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Grounding for couplers

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eng

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multicore copperset

Hello everyone,
I have designed a balanced low noise amplifier.
The specifications of my design:
-2.4 Ghz, min 10 db gain, max 2.5 db noise figure
-microstrip technology
-substrate rogers 6002, 60 mils thickness
-1A1306-3 couplers fron Anaren corp. (balanced amplifier)
This amplifier was manufactured with milling machine.
I need some practical informations.
First of all I have no equipment to drill a grounding via so I have to do it manually. For good grounding what are the things that I should do?I think in order to have couplers working properly I need a good grounding.
Also for soldering what kind of tricks can you recommend? I will do a lot of soldering stuff because there are so many lumped components; 2 couplers, 4 capacitors, 4 resistors (to get 50 ohm termination I'm using 2 x 100 ohm parallel) and 2 transistors.
Thanks in advance.
Regards,
 

flatulent

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eyelets

In years gone by you could buy eyelets which were little short copper cylinders with a rim at one end. You would put them through the drilled hole and bend the far end out to be another rim. Then you would solder both sides. This was sort of a poor person's via.

Does anyone reading this post know how to buy them these days?
 

hobbymat

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For microwave prototypes I'd recommend Multicore's Copperset system from Farnell. The vias (or bails) are short stubs of copper-plated solder wire, and they can be riveted to the PCB hole with a blunt punch (automatic punch with a flat head is good for home use). These come in three diameters: 0.8, 1.0 and 1.2 mm. However, they are not exactly cheap, as the bails cost something like $40 for a tube of 500.

You can also use short (1.8 mm for 1.6 mm PCB thickness) pieces of copper wire, punch them even with the board and solder to the pads. You should be able to end up with flat vias, that work well for the low gigahertz range. See e.g.:

http://www.electricstuff.co.uk/pcbs.html

For thinner and higher-frequency boards I'd probably use very small via holes (made with the same mill as the board itself) that are filled with good, conductive silver paint. Or then I'd just scale down the riveting process a bit and use a 0.15 mm wide soldering iron tip under my stereo microscope... :)

Good luck making good vias! Be careful and you'll succeed.

Hobbie
 

Spasomat

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Hi,

Bungard (w*w.bungard.com) has rivets for through hole plating. They have as well a hand operated machine for processing the rivets.

Regards,

Spasomat
 

hobbymat

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Seems that Bungard rivets might be a better solution than the Copperset bails. However, they probably need a specially shaped (negative doughnut-half) tip for a punch, in order to make the free end of the rivet nicely rounded. This is due to their length (2.2 vs. 1.8 mm), but they probably stay on the hole much better than Copperset vias that come off easily when soldering.

Besides, Bungard vias come also in the standard 0.6 mm OD, which helps design in tightly populated boards. Any info on pricing of these rivets?

Hobbie
 

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