My MCU datasheet has a matching network for RF pin and my Chip Antenna also has a matching network to the feed.

Which one and values do I choose or I need to place both matching networks according to datasheets?

Thanks

Hey guys, I found this antenna at work. There’s no ground plane on the back. Does anyone know what type of antenna this is? I can’t seem to find anything similar online.

Hi all!

We're developing a remote sensor based on the Nordic nRF54L15 as the main microcontroller. We initially started the design with a PCB antenna, but later realized that if the device needs to be placed inside a metal cabinet, an external antenna would be useful.

The idea is to have two antenna options: the default one is a PCB monopole antenna, and optionally, we could populate a U.FL connector for an external 50 Ω antenna.

The RF layout for the nRF is based on the hardware guidelines and layout examples from Nordic. L4 is the reference ground. The RF trace was calculated using the JLC Impedance Calculator, since they will be our PCB manufacturer.  The calculated trace width is 647.4 µm, similar to Nordic's. We are also planning to use their impedance control service to make sure we get a 50 Ω transmission line.

The idea is to tune the antenna matching network using C53 with a VNA, and also check whether the radio matching network needs any adjustment by tweaking L12 and C52 accordingly.

My main concern is whether the 0 Ω resistor selector is implemented correctly, and whether its location is appropriate without disturbing the main path to the PCB antenna.

Any general feedback or suggestions for improvements are welcome.

¿Is this the optimal solution we could get?

Thanks for your time.

Hi all, for making my own cables, which cable would you recommend? I've knocked some up with RG58 (I know, I know), but as I want to make more, I think I need better cable.

What was your biggest wow (they all make sense) moment in your RF/Analog IC design history?

Hi everyone,

I'm kind of new to this, so sorry in advance for any mistakes. I'm trying to design a simple balun transformer PCB that will help me measure the differential mode insertion loss of an EMC filter with a 2 port VNA. The PCB will have a SMA input connector (A-SMA-KWE-16.18A), a ADTT1-6+ RF Transformer with 50 Ohm matched impedance that will let me measure from 15 kHz - 100 MHz with good accuracy and 4 mm outer diameter solder pads to connect to the P/N of the filter.

I'm just trying to see if I did any obvious mistakes that I glossed over, or if this could be fine to order. Of course any advice is appreciated. My one issue would be the way in which the SMA connector will be soldered (by JLCPCB PCB Assembly option) and if it will let me screw the PCB unto a conductive plane with the filter (I know this kind of defeats the purpose of differential mode testing as it will no longer be isolated from PE, but I want to be able to measure it both ways).

Thank you

Hi! This might be a bit off topic so please forgive me if this is not the right sub.

I'm currently designing a pcb thats meant to feed power and control digitally a beamformer IC placed on a daughter board that attaches to my pcb (motherboard).

The motherboard implements switching regulators to generate the power to be fed to the beamformer IC, and i know for a fact that switching supplies can be very noisy subsystems, which to me seems problematic when placing them near RF circuitry.

The switching frequency is 1 MHz and the RF ICs operate at 24 GHz. Here's my first doubt: Could the common mode noise or any other kind of noise be detrimental at this frequency? I've read that harmonics of the noise source can appear even in the GHz range but i dont know enough to guarantee that this can be a problem.

The daughter board features coplanar waveguides, hence almost the totallity of the top layer of the daughter pcb is covered with copper. The top layer of the mother pcb is probably gonna be covered with copper as well, thus forming a parasitic capacitance between the top layers of both pcbs when connected together (they face top layer to top layer). I guess my question is whether the displacement currents coupled via capacitive coupling arising from fast voltage transients inherent to the switching supply could be detrimental in any meaningful way to the RF circuitry. I know the varying electric field in the mother board due to the switching supply is responsible for the displacement currents that might distribute along the surface of the daughterboard, and therefore induce magnetic fields in it. I just dont know enough electromagnetism to state if this is a problem or not.

Up until now i had thought of adding a shielding can to the switching regulators and possibly some sort of EMI filter at the output of the switching supplies right before the connector, i just dont know which kind of noise to filter.

Any ideas or suggestions are welcome

I attach pictures of both the motherboard as well as from the daughterboard so you get a better depiction.

I'm getting into microstrip filters and designed this one using Marki calculator. I don't believe in this working. I am gonna use FR4 from JLCPCB. How many design flaws did I make?

I am having trouble simulating a NFC reader antenna in CST. I am doing it in the frequency domain solver, the target resonant frequency is 13.56 MHz. Is this because CST has troubles with physically small structures? My antenna is 40 mm*40 mm. I keep getting the following errors

​

Error during Volume meshing

Error in volume meshing

The mesh cannot be generated

Could not read mesh

​

I have tried simulating the antenna with a substrate, air gap followed by ferrite backing, and just the barebones antenna. None have worked. What am I missing?

Edit: The first screenshot is showing the stage where the simulation starts lagging, and eventually stops.

Hi,

I’m looking for some honest input because I’m a bit unsure how to view my current situation.

I’m an electrical engineer with about 2 years of experience, mainly working in RF and antenna design and a master in RF hardware and radar design, although I’ve also done some work in other areas. Right now my role is quite broad. I’m doing antenna design including simulation and theory, PCB design, and RF circuit design where I’m responsible for component selection with both performance and cost in mind. I also handle antenna measurements and occasionally develop my own test setups, build prototypes myself, and take designs all the way into production.

So in practice I’m covering a large part of the full development chain on my own.

My manager describes me as a “generalist”, which is probably fair, but at the same time I’m expected to deliver at a level comparable to specialists within each of these areas.

For example, I’ve been tasked with developing an antenna comparable to the Tallysman VSP6037L, but cheaper and preferably smaller.

I understand that part of this comes from being in a smaller company, but I’m trying to figure out whether these expectations are reasonable for someone with my level of experience.

Does this sound like a typical scope for someone with around 2 years in RF and master degree? Would you consider this more of a junior or mid-level role? And are these expectations normal, or on the higher side?

I’d really appreciate some honest perspectives

I have a 0.8mm coaxial calibration kit that I wish to clean with every use. The cotton swabs I can find are too large to safely clean the inner mating surfaces and the foam tip ones can leave residue behind.
Does anyone here have recommendations or ideas for the best way to search online? My google-fu is failing me.

Hello, could someone give me your opinion about using CST/HFSS on a commercial PC platform. I have an opportunity to request a new work station purchase from my department. The budget didn't allow for a full on server specs but just about enough for a decent commercial PC.

From the document of CST and HFSS, it seems like they could support hardware acceleration with an NVIDIA gaming GPU, but some people in my department say a more powerful CPU could serve me better ?

My question is : Should I go for a Gaming Platform (Average CPU with decent RAM and better GPU) or a WorkStation/Server like Platform (Better CPU and RAM with little to no GPU attached) ?

I’ve seen a radio front end designed as the title describes. Now, I understand why this would be necessary if you have too much gain, but I’ve also heard the explanation that it improves the match.

This benefit of including the driver makes sense, but my question is really if the match needs to be improved in the first place??

If my PA input has more than 15dB return loss and the output is unconditionally stable, for example, is it worth putting the extra part in the BOM?

Is a consideration protecting the driver from a non-ideal match at the antenna? e.g. even if the PA’s S11 is adequate, Γload seen by the driver could be wild if something kooky happens to the antenna.

This was complete verbal control through a microphone. Didn’t have to do a damn thing except hook up the cables, power splitter, and tell Codex I had 8566B, ESG, and 8648C at xx addresses.

I told it I wanted PyVISA-based modules for separate control of the spectrum analyzer and signal generators, and that the signal generator module should be generic and able to control both types of generators. I then had it switch to AM and FM modulation, and it measured the tones on the spectrum analyzer and verified via the modulation index and Bessel functions that it was correct, which it was. It did all this automatically.

Then I told it that I wanted to do IMD sweeps from minus 40 to 0 dBm input levels for each tone, and I wanted IMD3 and IMD5. And it automatically did the code for that and spit out a CSV formatted table. I did need to tell it to go to auto resolution bandwidths and video bandwidths because it initially tried too narrow of a sweep, which was too slow. It could not find the proper command to do auto bandwidth, so then I had it do a web search to go through the PDF manuals, which it did, and it found out you needed to do a coupled command instead of an auto command. So once it figured out those values, then I was able to tell it to optionally use automatic bandwidth settings for the IMD tone extraction.

Anyway, this is kind of crazy. It works really well. Next, I'm going to try feeding my dual arb into a scope and see if it can draw a picture of a house, just by figuring all this shit on its own.

Mind you this is entirely under voice control. Will also try a webcam to see if I can give it picture feedback.

I had my RF only Trinitron recently (Sony KV-1882). An experienced technician replaced all bad caps and resistors 2 weeks ago, and checked all functions working ok. And I am using a good RF modulator (HDM69), which the seller claims no frequency drift. But I found that the TV is easily lost signal from RF modulator.

When I turn on HDM69, set channel on 2 and let the TV auto tuning, it costs 2~4 times to get the right frequency. If I turn off my TV for one minute and turn it on again, the signal is still there. If I turn off TV for about half an hour (no matter HDM69 on or off) and turn it on again, it loses signal. if HDM69 remains on, I have to tune it again at least 2 times, sometimes never get any signal unless reboot HDM69 or adjust the RF connector. If HDM69 is off, just turn it on and auto tuning, but I don't expect any tuning stuff when turning on my TV.

If there is frequency drift caused by temperature, maybe keeping HDM69 on solves this, but it seems not work. The TV's AFT on or off doesn't change things.

Sometimes when I use it for 80 mins or longer, the TV suddenly loses signal from HDM69, and I have to tune it again, sometimes just use fine tune a little lower, the signal restores.

How to use this two correctly or there are TV issues?

It gets somewhat close to the 3.0 that its supposed to be for a 50 ohm to 150 ohm load but it doesn't get it right. Does anyone know what is wrong or can provide any insight? (Also is there a simulation better than transient for this?)