This document summarizes key aspects of smartphone antenna design and the challenges associated with electromagnetic radiation. It discusses that smartphones have multiple antennas to support various wireless technologies. The different frequency bands used can interfere with each other, posing a major challenge. It also describes efforts to reduce electromagnetic interference and evaluate radiation absorption, known as Specific Absorption Rate (SAR). Regulatory bodies set safe SAR limits for public health as excessive radiation from phones is known to generate heat in human tissues.

1. The Smart Phone Evolution
 Multi-radio devices
 l Cellular: 2G, 3G, LTE, WiMAX
 l Wireless: Wi-Fi, Bluetooth
 l GPS, A-GPS
 l Mobile TV, FM radio
 l Multiple integrated functions
 l Camera
 l Interfaces (USB)
 l Touchscreen, keyboard
 l Memory cards
 l Wireless charging
 l Built-in projector
 l NFC (coming soon)

2. Smartphone antenna design
Smartphone antenna design there are multiple antennas on each phone:
 Primary Cellular Antenna (Transmit and Receive)
 Diversity Cellular Antenna (Receive Only)
 GPS Antenna (Receive Only)
 WIFI Antenna (Transmit and Receive)
 NFC Antenna

3. The Smart Phone Evolution

5. shared antenna
 The different frequency bands for cellular, GPS, and WLAN connectivity create
three main coexistence problems and are a major challenge for RF signal filtering
and processing in smartphones.

6. A GPS+WLAN extractor employs one bandpass filter each to permit the GPS and WLAN signals
through to the GPS and WLAN port. A dual notch filter at the same frequencies is used to allow
signals at all other frequencies through to the cellular receiver.

7.  WIFI antenna is typically located on the top of the device (near the GPS antenna
and diversity cellular antenna).
 WIFI antenna will be the smallest antenna. A half-wavelength at 2.4 GHz is 6.25 cm
(2.5"), and a half-wavelength at 5 GHz is 3 cm or just over an inch.
 GPS antennas bandwidth is fairly small. The GPS frequency is 1.575 GHz, with
virtually no bandwidth
 GPS antenna efficiencies are typically on the order of -3 dB to -9 dB..
 A half-wavelength at GPS frequency (1.575 GHz) is about 9.5 cm or 3.75 inches

8. METHODS TO ELIMINATE EMI OR DESIGN METHODS FOR EMC
 The effective methods to eliminate EMI are
 1. Shielding
 2. Grounding
 3. Bonding
 4. Filtering
 5. Isolation
 6. Separation and orientation
 7. Circuit impedance level control
 8. Cable design
 9. Cancellation techniques in frequency or time domain
 10. Proper selection of cables, passive components
 11. Antenna polarization control
 12. Balancing

9. Physical aspects of more receive antennas
• Cell coverage
• Network stability
• Link and system capacity
• Interference mitigation
• power consumption

10. Active Antenna System

11.  A cell phone 0.5 W output
power the phone transmits,
there is a loss of at least
50% for the antenna
efficiency, and at least 50%
for the radiation that is not
directed to your head.
Hence, we can safely take
0.125 W (=0.5*0.5*0.5)
Electromagnetic Effects: Heating

12.  Reducing the
harmful effect is the
need of present day
 Globally , a
parameter known as
Specific Absorption
Rate (SAR)
 SAR is defined as the
power absorbed per
mass of tissue and
has unit of watts/kg
Human contact with radiations

13. PROBLEM STATEMENT
 Radiations from cell
phone devices
produce heat
in human body
 Strong need to
reduce this harmful
effectSpecific Absorption Rate (SAR) is a
measure of the rate at which energy is
absorbed by the body when exposed to
a radio frequency (RF) electromagnetic
field

14. WHO DECIDES WHAT A SAFE EXPOSURE LEVEL IS?
 Currently, two international safety
bodies have developed exposure
guidelines for workers and for the
general public: the International
Commission on Non-Ionizing
Radiation Protection (ICNIRP); and
the Institute of Electrical and
Electronics Engineers (IEEE).

15. The map shows information on the status of the effective radio frequency
exposure limits applicable to mobile phones and similar devices.

16. EMC Tests for the Compliance
 Needs testing about
1) Intra-system EMC for stable operation, performance & quality
2) inter-system EMC for the protection of radio service (Radio law) and the safety from
danger regulation & certificate
EMC
Electromagnetic Compatibility
EMI
Electromagnetic Interference
CE (IEC/CISPR)
Conducted Emission
∙ Voltage
∙ Current
RS (IEC/TC77, ISO)
Radiated Susceptibility
∙ Magnetic Fields
∙ Electric Fields
RE (IEC/CISPR)
Radiated Emission
∙ Magnetic Fields
∙ Electric Fields
∙ Conducted Power
Disturbance
EMS
Electromagnetic Susceptibility
CE (IEC/TC77, ISO)
Conducted Susceptibility
∙ HF/LF
∙ Surge, EFT Burst
∙ ESD

17. Measuring SAR
SAR is critical to antenna design,
if the SAR is too high the antenna must be changed.
if the SAR is too high the transmit power is lowered
antenna positioning is critical. The antennas for mobile
phones are typically on the bottom of the phone, to keep
the radiating part of the phone as far as possible from the
brain region.
methods for dropping the SAR include impedance
matching changes and parasitic resonators

18. Parameters that can affect SAR include:
Types of radio service (cellular, PCS, , WLAN, etc.)
Types of modulations (CDMA, GMSK, TDMA, etc.)
Physical orientation to person
RF power level (in Watts or mW)
Changes to transmitter,antenna

19.  To legally sell a cell phone to
customers, the FCC limits the
radiation you can receive from the
phone when it is placed directly
against your ear.
The FCC and SAR

20. Why Samsung Cell Phones Are Rated The Lowest Radiation Cell Phones
The Samsung Galaxy Note 2 smartphone has a maximum
SAR of 0.17 W/kg (watts per kilogram).
The SAR for the Apple iPhone 4S is 1.11, and for the
Motorola Droid Razr Maxx, it is 1.54 W/kg.
RF shielded flip cover cases

21. Conclusion
Until now, man has been absorbing
the harmful, unseen EM radiations
without even being aware of it, but
now, with rapid advent in
technology this RF Radiation
pollution has started having ill
effects on human health and health
of animals.
Hence, there is an urgent need to
take precautionary steps.