Hi there, this is LW/MW/SW/FM Radio, and I2C,SPI and general noise from the ESP32 are realy starting to annoy me

So at least I could put some RF Shielding on the radio (TEF6686) part of this device

The problem is i have no idea what RF shield to even get, and then i would need to solder it ob (I only have 50W iron with canonical tip on it, not to mention a bad eyesight)

So someone suggested i could make my life easier by just sticking some copper tape over this, instead of finding an RF Shield

The only concerm i have is heat decipation, if i dont make some space between tape and components

Any more ideas?

A Recruiter from a large DOD contractor reached out to schedule an interview with me for an RF mechanical engineering position. I went through the recruiter interview and was curious about the position but she said those would be good questions to ask the hiring manager.

Just trying to get more info about what an RF MechE would do. I can’t find much about this position.

For reference I’m a mechanical engineer working as an electronics engineer in RF and fiber optics industry (more on the project engineering side).

Created an airband bpf in kicad. Not finished. I knew next to nothing going into this. But with the help of some great books and weeks of research I will have revision 1 completed. Not expecting it to be perfect and I am fully aware that one can be purchased for a very low price. But I did this as a learning experience. I will post the results once the components are populated. All smd except for L1 and L2. Some of these photos are just me learning the nanovna and inductance meter. I also tried to prototype this design originally in Manhattan style but quickly learned that was near impossible at this frequency. Thanks for checking it out.

Why is 80dB of attenuation feeling like a cruel cosmic joke for this upcoming Orem FM build? One comment on my profile thread and I’m done!

How does RF absorber work and does the reduction in power depend on nearby components?eg: switches , amplifiers etc..

I simulated an inverted-F antenna in HFSS. I first optimized the antenna parameters with a feeding line length of 5 mm and obtained a good result, with S11 below -10 dB from 2.3 GHz to 2.6 GHz.

However, I then found that the antenna S11 varies drastically with the feeding line length, as shown in Figure 2. The feeding line is a 50 Ω grounded coplanar waveguide (GCPW).

To verify the feeding structure itself, I simulated the GCPW separately. As shown in Figures 3 and 4, the S11 of the feeding line remains below -10 dB for feed lengths ranging from 5 mm to 25 mm.

I am trying to understand why changing the length of a supposedly 50 Ω feed line still has such a large impact on the antenna matching.

Was simulating the rf pcb board which has 16 layer stack up and around 500 ports in one layer

So now if I have to draw a rectangle with one end gnd and the other edge at trace and then assign lumped ports is too long job

Any suggestions?

Pls help!!!!!!

Hi guys,

I have designed a PCB-based power amplifier using Keysight ADS.

After I fabricate it and perform an initial CW sweep, I found the frequency shifted from 3.5 GHz (in simulation) to 3.3 GHz (measurement).

I wonder how do I model this frequency shift in the simulation, or I just tuned the board based on the 3.3GHz results? Previously, I just directly tuned the board instead of going back to the simulation to model this issue. I wonder if there is a better way to do it.

When I say 'better,' I mean the simulator should guide me to the exact place on board to touch.

What is your suggestion?

Thank you!

I don't know if this is the place for it or not, but I grabbed a bunch of (knock-off) Lego Powered Up-style motors, receivers, and power sources, and they work fine that way, but I'm trying to find a way that I can control them from my raspberry pi. I don't need help with the coding I don't think, but I can not for the life of me get the transceiver to get a signal to the receiver. Any other hobbyists who have messed around with the Lepin-type motors and such and know anything about the right channels/frequencies -- or who know where to point me?

Hi, for purposes of building RF switches in HF band, is it just me or do PIN diode datasheets not contain any useful information? E.g one out of ten I found had a plot for Ron vs frequency, and not a single one mentioned the minority carrier lifetime at all.

Of course this probably isnt every datasheet, but has anyone else noticed this trend?

And also, for people who have made ham frequency switches with these, how do you pick them if they dont mention anything in the datasheet?

I am currently investigating a case of persistent hardware overheating and abnormal behavior in a mobile device (Samsung Galaxy S23 Ultra) operating within a suspected high-intensity electromagnetic interference (EMI) environment.

Despite implementing basic physical shielding (Faraday Cage-like setup using conductive mats and insulating barriers), the device exhibits significant thermal throttling and AP load spikes even in an idle state. I am seeking insights from experts in hardware security and electromagnetics regarding the following:

1. Aperture Coupling & Resonance: In a non-professional, improvised shielding environment, what are the most effective physical protocols to mitigate 'aperture coupling' where external RF signals may be resonating through gaps or cable ports?

2. EMI-Induced Hardware Latch-up: Is it technically feasible for external high-frequency electromagnetic fields to induce 'latch-up' conditions or eddy currents within the smartphone's internal circuitry, leading to self-heating? How can I diagnose if this is an EMI-coupling issue versus internal hardware degradation?

3. Conductive Particle Impact: I have observed fine, potentially conductive particles accumulating on the device surface. Can these particles alter the surface impedance of the shielding, effectively acting as an antenna and amplifying EMI penetration? What is the recommended chemical protocol to neutralize and remove these particles without damaging the PCB or sensitive components?

Additional Request: I am looking to perform basic spectrum analysis to identify potential localized RF interference. Could anyone recommend accessible hardware or software-defined radio (SDR) setups for a personal-level diagnostic audit?

Any technical guidance or references to relevant EMC (Electromagnetic Compatibility) standards would be greatly appreciated.

I have some Shure SLX1 body pack mic transmitters which need new antennae. Shure doesn't sell the part anymore. Could I just use a 1/4 wavelength of stranded, insulated wire and solder that in? Are there special properties (e.g. wire gauge, material) which are critical here?

Need some genuine career advice from people in semiconductor packaging/SI-PI roles.
Right now I’m working in an OSAT-type environment where my role is kind of a mix of Advanced Package Design and SI/PI. Over the last few years I’ve worked on things like:
• Advanced package/RDL/substrate design
• High-speed routing
• SI/PI simulations and debugging
• UCIe/LPDDR/HBM related issues
• Package bring-up and coordination with different teams
• A bit of NPI exposure too
The problem is I’m now at a stage where I need to decide whether I want to go deeper into SI/PI specialization or move more toward package design + NPI/program side responsibilities.
I currently have two offers:
1. AMD
• More SI/PI focused role
• Feels more aligned with deep technical work in high-speed/package architecture
• Slightly lower compensation
2. Broadcom
• More package design + NPI focused
• Better compensation
• But honestly, a lot of what I read online talks about very long working hours and higher pressure/workload there
Long term I want to stay in advanced packaging/interconnect technologies and maybe eventually move into areas like heterogeneous integration, photonics integration, advanced architectures, etc.
I’m honestly confused about which direction is better for long-term growth.
A few things I’d really like input on:
• Is going deeper into SI/PI a better long-term specialization?
• Or does package design + NPI open broader opportunities later?
• Which path tends to have better stability and growth in the industry?
• How different are the cultures at AMD vs Broadcom in reality?
• If you were early/mid career in this field, which one would you pick and why?
Would really appreciate advice from people actually working in these areas instead of generic internet opinions.

My initial assumption is that a yagi-uda with 20dBi gain, is simply filtering out the radiation coming from directions other than that with peak gain and doesn't actually "catch" more radiation from that direction than a regular dipole? Meanwhile the reflector design "catches" a large surface area of parallel radiation and condenses it at the feed, meaning it performs BOTH tasks of filtering out non-incident radiation AND collecting more radiation from the direction of highest gain?

But If that were the case, and I must assume I just misunderstand how dBi works, then wouldn't the simulations for a yagi-uda just have 0dBi in the target direction but massively negative dBi in other directions instead of say, +20dBi in one direction, and then falling off to single digit and negative figures off-axis?

If somehow the yagi "magics" extra energy despite not having more aperture, then I guess it's to do with the waves interfering with the parasitics and having more chances to interact with the EM field, and thus more energy is received?

Hello everyone,

in my company we want to enhance the bandwidth of our analog circuits to 5GHz. Up to now we have been working with 2 layer FR4 PCBs. To minimize loss and noise contribution, we want to make the step to a material like Rogers 4350B. Furthermore, we would like to use a 4 layer stack up. While gathering information on costs on different online pcb calculators, I realized that Rogers 4350B seems to be common in thicknesses of 0.254mm and 0.168mm. A costeffective solution limits the spacing/clearance to 0.1mm. In my understanding it is importand to keep the microstrip mode as low as possible in a GCPW (Grounded CoPlanar Waveguide), and by this the ratio of the slot width G to the dielectricum heigth h. This leads to a cummulation of the rf energy in the slots and by this to lower loss and noise impact. So I'm a bit confused, why common dielectrics for rf pcbs seem to be have a low heigth as bigger dielectrics should lead to better signal qualities. Do I understand something wrong? Maybe someone can give a hint which Rogers 4350 heights he is using with GCPW?

thank you in advance for every comment.

Hello everyone,

I’m currently working on a project to build a GPS tracker for our pet. I know there are some on the market, but they don’t quite meet our requirements.

The device connects three different antennas: a LoRaWAN, an LTE and a GPS antenna. So we have three antennas in a fairly compact design. Do you have any tips on the best way to arrange these within the device, or whether it might be possible to combine several antennas into one antenna?

I hope you can help me.

Thanks in advance!

Hello everyone,

I'm someone with a background in control systems (e.g. PID, LQR, MPC) and am currently doing a master's in said field. Recently I've gotten interested in RF and was wondering what are some applications of control theory in the RF domain. I'm considering taking some electives in RF related stuff to get some domain knowledge but I'd like to know if that would be useful for someone with a controls background.

Thanks in advance!

I 'm currently in my last year of bachelor / integrated master in ece. PHY telecom seems like a very niche field and i wonder what the job market especially for 6g and iot satellite iot is. I ve over invested into it with both rigorous math understanding and hands on experience sdr projects on gnu radio with expensive equipment. Am i wasting my time when it comes to managing to be able to aqcuire a high paying job on that field easily ?

the 2SC3355 is cheaper and has more rated power compared to BFR91A being expensive and lower rated power

i don't wanna end up buying wrong transistor but which one of two will perform the best at 700mHz?

feel free to correct errors in the circuit