Bessel Filter Prototype Element Values

Visit the Anatech Microwave websiteOnline filter calculators and plotters can be found here.
Bessel filter complex poles can be found here.

Filter denormalization of formulas can be found here.

The table below lists prototype element values for the normalized lowpass function, which assumes a cutoff frequency of 1 rad/sec and source and load impedances of 1 Ω. Either an input capacitor (top reference line in table) or an input inductor (bottom line in table) can be used.

Convert values to other cutoff frequencies, impedances, and to highpass, bandpass or bandstop using the equations here.

 

Prototype filter schematic - capacitor input
Capacitor Input

Prototype filter schematic - inductor input
Inductor Input

OrderC1L2C3L4C5L6C7L8C9L10
12.000         
20.5762.148        
30.33740.97052.2034       
40.23340.67251.08152.2404      
50.17430.50720.8041.1112.2582     
60.13650.40020.63920.85381.11262.2645    
70.11060.32590.52490.7020.8691.10522.2659   
80.09190.27190.44090.59360.73030.86951.09562.2656  
90.0780.23130.3770.51080.63060.74070.86391.08632.2649 
100.06720.19980.3270.44540.55280.64930.7420.85611.07812.2641
 L1C2L3C4L5C6L7C8L9C10