Patent ID: 7990236

Claim:
A low-pass filter comprising an input portion, an output portion, a third connecting portion, a high impedance transmission portion, a first low impedance transmission portion, a second low impedance transmission portion and a pair of parallel aligned metal plates, the high impedance transmission portion electrically connecting the input portion and the output portion, the high impedance transmission portion comprising a first high impedance transmission portion and a second high impedance transmission portion the first and second high impedance transmission portions being symmetrical about the third connecting portion, the first low impedance transmission portion electrically connecting the input portion and one end portion of the high impedance transmission portion, the second low impedance transmission portion electrically connecting the output portion and another end portion of the high impedance transmission portion, one of the pair of parallel aligned metal plates electrically connecting to the third connecting portion, and the other metal plate electrically connecting to ground of a PCB through a via.