1. Spectrometer on a Chip NASA - PICASSO 2014-2017
Brian Drouin, Adrian Tang, Erich Schlecht, Emily Brageot, Adam Daly
Jet Propulsion Laboratory, California Institute of Technology
Jane Gu, Yu Ye
University of California, Davis
Frank Chang, Rod Kim
University of California, Los Angeles

2. Overview In-situ sensing of volatiles is critical to planetary science
Rover sensing package (Mars, moon, titan)
Atmospheric probe / balloon (Earth, Titan, Venus, Mars)
Exospheric point sensing (comets, icy moons)
Only compact instruments get to go
Mass /power vs. science return
Mass specs with limited resolution
Many limitations are addressed with SpecChip
Existing mm/submm sensors are sensitive, specific and multiplex capable - but not compact and power hungry (SUGARS, DeLucia/Batelle)
The SpecChip will replace major components reducing mass and power without compromising sensitivity, specificity or the discovery space

3. SUGARS (ASTID )

4. The SpecChip Concept
Leverage CMOS technology developed for communications to eliminate technical hurdles in the extension of microwave spectroscopy
Integrated CMOS millimeter transmitters/receivers have been demonstrated (SoCs)
On-chip signal processing will be matched to instrument design
Create a simplistic data/command interface that retains discovery style investigative sampling

5. Flygare-Balle RF System
RF components are
Waveguide coupled to
Antennae in cavity
SpecChip mmW System
CMOS chip is integrated
with mmW synthesizer
And switched into
couplings with antennae
Adrian Tang 4/30/2014, dual – use design leveraged from commercial radio product

6. SpecChip Milestone 9/19/14: Transmit Chip sent for Fabrication
Design Team
Design Role
Adrian Tang (JPL)
Lead
Yu Ye (UCD)
PA/Doubler
Rod Kim (UCLA)
Clock
Qun Gu (UCD)
Frank Chang (UCLA)
Library
Frank Hsiao (Broadcom)
USART
I-ning Ku (Broadcom)
ADC
Yen-Hsiang Wang (Bell Labs)
Patterning
David Murphy (Broadcom)
VCO/ILFD
Joseph Chen (UCLA)
Charge pump
Mike Pham (NVidia)
Shifter/Timer
Derek Yang (Qualcomm)
Analog MUX
Yuan Du (UCLA)
Power Sensor
SpecChip Milestone 9/19/14: Transmit Chip sent for Fabrication
86-94 GHz Transmitter with pulse modulation for
in situ spectroscopy
PICASSO 2014 funding (PI Brian Drouin) to develop a cavity
resonator with embedded CMOS transmitter and receiver will
enable compact, high sensitivity, high selectivity gas analyses

7. SpecChip Milestone 12/9/14: RECEIVE Chip sent for Fabrication
Design Team
Design Role
Adrian Tang (JPL)
Lead
Ran Shu (UCD)
Mixer/LNA
Yu Ye (UCD)
PA/Doubler
Rod Kim (UCLA)
Clock
Qun Gu (UCD)
Frank Chang (UCLA)
Library
Frank Hsiao (Broadcom)
USART
I-ning Ku (Broadcom)
ADC
Yen-Hsiang Wang (Bell Labs)
Patterning
David Murphy (Broadcom)
VCO/ILFD
Joseph Chen (UCLA)
Charge pump
Mike Pham (NVidia)
Shifter/Timer
Derek Yang (Qualcomm)
Analog MUX
Yuan Du (UCLA)
Power Sensor
SpecChip Milestone 12/9/14: RECEIVE Chip sent for Fabrication
86-94 GHz Receiver with for pulse detection for
in situ spectroscopy
PICASSO 2014 funding (PI Brian Drouin) to develop a cavity
resonator with embedded CMOS transmitter and receiver will
enable compact, high sensitivity, high selectivity gas analyses

8. Test Antenna
To be used to test receiver and transmitter outside of cavity
Patch on upper substrate
Feed on lower substrate
Return Loss
Impedance
Return Loss

9. Cavity coupling probe HFSS model
Couples to multiply-reflected Gaussian beam mode inside cavity.
Mirror
Simulated fields showing Gaussian mode excitation
Cavity
Probes

10. Coupler with spherical mirror
Model Q of 200 fundamental mode at 97.4 GHz
Antenna

11. Spec Chip Specifics
Transmitter design sent for Fabrication 9/19/14, Delivery 11/31/14
PCB design sent for Fabrication 11/6/14, Delivery 11/19/14
Receiver tape-out 12/10/14

12. Tape Outs

13. System Parts Thorlabs: 7cm x 7cm cage block 10 cm cage rods
Cage mount clamp
2” Optic mount
Edmunds Optics:
2” spherical mirror
PI:
Micropositioner
Custom:
Optic bracket

14. Vacuum chamber and mount
Electrical interfaces:
4 SMA
2 USB
1 DC 10 pin connector
2 LEMO connectors
gas inlet / pressure gauges
Vacuum pump

15. UC-Davis tests of components
Power Amp
Doubler

16. JPL Test of Receiver
Power spectrum measured in vacuo with quasi-optic detector (VD QOD)
Power level consistent with a few mW

17. Power Consumed is tiny Low power consumption is essential
Total Chip Power
200 mW consumed
Synthesizer
80 mW
ADC/cal/digital
60 mW PA
40 mW
Low power consumption is essential
For use in space and in concert with other measurements

18. Chip Schedule / Plan 9/19/14 Tx(1.0) tapeout, 11/30/14 delivery
Partial success, PA not working
12/10/14 Rx(1.0) tapeout, 3/30/15 delivery
Failed run due missing metal layer
3/1/15 Tx(2.0), Rx(2.0) tapeout
Delivery 6/15 (test integrated tuning of Tx/Rx)
5/15/2015 DDS(1.0)
9/X/2015 integrated DDS+Tx
11/X/2015 integrated DDS+Rx
Late 2015 for
New band Tx
Early 2016 for
New band Rx

19. Acknowledgements NASA – JPL RTD Timothy Crawford William Chun
Planetary Instrument Concepts for the Advancement of Solar System Observations
Astrobiology Instrument Development
JPL RTD
Timothy Crawford
William Chun
Marcoanto Chavez
Ken Cooper

20. Finesse vs. Bandwidth and Pulse width
nc = 89 GHz
Q = 1000
Dn = 89 MHz
tc = 1/(89 MHz) = 2 ns
nc = 89 GHz
Q = 10000
Dn = 8.9 MHz
tc = 1/(8.9 MHz) = 20 ns
Sensitivity goes as ~ I0QL, but bandwidth suffers as Q increases
What Q is reasonable? What t is reasonable?
Will these scale easily?