Band-Pass Filter (BPF) is a core filtering component for RF and microwave links. It only allows target useful signals within a specific frequency band to pass through, while drastically attenuating low-frequency, high-frequency interference, harmonics and spurious signals outside the passband.
Different from low-pass and high-pass filters, BPF has separate lower and upper cutoff frequencies of passband. It can accurately select signals in the target operating band and isolate unwanted spectrum such as LO leakage, image interference and transmitting harmonics.
It is categorized into passive LC band-pass filters, dielectric resonator band-pass filters, LTCC integrated band-pass filters, etc. Widely matched with Ku-band phased array T/R channels, satellite communication transceivers, radar receiver front-ends and frequency synthesizer SiP modules. Key performance indicators include in-band insertion loss, out-of-band stopband attenuation, bandwidth, VSWR and passband ripple.