Cavity, Comb Line and Interdigital Band Pass Filters
RLC Electronics' Cavity, Comb Line and Interdigital Band PassFilters are fixed tuned filters that feature sharp stop band rejection and lower losses that comparable tubular band pass filters.Parallel coupled round rod distributed resonators afford small size and high Q to achieve a near ideal bandpass response. Units are constructed to operate over the most severe military environmental conditions. Integral Low Pass Filters are available to extend the stopband to as high as 40 GHz. The type of filter selected is usually determined by the percentage 3 dB bandwidth desired.
Specifications
Model Number 1234
Filter Type 
Model Number 
Center Frequency Range (MHz) 
3 dB Bandwidth (% of fc) 
Number of Sections 
Stopband Attenuation 
Cavity 
CBPF 
500 to 26000 
0.2 to 3.0 
2 to 14 
See Curves on this page 
Comb Line 
CF 
500 to 36000 
3.0 to 25.0 
2 to 14 

Interdigital 
IBPF 
1000 to 26000 
25.0 to 67.0 
3 to 15 
Insertion Loss(max at fc): Curve 1, see this page. *VSWR: 1.5:1, Bandwidth: Curve 1, see this page *For no. of sections <= 8, VSWR is 1.5:1 For N=9 to 11, VSWR is 1.5:1 to 10 GHz, above 10GHz VSWR = 1.5+0.07(N8) For N=12 to 15, VSWR is 1.5:1 to 7 GHz, above 7 GHz, VSWR is 1.6+0.1(N11) Power Rating: IBPF 100 watts CF and CBPF 15 watts Impedance: 50 Ohms Environmental: MILE5400, Class 1A 
0.5 dB Bandwidth: Curve 2, see this page 1 dB Bandwidth: Curve 3, see this page Phase Linearity: 5 deg. Curve 4, see this page Connectors (female): Type Recommended Freq Rng (MHz) BNC DC1,000 N DC12,400 TNC DC15,000 SMA DC26,000 K DC40,000 
To designate the filter desired use:
1: Center frequency in MHz 2: 3dB bandwidth in MHz 3: Number of sections 
4: "N" for type N, "B" for BNC, "T" for TNC, "R" for SMA (female) "K" for 2.92mm (female) 
Example: IBPF3500100010R is a 3500 MHz center frequency, 1000 MHz 3 dB BW, 10 section filter with SMA(female) connectors.
Outline Drawings
CenterFrequency(MHz) 
Approximate Dimension Table 

W IBPF 
W CBPF,CF 
H 
L (N is the number of sections) 

501800 
2950 
3.75 
1.19 
1.125xN+.625 
8012000 
2.25 
1 
3.75 for N=2 N+.75 for N>2 

20014000 
1.38 
.75 
2.50 for N=2 .625xN+.625 for N>2 

40018000 
.94 
.63 
2.00 for N=2 .50xN+.5 for N>2 

800112000 
.75 
.56 
1.50 for N=2, 2.00 for N=3 2.50 for N=4 or 5, 3.00 for N=6 3.50 for N=7 or 8 

1200120000 
.70 
.53 
1.75 for N=2 to 4 2.38 for N=5 or 6 3.00 for N=7 or 8 

2000136000 
.53 
.38 
CONNECTORS 
R 
N 
T/B 
"C" Dimension 
.30 
.60 
.52 