How do I shield a sensitive RF receiver from the EMI of a nearby high speed processor?

How do I shield a sensitive RF receiver from the EMI of a nearby high-speed processor? Shielding is the most effective method for achieving high isolation when physical separation alone is insufficient: (1) Shield can design: a conductive enclosure (typically stamped brass or stainless steel, nickel-plated) placed over the RF circuit and soldered to grounded pads on the PCB. Shielding effectiveness (SE): 40-60 dB at 1-5 GHz, 20-40 dB at 10-30 GHz. The shield must be a complete enclosure: top, sides, and ground plane below. Any gap or slot in the shield reduces the effectiveness. Gap rule: a slot of length L reduces SE by 20 log(λ/L) dB. At 2.4 GHz (λ = 125 mm), a 10 mm slot: SE reduction ≈ 20 log(125/10) = 22 dB. Keep all slots and gaps < λ/20 (6 mm at 2.4 GHz). (2) Shield grounding: the shield must be connected to the PCB ground plane through: continuous solder along the perimeter (best), or multiple ground pads (every 3-5 mm along the perimeter, connected with solder paste). Fewer, widely spaced ground pads reduce the shielding effectiveness at high frequencies. (3) Two-compartment approach: for maximum isolation: shield the RF section (one compartment) AND shield the digital section (second compartment). Each compartment has its own shield can. The ground plane between the two compartments provides the bottom isolation. Total isolation: shield can A (30-40 dB) + ground plane (20 dB) + shield can B (30-40 dB) = 80-100 dB. (4) Shielding the processor: the processor is the primary EMI source (clock harmonics, SSN). Placing a shield can over the processor contains the EMI. The shield must cover the processor and all high-speed traces within the shielded area. Any trace that exits the shielded area must pass through a filtered feed-through (ferrite bead or capacitor to ground). (5) Practical considerations: height: the shield can must clear the tallest component inside (processor heat sink, inductors). Removable shields: some designs use clip-on shields (for repair and debug access). These have slightly lower SE than soldered shields due to the contact resistance. Thermal: the shield can acts as a secondary heat sink (conducts heat from components to the PCB copper). Ensure adequate thermal relief if the processor dissipates significant power.