How do I design a preselector filter bank for a wideband surveillance receiver?

Designing a preselector filter bank for a wideband surveillance receiver divides the receiver's total frequency coverage into multiple sub-bands, each with a dedicated bandpass filter, and uses RF switches to select the appropriate filter based on the tuned frequency. The design involves: dividing the frequency range into sub-bands (for a 2-18 GHz surveillance receiver: divide into 4-8 sub-bands, e.g., 2-4 GHz, 4-6 GHz, 6-8 GHz, 8-12 GHz, 12-18 GHz; each sub-band is approximately one octave wide; narrower sub-bands provide better selectivity but require more filters and switches), designing each bandpass filter (each filter covers one sub-band with: passband insertion loss < 2-3 dB, passband flatness < ±1 dB, out-of-band rejection > 40-60 dB (to protect the receiver from strong out-of-band signals), and return loss > 15 dB across the passband; filter technologies: microstrip coupled-line filters for 2-18 GHz, cavity filters for the lowest loss, suspended stripline for good performance and moderate size), selecting the RF switches (PIN diode switches or GaAs MMIC switches at the input and output of the filter bank; switch requirements: insertion loss < 1 dB, isolation > 40 dB (to prevent signals from leaking through non-selected filters), switching speed < 1-10 us (for rapid frequency hopping or scanning), and power handling > +20 dBm (to handle strong signals without compression)), and designing the switch matrix (the simplest topology is a single-pole, N-throw (SPNT) switch at the input selecting one of N filters, and another SPNT switch at the output; alternatively: cascaded SP2T switches in a binary tree provide lower loss for large N; the switch matrix must maintain 50-ohm impedance at all ports).