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Tubular Lowpass Filters

50Mhz to 20Ghz
Chebyshev Response
4 Convenient Sizes
Rugged Design


Bandpass Filter Part Number Description

Tubular Filter Part Number Description


1. Number of Sections

2. Series and package size

3. Cutoff Frequency, MHz (3 dB C/O Standard)

4. Input Connector

5. Output Connector
(if different from input)

(1) 6" RG 188 Standard
(2) Requires SMA Removable Connectors at High Frequencies

Bandwidth Designator
3 dB /(blank)
1 dB /A
equi-ripple /R
special /X
Connectors
Connector Type Designator
BNC - M BM
BNC - F B
Type N - Male NM
Type N - Female N
TNC - Male TM
TNC - Female T
SMA - Male SM
SMA - Female S
Overview
Bandpass
Lowpass
Dimensions



Tubular Lowpass Filters
P/N Freq.
Range
(MHz)
VSWR
(Typical)
Number of
Sections
Avg. Power
(Watts)
Operating
Temp.
(Deg. C)
Relative
Humidity
Impedance
LA 300-20000 1.5:1 2 - 10 2 -40 to +85 0 - 95% 50
LC 60-3000 1.5:1 2 - 10 15 -40 to +85 0 - 95% 50
LD 50-2000 1.5:1 2 - 10 40 -40 to +85 0 - 95% 50
LE 50-1000 1.5:1 2 - 10 200 -40 to +85 0 - 95% 50

Shock 10G
Vibration 20G
Contact factory for specific requirements not listed above.


Calculating Number of Sections
The curves shown indicate the stopband frequencies normalized to the 3 dB cutoff for filters of 2 to 12 sections. A ratio of stopband frequency to 3 dB bandwidth is used.

The curve shown indicates the frequency response resulting from the circuit used.

Example:
A LC-Series filter has a cutoff frequency of 650 MHz. A stopband attenuation of 30 dB is required at 900 MHz.

Calculate the number of sections as follows:

Example 1

Number of 3 dB bandwidths from cutoff frequency = The curve indicates that a minimum of 4 sections is required.

Insertion Loss Calculation
Knowing the number of sections, and cutoff frequency of the filter, insertion loss may be calculated from the following formula:

Loss = N x 0.2

Example: 4LC-650-S
1. Number of sections = 4
2. IL = 4 x 0.2 = 0.8 dB

Note: For Lowpass filters, insertion loss is calculated at 0.9 times the cutoff frequency

Lowpass Attenuation Chart
 
 
Tubular Lowpass
Filter Dimensions
Model Diameter
Inches / mm
LA .25 / 6.35
LC .50 / 12.70
LD .75 / 19.05
LE 1.25 / 31.70

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