Coaxial Cavity Tunable Bandpass Filter for Radar Applications

This paper presents a low-loss, post-manufacturing coaxial cavity tunable bandpass filter(BPF). A BPF with 5th degree Chebyshev bandpass response is discussed. It resonates at 2.8GHz with a Bandwidth of 450MHz. The lowpass prototype is used as a starting point in the bandpass filter design. Particularly in the passband, insertion loss of 0.2 dB, return loss greater than -20 dB are attained. A good spurious response and better rejection of -50dB characterized. The tuning screws are used to adjust the bandwidth and coupling screws are used to decrease the ripples in the filter. These kind of microwave cavity filter is beneficial for base stations, radar, and satellite transceivers and systems requires low insertion loss and good selectivity, The BPF is fabricated and validated.