narrowbandpass filter
narrowbandpass filter
(OP)
hi to all,
i am a new rf engineer and i want to build a filter in 2400-2500MHz band, with 20-30MHz bandwidth. Does anyone have an idea about such a narrowband filter? please any specific idea would be very helpful.
looking forward to an answer asap!!
i am a new rf engineer and i want to build a filter in 2400-2500MHz band, with 20-30MHz bandwidth. Does anyone have an idea about such a narrowband filter? please any specific idea would be very helpful.
looking forward to an answer asap!!





RE: narrowbandpass filter
The LC values can be obtained from standard filter handbooks like Zverev. The microstrip sections would have to come from specialist software I guess, but I am not familiar with that frequency range specifically.
RE: narrowbandpass filter
David
RE: narrowbandpass filter
that if a job is difficult, it may be worth to step back
and examine if it is necessary at all.
You have to check the temperature range and the S/N
ratio, any strong noise sources in the band, modulation
mode, analog/digital, (if digital, error correction ),etc.
What about mixing it down ? ( use perhaps HF preamp
with a wider band filter and do the rest of the filtering
at IF )
<nbucska@pcperipherals.com>
RE: narrowbandpass filter
RE: narrowbandpass filter
Centre Freq= 2.45GHz
3dB bandwidth= 25MHz
using a 3 pole 0.5dB Chebyshev low-pass prototype for 50 ohm input and 50 ohm output.
This PI-section filter simulates beautifully.
Input end: parallel pair C=237pF // L=17.8pH wired across the input
Series pair C=10.36fF - L=407nH, wired input to output
Output end: parallel pair C=233pF // L=18.07pH, wired across the output
The femto-farad capacitor and the pico-henry inductor make this design look infeasible.
Since the skirts have not been specified, let’s just try a single resonant pair.
It turns out that the input parallel pair from the first try is just about right C=237pF // L=17.8pH
It could be fine tuned to give the exact bandwidth and centre frequency, but the values are pretty close and are still stupid.
My third and final attempt produces values which are more sensible and I think they might be realisable with a microstrip design. There are 5 reactive elements involved. From the input there is a 7pF capacitor to ground. The filter is symmetrical, so there is also a 7pF capacitor to ground across the output. In the middle is a 4.5nH inductor to ground and this is coupled to the input and output pins by 0.5pF capacitors. These value roughly achieve the spec required. When parasitic elements are included as well then I don’t know. That requires a proper microwave simulator rather than a simple SPICE simulation.
RE: narrowbandpass filter
Their customer support should be happy to send you a sample kit.
RE: narrowbandpass filter
RE: narrowbandpass filter