Microstrip band-pass filter having first and second trapezoidal shape coupling portions connected by a connection portion
A band-PASS filter disposed on a printed circuit board comprises a first terminal, a second terminal, a first coupling portion, a second coupling portion and a connection portion. The first terminal and the second terminal are used to receive or output electromagnetic signals respectively. The first coupling portion and the second coupling portion are disposed between the first terminal and the second terminal to couple the electromagnetic signals. The connection portion is connected to the first coupling portion and the second coupling portion. The first terminal partly accommodates in a first coupling portion groove. The second terminal partly accommodates in a second coupling portion groove.
1. 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.
2. The band-pass filter as claimed in claim 1 , wherein the first terminal is symmetric about an axis, and the second terminal is also symmetric about the axis.
3. The band-pass filter as claimed in claim 1 , wherein the first coupling portion is symmetric about a first axis, the second coupling portion is also symmetric about the first axis, the first coupling portion and the second coupling portion are symmetric about a second axis, and the first axis is perpendicular to the second axis.
4. The band-pass filter as claimed in claim 3 , wherein the connection portion is strip-shaped and the connection portion is coaxial to the first axis.
5. The band-pass filter as claimed in claim 3 , wherein each of the first coupling portion and the second coupling portion comprises:
a first microstrip line, wherein a shape of the first microstrip line is a first right-angle trapezoid minus a first rectangle portion; wherein the first rectangle portion has a first rectangle portion first edge and a first rectangle portion second edge, the first right-angle trapezoid has a first right-angle trapezoid bottom edge and a first right-angle trapezoid right-angle edge, and the first rectangle portion first edge overlaps with the first right-angle trapezoid bottom edge; the first rectangle portion second edge overlap with the first right-angle trapezoid right-angle edge;
a second microstrip line, wherein the second microstrip line is a second right-angle trapezoid minus a second rectangle portion; wherein the second rectangle portion has a second rectangle portion first edge and a second rectangle portion second edge, the second right-angle trapezoid has a second right-angle trapezoid top edge and a second right-angle trapezoid right-angle edge, and the second rectangle portion first edge overlaps with the second right-angle trapezoid top edge, the second rectangle portion second edge overlaps with the second right-angle trapezoid right-angle edge; and
a third microstrip line has a third microstrip line first edge and a third microstrip line second edge, wherein the third microstrip line first edge is coupled to the first right-angle trapezoid bottom edge, and the third microstrip line second edge is coupled to the second right-angle trapezoid top edge, and a third microstrip line third edge defines a middle part, and the middle part is coupled to the connection portion.
6. The band-pass filter as claimed in claim 5 , wherein the third microstrip line has a shape that is a rectangle-shaped.
7. The band-pass filter as claimed in claim 5 , wherein the first microstrip line and the second microstrip line are symmetric about the first axis.
8. The band-pass filter as claimed in claim 5 , wherein the first coupling portion groove is defined by the first microstrip line, the second microstrip line and the third microstrip line in the first coupling portion; and the second coupling portion groove is defined by the first microstrip line, the second microstrip line and the third microstrip line in the second coupling portion; the first terminal and the third microstrip line define a first gap there between, and the second terminal and the third microstrip line define a second gap there between.
9. The band-pass filter as claimed in claim 8 , wherein the first terminal extends out from the first coupling portion groove, and the second terminal extends out from the second coupling portion groove.