SHAPE OF AIRCRAFT, CHANGE IN ORIENTATION, AREAS OF APPLICATION OF RAM
In war time, Fighter jets might plan a sortie waypoints as per fixed assets like airbases, SAMs, terrain, etc. So the jet can maintain flight at certain altitude & heading to have minimum RCS towards certain areas.
But the dynamic assets like moving ground SAMs, AWACS, enemy fighter jets can force to tactically alter the plan, waypoints & maneuver in roll, pitch, yaw axis which increases RCS towards certain angles.
The 5gen jets still use rudders but canted at angle matching the fuselage side wall. from the diagrams above, on rolling & banking, the surface area at that angle increases a lot for few seconds. The entire body is reflecting some RF energy.
This may compel to apply RAM on entire ventral/bottom side.
Earlier in capitalist country like USA, private companies developed their version of RAS & RAM whose quality would differ & cost of application & maintenance would be very high. Special machines would be needed to wrap the jet with RAM tapes, attach RAm panels, or paint the RAM.
Today multiple nations have developed their own RAS, RAM with easier application & reduced cost.
But bcoz of nature of RF radiation is not simple, & ultimately a fighter jet has to do so much maneuvering, sometimes to evade enemy jets & missiles, that RAM may have to be applied almost everywhere. So people usually prioritise only front RCS but side, top, back RCS now would become equal priority.