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The curve given on the right shows a slightly asymmetric frequency response resulting from the circuit used. Other schematics may be utilized to yield different attenuation characteristics (i.e. steeper on the high frequency side of the passband and shallower on the low side).

Example:
A CF-Series filter has a center frequency of 1000 MHz and a 3 dB bandwidth of 10 MHz. A stopband attenuation of 60 dB is required at 980 MHz and 1030 MHz.

The percentage bandwidth is 1%, calculated as follows:

For the first stopband requirement we have:

Number of 3dB bandwidths from center frequency =



From the CP/CF series attenuation curve, we find that a minimum of 7 sections are required.

The second stopband requirement is: Number of 3dB bandwidths from center frequency =

From the CP/CF series attenuation curve, we find that 5 sections minimum are required.

The greater number of sections must always be used to insure full specification compliance; therefore, a 7 section should be used.

Insertion Loss Calculation - Cavity

Knowing the number of sections, center frequency and bandwidth of the filter, insertion loss may be calculated from the following formula:

Example: 5CF2-915/25-N
1. Percentage BW = 25 / 915 x 100 = 2.7%
2. Q from CF series curves = 2.9
3. Number of sections = 5
4.

Example: 9EZ6-8725/1375-S
1. Percentage BW = 1375/8725 x 100 = 15.8%
2. Q from EZ series curves = 1.1
3. Number of sections = 9
4.