Author Topic: design methos for RF boards question  (Read 4617 times)

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Offline george79Topic starter

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design methos for RF boards question
« on: March 03, 2024, 12:29:53 pm »
Hello,
i want to design some amplifier boards for testing, practise and give to some friends to make RF linear amplifiers. Not high frequency, will be limited to the amateur bands with the upper at 50Mhz. I have found a lot of MRF300AN and MRF300BN and i will be focus to this Mosfet. MY main problem is how to make this boards on EASYEDA, and i mean the traces because they are not like the other we design and see everyday, the most of them are rectangular shapes and they connect the SMD parts.
Have anyone some experience to this please??
i upload some pictures to get an idea what i mean from some manuacturers.
 

Offline mag_therm

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Re: design methos for RF boards question
« Reply #1 on: March 03, 2024, 02:21:25 pm »
Hi  George79
Why is that rectangular block method needed?
It came from the days when proto boards were etched after etch resistant tapes (or painted lines)
were laid straight on bare copper forming the gaps between pads.
Other (tedious) method , bare copper was cut with knife against steel rule, and the copper peeled off.

Similar to your project, I have designed a wideband linear amp as driver for SiC mosfets for 7 ~ 14MHz.
As I expose and etch the board here, I break a lot of pcb rules.
These boards are on MG Chemicals double sided photo resist coated stock.
Only one side is exposed. The bottom side is left as solid shielding layer.
M3 stainless screws through the board pull the board down to a 6.3mm aluminim heatsink,
and also connect the ground rails on the exposed side.
https://app.box.com/s/h0689louibgyzqpooi6g0nsnq4hqputy

Your MRF300 look good for HF preamp.

My components, referring the the above trackwork image:
The preamp is FMB2227A  as inside out complementary (top right ).
The drivers are FTZ651/751 as inside out complementary (collectors in the big rectangle).
Two boards are needed to drive the finals in 45 Watt.
Finals are two Genesic G3R450MT17D_GeneSiC in push pull are on a separate heatsink (pads on the upper left edge).

I have one 45W linear amp working for a year on 20m ft8 and wspr.
I have just improved the track layout. About to try just one board driving the antenna via the filter for wspr.

The 45W version : Drain voltage adjustable 50 ~ 200 V. Efficiency about 50%
RF In 27dBm, Out 47dBm. Spect. An. is permanently connected to output via a Tee, to adjust the level and monitor the harmonics.
Regards
 

Offline MarkT

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Re: design methos for RF boards question
« Reply #2 on: March 03, 2024, 02:56:47 pm »
Quick search suggests using Solid Region in Easy EDA will do what you want.
 


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