An antenna is the most important device in a cell-phone in terms of wireless communication. If the antenna doesn't work very well, the signal strength drops drastically. For the design of cell-phone antennas, we can adopt a dipole, helical, PIFA (Planar Inverted F Antenna), or intennas.

1. Mokwon University
Yong Heui CHO(조용희)
yhcho@mu.ac.kr
Antennas for
Cell-Phones

2. First Cell-Phone
 Dr. Martin Cooper in Motorola
Motorola RAZR
Thin phone: 7.1 [mm]
2

3. Trend in Cell-Phone Development
 Volume and weight
Weight [g]
Volume [cc]
3

4. Retractable Antenna
 An antenna that you can retract
 Basically a dipole antenna with top
loading (looks like a hat)
$2 when you try to buy
$0.1 when you are a company
←amazon.com
4

5. Stubby Antenna
 When you open a cap, you can see a
helical antenna. (looks like a spring)
 You don’t have to retract. → It is
convenient for users.
 What is stubby anyway?
←shutterstock.com
5

6. Ceramic Helical Antenna
 High permittivity → Small antenna
size
6

7. Intenna
 Internal antenna: The antenna is in a
phone. You can’t see it.
 A phone case is strongly related to
an intenna.
7

8. Intenna for 3G Phone
 A metal pattern is served as an
antenna.
8

9. Triple-Band Antenna
 Intenna: internal antenna
 Resonance: 900, 1600, 1900 [MHz]
←empire.de
9

10. PIFA
 Planar Inverted F Antenna
Signal Input Radiator
Original From
Coaxial
Cable
PIFA
10
Integrated PIFA

11. PIFA for Notebook
11

12. PIFA for Cell-Phone
←antenova.com
12

13. Current Distributions
←empire.de
13

14. Antenna for Galaxy Nexus
 Can you point where the intenna is
now?
14

15. Impedance Matching for Phone
 Chip capacitors and inductors are
used to matching the antenna and
circuit.
15 ←ham-radio.com

16. Apple’s Antennagate
 Death grip: when you touch a certain
part of an iPhone 4, your call may be
dropped.
 Stainless steel frame as multi-band
antennas
16

17. Effect of Our Body to Phone
 Our body is a ground plane for a
phone. That means our body affects
the phone seriously.
17

18. SAR Measurement
 SAR: Specific Absorption Rate
 Your brain can absorb EM power.
The SAR measures how much power
your head does.
18 ←nearfield.org