Antenna performance in mobile phone is much more important than antenna design due to the very small size of antenna RF in a compact mobile phone device. Through near 20 years' research and development in RF, transceiver and antenna technology, Prof. Willie W. Lu carefully analyzed and evaluated each patent which Apple filed with USPTO on the antenna technology for iPhone and iPad, and pointed out that the major problem of iPhone antenna is the lack of optimal antenna optimization and calibration technology which result in the poor performance of its radio transmission between the iPhone and the basestation. Prof. Lu has writen a 500-pages report to address this technical issue based on the iPhone antenna patents Apple filed with USPTO. For more, please contact Prof. Lu at wwlu@ieee.org or visit http://4Gsummit.com to join our technical discussions.

1. 7th National Radio
Administration Experts
Council Meeting
Beijing, July 15th
Antenna Technology for
Mobile Phone Device
Case Study: iPhone/iPad
Prof. Willie W. Lu

2. Challenges in Mobile Phone Antenna
• Tradeoff between size and performance
• Handheld Interference Analytical Modeling
• Human Body Radio Absorbing Modeling
• Inter-band frequency I t f
I t b df Interference Modeling
M d li
• Intra-band channel Interference Modeling
• Multi-band Antenna Optimization Technique
• Multi-band Antenna Calibration Technique
• Radio Transmission Optimization and Link Budget
p g
• Multi-dimensional Handovers Calibration (V+H)
Antenna Performance is Much More Important than Antenna Design
Prof. Willie W. Lu,wireless innovation™
leading Cupertino, CA Page 2 © Willie W. LU, All Rights Reserved.
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3. Key Antenna Patents of iPhone/iPad – New Design
Principal Inventor: Dr. Robert W. Schlub, Sr. Director of Antenna Group, Apple Computer Inc.
1. 20100123632 MULTIBAND HANDHELD ELECTRONIC DEVICE SLOT ANTENNA 05-20-2010
2. 20100060529 ANTENNAS WITH TUNING STRUCTURE FOR HANDHELD DEVICES 03-11-2010
3. 20100007564 ANTENNAS FOR HANDHELD ELECTRONIC DEVICES WITH CONDUCTIVE BEZELS 01-14-2010
4. 20090305742 ELECTRONIC DEVICE WITH PROXIMITY-BASED RADIO POWER CONTROL 12-10-2009
5. 20090303139 HANDHELD ELECTRONIC DEVICES WITH ISOLATED ANTENNAS 12-10-2009
6. 20090278753 HANDHELD ELECTRONIC DEVICES WITH ISOLATED ANTENNAS 11-12-2009
7.
7 20090275370 HANDHELD ELECTRONIC DEVICES WITH ISOLATED ANTENNAS 11 05 2009
11-05-2009
8. 20090273526 HANDHELD ELECTRONIC DEVICES WITH ISOLATED ANTENNAS 11-05-2009
9. 20090256759 HYBRID ANTENNAS FOR ELECTRONIC DEVICES - PORTABLE ELECTRONIC DEVICE IS PROVIDED
THAT HAS A HYBRID ANTENNA 10-15-2009
10. 20090256758 HYBRID ANTENNAS FOR ELECTRONIC DEVICES - PORTABLE ELECTRONIC DEVICE IS
PROVIDED THAT HAS A HYBRID ANTENNA 10-15-2009
11. 20090153407 HYBRID ANTENNAS WITH DIRECTLY FED ANTENNA SLOTS FOR HANDHELD ELECTRONIC
DEVICES 06-18-2009
12. 20090051604 MULTIBAND ANTENNA FOR HANDHELD ELECTRONIC DEVICES 02-26-2009
13. 20090040115 ANTENNAS FOR HANDHELD ELECTRONIC DEVICES 02 12 2009
02-12-2009
14. 20080316121 WIRELESS HANDHELD ELECTRONIC DEVICE - HANDHELD ELECTRONIC DEVICE MAY BE
PROVIDED THAT CONTAINS A CONDUCTIVE HOUSING AND OTHER CONDUCTIVE ELEMENTS 12-25-2008
15. 20080316117 HANDHELD ELECTRONIC DEVICE ANTENNAS - HANDHELD ELECTRONIC DEVICE MAY BE
PROVIDED THAT CONTAINS A CONDUCTIVE HOUSING AND OTHER CONDUCTIVE ELEMENTS 12-25-2008
16.
16 20080316116 HANDHELD ELECTRONIC DEVICE WITH CABLE GROUNDING 12 25 2008
12-25-2008
17. 20080316115 ANTENNAS FOR HANDHELD ELECTRONIC DEVICES WITH CONDUCTIVE BEZELS 12-25-2008
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leading Cupertino, CA Page 3 © Willie W. LU, All Rights Reserved.
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4. Challenge to traditional Antenna Testing
Embedded Antenna Testing Much Difficult than Traditional Testing
Based on Testing with Anritsu, CETECOM, Comarco , LitePoint , RTX Telecom, etc.
Prof. Willie W. Lu,wireless innovation™
leading Cupertino, CA Page 4 © Willie W. LU, All Rights Reserved.
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5. How to combat Interference in mobile phone
Receiver
Diversity To combat distortion To combat Loss in SNR
Transmitter FREQ-SELECTIVE DIVERSITY TYPES
Power Control DISTORTION •Time (e.g Interleaving)
•Adaptive Equalization •Frequency (e.g, BW Expansion,
Antenna
(e.g decision Feedback, Viterbi Spread Spectrum FH or DH with
Calibration Equalizer) Rate Receiver)
Transmission •Spread Spectrum –DS or FH
Spread DS •Spatial (e g Spaced Receive
Spatial (e.g
Optimization •Orthogonal FDM (OFDM) Antennas)
•Polarization
Radio Repeater •Pilot Signal
Installation
FAST-FADING DISTORTION FLAT-FADING AND SLOW-
•Robust Modulation FADING
•Some Type of Diversity to get
•Signal Redundancy to increase
Additional Uncorrelated
Signaling Rate
Estimates of Signal
•Coding & Interleaving
•Error-Correction Coding
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6. Human Body Radio Absorbing Modeling
• Specific absorption rate
distribution of 1 900MHz
1,900MHz
cell phone held against
tilted head model
• Radiation increasing un-
linearly when closing to
head
• Interference increasing
un-linearly as well
• Radio Transmission
performance degrading
abruptly
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leading Cupertino, CA Page 6 © Willie W. LU, All Rights Reserved.
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7. Reconfigurable Multiband Antennas
• GSM900 (880-960)
• DCS1800 (1710-1785)
• PCS1900 (1850-1910)
• UMT2000 (1725 to 2055
Simulated and measured results of the experimental design:
return loss of quad-band antenna ( ─),
measured return loss of quad-band antenna (-o—o-),
simulated return loss of Bluetooth antenna ( - - -),
),
measured return loss of Bluetooth antenna (-+-+-),
and measured isolation between quadband and Bluetooth antennas ( -▫-▫-▫-▫-).
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leading Cupertino, CA Page 7 © Willie W. LU, All Rights Reserved.
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8. Wireless Device Antenna Choices
Loop
PIFA
Patch Monopole
M l MLA
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leading Cupertino, CA Page 8 © Willie W. LU, All Rights Reserved.
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9. Quad-Band PIFA - Example
The Inverted F antenna is a variant of the Monopole antenna
• reduce the height
• required PCB ground plane length is roughly λ/4
• miter-avoid a right angle microstrip bend, which results in a
poor current flow on the stub.
• taper -compensate the abrupt step transition between the
microstrip line feed and the antenna.
(1) Main PCB (printed circuited
broad), (2) battery, (3)speaker, (4)
patches for quad-band antenna, (5)
patch for Bluetooth antenna, (6)
ground strip, (7) feed strip (8)
strip strip,
upper PCB
f = c / 4(W + L)
*W -width of each patch
W
*L –length of each patch
Prof. Willie W. Lu,wireless innovation™
leading Cupertino, CA Page 9 © Willie W. LU, All Rights Reserved.
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10. Switchable Multiband Antennas
- volume reuse
I. Switched Feed: antenna volume
reuse i achieved b switching b
is hi d by i hi between
different feeding locations of the antenna.
II.
II Switched ground: antenna volume
reuse is achieved by switching or breaking of
y g g
the antenna’s connection to the ground.
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leading Cupertino, CA Page 10 © Willie W. LU, All Rights Reserved.
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11. Switched Feed
Resonant frequencies:
Mode 0:
∆L1 and ∆L2 are the extension lengths due to
capacitive or inductive loading effect at the
corresponding resonant frequencies
Mode 1:
∆L1 and ∆L3 are the extension lengths due to capacitive
or inductive loading effect at the corresponding resonant
frequencies
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leading Cupertino, CA Page 11 © Willie W. LU, All Rights Reserved.
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12. Switched Ground
Resonant frequencies:
Mode A:
∆L1 and ∆L2 are the extension lengths due to
capacitive or inductive loading effect at the
corresponding resonant frequencies
Mode B:
d3 is slot length whereas ∆L1 and ∆L3 are the
extension lengths due to capacitive or inductive
loading effect at the corresponding resonant
frequencies
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leading Cupertino, CA Page 12 © Willie W. LU, All Rights Reserved.
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13. Antenna Diversity Methods – Beyond Mobile Phone
To Mitigate These Problems, Diversity Techniques are Being
Developed
- Spatial Diversity is a widespread technique based on the use of an array of
sufficiently spaced antennas at either transmitter or receiver
y p
- Polarization Diversity takes advantage of existence of statistical
independence of different polarization states as a wave is scattered in the
environment
- Pattern Diversity uses the antenna itself to select angularly diverse
f
components of the scattered wave to mitigate fading and increase SNR
- Temporal Diversity exploits the multidimensionality of the channel to
improve SNR
- MIMO uses antenna arrays at both transmitter and receiver—multipath
propagation can actually be exploited to establish multiple parallel channels
Prof. Willie W. Lu,wireless innovation™
leading Cupertino, CA Page 13 © Willie W. LU, All Rights Reserved.
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14. Any question ?
Prof. Willie W. Lu
http://Willie.Lu
E-mail: wwlu@ieee.org
Prof. Willie W. Lu,wireless innovation™
leading Cupertino, CA Page 14 © Willie W. LU, All Rights Reserved.
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