1. LCAT1000-20 Substitution Conclusion The LCAT1000-20 can conditionally replace the original FMAT7620-20 part, with the key limitation being frequency range: the LCAT1000-20 supports only 0 Hz to 6 GHz, whereas the original part covers 0 Hz to 18 GHz. If the application frequency exceeds 6 GHz (e.g., in microwave communications, radar, or high‑frequency testing), the substitute cannot guarantee performance metrics such as attenuation accuracy and VSWR, potentially leading to signal distortion or system failure. Within the lower frequency band below 6 GHz, both parts share identical key parameters—20 dB attenuation, 50 Ω impedance, and 2 W power handling—and are electrically and mechanically compatible (SMA male connectors, coaxial structure), allowing for normal operation. Substitutability strictly depends on the actual system operating frequency: direct replacement is feasible only for low‑frequency applications; for wideband or high‑frequency scenarios, the original part must be used.