What is a channelized filter bank and how do I design one for a wideband receiver?

A channelized filter bank is an array of contiguous bandpass filters that divides a wide input bandwidth into multiple narrow sub-channels, enabling simultaneous processing of all frequency components across the full band. In a wideband receiver, the channelized filter bank is placed after the wideband low-noise amplifier and downconverter, splitting the signal into N narrower bands that can be independently digitized, detected, or analyzed. The design involves: determining the number of channels N (typically 4-64; more channels provide finer frequency resolution but increase system complexity and size), selecting the channel bandwidth B_ch = B_total / N where B_total is the total input bandwidth, designing the individual channel filters (each filter must have: center frequency spaced at B_ch intervals, passband bandwidth of B_ch with < 1 dB ripple, transition bandwidth that does not create gaps between channels, and adequate out-of-band rejection to prevent aliasing between channels), and designing the power distribution network (a wideband power divider that splits the input signal to all N filter inputs with equal amplitude and low loss; typically a binary Wilkinson divider tree or a Gysel divider for high power). Critical specifications include: channel-to-channel amplitude flatness (the maximum gain variation across the entire bank passband should be < 1-2 dB), crossover level (the response level at the transition between adjacent channels; typically -3 dB to -6 dB below the channel center passband, depending on whether the channels are contiguous or have guard bands), and group delay equalization (maintaining constant group delay across each channel and between channels to prevent signal distortion).