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