Waveguide Sliding Short

Its core function is to provide an electromagnetically short circuit with controllable phase, used for impedance tuning, resonator calibration, and VNA / network analyzer calibration in microwave / millimeter-wave systems.

Waveguide Offset Short (Fixed Offset Short Plate) is a high-precision total-reflection termination device in standard rectangular waveguides (such as WR series), where the metallic reflective plane is fixedly mounted offset from the central axis. Its core function is to provide an electromagnetically short circuit with controllable phase, used for impedance tuning, resonator calibration, and VNA / network analyzer calibration in microwave / millimeter-wave systems. Compared with a center-axis short (Standard Short), it achieves a specific reflection phase through a preset offset distance without any moving parts, making it ideal for batch calibration and fixed electrical performance tuning.

Core Principle

The reflective plane is not perpendicular to the waveguide central axis, but installed at a designed offset (typically 1/8, 1/4, 3/8 of the guide wavelength λg). It fully reflects the incident wave with a fixed phase shift (typically 180°), equivalent to a short-circuit load with specific reactance.

Electrical Characteristics

Magnitude of reflection coefficient ≈ 1 (total reflection)
Extremely high VSWR (typically ≥ 60:1 ~ 100:1)
Insertion loss ≤ 0.1 dB
Full waveguide band coverage

Key Formula

Input impedance:

Zin = jZ₀ · tan(β · L_offset)

Where:

β = 2π / λg
L_offset = offset length, which determines the phase and reactance characteristics

Typical Structure & Materials

Main body: High-conductivity metal (OFC / brass / silver-plated aluminum), precision machined for low loss and mechanical stability.
Reflective plane: Metal plate matched to the waveguide cross-section, designed at 1/8, 1/4, or 3/8 λg relative to the center frequency.
Flange: Compatible with UG, CPRG, FDP, BJ and other standard waveguide flanges, with sealing grooves and fasteners for easy installation.
Surface treatment: Silver plating / gold plating for improved conductivity and oxidation resistance; some models use anodization for harsh environments.

Specifications