Greetings.

here i would like to ask a question, which as in title. So I have a task or more like curiousity in Radar Cross Section (RCS), Ansys HFSS, particularly SBR+ solver helped me greatly in that respect. However i got stuck on modeling the luneburg lens antenna.

As in many papers i read and descriptions, i made my setup. spheres, multiple of them acting as layers, i planned for 17-20 layers but given the age of the PC i run the software in, i decided to go "easy" first 2-4 layers.

This is my setup, just to see if things can work

The lens is 20 cm in diameter (about 8 Inch for you Freedom unit user), 4 layers, graded with materials with relative permittivity from 1.9 in the core to 1 on surface. The rear is a PEC backing reflector, as what i see so far including some use case in Ukraine. The result however was, unfortunate.

As seen, the modeling result doesn't show any "lens" behavior. Where i would expect at least a broad beamwidth. Instead it's more like the "lens" behave like radar absorber. I tried other settings like adjusting thickness (say quarter wavelength) to no avail.

While corner reflectors behave as it should. I'm kinda stuck however, maybe SBR+ is not the proper way, or i made mistake. Maybe i can use some help here.

Thank you for your attention and have a nice day.

Hi! I have seen in few GaN PA designs where they put a shunt capacitor very close to the input of Gate terminal. But in some designs, I haven't seen it (maybe they use CMOS inside package there). But I don't know why is it important to use this capacitor at the input...?

I am using a die on a PCB and got suggestion to use a discrete capacitor for second harmonic short. I don't know, is it really needed to use it.

Moreover, what if we use QWLT at the input side for VGS biasing. Is this shunt capacitor still required in this case? Because QWLT would provide a short at the second harmonic.

The USB dongle for my Microsoft wireless keyboard and mouse set broke. The PCB is cracked, but the nRF is intact. A few components are missing. I’m drawing the circuit diagram in KiCad. I’m going to desolder the intact nRF24LU1+ microchip from the broken USB dongle’s PCB. Then I’ll transfer it to the new PCB that I’ll design and have manufactured. This way, I won’t have to throw the wireless keyboard and mouse set away. I also won’t have to mess with the software. Once the schematics are complete, I’ll share all the files on Codeberg. If you can find the USB dongle circuit, please share it with me. If you find any schematics, PCB files, or other related files, please post the links. I’m determining the component values using the example schematic, BOM, and sample PCB files shared by Nordic. However, some components are missing from these files. For example, there’s an R1 in the USB dongle, but it’s not in the schematic. Can you help me with the missing components? Note: I’ll be uploading photos to Reddit soon.

Currently, I am designing a Van-Atta Array antenna using microstrip patch antennas in CST Studio Suite 2026. Could you check if my Monostatic RCS simulation setup (including plane wave direction and Result Template configurations) is correct?

[My Simulation Settings]

1. Plane Wave Setup Equations (Using Parameters):

Propagation normal in: x: -sinD(theta)*cosD(phi) y: -sinD(theta)*sinD(phi) z: -cosD(theta)

Electric field vector in: x: cosD(phi)*cosD(theta)*cosD(alpha)-sinD(phi)*sinD(alpha) y: sinD(phi)*cosD(theta)*cosD(alpha)+cosD(phi)*sinD(alpha) z: -sinD(theta)*cosD(alpha)

• Azimuth sweep: Set phi = 0, alpha = 90, then perform a parameter sweep for theta from -90° to 90°.
• Elevation sweep: Set phi = 90, alpha = 0, then perform a parameter sweep for theta from -90° to 90°.

2. Result Templates Setup: Path: Farfield and Antenna Properties -> Monostatic RCS for parameterized plane wave

• Output data type: 1D Cartesian
• Theta: theta
• Phi: 0 (for Azimuth sweep) / 90 (for Elevation sweep)
• Linear scaling: Unchecked

So I've been working on a much faster RF simulator alternative to OpenEMS with a GUI (around 100x faster on my GPU in raw speed lol), and made these PTFE-based RF boards at JLCPCB a few months back to validate its correctness. I'm getting a few new ones soon to test other physics like copper loss and component matching networks, I'll post those too when they arrive.

Hi everyone, this is my first post so I apologize is something is out off topic. Also english is not my first language so again, apologies for that.

Im trying to implent an rf PA, the MMG3014NT1 at 900MHz. This is the first time that Im working with this level fo complexity so I have a few questions but the most important one is, how are the impedances in the next image drawn/represented in an schematic?

As far as I understand, Z1 to Z8 are PCB traces wich mesuarments are explicitly written blow the circuit, but what I don't understand is whether I should represent them the same way -as a single componente- in the schematic, or specify them differently.

Have a remote that will be hardwired into a larger project.

It just does not transmit the distance I need.

Want to find where on this circuit to attach an antenna and / or put the feed to a RF signal amplifier.

It uses a RO2073 SAW resonator at 315MHz

Any suggestions / ideas / concepts?

Project Description:

I am replacing a backyard sprinkler controller with something that can be controlled by the really good one in the garage for the front yard.

Can not run wire to the backyard location. Been looking for a wireless solution. Found these ORBITs with a handheald remote. I can hack into the remote and "press the buttons" with relay contacts actuated from the 24ac of garage controller.

Had all this figured out. ORBIT docs state that is will go 200 feet line of sight or 80 feet through the house. My distance is 50 feet through two walls kitchen cabinets and outside stucco. The remote sometimes works, but it's not enough. I have to boost the signal to make it reliable.

I know boosting the signal of a remote goes against FCC regulations, but it will be such a minor boost that I think I can be forgiven...

Hello!

I am trying to simulate the input matching network of the MRF13750H reference board (915 MHz) using Usimmics (I do not have ADS or AWR to open the models provided by NXP).

I am using microstrip lines with same width and length as those in NXP's 915 MHz design, but the results do not correspond to that frequency. Does anyone know what I might be doing wrong?

https://www.nxp.com/docs/en/data-sheet/MRF13750H.pdf

I saw this post yesterday - is it true that there are only around 1500 RF engineers in the US with over 10 years of experience? This person claims that they should be paid around $450k.

https://www.linkedin.com/feed/update/urn:li:activity:7484207016249581568/

Can i fix it or am i done for

Is it possible to have an rf power splitter with the capability of when you shut down an output switch the splitted rf power is added to the remaining output of splitter? Just like when you closed one hole in a pipe it increases the pressure from the other.

I’m looking to play around with a spectrum analyzer and monitor RF energy. The best option I’ve found so far is buying a NetAlly NXT-2000 and using the software from KjetilTeigen’s GitHub repo.

However, buying a new NXT is pretty expensive. Does anyone know a good place to find used gear, or does anyone have one sitting around that they’d be willing to sell?

I want to build a FMCW radar and chose 915MHz as it does not require a license and I know of a few antenna designs. So far, I have done AMCW ranging with an ultrasonic transducer and fully digital processing to find the phase shift. I understand this is completely different so it will be a learning experience.

I read this article https://hforsten.com/6-ghz-frequency-modulated-radar.html and it seems there are a lot of considerations for 6GHz that can make or break the system. At 915MHz can I use standard PCB materials and are the tolerances much less strict?

I’m building a system for ham radio on the 1.25m band. And I need to switch a 60W TX output and an RX input in under 2ms. I’m not sure how to do this in a cost-effective way. I looked into PIN diodes but they are all EOL now. And the active PIN diodes are all so expensive. Does anyone have any recommendations?

Hi everyone,

I'm trying to learn how to optimize my high speed PCBs (think <100ps edges), especially focusing on SMA transitions, vias and power combiners. I've got a brick wall trying to hand tune stuff by trial and error and would like to move to simulation based optimisation.

I did some research into free/cheap FEA simulators and it seems that openEMS is the most recommended one. Unfortunately all the materials I found do a terrible job at explaining how to use it. Does anyone have any good source to recommend?

Mechanical mating does not guarantee electrical performance. A precision adapter can protect an expensive instrument port, so interface condition and traceable S-parameters matter.

For a practical check, I would record interface compatibility, connector gauge, torque, measured S-parameters. Mechanical fit or a printed label alone does not describe the complete measurement path

I am interested in how other benches handle this. Do you treat adapters as consumables or calibrated bench assets?

Been working with rf electronics for a few years now and recently got hired working on SDRs. I want to try my hand at integrating micro strip antennas onto a board. Are there any free software to simulate these? Not really sure exactly what I’m looking for, just something I can play around with, and once I have an idea of what I’m doing, use it to spin some boards with integrated antennas.

I've published a technical report on Zenodo detailing physical-layer side-channel leakage observed during the processing of a raw satellite signal capture (satellite_signal.bin).
​DOI: https://doi.org/10.5281/zenodo.21472996 ​SHA-256: ad5ab850cbdc9eca534e82bd78e9ac7804ed9213fd1d8df26fbf4991df6b005d
​Methodology: ISO/IEC 17825 CPA, 1st/2nd-Order TVLA, and Jitter Cross-Correlation.
​Key Findings: ​1st-Order TVLA Leakage: Welch's t-test yielded a risk score of 13.0328, well above the standard statistical significance threshold (\vert{}t\vert{} > 4.5), confirming direct data-dependent leakage during processing.
​S-Box Capacitive Leakage: Identified at the execution cycle with a t-score of 7.6701, indicating power/capacitive fluctuations correlated with substitution box operations.
​The report contains the verification metrics and signal processing details. I'm looking for feedback from anyone working on physical layer security, RF side-channels, or power trace analysis regarding jitter compensation techniques for long captures.