CC1190: Chip Antenna Implementation

Steve1234

Part Number: CC1190
Other Parts Discussed in Thread: CC1101,

I am trying to design a Sub-GHz system using CC1101 - CC1190 combination.

While designing, I am referring to example design [SWRR077] CC1101-CC1190EM 915MHz Reference Design.

I followed the reference design mostly, except for antenna part, which I have replace with something other than whip antenna due to cost issue.

So, I believe I can finish my design keeping everything same as reference design except for the red and blue part circled part below

For antenna, i chose Johanson 0915AT43A0026.

1. Can I replace Red circled part with pi network, and blue circled part with antenna as shown below?

2. After pi network, should I need "50 Ω feed line" to connect to Green part?

3. Can I keep the values of green part the same as reference design?

Thank you.

over 6 years ago

0 TER over 6 years ago

TI__Guru**** 317180 points

If you want to use this chip antenna you have to remove the SMA and connect the point marked * on the chip antenna layout figure to the line that was connected to the SMA.

Reason: The red circle on the CC1101-CC1190 schematic is impedance tuning and most important, filtering. The SMA line is a 50 ohm point.

On the chip antenna figure the * point is a 50 ohm point while the red circle is impedance matching to the antenna.

0 Steve1234 over 6 years ago in reply to TER

Intellectual 350 points

So, basically, all I have to modify is replace blue circle on CC1101-1190 schematic with the entire chip antenna figure at the * point?

0 TER over 6 years ago in reply to Steve1234

TI__Guru**** 317180 points

Yes.

When you have done the schematic you can take a screen shot of the relevant part for review

0 Steve1234 over 6 years ago in reply to TER

Intellectual 350 points

I used the Original drawing from [SWRR077] CC1101-CC1190EM 915MHz Reference Design, and just patched modified part for easy comparison.

Basically, I kept everything, including connections and component values, the same except replacing SMA antenna with the patched part above.

0 TER over 6 years ago in reply to Steve1234

TI__Guru**** 317180 points

Looks good!

0 Steve1234 over 6 years ago in reply to TER

Intellectual 350 points

Thank you!!

I have a few more question for you.

1) From the final schematic I uploaded, should I adjust the trace width/length to make 50 Ohm resistance at point C? or can I just ignore it?

2) I think it would be difficult to tell before the actual experiment, but how far of a distance can i expect for a pair of module above design to be able to communicate with each other in the free space? I am considering among a few antenna options for their range and cost.

0 TER over 6 years ago in reply to Steve1234

TI__Guru**** 317180 points

1) Depends on the trace length. If the length is less than about 1/10 wavelength the line will not behave like a transmission line. I would select a trace width that is close to what a transmission line should be but if the line is short you can adjust this to fit with your layout.

2) You can get an estimate if you try out http://www.ti.com/tool/RF-RANGE-ESTIMATOR. If you are not finding the exact combination of chip and antenna, use the one that gives the sensitivity/ gain numbers that are closest to what you have in your case.

0 Steve1234 over 6 years ago in reply to TER

Intellectual 350 points

Thank you.

I think I got the knowledge i wanted.

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CC1190: Chip Antenna Implementation