Microstrip band-pass filter having first and second trapezoidal shape coupling portions connected by a connection portion

A band-pass filter disposed on a PCB comprising:

• a first terminal and a second terminal, configured to receive and output electromagnetic signals respectively;
• a first coupling portion with a first coupling portion groove and a second coupling portion with a second coupling portion groove, coupled to the first terminal and the second terminal, respectively;
• and
• a connection portion, connected the first coupling portion to the second coupling portion;
• wherein the first terminal is partly accommodated in the first coupling portion groove, and the second terminal is partly accommodated in the second coupling portion groove;
• wherein a first gap is defined between the first terminal and the first coupling portion, and a second gap defined between the second terminal and the second coupling portion, and a width of the first gap exceeds a width of the second gap.