The circular waveguide probe coupler is a field coupling device specially designed for circular waveguides which transmit modes such as TE₁₁ and TM₀₁. It adopts a metal probe array to capture electric and magnetic field energy inside the circular waveguide, realizing power sampling, mode monitoring and directional coupling.
Made of aluminum or brass with gold / silver plating for high-frequency applications. Dimensions are customized according to operating frequency bands such as S/C/X/Ku to ensure single-mode transmission of dominant TE₁₁ / TM₀₁ modes. The inner wall features high smoothness and circularity precision to suppress mode distortion and unwanted reflection.
Composed of 2 to 8 copper or gold-plated metal probes, evenly arranged circumferentially around the circular waveguide, such as 4 probes at 90° intervals or 8 probes at 45° intervals, vertically inserted through the waveguide wall.
The insertion depth and mounting position are adjustable: deeper insertion provides tighter coupling; probes aligned with electric field peak areas, including the central region for TM₀₁ mode and polarization direction for TE₁₁ mode, achieve maximum coupling efficiency.
Two mainstream types are available: single probe for simple power sampling, and multi-probe array for high directivity and mode discrimination.
Equipped with standard SMA / N-type coaxial connectors or compact waveguide flanges. Integrated waveguide-to-coaxial transition allows direct output of coupled signals to power meters, spectrum analyzers and other test instruments.
High-precision matched loads (built-in or external) are connected to isolated ports to absorb backward leakage energy and improve directivity. The sealed shielding housing effectively isolates electromagnetic interference and ensures long-term mechanical structural stability.
