesignof2011
Changestotheinputtransistor,2nd transistor,andinputgatebiasresistor
Changingout3rd FETflattensgain.
The Next Generation Very Large Array
0 5 10 15 20 25 30 35 40 45 50 55 60Frequency (GHz)
Gain and Noise of MMIC 50LN4
-40-35-30-25-20-15-10
-505
10152025303540
8 GHz6.43
50 GHz10.5
TE()50LN4
DB(|S(1,1)|)50LN4
DB(|S(2,1)|)50LN4
DB(|S(2,2)|)50LN4
|Eqn(Tmin_NGC)|Output Equations
|Eqn(Tmin_50LN4)|Output Equations
The Next Generation Very Large Array
Confusions,Confessions,Conclusions
• Developmentcompleteonasetoftestbedsto50GHz• Improvedmodelsto50GHzachievedforNGC• ImprovedMMICdesignnearlycompleteforNGC• CurrenttestinginprogressofOMMICprototypeLNA• Currentworkprogressingonimprovedmoduledesign
