You can already expect my knowledge level In antenna designing (newbie). This may be or may not be a stupid question. The reason is I don't know about this very much.

Iam designing a PCB for ESP32 Pico D4 and Iam using a chip antenna from Johnson technology. The PCB is 3cm X 2cm dimension. Like I already said Iam new to antennas things. So I kept the basic design guidelines like ground clearance via sticking and components clearance. But what Iam stuck with is the matching network, In esp32 datasheet they are using a PI match network and in the antenna datasheet they were using two inductor which is grounded with feedline. Can anyone explain me which matching network I needed to use and how I determine the component values?

The main confusion that I have is even I got what type of matching network I needed to use. But I don't know how to calculate the values for the matching network components! Datasheet:datsheet

Thanks in advance!!!

  • \$\begingroup\$ Oh, the (one and only) chip antenna from Johnson Technology!!! \$\endgroup\$
    – Andy aka
    Commented Apr 24, 2020 at 12:32
  • \$\begingroup\$ Can you provide a schematic of that impedance network from Datasheet or a link to the Datasheet. \$\endgroup\$
    – Leoman12
    Commented Apr 24, 2020 at 13:12
  • \$\begingroup\$ mouser.in/ProductDetail/609-2450AT42B100E \$\endgroup\$
    – Suhail Jr.
    Commented Apr 24, 2020 at 13:40
  • 1
    \$\begingroup\$ The way to go is using the smith chart to find the right component values. Google for antenna matching smith chart. There are even youtube videos about that. \$\endgroup\$
    – stowoda
    Commented Apr 24, 2020 at 13:42
  • \$\begingroup\$ Just going to mention that they provide help resources on that Datasheet for determining new values for the matching network. \$\endgroup\$
    – Leoman12
    Commented Apr 24, 2020 at 14:38

1 Answer 1


If you have exactly the same PCB and setup as shown in the datasheet, you can use the same tuning components. But this is unlikely.

Often you have tiny differences. In that case you need to measure the impedance of the antenna e.g. with a vector network analyzer (VNA).

Then you can tune the antenna with e.g. the smith chart. The topology (pi or T network) does not matter.

Practical advice: If you do no tuning, i.e. you just connect the antenna with a 0E resistor, you often get good performance. Tuning is required for highest performance


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