1BFCdiffDwingeloo, 13 December 2011

AA-mid / SKA

BeamFormerChip differentialBFCdiff

Stéphane BosseSéverin Barth

2BFCdiffDwingeloo, 13 December 2011

AA-mid / SKA

Cost

General System of Differential BeamFormer

Channel 1

Beam 1

Beam 2

R0

R0 = 200 or 150 ohms

BufferIsolation

R0

R0

R0

Channel 2

Channel 3

Channel 4

R0

R0

3BFCdiffDwingeloo, 13 December 2011

AA-mid / SKAChannel System of Differential BeamFormer

Input Amplifier1 input2 outputs (2 beams)

PhaseShifting8 cellsn*22.5°

Switch0-180°

VGA8 cellsn*0.6 dB

BufferIsolation

4BFCdiffDwingeloo, 13 December 2011

AA-mid / SKALayout of Differential BeamformerChip

X = 1.622 mm with sawlaneY = 1.772 mm with sawlane

Surface = 2.9 mm2

Current = 149.45 mA

Power supply = 3.3 V

Power consumption = 494 mW

Process Qubic4X NXP version 9.0

Differential Beamformer4 channels 2 Beams

PhaseShifting = 360 ° 4 bits (step = 22.5 °)

VGA = 4.5 dB 3 bits

Differential Input impedance matching= 200 or 150 ohms

Differential Output impednce matching= 200 or 150 ohms

Digital control : I2C or SPI

5BFCdiffDwingeloo, 13 December 2011

AA-mid / SKASimulation Layout RC parasitics / Phaseshifting6th state of gain (with inductance Bonding ~ 1,5 nH)

Frequency GHz

dBGain Sdd21 1 input -> 1 output

400 MHz 1500 MHz

16 states of phaseshifting400 MHz 1500 MHz

Frequency GHz

Reflexion Sdd11 1 input

Reflexion Sdd22 1 output

16 states of phaseshiftingdB

Phase Sdd21 1 input -> 1 output

Frequency GHz

16 states of phaseshifting

degree

Frequency GHz

dB Common mode Scc21 1 input -> 1 output

400 MHz

1500 MHz

16 states of phaseshifting

- 12 dB

6BFCdiffDwingeloo, 13 December 2011

AA-mid / SKASimulation Layout RC parasitics / VGA

0 degree of phaseshifting

Frequency GHz

400 MHz 1500 MHz

Gain Sdd21 1 input -> 1 output

8 states of gain

dB

Frequency GHz

400 MHz 1500 MHz

8 states of gain

Reflexion S11 1 input

Reflexion Sdd22 1 output

dB

Phase Sdd21 1 input -> 1 output

Frequency GHz

8 states of gain

degree

7BFCdiffDwingeloo, 13 December 2011

AA-mid / SKASimulation Layout RC parasitics

Noise Figure

Frequency GHz

System Noise Figure

16 states of phaseshifting

dB

Eg

200 ohms

Channel 1

Channel 2 Channel 3

Channel 4

Beam 1

Beam 2

System Noise Figure = NF-6.02

Frequency GHz

System Noise Figure8 states of gain

dB

200 ohms 200 ohms

200 ohms

200 ohms

8BFCdiffDwingeloo, 13 December 2011

AA-mid / SKASimulation Layout RC parasitics / Linearity

Eg

200 ohms

200 ohms 200 ohms

200 ohms

200 ohms

200 ohms

Channel 1

Channel 2 Channel 3

Channel 4

Beam 1

Beam 2

f1

f1

PindBm

PoutdBm

Theory : OIP3 ~ Pout-1dBm + 10.8

EMBRACE : OIP3 ~ Pout-1dBm + 8

400 MHz 1500 MHz

Pout-1dBm -7.53 dBm -9.7 dBm

OIP3 4.2 dBm 0.75 dBm

P-1dBm + 8 0.43 dBm -1.7 dBm

C/IPin = -40 dBm

56 dB 54 dB

The classical simulation of intermodulation order 3rd (OIP3) is unreliable.Add 8 dBm to the output compression point is better.

9BFCdiffDwingeloo, 13 December 2011

AA-mid / SKASimulation Layout RC parasitics / Linearity

Eg

200 ohms

200 ohms

200 ohms

Channel 1

Beam 1

Beam 2

Eg

Channel 2

Eg

Channel 3

Eg

Channel 4

f1

PindBm

f1

PindBm

f1

PindBm

f1

PindBm

f1

PoutdBm

400 MHz 1500 MHz

Pout-1dBm 3.6 dBm 1.6 dBm

OIP3 16.9 dBm 12.5 dBm

P-1dBm + 8 11.6 dBm 9.6 dBm

C/IPin = -40 dBm

56 dB 54 dB

10BFCdiffDwingeloo, 13 December 2011

AA-mid / SKAFuture phase shifting BFC / discussion

Reduce the phaseshifting step : 22.5 ° 11.25° 5.1° ?

Add integrated time delay at 2 beams : 2 integrated time delay / BFC ?

Choose an OIP3 value to reduce consumption ?

Reduce « squint » (squint is proportional to the distancebetween antennas)

Example : OIP3 = 5 dBm -> consumption = 250 mW OIP3 = 8 dBm -> consumprion = 500 mW OIP3 = 11 dBm -> consumption = 1000 mW

Add a True VGA, gain = [-30 dB .. 0 dB] 6 bits for example ?

Add channels or beams ?Example : 8 channels 2 beams

4 channels 4 beams

Add Temperature and Bias voltage control monitoring ?

BFC with Qubic4Xi process, lower consumption (can be)

Bias voltage RF & digital = 3.3 Volts