August 19, 2025

In rectangular waveguides (e.g., WR-90), ​​dimension A (0.9″)​​ determines the ​​cutoff frequency (6.56GHz for TE10)​​, while ​​B (0.4″)​​ affects ​​higher-mode suppression​​ (TE20 starts at 13.1GHz). The ​​A/B ratio (2.25:1)​​ optimizes ​​single-mode bandwidth (8.2–12.4GHz)​​ with ​​0.1dB/m loss​​. ​​Tolerances (±0.001″)​​ must avoid ​​VSWR >1.2​​, and ​​A > λ/2​​ prevents ​​evanescent wave decay​​. ​​B < A/2​​ minimizes ​​TM11 […]

The key points of circular waveguide size include: the diameter needs to match the operating frequency, such as a diameter of 22.86mm is suitable for 10GHz; the wall thickness should be at least 0.5mm to reduce losses; the length should avoid integer multiples of half wavelength to prevent resonance; the material should be aluminum or