Antenna

rahuldapp · Antenna-Theory.com Newbie Joined: 18 Nov 2014 Posts: 3

Hey! I'm working on a project involving external antenna design to boost signals for smart phones. Can we couple the feeds wirelessly somehow and try out? Is that a feasible option? Please help me

E Kafeman · Posted: Thu Nov 20, 2014 11:56 pm Post subject:

External antenna coupler is possible but it cost transmission loss between coupler and internal antenna. Well designed will typical loss be 3-6 dB.
Possible but not any real boost.
This type of coupling is a common solution to improve transmission for a cellphone placed inside a car, with aid of an external antenna.

admin · Site Admin Joined: 03 Jan 2007 Posts: 247

Note that metallic phones such as the iPhone 4/5/6 and HTC One have antennas that are not internal - the external metal is the antenna. So you don't even need to couple to it, you can copper tape right to it.

Here's an example:
http://antenna-theory.com/iphone-range-extender.php

if you steal my idea, just make sure to credit me Smile

E Kafeman · Posted: Fri Nov 21, 2014 6:34 pm Post subject:

rahuldapp · Antenna-Theory.com Newbie Joined: 18 Nov 2014 Posts: 3

@admin: Well, thank you admin for your idea.. Of course, I'll credit you Very Happy

Also, I have to investigate and find out solution in a general case. Yet, your idea has been really helpful. Thanks!

rahuldapp · Antenna-Theory.com Newbie Joined: 18 Nov 2014 Posts: 3

@Kafeman: Thank you for replying! Very Happy

How do we couple them? I would need a bit more detail.. Can you please provide?

E Kafeman · Posted: Sun Nov 30, 2014 1:05 am Post subject:

Sorry but details will be your part to handle, or you can pay me, as I do such things for living.
Designing a coupler is much as any antenna developing process:
Optimize for lowest possible system loss S21, whatever S11 is, and finally normalize impedance with aid of a matching network.

Have been involved in design of this one.
That coupler is multi-band and designed for a special phone model, allowing for better performance.
A general coupler, single band, is easier to design.
Buy something like this and do some reverse engineering or improve it to fit your need.
Performance for a such coupler will be very depending on phone model that is selected as RF current along phone ground can vary a lot between models due to ground size and its internal antenna locations.

Admin is correct, no need for a coupler for an iPhone, but whatever you connect, is it probably already covered by Apple patents.

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