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I'm designing a pcb with a Sub-1GHz chip and I'd like to add a chip antenna on my design. I choosed one of the johanson technology products, especially this one https://www.johansontechnology.com/datasheets/antennas/0900AT43A0070.pdf In the datasheet I see many references of matching network close to antenna.

The question is: Is really needed to place a matching network if the anntena's feed line has exactly the same impedance as antenna's input? (50 Ohm in my case).

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  • \$\begingroup\$ Thinks maximum power transfer, thinks high standing wave ratio (SWR) for a mismatch, thinks manufacturer's recommended circuit so I'd say yes it is. \$\endgroup\$ – JIm Dearden Mar 25 '17 at 14:12
  • \$\begingroup\$ If the distance is less than 1/10 the wavelength there isn't much point \$\endgroup\$ – Leon Heller Mar 25 '17 at 14:26
  • \$\begingroup\$ If the impedance in both two sides (pcb trace and input of antenna) are identical, there would be maximum power transfer. Isn't there? \$\endgroup\$ – MrBit Mar 25 '17 at 14:49
  • \$\begingroup\$ Yes, but they're telling you the matching network is needed to make the antenna have 50-ohm input impedance. They're also giving you the ability to tune the performance in case your pcb material is slightly off in dielectric constant (very common with low cost materials) or your geometry is slightly off from ideal, or some nearby conductor (like the housing of your circuit) affects the antenna. \$\endgroup\$ – The Photon Mar 25 '17 at 15:36
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    \$\begingroup\$ Repeating the points made above, your antenna is designed to meet 50Ohm impedance. For various reasons it may not be 50 Ohm precisely. In these cases, you may or may not want the tuning network, depending on your mismatch. IMO, its better to design it and leave it unpopulated than needing one and not having it. \$\endgroup\$ – Wesley Lee Mar 26 '17 at 12:36

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