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Copyright © Gapwaves 2017
GAPWAVES AB (publ)Antenna Technology for 5G
2017-11-23
Copyright © Gapwaves 2017
Power dissipation, tough numbers
+64 dBm 1.1 kW 80x80 mm
Copyright © Gapwaves 2017
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
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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
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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
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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%
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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
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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
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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
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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
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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
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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
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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
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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
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Conclusion
+64 dBm 0.1 kW1.1 kW 80x80 mm
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Thank you for your attention
www.gapwaves.com
Thomas Emanuelsson, [email protected]