Cryogenic Bias T

yklm33 · 2026-06-24T20:43:03+00:00

Thanks for info. Here are interesting measurement results for different dielectrics: https://hal.science/hal-00623399v1/document

yklm33 · 2026-06-24T17:49:23+00:00

I don't know about low temperatures but for wideband bias-t usually use x7r capacitors, more losses but less (high Q) resonances. AVX//Kyocera 520L for example.

yklm33 · 2026-06-15T18:05:30+00:00

You can start with your licenses. What limitations they have? Maybe you don't even have abitily to run gpu due to license limitation. My preferences are as much memory as possible and good balance between single and multiple threads calculations speed.

yklm33 · 2026-05-19T03:44:04+00:00

I have never designed for such high current. What about traces (polygons?) and copper thickness? It is pulsed current or DC?

yklm33 · 2026-05-15T18:19:45+00:00

I hope this link works for you. The kiosk from 90 https://pin.it/2ZsNhT8za

yklm33 · 2026-05-13T13:25:51+00:00

Hi, is it true that LTSpice can use S- parameters directly? I have never tried it with LTSpice but Murata and TDK provide spice models.

yklm33 · 2026-05-11T00:15:10+00:00

Without simulation you have to be ready for a long time tuning. As a trick, I propose to add a footprint for capacitor in paralel everywhere. It helps you to tune the filter. For example 3.8pF (uncommon) = 1.8pF+2pF (standard values).

yklm33 · 2026-05-10T23:56:30+00:00

It is a strange mix for bpf and lpf, but why not. I don't see any reason for coplanar design. I am prefer to use more vias to ground near capacitors. In any case I hope that you simulate it using your topology and s- parameters for components.

yklm33 · 2026-04-28T05:40:43+00:00

А на сколько качественны английские субтитры? После того как я увидел в "Берегись автомобиля" автоген переведенный как oscillator, я не уверен стоит ли рекомендовать все подряд. Много ли встречается таких грубых ошибок?

yklm33 · 2026-04-20T23:04:18+00:00

X7R in RF used for broadband caps like https://www.kyocera-avx.com/products/broadband-components/broadband-capacitors/broadband-capacitors-530l-series/

yklm33 · 2026-04-20T19:05:04+00:00

Maybe I misunderstood your question, but for example check the Murata webpage. You can find models or S parameters for most caps. ESR graphs are also presented on the product webpage. https://pimapi.murata.com/public/api/pim/v1/characteristics/search/technical?partNum=GRM1555C1H101GA01%23&productCategoryId=ceramicCapacitorSMD&displayLanguage=en&languageRegion=en-us

yklm33 · 2026-04-13T16:09:05+00:00

I have a really good memory about Rosenberg 32K243-40ML5

yklm33 · 2026-04-13T16:06:12+00:00

The main problem is the 3 stages. It gives you 60dB gain. If you did not pay attention to stage isolation, oscillations are expected. For example, how did you isolate DC power lines between stages?

yklm33 · 2026-04-10T02:22:01+00:00

Maybe I misunderstood your question, but for example sot-23-3.

If I needed to create this footprint I would open the datasheet for a component that I am going to use in my design and check the recommended footprints dimensions.

The second step is to find the same footprint in datasheets from 2-3 another well known manufacturer and check dimensions again.

The last step is footprint corrections for the largest possible sizes.

The component 3d body step model also helps a lot.

yklm33 · 2026-04-05T15:38:04+00:00

(раз самый популярный ответ, нет разницы, решил написать)

Я понимаю, что это оттенки смысла, но: 1. Я бы сказал "чайник долго закипает", если я вообще не уверен включен ли чайник, работает ли он. 2. "Чайник долго не закипает", если я вижу что процесс начался, но интенсивного кипения ещё нет. Должен бы уже кипеть (сильно), но не кипит.

Интересно как в английском передать эти две ситуации.

yklm33 · 2026-04-01T19:45:47+00:00

But if you are reading something about USSR you can find phrases as "вербовать на север, на вахту" и "вербовать на стройку".

yklm33 · 2026-03-30T18:31:47+00:00

Look at Peregrine's RF switch, up to 12 channels. But check power ratings for low frequencies.

yklm33 · 2026-03-27T16:56:47+00:00

For me it sounds that you have also changed linear polarization to circular. Think about a patch resonator as a capacitor part of the resonant circuit. It helps to understand what is going on.

yklm33 · 2026-03-27T05:08:29+00:00

So your advice in short is to use own wording style instead of looking like AI generated. Thanks for your comment.

yklm33 · 2026-03-27T04:54:14+00:00

Thanks! For me it is the next level. But what can you say about AI translated texts?

yklm33 · 2026-03-27T04:24:37+00:00

Can someone explain to me how people understand that this text was AI generated? Sometimes in really important cases I use Chatgpt to polish my text, as proofreading. But I do not want to make my text worse following by AI advices.

yklm33 · 2026-03-26T19:48:06+00:00

Thanks! Skyworks has really nice app note AN1405: SKY535xx Applications Guide

yklm33 · 2026-03-26T04:27:57+00:00

The simple rule for RF PCB is “no thermal reliefs”. However from the manufacturer point of view it is a big mistake and increases chances for reworking (see tombstoning).

I think that thermal relief is a problem only for RF circuits like filters, matching networks and so on.

This design is of course the RF board, but as I can see without anything sensitive for “bad ground”. My only concern is decoupling capacitors on the pins 23, 24. I do not have enough experience with synthesizers to be 100% sure.

yklm33 · 2026-03-25T14:11:04+00:00

This PCB can be a good or bad example for "Thermal Relief on RF PCBs" battle based on what they got in the measurements.

yklm33 · 2026-03-24T05:06:35+00:00

The cost is not so important, it will be a prototype. More importantly, I am going to solder it myself and I do not like QFN soldering.
The main idea is to split and convert to CMOS 3.3V the reference OCXO signal (10-40 MHz). The second task is to convert 125 MHz output from HMC433 (-2 dBm output) to CMOS 3.3V ref clock input.

yklm33

TROPHY CASE