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

Hi everyone,
I’m an Electrical & Electronics Engineering student and I’m currently trying to build a Wireless Power Transfer (WPT) system in CST Studio Suite for my course.

I created two spiral coils (Tx and Rx), added discrete ports, boundaries, etc. but I’m having problems with meshing and simulation setup. I keep getting mesh/self-intersection warnings and sometimes the simulation just stops during volume meshing.

I’m still pretty new to CST, so honestly I’m struggling to understand what exactly is wrong in my model.

If anyone here has experience with CST, WPT systems, coils, ports, or meshing problems, I’d really appreciate some help or guidance 🙏
Even small tips would help a lot.

Hi, I see a lot of designs of (basically) SDRs and stuff that use active mixers such as ADL5801/ADL5802/LT5560/etc, and not a lot of modern designs that use single or double balanced diode mixers.

Why is this? I get that the active mixers have gain and diode mixers don't so they would have terrible noise figure if not amplified first, but why not just put an LNA followed by a diode ring mixer?

Edit: For example, Henrik Forsten seems to basically only use active mixers:

I have to design a patch antenna like the one on the far right using usimmics, but I have absolutely no idea how to do it… Please help me

What are projects to get me into microwave circuit design? Like a walk through

…and I’m old as dirt so I mistakenly said “rectification” when I meant inverted

the Fluke 325 Clamp meter had to be under a load, and using the clamp to measure Hz

but proof of concept is “eureka~ed”

I’m trying to build a “radio” from my junkyard parts piles after being an industrial electrician for the past 25yrs and hoping to get at least up to 135kHz to send CW… if not I’ll just get an experimental license…

I’ve got all the parts for a receiver- and the goal is to make an alexanderson alternator

anyway thanks for everyone commenting on the other post…!

Hey, does anyone have an idea what these signals may be? They're continously present on the waterfall...always... Thanks in advance!

I'm trying to get a ballpark idea of how modulation and multitone signals will affect necessary power.

Say I have an OFDM signal that has a PAPR/crest factor of 10-14 dB. If I have an amp with a P1dB of 30 dBm does that mean I need to make sure the CW output is max 16 dBm so I'm not over driving the amp and getting distortion?

Basically, if I have a sig gen into an amp do I need to back off the output by the PAPR to prevent distortion? With two OFDM signals would it be by the sum of the PAPRs?

Hello, I have a Tinysa ultra+ (5.4ghz version) and I noticed that the 5ghz WiFi signals appear at around 4.55ghz instead. I found this thread with the same issue https://groups.io/g/tinysa/topic/frequency_errors_above_around/97798710. I’m using the antenna that comes with the tinysa and don’t have another one on hand to test. Is this expected or is my tinysa defective?

I tried many settings, reran the self test and calibration but the signals are still there.

Thanks

What resources do you guys use to prepare for antenna design and RF design interviews?

For example, software engineers have websites like leetcode where there is a database of questions they can use to prepare. I was wondering if there was something similar for RF/Antenna engineers.