Designing Small form factor PCB antenna

[sangar]

Hi all,

I am working on a project which uses CC1352P Wireless SoC. One of the critical requirement of our design is that the PCB antenna should be fitted in 10mm x 30mm area and actual board size will be 25mm x 30mm...In the CC1352P TI Launchpad reference design, PCB antenna area 58 mm x 25mm...Well, first of all, bringing the PCB antenna inside 10mm x 30mm is possible. Second of all, this will reduce the antenna efficiency in terms of range it covers...I know that reducing the conductor length of the PCB antenna will change the resonance frequency of it but we can correct that by make use of matching network...Please suggest...

Thanks,
Muthu

[Mr. Scram]

Hi all,

I am working on a project which uses CC1352P Wireless SoC. One of the critical requirement of our design is that the PCB antenna should be fitted in 10mm x 30mm area and actual board size will be 25mm x 30mm...In the CC1352P TI Launchpad reference design, PCB antenna area 58 mm x 25mm...Well, first of all, bringing the PCB antenna inside 10mm x 30mm is possible. Second of all, this will reduce the antenna efficiency in terms of range it covers...I know that reducing the conductor length of the PCB antenna will change the resonance frequency of it but we can correct that by make use of matching network...Please suggest...

Thanks,
Muthu

What about an SMD antenna? That should potentially be more compact, though the ground plane size may still be an issue.

[hendorog]

A quick google says that the CC1352P targets both sub 1GHz and 2.4GHz.

So the question is, what frequency antenna do you want?

[sangar]

Hi,

Thanks...Ours is Sub-GHz...The TI EVK has a monopole PCB antenna which supports both sub-GHz and 2.4 GHz by tuning the matching network...Please find the attached image...


Thanks,
Muthu

[Dubbie]

Check out the products from Johansen Technology. They have some amazing chip antennas.
Their support is great and they’ll review your layout for free.

[sangar]

Hi Dubbie,

The module I am designing going to be a coordinator in parking sensor application...I have no idea about the End node and their antenna...So, I am expecting a 100 feet range from our wireless module (coordinator)...As customer recommends PCB antenna, I am talking about PCB antenna here...If chip antenna gives better range than PCB, we will recommend this to our customer...So,  my question is that which gives better range, PCB antenna (Or) chip antenna?...


Edit:
I have just found Miniature PCB helical antenna which has small form factor 19mm x 11mm from Texas instruments DN038 for Sub-GHz applications...This works for the range I want ?

[ThomasDK]

One of the critical requirement of our design is that the PCB antenna should be fitted in 10mm x 30mm area and actual board size will be 25mm x 30mm...

Here be dragons...

An ideal monopole antenna needs an infinite ground plane. In practice a quarter wavelength will do, but you are way below that - that's your number one problem.

It's true that you can make anything resonate by adjusting the matching filter, but that doesn't mean that it will actually work as an antenna. If you really need it to be that small (and an external antenna isn't an option), go for a chip antenna to maximize the available space for the ground plane. No matter what, the range is going to be horrible.

[sangar]

Hi All,

Well, I have just received the range information from the customer and it should cover 150 meters...I am thinking about implementing the miniature helical PCB antenna supplied by TI for 868 MHz applications and gain of this antenna would be 0dB...The maximum power of the transmitter 20dBm...Is it possible to cover 150 meters with the helical PCB antenna?... Please suggest


Thanks,
Muthu

[Mr. Scram]

Chip antennas I have seen for 2.4 GHz are less than useless, IMHO.

One would do far better with a short piece of stiff wire, or alternatively, merely terminating your antenna connection at a u.fl socket and including an external antenna which the user could use or replace.  (I don't know anything about regulatory issues which would definitely figure if a device was sold commercially- though. Double check that whatever you do is legal!) 

2.4 GHz antennas vary a lot on how well they might work at lower frequencies.

One that likely would work well: You could likely terminate two 1/4 wave wires at the same point on a PCB and cut one to the lower, longer frequency and one to 2.4 GHz and that would likely work well if both were parallel to one another, separated by a bit of space, and given some free space surrounding them to work.

It would be the UHF version of the multiple frequency vertical or fan dipole.

What do mean by "less than useless"? That suggests the product group isn't viable. Traditionally chip antennas should be able to perform better in less space due to more consistent and predictable manufacturing.

[Gribo]

150m is doable in 2.4GHz with a PA/LNA (CC2590 for example), without it, you will be lucky to get 30m. On the sub 1GHz side, it really depends on the allowed EIRP limit you are targeting.
Since the transceiver can have a 4KHz channel, if your required data rate allows it, you can get 150m range without a PA/LNA.

[cdev]

I was accidentally responding to a different thread. Which you probably figured out. I agreed with you, they can be big problem solvers, generally. But some kinds are picky about their electrical environment for optimum operation. More so than some other kinds of antennas.

What do mean by "less than useless"? That suggests the product group isn't viable. Traditionally chip antennas should be able to perform better in less space due to more consistent and predictable manufacturing.