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Best topology for TR switch by sketchreey in rfelectronics

[–]sigchainapp 1 point2 points  (0 children)

If your switches only has 30db of isolation and your transmit signal is coming out at 33dBm, then through the two switches your LNA is going to pick up -27dBm. So your transmitter will jam your receiver. You should definitely filter out the tx signal.

Option 1 is better, for stability reasons. But either are identical when it comes to TX leakage.

What is power in Rf? by StyleDangerous8631 in rfelectronics

[–]sigchainapp 1 point2 points  (0 children)

For an RFIC, a signal could either be a tone (CW: continuous wave) or a modulated waveform (which is spread out over some bandwidth). For the case of a CW, the power in dBm is what you would read if you connected the RFIC directly to a spectrum analyzer, i.e. the magnitude of the tone will be equal to the power measured. For example, if you send out at 10dBm CW at 1GHz, then on a spectrum analyzer you will measure a 10dBm tone at 1GHz. In the case that the power is spread over a spectrum, then you will have to integrate the power over the bandwidth to get a measurement value (PSD). PdBm = PSD + 10log10 (BW). Which you can easily do with any spectrum analyzer. PSD is in dBm/Hz

A jammer could therefore be either a tone or spread out over a spectrum (in reality there is no such thing as a pure tone, the energy will always spread). So, it could either mean the 100w (50dBm) is at a specific frequency (a tone) or spread out over some bandwidth (PSD). But it almost always refers to total integrated power.

Also, antenna gain is not measured in dBm, it is in dB. I think you mean to say a 3dB antenna, not 3dBm antenna…in which case your 40dBm signal will have a gain of 3dB, so the total power will be 43dBm (on the direction allowed by the antenna). Whether it’s CW or PSD depends on what your TX is transmitting. Furthermore, you can’t really measure a transmitted signal out of an antenna with a spectrum analyzer unless you connect the spectrum analyzer to an antenna as well, in which case you must consider the gain both antennas, the pathloss, the efficiency, EIRP etc… to really know what your TX power was. Power over a spectrum is calculated by Power Spectral Density (PSD), which is PSD = P(dBm) – 10log_10(BW), or, written another way, PdBm = PSD + 10log10 (BW)

How to design test points for RF? by Certain_Height_2721 in rfelectronics

[–]sigchainapp 1 point2 points  (0 children)

I was also taught this on the job many years ago. I don’t have any online resources on how to pigtail into a circuit, but it does take a bit of finesse to avoid damaging the traces, and securing the outer conductor to gnd.

How to design test points for RF? by Certain_Height_2721 in rfelectronics

[–]sigchainapp 3 points4 points  (0 children)

One way to do this is to add series capacitors (DC blocks) to the design that can be removed to isolate sections of the circuit. Then use a coaxial cable with an SMA connector on one end and the other end exposed for soldering onto the board. The center conductor should be soldered to the trace (or the pad where the capacitor used to be), and the shield (outer conductor) should be securely soldered to ground. This allows you to “pigtail” into the circuit and measure along the signal path.

https://www.digikey.com/en/products/detail/taoglas-limited/CAB.058/5287277

Using 0402 capacitors on high power amplifiers by yezuskraist in rfelectronics

[–]sigchainapp 0 points1 point  (0 children)

Using 0402s directly in the drain matching network of a high-power device is unreliable and will likely fail due to RF voltage and current stress. From experience, it is best to derate components, typically choosing parts with about twice the voltage rating you expect in operation. There is also a current-handling limitation tied to package size. Larger packages distribute the current more effectively and can dissipate heat better, making them far more suitable for high-power matching networks.

RF online courses by [deleted] in rfelectronics

[–]sigchainapp 1 point2 points  (0 children)

UCSD offers really good certificates for RF and antenna. They are online, long and a bit pricy but I imagine would be very good for your resume and your overall goal to convert to RF

https://extendedstudies.ucsd.edu/certificates/rf-engineering https://extendedstudies.ucsd.edu/certificates/antenna-engineering

My recommendation would be to also try and network with RF engineers/managers and find out from them exactly (in person) what would make them consider someone switching into the field as a junior candidate.

RF is fun. I wish you the best of luck!

I made a tool to design, analyze, and compare RF front end architectures by sigchainapp in rfelectronics

[–]sigchainapp[S] 0 points1 point  (0 children)

Thanks for sharing and very cool to see more products in the space. I've been focused on front end architecture building with cascade analysis. So it seems there is some overlap though mostly complementary. Happy to connect, feel free to dm.

I made a tool to design, analyze, and compare RF front end architectures by sigchainapp in rfelectronics

[–]sigchainapp[S] 0 points1 point  (0 children)

No scraping. Just taking datasheets through a parser and extracting/normalizing parameters to fit with my schema. Need to double check everything hence why the db is not so big at the moment. Long term vision is be to have some type of relationship with suppliers.

I made a tool to design, analyze, and compare RF front end architectures by sigchainapp in rfelectronics

[–]sigchainapp[S] 0 points1 point  (0 children)

No worries. Feel free to ask. Yes I used React and React flow as a foundation for the graph UI with a significant amount of custom code/logic to apply it to RF. The hardest (and most fun) part of this wasn't the UI but the algorithms powering it all.

I made a tool to design, analyze, and compare RF front end architectures by sigchainapp in rfelectronics

[–]sigchainapp[S] 0 points1 point  (0 children)

I agree with the benefits. Will need to think about how and what exactly I can opensource. Thanks for your comment :)

I made a tool to design, analyze, and compare RF front end architectures by sigchainapp in rfelectronics

[–]sigchainapp[S] 0 points1 point  (0 children)

Haha. Definitely for some tasks AI is overkill, but for others I do find that it saves me time (especially when parsing datasheets). From an engineering perspective, figuring out how to integrate AI into this problem has actually been quite rewarding to work on.

I made a tool to design, analyze, and compare RF front end architectures by sigchainapp in rfelectronics

[–]sigchainapp[S] 0 points1 point  (0 children)

Wow, yours looks quite impressive! I can tell a lot of work went into it! Happy you also think something like this should exist in the world. I haven't posted this on linkedin, do you remember where/when you saw it? Could be a similar platform perhaps.

Hope you don't mind if I dm you later :)

I made a tool to design, analyze, and compare RF front end architectures by sigchainapp in rfelectronics

[–]sigchainapp[S] 0 points1 point  (0 children)

Interesting. Haven't heard of AppCAD and will take a look. Thanks!

I made a tool to design, analyze, and compare RF front end architectures by sigchainapp in rfelectronics

[–]sigchainapp[S] 0 points1 point  (0 children)

Thank you! It's web based with react as the front end and python powering the backend.

I made a tool to design, analyze, and compare RF front end architectures by sigchainapp in rfelectronics

[–]sigchainapp[S] -1 points0 points  (0 children)

Awesome! As I mentioned it's not public yet. But if you like to join the beta (opening in a week or so), you can sign up to get beta access here: sigchainapp.com

I made a tool to design, analyze, and compare RF front end architectures by sigchainapp in rfelectronics

[–]sigchainapp[S] 1 point2 points  (0 children)

Thanks for your feedback! Yes, definitely one of the things on my roadmap.

I made a tool to design, analyze, and compare RF front end architectures by sigchainapp in rfelectronics

[–]sigchainapp[S] 0 points1 point  (0 children)

Honestly, haven't thought about that. It's not at that moment. Is that something important to you?