Description

A waveguide (WG) bandpass filter is a precision RF component that allows signals within a specific frequency band to pass while rejecting those outside it. These filters are prized for their low insertion loss, high power handling, and excellent selectivity, especially in microwave and millimeter-wave systems. Core Design Features: - Structure: Typically consists of a series of resonant cavities or inductive irises inside a hollow waveguide. These cavities are spaced at λ/4 intervals to create the desired passband response. - Frequency Range: Depends on the waveguide size—e.g., WR90 for X-band (8.2–12.4 GHz), WR28 for Ka-band (26.5–40 GHz). - Bandwidth: Usually 1–10% of the center frequency, though wider bandwidths are achievable with advanced coupling techniques. - VSWR: Often ≤ 1.2:1, ensuring minimal reflection. - Rejection: Out-of-band attenuation can exceed 40 dB, critical for adjacent channel suppression. Applications: Used in radar, satellite transponders, electronic warfare systems, and high-frequency test setups. For example, in satellite systems like APSTAR-6, a WG bandpass filter ensures clean channel separation and prevents spurious emissions.