High Performance Handset Antenna Design Using … High Performance Handset Antenna Design Using RF...
Transcript of High Performance Handset Antenna Design Using … High Performance Handset Antenna Design Using RF...
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High Performance Handset Antenna Design Using RF MEMS Capacitors Co-authors Jianfa Wang, ZTE MT (nubia) Zhisheng Tian, ZTE MT (nubia) Paul Tornatta, Cavendish Kinetics Li Chen, Cavendish Kinetics Presenter: Larry Morrell, Cavendish Kinetics
November 6, 2014
Outline
CK at a glance Market Drivers Benefits of Aperture Tuning Device Requirements for Aperture Tuning Comparison of Tuned and Non-tuned Antenna in
Smart Phone configuration Product Roadmap Summary
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Cavendish Kinetics Snapshot
Business Tunable RF solutions - focused on Smartphone/Tablet antennas
Market Size > $2B for Tunable RF Front-end Components by 2015
Solution Industry’s highest-performance Antenna Frequency Tuning Solution
Locations San Jose, CA (HQ); Netherlands; Asia (3 locations)
Patents & IP >100 patents & applications
Major Investors Tallwood Venture Capital, Wellington Partners, Qualcomm Ventures
Company Status
Technology & Product qualified over process and temperature, released to Production. In mass production on Nubia Z7 Smartphone. Design-in process on a number of additional platforms
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Cavendish partners with antenna companies to create tunable antennas
Decreasing antenna efficiency is degrading connection quality Antenna frequency tuning is becoming a requirement
1995 2000 2005 2010 2015
75%
50%
25%
Ante
nna
Effic
ienc
y
Internal antennas
More radios
Full screen phones Multi-mode
12+ bands
Outstanding Connection Quality
Antenna Tuning
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Antenna Size and LTE Spectrum kill Antenna Performance
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1200 mm3 500-700 mm3
Efficiency ~ Size/Wavelength
Bandwidth
Antenna volume shrinking
Smaller antenna = Lower Efficiency
1/2/3/4/5/7/8/12/17/20/29/34/38/39/40/41
GSM/CDMA/TD-SCDMA/TD-LTE/FDD-LTE
Antenna covers wider bandwidth
700 - 960 1700-2100 2300-2700
Efficiency ~ Size/Wavelength
Bandwidth
Wide bandwidth = Lower Efficiency
Full screen, Thin Form Factor, Metal Backs, Rim-frame antennas
LTE deployed in new RF bands
Antenna Impedance Tuning is not Antenna Frequency Tuning
PIFA Radiating Element
Feed Point
Shorting Pin
Ground Plane
Free Space Wave Antenna Frequency Tuning (AFT) Optimizes radiation efficiency from the antenna terminals into free space
Antenna Impedance Tuning (AIT) Optimizes power transfer from the transmission line (guided wave) into the antenna terminals
Variable Capacitor
Matching Network
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Antenna Aperture Tuning dramatically increases efficiency Impedance Tuning cannot improve antenna efficiency
0%
10%
20%
30%
40%
50%
60%
600 700 800 900 1000
Typical Smart Phone Antenna – Perfectly Matched
antinout PP η X =
AIT delivers matched
power
AFT increases radiated
efficiency
Power (out) = Power (in) x Efficiency Antenna Frequency vs. Efficiency
IM Network
AFT
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Key Requirements for Aperture Tuning Antenna Performance
Impact Requirements for Aperture Tuning
Antenna Efficiency TRP, TIS Low Cmin Low ESR High Q
Cmin 0.8pF, 0.6pF ESR < 0.5 Ohm Q> 150 @ 2GHZ Q> 225 @ 750 MHz
Tuning Range Band Coverage C-range >3:1 High SRF
4:1, 5:1 SRF>8GHz
Low Noise TIS High IIP3 Low harmonics Low parasitics
IIP3 > 65dBm Tx spurious< -85dBm Rx spurious< -120dBm
Voltage Handling IP3, Harmonics >30V RMS 40 V RMS (57 V p-p)
Small Size Cost, Performance Board space Low cost
2 mm2
Most important features for aperture tuning: Q, Ratio, Size and Cmin
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nubia Z7: Smartphone with SmarTune™
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7.6 mm
Antenna Design Using Frame Antenna Geometries
Ground Ground
Continuous Frame Frame with Breaks
Frame connected to ground
Frame used as radiating element counterpoise Sections of frame used as ground or radiating elements
F G F G
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CK SmarTuneTM tunes low band with direct connect to Frame Antenna
F G
SmarTuneTM direct connection to Low band portion of the PIFA
Mid band not affected by low band tuning
High band resonance using part of the frame as a parasitic radiator
700-960MHz 1710-2170MHz
2300-2700MHz
SmarTuneTM
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CK SmarTuneTM tunes mid band with parasitic resonator
F G
High band resonance using part of the frame as a parasitic radiator
2300-2700MHz
SmarTuneTM
824-960MHz 1710-2170MHz
Tuned parasitic radiator coupled to the mid band section of the antenna
Low Band not affected by mid band tuning
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CK SmarTuneTM tunes high band with parasitic resonator
F G
High band resonance using part of the frame as a parasitic radiator
SmarTuneTM
824-960MHz
Mid band not affected by high band tuning
Low Band not affected by high band tuning
2300-2400MHz 2500-2700MHz
1710-2170MHz
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China Mobile LTE/3G/2G Spectrum Band Support Requirements
Low-band Chin
a M
obile
Pe
rfor
man
ce S
pecs
Global 2G/3G Spectrum
Despite the twin performance challenges of a thin ID and 13 different spectrum bands
SmarTune enabled nubia’s Z7 to provide industry leading LTE performance ABOVE the China Mobile requirements
Mid-band High-band
GSM B5; B8 B2; B3 TD-SCDMA B34; B39 WCDMA B5 B1; B2 TD-LTE B39 B40 2.3-2.4 B38; B41 (2496-2690) FD-LTE B20 (791-862) B1; B3; B4 B7
960 1710 2700 2170 2300 2400 2500 820 Spectrum (MHz)
Mid/ High
>80% >40%
ISM
Z-7 Antenna structure
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Tuning Technique Variable-valued shunt capacitor attached to one or more antenna structures Antenna: Narrow band, High Efficiency
Possible to tune each element independently CK, Nubia and antenna partners (2) determined that HB was in need of improvement
TRP Comparison – Tuned PIFA vs. Non-Tuned PIFA
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Frequency MHz
TRP
dBm
B40 B41
Antenna tunes between B40 and B41
Other Bands not effected by tuning
Tunable PAs: • Improved Efficiency • Increased band coverage • Reduced Power draw
Tunable Filters: • Improved Efficiency • Increased band coverage • BOM improvements
PA
LNA
PA
High Band
ASM
RFIC
Low Band
PA Module
LNA
Better Switches: • 10x lower insertion loss • Increased switch throws • BOM improvements
Antenna Tuning:
Cavendish’s Roadmap: RF MEMS for EVERY RF Application
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Summary
Industrial design trends, extended frequency range, and added features are driving the need for tunable antennas
Aperture tuning provides best performance over frequency Tuning element must meet key critical performance parameters, like low
ESR and low Cmin to be viable for aperture tuning Nubia Z7 SmartPhone results:
• >40% improvement over spec in B4 • >80% improvement over spec in B41
RF MEMS in full mass production for Antenna Tuning Also applicable to switches, filters, power amplifiers
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Thank You
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