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Slotline Stepped-impedance resonators (SIR) loaded with p-i-n diodes are used to develop bandpass filter (BPF) integrated switches in this brief. The loaded diodes are used to switch the resonant conditions of the short-ended slotline resonators. The equations for their resonant conditions under different loads at different locations are derived and discussed. With these derived equations, the switchable filters are designed and synthesized using the classical coupled-resonator filter theory. The design concept is demonstrated by a Cascaded Quadruplet (CQ) BPF-integrated single-pole single-throw (SPST) switch at center frequency $f_{0}\,\,=$ 1 GHz with 47.7 dB OFF-state suppression (OSS). Finally, two compact BPF-integrated single-pole double-throw (SPDT) switches are designed and fabricated. One of them combines source-load (S-L) coupling and introduces two additional zeros outside the desired passband to improve the frequency selectivity. The other on fractal common feeding line is developed to reduce the impact of accumulated residual admittances from OFF-state channels, which shows high roll-off rate of sidebands as well as high port-to-port isolation of 53.1 dB, and its overall circuit size is only $0.051 \lambda \text{g} ^{\mathrm{ 2}}$ .

The wet flue gas desulfurization is the main technology used today in China. Aimed the sintering gas desulfurization tower, Fluent software is used here to simulate the flow in the tower with different gas entrance angle and velocity, and we have got the effect of sintering gas entrance angle and velocity on the flow in the tower. The result shows: an appropriate increase of the gas entrance velocity and a downward inclined angle will be helpful for extending the residence time in the tower of the sintering gas and it will also improve the flow in the tower. This research could provide reference for the design and application of new wet flue sintering gas desulfurization tower later.