Electronics > RF, Microwave, Ham Radio

Ultra low insertion loss SPDT 1.4GHz RF switch

<< < (3/3)

TimFox:

--- Quote from: srce on October 21, 2021, 02:32:07 pm ---
--- Quote from: MartinL on October 21, 2021, 12:43:12 pm ---What are you trying to do? Whatever it is, if it depends on getting better than 0.17dB loss in a switch, then I think you probably need a different approach.

--- End quote ---
A switch for a Dicke Switch radiometer. The switch goes in front of the LNAs so minimising loss is critical. Any ideas for a different approach?

--- End quote ---
What is the noise figure of that radiometer?  The attenuation added before that input will degrade the LNA noise figure by the attenuation value.

srce:

--- Quote from: TimFox on October 22, 2021, 05:08:44 pm ---
--- Quote from: srce on October 21, 2021, 02:32:07 pm ---
--- Quote from: MartinL on October 21, 2021, 12:43:12 pm ---What are you trying to do? Whatever it is, if it depends on getting better than 0.17dB loss in a switch, then I think you probably need a different approach.

--- End quote ---
A switch for a Dicke Switch radiometer. The switch goes in front of the LNAs so minimising loss is critical. Any ideas for a different approach?

--- End quote ---
What is the noise figure of that radiometer?  The attenuation added before that input will degrade the LNA noise figure by the attenuation value.

--- End quote ---
The datasheet figure for the 1st LNA is about 0.2dB, so even though 0.17dB is pretty good for a switch, it's a significant degredation in the overall NF.

TimFox:
Remember that the NF gives the noise added to the (theoretical minimum) noise from the source impedance, not the SNR itself.

awallin:

--- Quote from: srce on October 21, 2021, 11:12:53 am ---
Can anyone recommend anything better than an Infineon BGS12PN10? Insertion loss is given as around 0.17dB at 1.4GHz.


--- End quote ---

mechanical coaxial relay from e.g. mini-circuits?
https://www.mini-circuits.com/WebStore/dashboard.html?model=RC-1SPDT-A18
rated to 18 GHz (!) - so 1.4 GHz is a low frequency and datasheet p.4 shows something under 0.05 dB for 1.4 GHz
they might have only the SPDT switch without box, psu and ethernet/usb interface also as a product.

SQ9MT_PL:
A good (expensive) mechanical relay will always perform better than a solid state one.
However, such relays are more and more often used in measuring electronic systems and it is "not from yesterday" the best if it is possible for you to present the system in which it is supposed to work.
The question is what parameters you want to achieve and choose the price-quality ratio. Well, not to mention that such a mechanical switch will be large due to its design.

Navigation

[0] Message Index

[*] Previous page

There was an error while thanking
Thanking...
Go to full version