PIM Calculator
Calculate 3rd, 5th and 7th order passive intermodulation products for two carrier frequencies.
PIM products: 3rd order (2f₁−f₂, 2f₂−f₁), 5th order (3f₁−2f₂, 3f₂−2f₁), 7th order (4f₁−3f₂, 4f₂−3f₁)
PIM Product Formulas
When two carriers at frequencies f₁ and f₂ pass through a non-linear component (connector, cable, antenna), intermodulation products appear at new frequencies. The odd-order products closest to the carriers are the most problematic:
3rd Order (strongest)
2f₁ − f₂ and 2f₂ − f₁
5th Order
3f₁ − 2f₂ and 3f₂ − 2f₁
7th Order
4f₁ − 3f₂ and 4f₂ − 3f₁
Products that fall within ±1 MHz of either input carrier are flagged as potentially in-band, where they can degrade receiver sensitivity. 3rd order products are the most powerful and therefore the primary concern in network planning. To check which cellular band a PIM product frequency falls into, use the frequency to band converter. PIM levels are reported in dBm — use the converter to switch between logarithmic and linear power units.
Frequently Asked Questions
What is PIM (Passive Intermodulation)?▾
PIM is the generation of new, unwanted frequencies that occurs when two or more high-power signals pass through a passive component — such as a connector, cable, antenna, or duplexer — that has even slight non-linearity. PIM is a major issue in cellular base stations because the interference products can fall directly into the receive band, raising the noise floor and degrading cell performance.
Why are odd-order PIM products more important than even-order?▾
Even-order products (2f₁, f₁+f₂, etc.) tend to fall far from the original carriers and are filtered out easily. Odd-order products — especially 3rd order (2f₁−f₂, 2f₂−f₁) — fall close to the original carriers. In a 2-carrier system, these often land directly in the receive band while the transmit carriers are active, creating in-band interference that cannot be filtered without affecting the wanted signal.
What causes PIM in a passive component?▾
Common PIM sources include loose or corroded connectors, contaminated contact surfaces (dirt, oxidation, finger grease), ferromagnetic materials (nickel plating, steel hardware), poorly torqued connectors, and damaged or kinked cables. Even a small non-linearity in a high-power passive path can generate PIM products strong enough to desense a receiver by several dB.
How is PIM level measured and what is a good value?▾
PIM is measured by applying two high-power carriers (typically 2 × 20 W / 43 dBm) and measuring the power of the 3rd-order products at the receive port. IEC 62037 / 3GPP define a pass/fail threshold for antenna system components — typically −153 dBc (−110 dBm) for Class A. Lower (more negative) values are better; values above −140 dBm in the receive band can start to impact base station sensitivity.