www.cavendish-kinetics.com

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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