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I'm working on a project that requires impedance matching and I'm going to match a 50 Ω antenna to a RF amplifier SST12LP22. However, I'm not sure how can I get the impedance of the amplifier from the datasheet in order for me to design the matching circuit, or I will need to measure it?

Datasheet: https://docs-apac.rs-online.com/webdocs/135d/0900766b8135d29f.pdf

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    \$\begingroup\$ As the MAX2235 is for 900 MHz applications you're firmly in the "RF" world. That means you need to know what you're doing so know how you would achieve an impedance match and know how to use a network analyzer to measure how good the match is. If "RF" is still "black magic" to you then I urge you to study the subject. There are plenty of good books and courses. If you just "dive in" and "do something" chances are it will end in disappointment as you have no idea what's going on. \$\endgroup\$ Feb 28, 2019 at 10:09
  • \$\begingroup\$ Hi, I'm so so sorry.... I think I just copied the wrong component code. It was SST12LP22. It actually my first time touching RF field so that's why I'm abit confused. \$\endgroup\$
    – poppywhale
    Feb 28, 2019 at 10:19
  • \$\begingroup\$ Well, this SST12LP22 is "even worse" as it is for the 2.4 GHz band, all that I wrote in my comment still holds. There is a reason why (experienced) RF engineers are hard to find, RF it isn't something you can do without the right background and experience. \$\endgroup\$ Feb 28, 2019 at 10:44
  • \$\begingroup\$ I might not an expert, an experienced engineer. I'm just trying to understand and learn so that's why I don't know why you will said so. As I know, 2.4Ghz is within the microwave range so I may I know what I've missed out? \$\endgroup\$
    – poppywhale
    Feb 28, 2019 at 10:59
  • \$\begingroup\$ @poppywhale please edit your question to fix your copy&paste error. Also add a link to the datasheet. \$\endgroup\$ Feb 28, 2019 at 11:01

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In the figures at the end of the datasheet there are some matching networks. Use those. To get the impedances, look at the S-parameters, and you can convert those to impedances.

Based on the s-parameters in the datasheet the device is already pretty close to 50 ohm on both input and output between 2 - 3 GHz.

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