Transcript EOVSA Slide Collection - Owens Valley Solar Array

Warm Front End (2-meter)
Wes Grammer
NRAO
EOVSA Preliminary Design Review
March 15-17, 2012
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Outline
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Design requirements
Block diagrams
Cascaded gain/noise analysis (FE + BE)
Component selection
Thermal management
Mechanical layout and enclosure
Interfaces (mechanical and electronic)
Production assembly and test
Costing and schedule
EOVSA Preliminary Design Review
March 15-17, 2012
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2-meter Warm Front End Design
Requirements and Specifications
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1-18 GHz instantaneous BW, dual linear polarizations
Overall Tsys < 400K, at ambient (~298K)
Gain stability < 1%, phase stability < 1°, over TBC sec.
Receiver outputs modulated on SMF, range > 2 km
Active temperature control, < ±0.1C diurnal stability
Overall volume should fit within a 12” dia. x ~12” long
cylinder, excluding antenna feed and connectors
• Total weight < 20 lbs (9.1 kg)
• Sealed enclosure and bulkhead connectors to IP67,
suitable for outdoor installation
• MTBF > 26,000 hrs (3 yrs)
EOVSA Preliminary Design Review
March 15-17, 2012
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Front End Assembly Block Diagram
Front End Module Assembly Enclosure, 2-Meter Antenna
Ethernet
I/O
U2
ETH[8..1]
ETH[1..8]
M&C I/O
IO[1..15]
GND
+3.3V
+3.3V
LNA_BIAS1
A1
ATN1
V RF In
1-18 GHz
IN
CP1
35 dB gain, 1 dB NF
+2.5 dBm Po_1dB
Low Noise Factory
LNF-LN1_13C
1-Bit Digital
Attenuator
A3
PAD1
FILT1
OUT
-2 / -12 dB
RH Laboratories
12-2085
ATN3
IN
28 dB gain, 4 dB NF
-3 dB
+18 dBm Po_1dB
Mini-Ckts
Herotek
BW-S3-2W263+
A0118284018B
18 GHz Lowpass
<Manuf acturer>
<Manuf acturer p/n>
20 dB Coupler
Kry tar
180120
A5
5-Bit Digital
Attenuator
OUT
5 - 25 dB atten. @18 GHz
Hittite HMC939LP4
IN
31 dB gain 5 dB NF
+20 dBm Po_1dB
Ciao Wireless
CA118-455
CP3
D2
Schottky Detector
Kry tar
201AP
+24V
SPL1
A8
1
V
IN
RF
LNA_BIAS1
VPOL_POUT
LNA_BIAS2
HPOL_POUT
WDM1
F.O. Diplexer
Optilab
+24V
H/V
FO Out
FO OUT
2
30 dB ENR
Noisewav e
NW18G-30-CS
2-way Splitter
Weinschel
WA1515
Two-stage HEMT bias
EOVSA-FE-2M-AUX-A
EOVSA
Dual detector preamp
EOVSA-FE-2M-AUX-A
EOVSA
LNA_BIAS2
CP2
A2
ATN2
H RF In
1-18 GHz
IN
20 dB Coupler
Kry tar
180120
D3
Schottky Detector
Kry tar
201AP
35 dB gain, 1 dB NF
+2.5 dBm Po_1dB
Low Noise Factory
LNF-LN1_13C
1-Bit Digital
Attenuator
-2 / -12 dB
RH Laboratories
12-2085
A4
PAD2
FILT2
OUT
ATN4
IN
28 dB gain, 4 dB NF
-3 dB
+18 dBm Po_1dB
Mini-Ckts
Herotek
BW-S3-2W263+
A0118284018B
18 GHz Lowpass
<Manuf acturer>
<Manuf acturer p/n>
CP4
A6
5-Bit Digital
Attenuator
OUT
5 - 25 dB atten. @18 GHz
Hittite HMC939LP4
+V
H
A7
D1
RF
ANT1
Dual Log-Per.
TECOM
805920-002
OPT_TX1
F.O. Transmitter
Optilab
LT-20
RF
20 dB Coupler
Kry tar
180120
+V
Embedded MPU
Rabbit RMC4000
OPT_TX2
F.O. Transmitter
Optilab
LT-20
IN
31 dB gain 5 dB NF
+20 dBm Po_1dB
Ciao Wireless
CA118-455
20 dB Coupler
Kry tar
180120
DC Power
Inputs A&B
DC-B[2..1]
+12V "B"
DC-A[6..1]
RT1
TSENSE
+12V "A"
-12V
t
+24V
Laird
TEC1 DA-075-24-02-00-00
TE Assembly
FAN+ FAN-
T EC+ T EC-
Laird
TEC2 DA-075-24-02-00-00
TE Assembly
FAN+ FAN-
T EC+ T EC-
TE Assy
Connect
TE_CTRL[6..1]
EOVSA Preliminary Design Review
March 15-17, 2012
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2-Meter Front End Optical Fiber,
M&C and DC Supply Routing
AUXCAB
FRONT END ASSY
TE_CTRL[6..1]
TE_CTRL[6..1]
SW1
ETH[1..8]
FO_ETH[2..1]
Buried
FO Cable
SMF[12..1]
ETH[8..1]
FX[1..2]
Ethernet Switch w/FO Inp
Moxa EDS-205A-S-SC-T
SMF[12..1]
FO_ANLG
FO OUT
DC_IN-B[2..1]
DC-B[2..1]
DC_IN-A[6..1]
DC-A[6..1]
2-Meter Front End Assembly
Auxiliary Equipment Cabinet
Antenna Control Cabinet
2-Meter Antenna Apex
EOVSA Preliminary Design Review
March 15-17, 2012
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System Cascade Analysis (1)
• Excel workbook created to perform stage-bystage cascaded analysis of the following:
– System gain, including mismatch loss
– Noise temperature
– Gain ripple and slope over IF bandwidth
– Output spectral power density and total power
– 1 dB compression point, and output margin
– Third-order intercept point (IP3)
– Output IMD level, assuming strong interference
EOVSA Preliminary Design Review
March 15-17, 2012
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System Cascade Analysis (2)
• Component data entered in tables
• Effect of cables and adapters estimated
• Analyzed at four different input levels: -73, -60,
-50 and -35 dBm, at 18 GHz
• Simplifications and assumptions:
– Worst-case parameters mostly used (min. gain, IP3
and P1dB; max. loss, VSWR and NF) @ 18 GHz
– Average of mismatch error used for cascade
– Antenna conductor and dielectric loss unknown, a
figure of 0.5 dB was arbitrarily assigned
– Input level of optical TX is nominally +6 dBm
EOVSA Preliminary Design Review
March 15-17, 2012
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EOVSA Preliminary Design Review
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System Cascade Analysis (3)
• Key results, after optimization:
– ENR of 30 dB required with specified splitter and 20
dB coupler, in order to inject ~ 400K noise
– LNA still ~6 dB below compression at -35 dBm max
input, other amps better.
– Overall Tsys < 330K up to -50 dBm, but rises way over
400K for strongest input, from added atten.
• Effect greatly reduced by driving optical TX at upper end of
its linear range (+11 dBm) for this case. Overall Tsys is still
slightly higher than spec, ~420K
• May slightly complicate software to set atten. levels
EOVSA Preliminary Design Review
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System Cascade Analysis (4)
• Results (cont):
– Optical TX drive at lowest signal input:
• +4.3 dBm, at 18 GHz w/min. nom. setting -> -0.7 dB
margin!
• Extreme case, due to steep gain slope of LNA at this
end (~2 dB/GHz). Gain over most of band nearly 5 dB
higher, thus total power from 1-18 GHz will be higher
than worst-case above.
– Around 10 dB headroom in the digital attenuator,
for reducing system gain, for non-worst case
EOVSA Preliminary Design Review
March 15-17, 2012
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System Cascade Analysis (5)
• Limitations of analysis tool:
– Cascaded gain ripple and slope are incomplete; lack of
component data, unknown dependence on phase
– No broadband frequency dependence of component
parameters is modeled; lack of time and hard data
– Output power is assumed linear; no attempt made to
model saturation or near-saturation behavior
– Did not model change in solar input power across
frequency, or effect on total output power through
components having significant gain slope (e.g., LNA)
– Analyzed only main signal path; noise source with
splitter and coupler done separately and manually
EOVSA Preliminary Design Review
March 15-17, 2012
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Component Selection Criteria
• Flat frequency response, where possible
• Good VSWR, where possible, to limit mismatch loss
and gain ripple
• Integration of multiple functions into a single package
where cost-effective, for better performance, fewer
interconnects, saves critical space
• For amplifiers, lowest power dissipation that still meets
output drive requirements
• Common bias voltages (e.g., +12V), where possible
• Cost is critical: As there are 30 each of most Front End
component types in the array, an expensive item can
have a large impact in the overall budget.
EOVSA Preliminary Design Review
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EOVSA Preliminary Design Review
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Hittite 5-bit Digital Attenuator
EOVSA Preliminary Design Review
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Optilab LT-20/LR-30 Link Loss
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Thermal Management
• Active cooling to be used, for following reasons:
– Limited volume with high component packing density
– Relatively large thermal dissipation (~64W max, est.)
– External ambient temp can reach +45C or more, also has
direct solar exposure
– Will allow best receiver gain stability w/reliability
• Requirements:
– Robust, reliable system for harsh outdoor environment
– Reasonable installation and operating costs
– Compact and lightweight (portion mounted on antenna)
EOVSA Preliminary Design Review
March 15-17, 2012
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Options for Front End Cooling
• Liquid cooling
– Very compact, lightweight, quiet (on Front End side)
– Works best when cooling a device to a temperature close to the
surrounding ambient. Supply line (cold side) needs to be
insulated for most efficient operation.
– Requires a remote pump and chiller assembly – raises cost
• Direct thermoelectric cooling
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Compact, efficient, and light enough for use on antenna
Works well over wide ambient temperature range
No coolant required, only DC power – easier to test and install
Reversible; can heat or cool as required, with suitable controller
Fewer, lower-cost system components
Requires external fans, which limit MTBF
EOVSA Preliminary Design Review
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Laird 71W TE Assembly, Controller
EOVSA Preliminary Design Review
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Internal layout considerations
• Cascade from feed outputs to LNAs should be as
short and direct as possible, to minimize losses
• Optical TX modules drive overall placement,
because of their large size and power dissipation.
• Good heat sinking for active components a must,
for gain stability and long field life
• Interface connectors should be located at the
opposite end of enclosure to the feed, for ease of
access and minimal antenna obstruction.
• Design for easy assembly, testing, serviceability
EOVSA Preliminary Design Review
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Enclosure Design Requirements
• Weather-tight to IP67 (no dust or non-submerged
water ingress); one-piece replaceable seals
• UV-resistant material, rated for outdoor use
• Clamshell design, for easy assembly and service
• Well-insulated, to minimize ambient thermal
loading, for a stable internal environment
• Base strong enough to support 9 kg max weight,
nor break under expected handling in the field
• Low cost COTS catalog item, if possible
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Warm Front End Assembly
Conceptual Mechanical Layout
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Front End Assembly Interfaces
• Hardware:
– (2) SMA-M inputs from antenna feed
– (1) SM fiber connector output; possibly LC/APC
– (1) 10/100Base-T Ethernet I/O for all M&C
– (3) MIL-DTL-26482 multi-pin connectors, for DC
power input to Front End electronics, TE coolers
• Software:
– Refer to table in following slide
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Signal Name
X Pol from Ant
Y Pol from Ant
ND Ctrl
LNA Vd Ctrl X-Pol
LNA Vd Mon X-Pol
LNA Id Ctrl X-Pol
LNA Id Mon X-Pol
LNA VG Mon X-Pol
LNA Vd Ctrl Y-Pol
LNA Vd Mon Y-Pol
LNA Id Ctrl Y-Pol
LNA Id Mon Y-Pol
LNA Vg Mon Y-Pol
Atten1 Ctrl X-Pol
Atten1 Ctrl Y-Pol
Atten2 Ctrl X-Pol
Atten2 Ctrl Y-Pol
TX PwrIn Mon X-Pol
TX PwrIn Mon Y-Pol
Temp Mon X-Pol
Temp Mon Y-Pol
LaserTX Alrm Mon X-Pol
LaserTX Alrm Mon Y-Pol
Temp Alrm Mon
TE Cooler M&C
X / Y Pol from FE
Dir.
In
In
In
In
Out
In
Out
Out
In
Out
In
Out
Out
In
In
In
In
Out
Out
Out
Out
Out
Out
Out
I/O
In
Type
RF Power
RF Power
Bool
Float
Float
Float
Float
Float
Float
Float
Float
Float
Float
Bool
Bool
Integer
Integer
Float
Float
Float
Float
Bool
Bool
Bool
RS-232
RF on fiber
Mode
Analog Elec
Analog Elec
Digital Elec
Digital Elec
Digital Elec
Digital Elec
Digital Elec
Digital Elec
Digital Elec
Digital Elec
Digital Elec
Digital Elec
Digital Elec
Digital Elec
Digital Elec
Digital Elec
Digital Elec
Digital Elec
Digital Elec
Digital Elec
Digital Elec
Digital Elec
Digital Elec
Digital Elec
Digital Elec
Analog Fiber
Range Min Range Max
-70
-35
-70
-35
0
24
0
1.5
0
1.5
0
50
0
50
-4
0
0
1.5
0
1.5
0
50
0
50
-4
0
0
10
0
10
0
31
0
31
0
20
0
20
-20
60
-20
60
n/a
n/a
n/a
n/a
10
50
n/a
n/a
-30
-35
EOVSA Preliminary Design Review
Unit
dBm
dBm
V
V
V
mA
mA
V
V
V
mA
mA
V
dB
dB
dB
dB
dBm
dBm
degC
degC
n/a
n/a
degC
n/a
dBm
Connector
SMA
SMA
Ethernet
Ethernet
Ethernet
Ethernet
Ethernet
Ethernet
Ethernet
Ethernet
Ethernet
Ethernet
Ethernet
Ethernet
Ethernet
Ethernet
Ethernet
Ethernet
Ethernet
Ethernet
Ethernet
Ethernet
Ethernet
Ethernet
DB9 male
SC/APC
Freq/Rate
1-18 GHz
1-18 GHz
1 Hz
1 Hz
1 Hz
1 Hz
1 Hz
1 Hz
1 Hz
1 Hz
1 Hz
1 Hz
1 Hz
1 Hz
1 Hz
1 Hz
1 Hz
50 Hz
50 Hz
1 Hz
1 Hz
1 Hz
1 Hz
1 Hz
1 Hz
1-18 GHz
March 15-17, 2012
Precision
N/A
N/A
1 ms
1s
1s
1s
1s
1s
1s
1s
1s
1s
1s
1 ms
1 ms
1 ms
1 ms
1 ms
1 ms
1s
1s
1s
1s
1s
1s
N/A
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Production Assembly, Testing
• Production process steps
– Two-port VNA measurement of amplifiers, filters,
digital attenuators, couplers, and optical link sets
– Assembly of receiver halves (w/o WDM, noise src)
– Two-port VNA measurement of half-RX, w/Opt RX
– Final assembly of full receiver
– Test noise source functionality
– Verification of M&C functionality and cooling system
function in a test chamber at 50°C
– Documentation: Test results, configuration (s/n) list
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Production area at NTC Photonics Lab
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Component Costing, Delivery
• All RF components except LPF have been specified,
price/delivery quotes received
• Good estimates or preliminary pricing on remaining
electronic components
• Enclosure, connector and cable pricing are rough
estimates, final TBD
• Longest lead times:
– TECOM antennas (21 weeks); use existing OVSA units for
prototype Front Ends
– 1-bit digital attenuator (18 weeks); can be shortened to 8
weeks for 30% extra
– Many other have 12-16 week leads, but only for large qty
EOVSA Preliminary Design Review
March 15-17, 2012
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EOVSA Preliminary Design Review
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Important Schedule Dates
for Front End Prototypes
• Have all RF components and COTS support electronics on order by
mid-April at the latest
• Complete mechanical CAD models and fabrication drawings by May
1, send out for quotes, begin fab in mid-May
• May 1 – June 30: Design, PCB fab and component ordering for
custom support electronic boards
• July 1 – July 15: Order cables, connectors, wire, remaining
components for prototype unit construction and site installation
• July 1 – August 1: RF component characterization
• August – September: Assemble and test 3 prototypes
• October 1: Ship 3 prototypes to California for installation
• Front End embedded firmware and test software may need to be
farmed out, in the interest of saving time. This could happen during
July and August, in parallel with assembly.
EOVSA Preliminary Design Review
March 15-17, 2012
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