24GHz band-pass filter

A 24 GHz band-pass filter, comprising:

• a step impedance resonator comprising:
• a first main portion electrically connected to a first signal input/output port, wherein the first main portion comprises:
• a first signal coupling portion comprising a first impedance portion and a first coupling line segment surrounding the first impedance portion;
• a second signal coupling portion comprising a second impedance portion and a second coupling line segment surrounding the second impedance portion;
• a third impedance portion electrically connected to the first impedance portion, wherein an impedance value of the third impedance portion is greater than an impedance value of the first impedance portion;
• and
• a fourth impedance portion electrically connected to the second impedance portion, wherein an impedance value of the fourth impedance portion is greater than an impedance value of the second impedance portion;
• a second main portion electrically connected to a second signal input/output port, wherein the second main portion comprises:
• a third signal coupling portion comprising a fifth impedance portion and a third coupling line segment surrounding the fifth impedance portion;
• a fourth signal coupling portion comprising a sixth impedance portion and a fourth coupling line segment surrounding the sixth impedance portion;
• a seventh impedance portion electrically connected to the fifth impedance portion, wherein an impedance value of the seventh impedance portion is greater than an impedance value of the fifth impedance portion;
• and
• an eighth impedance portion electrically connected to the sixth impedance portion, wherein an impedance value of the eighth impedance portion is greater than an impedance value of the sixth impedance portion;
• and
• a connection portion disposed between the first main portion and the second main portion to electrically connect the first main portion with the second main portion, wherein one terminal of the connection portion is electrically connected to the third impedance portion and the fourth impedance portion, the other terminal of the connection portion is electrically connected to the seventh impedance portion and the eighth impedance portion, an impedance value of the connection portion is greater than an impedance value of the third impedance portion, an impedance value of the fourth impedance portion, an impedance value of the seventh impedance portion an impedance portion and an impedance value of the eighth impedance portion;
• a first U-shaped feeding portion electrically connected between the first main portion and the first signal input/output port;
• a second U-shaped feeding portion electrically connected between the second main portion and the second signal input/output port;
• a plurality of short-circuit stubs electrically connected to the first coupling line segment, the second coupling line segment, the third coupling line segment, and the fourth coupling line segment in a one-to-one manner;
• and
• a plurality of open-circuit stubs electrically connected to the first U-shaped feeding portion and the second U-shaped feeding portion in a one-to-one manner.