IEC 60153: Hollow Metallic Waveguides — The Microwave Highway for High-Frequency Signals

Hollow Metallic Waveguides: The “Highway” for Microwave Signals — IEC 60153

IEC 60153-1:2016 specifies hollow metallic waveguide dimensions and electrical characteristics. At frequencies reaching tens of GHz — satellite communications, radar, radio astronomy — signals cannot travel through coaxial cable (attenuation is too high) and must use waveguides.

Why waveguides? Coaxial cable attenuation above 10 GHz exceeds 1 dB/m, while a rectangular waveguide (e.g., WR-90 for X-band 8.2–12.4 GHz) achieves ~0.1 dB/m — an order of magnitude lower. The trade-off: cutoff frequency — signals below the cutoff frequency simply cannot propagate (the waveguide behaves as a high-pass filter). Cutoff depends on the broad-wall dimension a: f_c = c/(2a).

Standard waveguide sizes: WR-284 (S-band 2.6–3.95 GHz, a=72.1 mm), WR-90 (X-band 8.2–12.4 GHz, a=22.9 mm), WR-28 (Ka-band 26.5–40 GHz, a=7.11 mm). Higher frequency → smaller waveguide → by W-band (75–110 GHz), a=2.54 mm — manufacturing precision becomes a major challenge.

TN Lab — At microwave frequencies, cable becomes waveguide. Cutoff frequency is the first gatekeeper.