[SOLVED] High Frequency PCB design

[manchandaprabhav]

Hello everyone,
I am designing a PCB for a diode mixer at 12 GHz.

So far, I have selected Rogers RO4350B as my substrate. Going with a single-layer microstrip design.

As I want to check my output at IF (50 MHz) with a varying load resistance, I am looking for a potentiometer.
The potentiometer range to be expected is 50 Ohms to about 100k Ohms. I have looked at a few options on Mouser, but there seems to be a lack of them for SMD technology.

Can someone help me find a good one?
Also, if someone has experience with a particular substrate, any tips on the layout or design?

Kind Regards,

 

[BigBoss]

Potentiometers are not used at RF frequencies. If you would like to use a variable Load, you should use Sliding Tuner or fixed resistor loads.( change by snap-on or any method )

 

[manchandaprabhav]

@BigBoss, yes, Potentiometers are not used at high frequencies. But, as I have mentioned, my IF is at 50 MHz. This is why a potentiometer would do the job.

 

[FvM]

This is why a potentiometer would do the job.

Surely not act as a 100k resistive load at 50 MHz. Even a chip resistor can't, simply due to its parasitic capacitance.

 

[manchandaprabhav]

@FvM Do you know where can I find a model? No manufacturer seems to include it.

 

[vfone]

SMD trimmer pots made on Alumina works up to few hundred of MHz..

https://www.te.com/commerce/DocumentDelivery/DDEController?Action=showdoc&DocId=Catalog+Section%7F1773442-9_Variable_Resistors%7F0606%7Fpdf%7FEnglish%7FENG_CS_1773442-9_Variable_Resistors_0606.pdf%7F1773442-9