A new 5 GHz Receiver for a Galactic Experiment

transcript

9 November 2009 3º Congresso URSI Portugal

A new 5 GHz Receiver for a Galactic

Experiment

Miguel BerganoGRIT – Aveiro

www.av.it.pt/gem

FCT Grants• POCTI/CTE-AST/57209/2004• PTDC/CTE-AST/65925/2006

Overview

9 November 2009 3º Congresso URSI Portugal 2

Unveil the Sky to CMBR;

Applicable to a Galactic Experiment;

High sensitivity radiometer;

Superheterodyne Receiver with Double Down Conversion – Zero IF;

IF chain developed and tested;

Full Digital Back-end;

Stokes Parameters Calculation.

What is CMBR?• Cosmic Microwave Background Radiation

• Best “Big-Bang” relic (Fossil);

• First Sky map: 1992 by COBE satellite COBE (PI G. Smoot,

was awarded the Physics Nobel Prize in 2006 for this discovery)

• CMBR fluctuations (anisotropies) allow to determine the geometry, age of the Universe.

GEM – Galactic Emission Mapping

• Survey of Syncrotron Polarization@ 5 GHz

• North/South Hemisphere (Portugal and Brasil)

• 80% sky coverage

Radiometer?

High sensitivity, well calibrated microwave receiver;

Detect and measure celestial sources;

Radiómetro

WattsKBGTP A

23-101,38BoltzmanndeConstante

TAVout

Radiometer Types Amplification:

• Direct;

• Superheterodyne

Accuracy:• Dicke Radiometer

• Noise Injection Radiometer

• Total Power Radiometer

TTT NA2

Superheterodyne Receiver

(Base-band Complex Correlator)

Novel approach to digital correlators!

The radiometer/polarimeter gain budget:

Antenna

Receiver

NFTOTAL= 6,1KGainTOTAL= 104 dB9

Receiver Requirements

• System Temperature about ~ 20K

• Sensitivity ~ 2mKs-1/2

• Frequency 5GHz with 200MHz Bandwidth

• Gain ~ 100dB

• Suitable for Stokes Parameters Calculation

• LNA Cryocooled PHEMT Amplifiers

LNA Characteristics

GaAs HEMT Low Noise Transistors

Noise Figure between 0,1 and 0,3 dB

Total Gain approximately 22 dB

Noise and S-parameters Simulation in ADS

Substrate to be used: RT5880

CompanyNF

@Freq.

MGF4953 Mitsubishi 0,40 13,5 12

MGF4419 Mitsubishi 0,50 12 12

ATF-36077 Agilent 0,5 12 12

NE3511S02 NEC 0,30 13,5 12

FHX13X Fujitsu 0,45 13 12

No longer manufactured

SIMULATIONS S and Noise Parameters provided by the

manufacturer Adjustments of components to obtain the

desired result Challenge is to create good matching networks,

that will provide the lowest NF; Obtain a large frequency band of low NF.

DeviceNF

(dB @ 5GHz)

MGF4941 from Mitsubishi 0,25 13,8

MGFC4419 from Mitsubishi 0,28 12,3

MGF4931 from Mitsubishi 0,48 11

ATF-36077 from Agilent 0.32 13

NE3511S02 from NEC 0,25 13

FHX13X from Fujitsu ------ 14

Design Constraints

Using the Noise Parametersprovided, and following theusual procedure to design ainput and output matching

networks, a LNA with

NF=0,35dB and 13,4dB of gain

MB050109

IF part designed and tested

IF Chain+RF Filter

4.9GHZ; B=600MHzCoupled Line filter

B=200MHz; 31dB; ButterworthMMIC (best response flatness)

Flat gain; 71dB;Digital attenuation

120dB isolation between portsFrequency 600MHz; VCO; MMIC Amp.;

PLL synthesyzer; 7dBm

Microwave Passive Filter

Central Frequency = 4,9 GHz;

Bandwidth = 800 MHz;

Coupled Lines;

ADS Design aided;

Electromagnetic Simulation.

Substrate – RO4003C

Substrate Thickness H 20 mil

Relative Dielectric Constant εr 3,38

Conductor Thickness T 0,35μm

Dielectric Loss Tangent tan δ 0,0021

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 190 20

frequency [GHz]

S - parameter

dB(S(2,1))

dB(S(1,1))

dB(S(1,2))

dB(S(2,2))

Vcc =8V

IF Pre - Amplifier

Gain = 31 dB

Slope Compensation Network;

Gain variation with frequency;

Gain variation with Temperature;

S-Parameters Simulation.

High Q filter;

Central Frequency = 600 MHz;

Bandwidth = 200 MHz;

T configuration

Butterworth Prototype;

Hand made Inductances

ADS Design aided;

Amplifier Filter

P1dB = -24 dBm

Vcc =8V

IF Amplifier

Gain = 71 dB;

Flat gain;

Digital attenuation control;

Slope Compensation Network;

Gain variation with frequency;

Gain variation with Temperature;

S-Parameters Simulation.

P1dB = -61 dBmIP3= -41 dBm

Converter

75 1455 210

Frequency [MHz]

Converter output

LO90º

Zero – IF Conversion (LB = 100MHz);

Phase (I) and Quadrature (Q) Modulation;

Signal Amplification (GSINAL = 16 => 25 dB);

Port Isolation = 120 dB;

Suitable for Stokes Parameters Calculation;

Microstrip Lines with equal lengths;

Protection (outside interference & parasitics).

Local Oscillator

10 dBm

0º≈ 7 dBm

≈ 7 dBm

0,6 dBm

Frequency = 600 MHz with 7 dBm;

Provides the converter with 4 signals

PLL Sinthesized;

Microstrip Lines with equal lengths;

Protection (outside interference & parasitics).

Full 4-channel Digital CorrelatorCorrelations computed in aFPGA after signal digitalization(ADC interleaving) and outputsI,Q,U Stokes signals:

Why an FPGA Cyclone II from ALTERA?

• Embedded Multipliers;

• Number of pins;

• Frequency.

Digital CorrelatorISA Interface output

• ADCs AD9481 from Analog

Devices.

• 250 Msps

• 8 bits of resolution

Analog inputs • FPGA EP2C8Q208C7 Cyclone II from ALTERA

• 8256 LE.

• Number of 9 bits multipliers = 36;

• 208 pins

• Speedgrade 7

Active Serial mode

programming interface

Cristal Oscilator

100 MHz

1. Signals correlation from the 4 ADCs, (8 bits sum and

multiplications every)

2. Integration of correlated signals.

3. Output Stokes parameters to PC104

FPGA calculates the Stokes parameters (I, Q, U).

(VHDL code implementation by Francisco Fernandes)

Full Digital Correlator

FPGA is an ALTERA

Cyclone II and works at

100 MHzFPGA

I, Q, U

100 MHz

Cyclone II

N+1ADC 2

N+1ADC 3

N+1ADC 4

8 bits of resolution200 MSPS

0,5Vpp

I,Q,U,V=F(ADC1,ADC2,ADC3,ADC4)

9 November 2009 3º Congresso URSI Portugal09/11/09 2º Congresso URSI Portugal 23

Main Features of PC104 (MOPSlcdLX*)

Hardware• 500 MHz AMD LX800

Processor• 256 MByte DDR-RAM• ChipDisk IDE 1 GByte• Support: ISA, Ethernet• Power supply: 5V

Software• Linux, kernel 2.4• Dedicated, custom-made

software for FPGA communication via ISA bus (C lang. –implemented by Francisco Fernandes).

• SSH File transfer.

* www.kontron.com/MOPS

LIRAeLinux for Radio Astronomy embedded

LIRAe is a microlinux distribution, to run on CPU embedded systems and control radioastronomy digital correlators based on FPGA chips.

The system was tested and runs on a PC104 from Kontron, model MOPSlcdLX.

Download available soon.LIRAe main developer: Francisco Fernandes

email : ff@av.it.pt

Mechanical Layout

Receiver photo

Conclusion : Radiometer facts

Tsys < 20 K; B = 200 MHz; 104 dB gain

High-performance IF strip

Latest RF tech+ microstrip design + MMIC

New Radioastronomy Design:

Zero-IF Converter + I,Q modulation

Digital Correlator : 4-channel, FPGA implemented processing 16Gbps!

An SKA (Potential!) Digital Demodulator

Dynamic Range: Total=20dB, Instantaneous=80dB

Suitable for state of the art RA applications.

MoU with ESA Planck Science Team.27

Muito obrigado pela atenção...

A new 5 GHz Receiver for a Galactic Experiment

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