Strip-line type bandpass filter

A bandpass filter comprising:

• a plurality of resonators formed of a plurality of strip lines said plurality of resonators being spaced apart by gaps and being coupled across said gaps, each conductive strip line of each resonator being formed substantially in a straight line and having first and second ends with first and second inclined edges, respectively, such that the width of the conductive strip line varies at first and second ends where coupling across the gaps occur, wherein said first and second inclined edges of the first and second ends have the same angle of inclination, and said first and second inclined edges incline in opposite directions.

A bandpass filter comprising:

• a plurality of resonators formed of open-end strip lines with inclined edges, each open-end strip line of each resonator substantially having a shape of a parallelogram, said plurality of resonators being arranged in a straight line such that pairs of parallel edges of said resonators are parallel to said straight line.

A bandpass filter comprising:

• a plurality of resonators formed of open-end strip lines, each open-end strip line of each resonator substantially having a shape of an isosceles triangle, wherein adjacent resonators are oppositely cascaded to form a straight line;
• and bases of the isosceles triangle of said plurality of resonators are parallel to each other along said straight line;
• and each resonator is coupled through both oblique sides of the isosceles triangle.