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Is it possible to design a good bandpass filter with center around 1GHz, using capacitors and inductors?

Or does these components perform too poorly at these frequencies?

I would rater not try to design my filter as a cavity filter (soldering pipes and all).

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  • \$\begingroup\$ For low powers you could use a microstrip or SAW filter. \$\endgroup\$ – Bitrex Oct 21 '11 at 10:44
  • \$\begingroup\$ How narrow does the filter need to be, i.e. what should the Q be, ideally ? \$\endgroup\$ – Paul R Oct 21 '11 at 16:33
  • \$\begingroup\$ It needs to be really narrow, but I found a lot of suitable saw-filters. So I think maybe two saw-filters will do the job. \$\endgroup\$ – JakobJ Oct 21 '11 at 19:53
  • \$\begingroup\$ No, you wouldn't normally use lumped LC components for this unless your requirements were very loose. How many of these filters do you actually need? If this is a one-off project that doesn't need to be very reproducible, just search eBay for "ghz filter" and you'll see some ready-made options that may work. \$\endgroup\$ – John Miles Oct 22 '11 at 3:09
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A 1 GHz filter can be built using lumped elements and might be suitable for your purposes, but a better filter could be built using microstrip or a cavity. It depends on your requirements. The filter type depends on the performance you require; for instance, a Butterworth filter is optimal in terms of pass-band ripple.

I use this software for LC filter design: http://tonnesoftware.com/elsie.html. It's excellent.

I'd prototype the filter on a piece of PCB material, and test and adjust it using a suitable signal generator and RF meter. If it's a one-off, you can simply mount it in a screened enclosure with the input and output connectors.

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