Mechanically Tuned Combline Waveguide Filter with CABW for Wireless Applications

This paper presents a tunable waveguide (WG) bandpass filter based on a two-pole Chebyshev waveguide with a coaxial resonator, designed for a central frequency of 2.4 GHz. Using a mechanical tuning method via a tuning screw, the filter achieves a frequency range of 2.2 GHz-2.45 GHz with constant 70 MHz bandwidth and a maximum insertion loss of 0.15 dB. The compact design (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$30 \times 24 \times 60 \text{mm}^{3}$</tex>) offers a high-quality factor, outperforming other tuning methods reported in the literature.