GAPWAVES AB (publ) - ETSI · 2 –4% PAE at back-off The need The solution § Digital...

Copyright © Gapwaves 2017

GAPWAVES AB (publ)Antenna Technology for 5G

2017-11-23


Power dissipation, tough numbers

+64 dBm 1.1 kW 80x80 mm


Ø ICT uses ~4% of the worlds electricity consumption*

Ø The same carbon footprint as the aviation industry

5G requires new energy efficient solutions

Ø Exponential data growth will drive energy consumption

*ICT-Energy CSA Workshop


5G

Ø Active antennas with beamforming

Ø The beam is focused to the active user

Ø Electrically scanned antennas require significant increase of electronics

At mmWave, steerable antennas are used for efficient use of energy to compensate for atmospheric loss


Today’s active antennas at 5G frequencies are inefficient

Today’s solutions

Ø Meet performance requirements but are too expensive and power consuming

or

Ø Are cost effective and low power but do not meet the performance requirements


The power efficiency in today’s antennas are limited due to…

Poor antenna efficiency Low amplifier efficiency System level limitations

BF

2 – 4%25 – 40%


Current antennas require a trade-off between Losses and Cost

Waveguide based

Substrate based

+ Low power losses and high aperture effiency

+ 80 – 90% antenna efficiency

– Difficult to manufacture à Costly

– Difficult to integrate with electronics

– High power losses and low aperture efficiency

– 25 – 40% antenna efficiency*

+ Easy to manufacture à Low cost

+ Easy to integrate with electronics

?

Trade-off


Power amplifiers with high efficiency are not available

§ High order modulations with high peak-to-average ratios require significant power back-off ~9 dB

§ Off-the-shelf amplifiers at millimeter waves achieve only 2 – 4% PAE at back-off

The need The solution

§ Digital Pre-Distortion, DPD, and high efficiency amplifiers e.g. Doherty

§ State-of-the-art amplifiers at millimeter waves achieve ~15-20% PAE at back-off

The complication

§ Added components use up valuable design space

§ Added circuit board routing is necessary for feedback signals from PAs to DAC

PAE (%)

Output power (dBm)

PA PA PA PA

~9 dB


The optimal number of RF channels require high power amplifiers in a small space

Example

§ 65 dBm EIRP

§ 9 dB back-off from OP1dB

§ One element per RF channel

§ Dual polarization

§ 80% antenna efficiency

§ 15% amplifier efficiency

§ Analog beamforming, LNA and driver circuitry ~350 mW per channel

0

100

200

300

400

500

0 100 200 300 400 500 600

POW

ER C

ON

SUM

PTIO

N [W

]NUMBER OF RF CHANNELS

GaN GaAs SiGe / CMOS

~200 W


A combination of technology fundamentals and building practice requirements needs to be fulfilled

High amplifier efficiency

High antenna efficiency

Technology fundamentals

High cooling ability

Effective use of circuit board space

Low loss RF interconnects

High manufacturability

Building practice requirements

Energy efficient active antennas


The Technology of Gapwaves

Structured metal surface (AMC) prevent leakage

Flat metal surface

Wave

No electrical contact between layers

Gap waveguides

An Artificial Magnetic Conductor (AMC) surface prevents field leakage without metallic contact

Benefits

§ Low power losses ~Rectangular waveguides

§ Low coupling between adjacent lines

§ Simplifies assembly of multilayered structures

§ Enables production using die-casting

§ Enables integration of active circuits


Gapwaves Antenna Technology applied at 28 GHz

1. Antenna slots 2. Antenna feeding 3. Filters 4. Active circuits 5. Shielding cover 6. Heatsink

Cooling of active circuits from both sides


Gapwaves Antenna Technology applied at 28 GHz

Gap waveguide based antenna feeding and filters require no metal contact

Gap waveguide shielding require no metal walls freeing up board spaceAll metal waveguide based antenna enable high efficiency

Low loss contactless RF interconnects from microstrip to waveguide


Case study, Performance Comparison to State-of-the-ArtGapwaves State-of-the-art Difference

Circuit technology GaN single channel MMIC front-end, CMOS 16 channel driver and BF

SiGe 16 channel RFIC with integrated Front-end, driver and BF

Amplifier efficiency 15% N/A

Output power (9 dB back-off) 35 dBm 24 dBm +11 dB

Power losses -1 dB (80%) -4.0 dB (40%) +3 dB

Antenna directivity 30 dBi 24 dBi +6 dB

EIRP 64 dBm 44 dBm +20 dB

Level of beam steering +-50 degrees horizontally

+-15 degrees vertically+-30 degrees in both directions Reduced number of units to

cover 360 degrees

Beamforming method Analog 5 bit Analog 5 bit None

Polarization Dual Dual None

Total power consumption (Tx + Rx) 113 W 66 W +30 W

Power consumption scaled to +64 dBm EIRP 113 W 1112 W (with 4 units and a 6.3x

increase of output power) 10x better power efficiency


Conclusion

+64 dBm 0.1 kW1.1 kW 80x80 mm


Thank you for your attention

www.gapwaves.com

Thomas Emanuelsson, [email protected]

GAPWAVES AB (publ) - ETSI · 2 –4% PAE at back-off The need The solution § Digital...

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