A waveguide (WG) low pass filter is designed to pass RF signals below a specific cutoff frequency while attenuating higher-frequency components. These filters are essential in microwave systems for suppressing harmonics, eliminating spurious signals, and protecting sensitive components. Key Characteristics: - Operating Principle: Uses reactive elements—like inductive irises or capacitive posts—embedded in the waveguide to create high impedance for unwanted high frequencies. - Frequency Range: Can be tailored from 12.4 GHz up to 220 GHz, depending on the waveguide size (e.g., WR-90 to WR-3). - Insertion Loss: As low as 0.15 dB in the passband. - Rejection: Up to 80 dB beyond the cutoff frequency. - Design Types: Corrugated, stepped-impedance, or waffle-iron structures for enhanced stopband performance. - Applications: Radar front ends, up/down converters, satellite payloads, and test setups.