12.5 GHz Channel Spacing Compact Interleave Filter Using 1.5% Δ Waveguides

We report the first fabrication of a compact I att ice-form interleave filter with a channel spacing of 12.5 GHz. The circuit size was reduced to 1/4 the size of the original filter by using the 1.5 %-A waveguides. We achieved a flat passband and low crosstalk with a low insertion loss of 2.7 dB.