How do I route a high speed LVDS signal near an RF circuit without causing interference?

How do I route a high speed LVDS signal near an RF circuit without causing interference? LVDS (Low-Voltage Differential Signaling) is one of the better-behaved digital interfaces for mixed-signal environments, but careful routing is still needed to prevent coupling to RF circuits: (1) Why LVDS is better than single-ended: LVDS uses differential signaling with 350 mV swing (much lower than CMOS 3.3V or LVCMOS). The differential mode fields cancel in the far field, reducing radiated EMI by 20-30 dB compared to single-ended signals. Common-mode emissions are the primary concern (caused by skew, asymmetric routing, and coupling imbalance). (2) Routing guidelines near RF: keep LVDS traces ≥ 10 mm from RF traces (25 mm preferred for GPS/cellular receivers). Route LVDS on inner layers (stripline) to benefit from ground plane shielding. Route LVDS perpendicular to RF traces when crossing is unavoidable (minimizes coupled length). Maintain tight differential coupling (spacing ≤ 2× trace width) to maximize common-mode rejection. Match P and N trace lengths within ±2 mil to minimize mode conversion and common-mode radiation. Use ground via fencing between LVDS and RF routing regions (vias every 2-3 mm). (3) Return current management: the LVDS return current flows in the ground plane directly beneath the traces. If the LVDS traces cross a ground plane gap or change reference layers: the return current must find an alternative path, creating a large current loop (antenna). Ensure continuous ground reference under the entire LVDS route. When transitioning layers: place ground vias adjacent to the signal vias (within 15-20 mil) to provide a return current path. (4) Clock vs data: LVDS clock signals have a narrowband spectrum (strong harmonics at f_clk and multiples). If a clock harmonic falls in an RF band: the harmonic is a strong, coherent interferer. LVDS data signals have a spread spectrum (data transitions are random, energy is distributed across the Nyquist bandwidth). Data coupling is less likely to cause narrowband interference but contributes to the broadband noise floor. Prioritize isolation of LVDS clocks over LVDS data.