Transcript SIS mixers for 1mm band A. Navarrini, G. Engargiola, R. Plambeck (Berkeley) N.

SIS mixers for 1mm band
A. Navarrini, G. Engargiola, R. Plambeck (Berkeley)
N. Wadefalk (Caltech)
• short term: increase bandwidth of existing
BIMA mixers to 4 GHz
• long term: develop new generation of 1mm
mixers using UVa SIS mixers
Current BIMA 1mm receivers
• DSB, fixed-tuned SIS mixers
• single SIS junction devices fabricated by G. Engargiola at
U. Illinois
• 800 MHz IF band, 1.4 - 2.2 GHz (limited by IF amp)
TocircularWGandfeed-horn
F
ront
block
Full-height to
half-height
WGtransition
W
G
cavity
S
IS
junction
1mmMixer Block
R
ear
block
DSB receiver temperatures ~ 50 to 80 K
(measured outside dewar, including all optics losses)
5.5 K
4.5 K
3.6 K
Need to replace narrowband IF amplifier
• ALMA solution is to build I.F. amplifier from
discrete transistors
– more flexibility in matching impedance of SIS junction
• our preferred solution is to use InP MMIC
– WBA13, developed by Weinreb and Wadefalk for ATA
– 35 dB gain, noise temp 3-6 K
– 10-20 mW power dissipation
Comparison of amplifier gains, noise temperatures
ALMA Band 6 amplifier,
designed for 4-12 GHz
Gene Lauria, ALMA Band 6 PDR, Apr 2004
WBA13 MMIC, designed
for 0.5-11.5 GHz
Wadefalk and Weinreb
Option 1: replace amplifier on 12 K stage
with MMIC module
(WBA13 amplifier module provided by N. Wadefalk)
Feed-horn
Stainless ste
coaxial cab
WBA13
mod
Option 1: Trcvr DSB measured with 0-6 GHz I.F.
filter comparable to narrowband results
90
80
SIS Mixer cascaded with WBA13 coaxial module
Trec,DSB [K]
70
60
50
40
200
210
220
230
240
250
LO Frequency [GHz]
260
270
Option 1: gain and noise from 0-9 GHz
ripple tolerable from 225-240 GHz, bad outside this range
90
-35
Cold Load
Ambient Load
-40
70
Vd=1.2 V; Id=15 mA; Iga=Igb=25 uA
Mixer temperature: 3.86 K
Trec,DSB(0-6 GHz)=47 K @ 2.25 mV
-45
-50
Trec,DSB [K]
IF Output Power [dBm]
80
SIS cascaded with WBA13 Amplifier module
SIS: Vdc=2.1 mV; ILO=50 uA
WBA13: Vga=0.55 V; Vgb=0.55 V;
225 GHz
225 GHz
-55
-60
SIS cascaded with WBA13 Amplifier module
SIS: Vdc=2.1 mV; ILO=50 mA
WBA13: Vga=0.55 V; Vgb=0.55 V; Vd=1.2 V; Id=15 mA; Iga=Igb=25 uA
-65
Mixer temperature: 3.86 K
Trec,DSB(0-6 GHz)=47 K @ 2.25 mV
50
225 GHz
-70
0
1
2
3
4
5
6
7
8
60
40
9
0
1
2
IF Frequency [GHz]
3
4
5
6
7
8
9
IF Frequency [GHz]
-80
400
SIS Mixer cascaded with WBA13 amplifier module
Cold Load
Ambient Load
Junction from wafer 5: R N=14.2 Ohm - Block: 31-015-1
SIS: Vdc=2.0 mV ; ILO=35 uA;
260
Mixer Temp: 4.7 K; 2" stinless steel coax. cable
+50 Ohm IMN + JCA amp. 1-10 GHz
300
-100
-110
260 GHz
GHz
Trec,DSB(0-6 GHz)=85 K
Trec,DSB(1.2-2.2 GHz)=83 K
Trec,DSB(2-4 GHz)=87 K
Trec,DSB(4-8 GHz)=88 K
250
Trec,DSB [K]
IF Output Power [dBm]
-90
350
200
150
SIS Mixer cascaded with WBA13 amplifier module
-120
Junction from wafer 5: RN=14.2 Ohm - Block: 31-015-1
SIS: Vdc=2.0 mV ; ILO=35 uA;
Mixer Temp: 4.7 K; 2" stinless steel coax. cable
+50 Ohm IMN + JCA amp. 1-10 GHz
100
50
260 GHz
-130
0
0
1
2
3
4
5
6
IF Frequency [GHz]
7
8
9
0
1
2
3
4
5
6
IF Frequency [GHz]
7
8
9
Option 2: integrate MMIC directly into mixer block
• MMIC tended to oscillate; had to switch from WBA13 to
lower-gain WBA12
• mixer block at 4.65 K instead of 3.85 K
• gain ripple still a problem
WBA12
biascircuit
Cavity
Mixer
forfixed chip
magnet
WG
cavity
WBA12
Option 3: incorporate pre-packaged WBA13
(ATA module) into thermally-split block
12 K
TeCu Mixer
block
3.8 K
Feed-horn
WBA13
module
Option 3: DSB noise temperatures
0-6 GHz I.F. filter
90
80
SIS Mixer cascaded with WBA13
module using thermally split blocks
Trec,DSB [K]
70
60
50
40
200
210
220
230
240
250
LO Frequency [GHz]
260
270
Option 3: gain, noise from 0-6 GHz
(ripple much improved, but gain falls off above 3 GHz)
200
-40
-50
SIS+ATA WBA13 Module
SIS:
Vd=2.25 mV; ILO=38 uA
WBA13: Vd=1.19 V; Id=31.5 mA
160
140
-60
Trec, DSB [K]
IF Output Power [dBm]
225 GHz
180
225 GHz
-70
SIS+ATA WBA13 Module
SIS:
Vd=2.25 mV; ILO=38 uA
WBA13: Vd=1.19 V; Id=31.5 mA
-80
1
2
3
80
40
225 GHz
20
-100
0
100
60
Vga=0.38 V; Iga=25.4 uA
Vgb=0.38 V; Igb=25.4 uA
Tphys,mixer=3.83 K
Trec(0-6GHz)=53 K
-90
Vga=0.38 V; Iga=25.4 uA
Vgb=0.38 V; Igb=25.4 uA
Tphys,mixer=3.83 K
Trec(0-6GHz)=53 K
120
4
5
0
6
0
1
IF Frequency [GHz]
2
3
4
5
6
5
6
IF Frequency [GHz]
300
260 GHz
Cold load
Ambient load
-65
SIS:
Vdc=2.3 mV; ILO=36 uA
WBA13: Vd=1.19 V; Id=31.5 mA
Vga=0.38 V; Iga=25.4 uA
Vgb=0.38 V; Igb=25.4 uA
Tphys,mixer=3.83 K
Trec(0-6GHz)=79 K
200
-70
260 GHz
-75
Trec [K]
IF Output POwer [dBm]
-60
SIS:
Vdc=2.3 mV; ILO=36 uA
WBA13: Vd=1.19 V; Id=31.5 mA
-80
Vga=0.38 V; Iga=25.4 uA
Vgb=0.38 V; Igb=25.4 uA
Tphys,mixer=3.83 K
-85
100
260 GHz
-90
0
0
1
2
3
4
IF Frequency [GHz]
5
6
0
1
2
3
4
IF Frequency [GHz]
broadening bandwidth of BIMA 1mm
mixers to 4 GHz: short term solutions
option
advantages
1
• no need to rebuild mxr blocks
• no extra heat load on stage 3
• amplifier oscillations unlikely
• huge gain ripples below 220,
above 240 GHz
• must build new mixer blocks
• increased heat load on stage 3
2
3
disadvantages
• lower gain and noise ripple
• must build new mixer blocks
if we must have 4 GHz bandwidth by Fall 2005,
option 1 probably is best
Longer term
• goal: DSB Trcvr = 25 K, 8 GHz I.F. bandwidth
• switch to ALMA Band 6 devices
– we have only ~50 usable UI junctions
– NRAO has contracted for 9 UVa wafers, each with 1066
devices (9600 devices); approx 50% are usable
– if necessary, we could contract with UVa for an additional
wafer
• construct thermally split block with WBA13 IF amp
– operating WBA13 at 12 K reduces heat load on 4 K refrig,
may also improve 1/f gain stability of MMIC
ALMA Band 6 SIS devices
• DSB Trcvr ~ 20 K
• series array of 4
junctions – avoids
problems with
saturation, but
requires more LO
pwr
Tony Kerr has given us 4 ALMA devices to try
ALMA is building sideband separating mixers,
but we would use devices as DSB mixers
• sideband separation requires complex mixer block,
carefully phase-matched preamps
• NRAO estimates ~25% acceptance rate for ALMA mixers
from ALMA Band 6 PDR, Apr 2004
ALMA sideband separating mixer block
with attached preamps
Sensitivity comparisons