SIS mixers for 1mm band A. Navarrini, G. Engargiola, R. Plambeck (Berkeley) N. Wadefalk (Caltech)
description
Transcript of SIS mixers for 1mm band A. Navarrini, G. Engargiola, R. Plambeck (Berkeley) N. Wadefalk (Caltech)
SIS mixers for 1mm bandA. 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
SIS junc tio n
Fro nt b lo c k
SISb ia s
Alig nm e nt p ins
Rea r b lo c k
50 O hmIF ne two rk
C a vitie s fo rfixe d m a g ne t
WGc a vity
To IF Am p lifie r
1 m m M ixe r Blo c k
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)
5.5 K
4.5 K
3.6 K
DSB receiver temperatures ~ 50 to 80 K(measured outside dewar, including all optics losses)
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
WBA13 MMIC, designed for 0.5-11.5 GHz
Gene Lauria, ALMA Band 6 PDR, Apr 2004 Wadefalk and Weinreb
Option 1: replace amplifier on 12 K stage with MMIC module
(WBA13 amplifier module provided by N. Wadefalk)
Fe e d -ho rn Sta in le ss ste e lc o a xia l c a b le
WBA13 a m p lifie r m o d ule
SIS m ixe r b lo c kIF o utp utDC m a g ne t
Option 1: Trcvr DSB measured with 0-6 GHz I.F.
filter comparable to narrowband results
Option 1: gain and noise from 0-9 GHzripple tolerable from 225-240 GHz, bad outside this range
0 1 2 3 4 5 6 7 8 9
-130
-120
-110
-100
-90
-80
260 GHz
SIS Mixer cascaded with WBA13 amplifier moduleJunction from wafer 5: R
N=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
Cold Load Ambient Load
IF O
utpu
t P
ower
[dB
m]
IF Frequency [GHz]
0 1 2 3 4 5 6 7 8 90
50
100
150
200
250
300
350
400
260 GHz
Trec,DSB(0-6 GHz)=85 KT
rec,DSB(1.2-2.2 GHz)=83 K
Trec,DSB(2-4 GHz)=87 KTrec,DSB(4-8 GHz)=88 K
SIS Mixer cascaded with WBA13 amplifier moduleJunction from wafer 5: R
N=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
Tre
c,D
SB
[K]
IF Frequency [GHz]
225 GHz
260 GHz
Option 2: integrate MMIC directly into mixer block
M ixe rc h ip
WBA12 WGc a vity
M ixe rb ia s c irc u it
WBA12b ia s c irc u it
IF o utp utIF ne two rk
C a vityfo r fixe dm a g ne t
• 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
Option 3: incorporate pre-packaged WBA13 (ATA module) into thermally-split block
3.8 K12 K
Option 3: DSB noise temperatures0-6 GHz I.F. filter
200 210 220 230 240 250 260 270
40
50
60
70
80
90
SIS Mixer cascaded with WBA13 module using thermally split blocks
Tre
c,D
SB
[K]
LO Frequency [GHz]
Option 3: gain, noise from 0-6 GHz(ripple much improved, but gain falls off above 3 GHz)
0 1 2 3 4 5 6
-90
-85
-80
-75
-70
-65
-60
260 GHz
SIS: Vdc
=2.3 mV; ILO
=36 uAWBA13: V
d=1.19 V; I
d=31.5 mA
Vga
=0.38 V; Iga
=25.4 uA V
gb=0.38 V; I
gb=25.4 uA
Tphys,mixer
=3.83 K
Cold load Ambient load
IF O
utpu
t P
Ow
er [
dBm
]
IF Frequency [GHz]
0 1 2 3 4 5 60
100
200
300
260 GHz
SIS: Vdc=2.3 mV; ILO=36 uAWBA13: V
d=1.19 V; I
d=31.5 mA
Vga
=0.38 V; Iga
=25.4 uA V
gb=0.38 V; I
gb=25.4 uA
Tphys,mixer
=3.83 K T
rec(0-6GHz)=79 K
Tre
c [K
]
IF Frequency [GHz]
225 GHz
260 GHz
broadening bandwidth of BIMA 1mm mixers to 4 GHz: short term solutions
option advantages disadvantages
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
2 • must build new mixer blocks
• increased heat load on stage 3
3 • 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
• sideband separation requires complex mixer block, carefully phase-matched preamps
• NRAO estimates ~25% acceptance rate for ALMA mixers
ALMA is building sideband separating mixers, but we would use devices as DSB mixers
from ALMA Band 6 PDR, Apr 2004
ALMA sideband separating mixer blockwith attached preamps
Sensitivity comparisons