Micro-strip bandpass filter for loading interdigital trough line structures based on substrate integrated waveguide (SIW)

The invention discloses a micro-strip bandpass filter for loading interdigital trough line structures based on a substrate integrated waveguide (SIW). The micro-strip bandpass filter is composed of three adjacent resonators, wherein two columns of plated through holes with a first interdigital trough line in the middle of the plated through holes are shared by the first resonator and the second resonator; two columns of plated through holes with a second double-trough line in the middle of the plated through holes are shared by the second resonator and the third resonator; a first port is formed in the middle of one side of the first resonator; L-shaped trough lines are respectively arranged at two sides of the junction of the first port and the plated through holes; a second port is formed in the middle of the other side of the third resonator; L-shaped trough lines are respectively arranged at two sides of the junction of the second port and the plated through holes; and the first interdigital trough line and the second interdigital trough line are formed by connecting four horizontal trough lines end to end. According to the micro-strip bandpass filter, the selectivity of the filter is improved; and the parasitic transmission band of the filter can be inhibited.