Breaking News
Comments
Newest First | Oldest First | Threaded View
Brakeshoe
User Rank
Rookie
re: Skycross: Antenna challenges in smartphones and tablets with 4G rising
Brakeshoe   3/3/2011 11:39:02 PM
NO RATINGS
Note on second paragraph on second page: "The coupling magnitude is inversely proportional to the separation distance..." And is also reduced by the scalar dot product of the angular difference in polarization when linear polarization is used.

Brakeshoe
User Rank
Rookie
re: Skycross: Antenna challenges in smartphones and tablets with 4G rising
Brakeshoe   3/3/2011 11:32:10 PM
NO RATINGS
Remember, a modulated RF signal will have sidebands. Let's look at the simplest case of a broadcast AM radio (6A3, double sideband full carrier) signal operating with a carrier frequency f(c) of 600 kHz modulated at 100% with a 4.0 kHz sinusoid. We now have a signal that occupies the spectrum from 596 kHz to 604 kHz, and the Q of the output amp stage as well as the antenna must be low enough to not trim off the sidebands.

sajid.bashir
User Rank
Rookie
re: Skycross: Antenna challenges in smartphones and tablets with 4G rising
sajid.bashir   3/3/2011 7:01:09 PM
NO RATINGS
I am still confused. AS I know is the antenna size is directly related to wavelength so at higher frequencies we can have smaller antennas. The efficiency is directly related to size as it allows capturing more energy. If this is true then how does bandwith relate to antenna size?

zeeglen
User Rank
Blogger
re: Skycross: Antenna challenges in smartphones and tablets with 4G rising
zeeglen   3/3/2011 6:17:04 AM
NO RATINGS
@JWC Good point. I was considering only single element with length reduction below 1/2 (dipole) and 1/4 (ground plane) wavelength. Next marketing breakthrough - a log periodic on a cellphone! (Just kidding)

JanineLove
User Rank
Blogger
re: Skycross: Antenna challenges in smartphones and tablets with 4G rising
JanineLove   3/2/2011 7:21:26 PM
NO RATINGS
I fixed this in the article above.

jwc
User Rank
Rookie
re: Skycross: Antenna challenges in smartphones and tablets with 4G rising
jwc   3/2/2011 3:39:51 PM
NO RATINGS
Big often relates to narrow band but it doesn't always mean narrow band. For example log-periodic antennas are huge yet they cover enormous bandwidths. I'm sure there are many other examples.

zeeglen
User Rank
Blogger
re: Skycross: Antenna challenges in smartphones and tablets with 4G rising
zeeglen   3/2/2011 11:41:27 AM
NO RATINGS
Paul, thank you for clearing this up.

SkyCross CTO
User Rank
Rookie
re: Skycross: Antenna challenges in smartphones and tablets with 4G rising
SkyCross CTO   3/1/2011 9:14:15 PM
NO RATINGS
You are not missing something, you are correct - Bandwidth and size are DIRECTLY related, not inversely related.

zeeglen
User Rank
Blogger
re: Skycross: Antenna challenges in smartphones and tablets with 4G rising
zeeglen   3/1/2011 4:03:27 PM
NO RATINGS
"[Simply stated, these limitations are: "Bandwidth and antenna size are inversely related" and "efficiency and antenna size are directly related." This means that in general, a larger antenna will have larger bandwidth and efficiency.]" This is a bit confusing, if bandwidth is inversely related to antenna size, then a larger antenna would have a smaller bandwidth. The few times I made short antennas the bandwidth decreased as antenna length decreased. Am I missing something? Otherwise a very interesting and well-written article.



Flash Poll
EE Life
Frankenstein's Fix, Teardowns, Sideshows, Design Contests, Reader Content & More
Engineer's Bookshelf
Caleb Kraft

The Martian: A Delightful Exploration of Math, Mars & Feces
Caleb Kraft
6 comments
To say that Andy Weir's The Martian is an exploration of math, Mars, and feces is a slight simplification. I doubt that the author would have any complaints, though.

The Engineering Life - Around the Web
Caleb Kraft

Surprise TOQ Teardown at EELive!
Caleb Kraft
Post a comment
This year, for EELive! I had a little surprise that I was quite eager to share. Qualcomm had given us a TOQ smart watch in order to award someone a prize. We were given complete freedom to ...

Design Contests & Competitions
Caleb Kraft

Join The Balancing Act With April's Caption Contest
Caleb Kraft
58 comments
Sometimes it can feel like you're really performing in the big tent when presenting your hardware. This month's caption contest exemplifies this wonderfully.

Engineering Investigations
Caleb Kraft

Frankenstein's Fix: The Winners Announced!
Caleb Kraft
8 comments
The Frankenstein's Fix contest for the Tektronix Scope has finally officially come to an end. We had an incredibly amusing live chat earlier today to announce the winners. However, we ...

Top Comments of the Week
Like Us on Facebook
EE Times on Twitter
EE Times Twitter Feed

Datasheets.com Parts Search

185 million searchable parts
(please enter a part number or hit search to begin)