Special

Filter Attenuation
The attenuation curves show the typical shape for the coaxial resonators for n=2 thru n=6. Use the formula below to determine the number of sections needed for the required attenuation.

Example:
Center Frequency = 1910 MHz
3 dB BW = 25 MHz
Stopband Frequency = 2000 MHz
Attenuation = > 50 dB

It is determined that 4 sections are required to meet >50 dB attenuation at 2,000 MHz.

Insertion Loss Calculation
Parameters needed:
1) Number of Sections (N
2) Typical Resonator Qu (Qu)
3) Center Frequency (Fo)
4) 3 dB Bandwidth (BW)

Ql = Fo/BW
K = Qu/Ql

The formula is as follows:
l.L. = N*.63*20*LOG10(1+(1/(K-1)))

Example:
CF = 1910
3 dB BW = 25
Qu = 625 (6MM/Er 38.6)
N = 4

I.L. = 4*.63*20*LOG10(1+(1/(8.18-1)))=2.85 dB