wvr workshop, wettzell, 2006 10 10miroslav pantaleev development of the dicke-switched wvr prototype...
TRANSCRIPT
WVR workshop, Wettzell, 2006 10 10 Miroslav Pantaleev
Development of the Dicke-switched WVR prototype for ALMA
Magne Hagström, Lars Pettersson and Leif Helldner
Collaboration with
WVR workshop, Wettzell, 2006 10 10 Miroslav Pantaleev
WVR workshop, Wettzell, 2006 10 10 Miroslav Pantaleev
Development of the Dicke-switched prototype for the ALMA WVR
Radiometer design - Double Dicke
Critical components
Lab tests
SMA - tests
Single Dicke prototype
WVR workshop, Wettzell, 2006 10 10 Miroslav Pantaleev
Optics layout - Double Dicke
M5
M5
C2
M4
C1
M3
Chopper wheel to select between sky - calibration
Measure all the time
Cryo cooler as cold load
Warm mixers and LNA
WVR workshop, Wettzell, 2006 10 10 Miroslav Pantaleev
Calibration Hot and Cold
Solenoid Vane
Hot load
WVR workshop, Wettzell, 2006 10 10 Miroslav Pantaleev
Chopper wheel function and design goals
Reliable > 10 years of continuous running
Small blade diameter – cut a small beam waist
Phase locked to external square wave
WVR workshop, Wettzell, 2006 10 10 Miroslav Pantaleev
Chopper blade
Dynamically balanced chopper wheel
No holes to avoid turbulences
WVR workshop, Wettzell, 2006 10 10 Miroslav Pantaleev
Chopper support
Bearings – SKF
Lifetime – more than 25 years (depending on the operational rpm)
Flexible coupling to dump vibrations
WVR workshop, Wettzell, 2006 10 10 Miroslav Pantaleev
Chopper protective cover
WVR workshop, Wettzell, 2006 10 10 Miroslav Pantaleev
Chopper blade positioning
Brushless motor3600 step encorder
S/Rinput
Choppercontrolelectronics
WVR workshop, Wettzell, 2006 10 10 Miroslav Pantaleev
Chopper timing
Chopper speed = 10.42 Hz
48 ms
-36 dBbeam
Blanking = 3.2 ms 6.7 %
Blade Jitter 0.2 ms
-.9 ms
89 A/D samples
Dicke radiometer Sampling rate and Chopper timing
Chopper
edge
A/D sampling rate
= 0.5 ms
WVR workshop, Wettzell, 2006 10 10 Miroslav Pantaleev
Measured chopper data
Chopper blade jitter
WVR workshop, Wettzell, 2006 10 10 Miroslav Pantaleev
Block diagram Double Dicke
6 dB
LP 960 MHz
LP 2315 MHz
LP 3800 MHz
BP 3,95-6,45
BP 2,55-3,80
BP 1,56-2,32
BP 800-960
GunnIsolator
91,6 GHz
Coupler
-3dB
-3dB
Harm.
Diplexer
6 dB
Ch 1
Ch 2
Phase lock6 dB
6 dB
6 dB
Mixer
G=47 dBG=32 dB
Powersupply
IF= .5 - 8 GHz
WVR Dicke version
0.048 dB/C 0.070 dB/C
LO power0.026 dB/C
0.017 dB/C -0.004 dB/C
Fixed Atten.
4 way P/S
Power Splitter
Phase Lock
Copper control
Calibration control
Temp. control
Micro- processor
-0.9 dBm / 10 GHz(1 dB Comp.= +14 dBm)
-23 dBm / B
WVR workshop, Wettzell, 2006 10 10 Miroslav Pantaleev
Mixer
WVR workshop, Wettzell, 2006 10 10 Miroslav Pantaleev
3 dB, 91.6 GHz power divider
Waveguide branch type couplers – many section required to cover wide bandwidth
Double probe structure is coupled to the E-field in a waveguideBy courtesy of V.Vassilev
WVR workshop, Wettzell, 2006 10 10 Miroslav Pantaleev
DSB - Noise temperature Double Dicke
WVR workshop, Wettzell, 2006 10 10 Miroslav Pantaleev
Sensitivity
WVR workshop, Wettzell, 2006 10 10 Miroslav Pantaleev
Filter bands
0 1000 2000 3000 4000 5000 6000 7000
MHz
-30
-25
-20
-15
-10
-5
-0
dB
WVR Filter bands
The LO frequency is kept very close to line frequency.
Mixers are double sideband.
Four IF channels with larger bandwidth away from the centre of the line.
WVR workshop, Wettzell, 2006 10 10 Miroslav Pantaleev
Filter and video assembly
WVR workshop, Wettzell, 2006 10 10 Miroslav Pantaleev
Custom designed filters
Bandpass filter B (1.565GHz – 2.315GHz)
Ring resonators bandpass filter
Compact, low insertion-loss, sharp-rejection, and wide-band application
WVR workshop, Wettzell, 2006 10 10 Miroslav Pantaleev
Calibration reference loads
• Two reference temperatures with a T 150 K,
one of them close to sky the temperature
Peltier element - not possible to get below – 50 ºC
Noise diode - only 4 dB ENR
Sterling cooler
Cool a microwave absorber to below 150 K.
Stabilize the temperature of the absorber to < 0.05 K
Absorber reflectivity > 30 dB at 183 GHz.
Maintenance free time 10 years.
WVR workshop, Wettzell, 2006 10 10 Miroslav Pantaleev
Cooling power
WVR workshop, Wettzell, 2006 10 10 Miroslav Pantaleev
Cooled load mount
WVR workshop, Wettzell, 2006 10 10 Miroslav Pantaleev
Thermal stabilization
Insulation
Frame with Peltier cooler
IF temperature regulation
WVR workshop, Wettzell, 2006 10 10 Miroslav Pantaleev
Single Dicke
WVR workshop, Wettzell, 2006 10 10 Miroslav Pantaleev
Block diagram Single Dicke
6 dB
LP 960 MHz
LP 2315 MHz
LP 3800 MHz
BP 3,95-6,45
BP 2,55-3,80
BP 1,56-2,32
BP 800-960
GunnIsolator
91,6 GHz
Coupler
-3dB
-3dB
Harm.
Diplexer
6 dB
Ch 1
Ch 2
Phase lock6 dB
6 dB
6 dB
Mixer
G=47 dBG=32 dB
Powersupply
IF= .5 - 8 GHz
WVR Dicke version
0.048 dB/C 0.070 dB/C
LO power0.026 dB/C
0.017 dB/C -0.004 dB/C
Fixed Atten.
4 way P/S
Power Splitter
Phase Lock
Copper control
Calibration control
Temp. control
Micro- processor
-0.9 dBm / 10 GHz(1 dB Comp.= +14 dBm)
-23 dBm / B
WVR workshop, Wettzell, 2006 10 10 Miroslav Pantaleev
Optics layout - Comparison
WVR workshop, Wettzell, 2006 10 10 Miroslav Pantaleev
Physical size comparison: Double -Single Dicke
Cost saving pre-production design work
Single Dicke Receiver
Replacement of the Hymatic Sterling cooler with a Peltier cooler
Replacement of the cold load with a cool/hot load combination
WVR workshop, Wettzell, 2006 10 10 Miroslav Pantaleev
Cold load
Single Dicke Receiver
Replacement of the Hymatic Sterling cooler with a Peltier cooler
Replacement of the cold load with a cool/hot load combination
WVR workshop, Wettzell, 2006 10 10 Miroslav Pantaleev
Current status
WVR workshop, Wettzell, 2006 10 10 Miroslav Pantaleev
IF linearity
NoiseDiode
ENR=15.2 dB
Atten.1:stIF
2:ndIF
6 dB
SpectrumAnalyzer
(20 GHz bandpower)
Fixed
3 dB