Patent ID: 7616080

Claim:
A bandpass filter (BPF) comprising: a first, a second, a third and a fourth dielectric substrate each sequentially stacked; a first around pattern printed on a bottom surface of the first dielectric substrate; a stripline pattern formed between the first dielectric substrate and the second dielectric substrate and operated as a stub; a second ground pattern formed between the second dielectric substrate and the third dielectric substrate; a filter pattern formed on a top surface of the fourth dielectric substrate and connected to the stripline through a via; an input coupled line filter formed on a top surface and a bottom surface of one side of the fourth dielectric substrate for transmitting to the filter pattern a signal inputted from outside to be filtered; and an output coupled line filter formed on a top surface and a bottom surface of the other side of the fourth dielectric substrate for outputting to the outside the signal filtered by the filter pattern.