I am currently trying to place an CC2540 on my circuit. I have a circuit using an AT-09 module that uses a CC2540 but I am trying to separate the CC2540 from the AT-09. I am using this diagram, https://www.ti.com/lit/ds/symlink/cc2540.pdf?ts=1648786274233&ref_url=https%253A%252F%252Fwww.google.com%252F (PAGE 24). I see they define everything but the antenna. Is the antenna even required with the CC2540? I assume the CC2540 being BLE it should be able to transmit and receive data without external assistance. If I need the antenna (50 ohms). Where can I get one that can fit on a PCB?

If the antenna on the diagram provided above isn't required, where do I get Tx/Rx data?

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    \$\begingroup\$ You obviously need an antenna for any type of radio communication. How else do you suggest the RF signals will come in/out of the transceiver? There are literally thousands of different 50Ω antenna models out there, all with different physical size, frequency band, antenna gain etc. Go look for one that suits your application. If you can't manage to do that, start by reading a book on basic radio communication. \$\endgroup\$
    – Klas-Kenny
    Apr 1, 2022 at 5:05
  • \$\begingroup\$ @Klas-Kenny Thanks for the reply, I'm definitely new to this, I assumed CC2540 could receive for me. Guess not, could you provide a link for an antenna \$\endgroup\$ Apr 1, 2022 at 5:47

1 Answer 1


If you are new to all this, I have some advice for you. Instead of trying to make the complete circuit on your own, try using some ready-made modules like this. These modules are designed by experts and companies focused on RF. You will have a higher chance of getting things working immediately.

You can use the module as a component in your schematics. The reason I am suggesting this is because doing RF layout takes some experience and testing will take some expensive equipment. If you want to do this and learn this stuff, please go ahead by all means but in most cases, a person is focused on a product, and spending too much effort on this might not be the most productive way to develop the product/prototype.

  • \$\begingroup\$ Thanks for the answer! Also, I understand everything in the schematic I linked in my question except the antenna. Is the antenna just one element I can place on my circuit? Or is it another complex circuit I would have to design? \$\endgroup\$ Apr 1, 2022 at 17:50
  • \$\begingroup\$ Antenna can be like one SMD component. It could be a PCB trace as well. However the important thing is the matching circuit between the IC and the antenna. You will find a series of inductors and capacitors. You will find their values in the schematics. However, in reality, you might have to tweak those values to get the best RF performance. This is required because the layout and PCB specs play a huge role (trace inductance, parasitic capacitance etc can add to the component values). In order to test the performance you will need some equipment (costly ones). \$\endgroup\$ Apr 2, 2022 at 18:11

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