• State
  • Locked Locked
  • Replies 7 replies
  • Subscribers 53 subscribers
  • Views 1085 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

CCS/CC1310: CC1310 Antenna 868Mhz

Mirko Pribisic
Intellectual 280 points
Part Number: CC1310

Tool/software: Code Composer Studio

HI,

I have developed CC1310 base Concentrator  with 2 layer board. Antenna, I used is the same as LAUNCHPAD one for 868Mhz.

I loaded concentrator software  from TI example code into this design and 4 sensor nodes I used LAUNCHPAD.

Everything works but range of communication is about 20m compared to LAUNCHPAD  based sensor-concentrator  200m.

Probably antenna should is unmatched?  How I can easily match this antenna without complex RF equipment?

I can see LAUNCHPAD has left  C24, C58 & R12 for matching. Right now there is no C24 & C58 but R12=1.8pF 

What component you would recommend for this PI filter to go into matching direction?

RF_CC1310.pdf

  • 0
    TI__Guru**** 317180 points
    - Look through the "Range Debug Check List" in the Exc el shhet found here: e2e.ti.com/.../375556 The most important is that you check that the conducted performance is as expected.
    - The matching of the antenna is dependent on the size of the ground plane. The casing and the distance to other objects also impact the matching.
    => The antenna has to be retuned if the PCB etc are not equal to what is used on our reference designs. You need a VNA to do this. It's a couple of pocket VNAs on the market that is good enough for antenna matching.
  • 0 in reply to TER
    Intellectual 280 points

    I have  -40dB  RSSI  @1m distance from the transmitting LAUNCHPAD, what indicate not tuned  antenna as I understood it is normal for launchpad around -20dB?  Please if you could post some doc.  of antenna tuning process. Thanks

  • 0 in reply to TER
    Intellectual 280 points

    Hi TER,

    If I understand correctly , TI LAUNCHPAD has C24,C58 not assembled and R12=1.8pF  to use pcb antenna as is .

    The C24,C58 & R12 makes Pi filter for antenna matching. What is expected Pi filter   value ranges? Just for orientation!

    Does it expects C24 & C58 to be capacitors and R12 to be small inductor?

  • 0 in reply to Mirko Pribisic
    TI__Guru**** 317180 points
    The place holder is for a pi filter but to do impedance matching you typically need one shunt and one series component. The value or if it should be a L or a C is dependent on which impedance you need to match. Try to play around with a smith chart program. Also see DN024 (www.ti.com/.../swra227e.pdf ) for the expected impedance for this antenna.
  • 0 in reply to TER
    Intellectual 280 points

    Hi

    I did antenna matching with VNA and C24=2.7pF, R12=2.2nH.  I set up LAUNCHPAD transmit  and my board receive.

    RSSI  on my board is 18dB at 1m distance.  RSSI  TI board to TI board is 17dB  so it is very close now.

    However  TI board still receive packets at 200m but my board stops packet reception at 35m.

    Baloon components are the same as suggested by TI including layout with only difference of two layer board.

    Is this low range reason 4 layer board v.s 2 layer or could be something else?

  • 0 in reply to Mirko Pribisic
    TI__Guru**** 317180 points
    Have you done:
    Look through the "Range Debug Check List" in the Exc el shhet found here: e2e.ti.com/.../375556 The most important is that you check that the conducted performance is as expected.

    as suggested in an earlier post? If so, please present the results.