Patent ID: 8334733

Claim:
A left-handed filter comprising: a first capacitor; a second capacitor having one end connected to one end of the first capacitor; a first inductor having one end connected to a connection point of the first capacitor and the second capacitor, and another end connected to a ground; a second inductor having one end connected to another end of the second capacitor and another end connected to the ground; an interstage coupling element having one end connected to another end of the first capacitor and another end connected to the ground; a third capacitor having one end connected to one end of the interstage coupling element; a fourth capacitor having one end connected to another end of the third capacitor; a third inductor having one end connected to a connection point of the third capacitor and the fourth capacitor, and another end connected to the ground; a fourth inductor having one end connected to another end of the fourth capacitor and another end connected to the ground; a first input and output coupling element connected to another end of the second capacitor; and a second input and output coupling element connected to another end of the fourth capacitor, wherein the first capacitor and the third capacitor are arranged in symmetrical positions with respect to the interstage coupling element, wherein the second capacitor and the fourth capacitor are arranged in symmetrical positions with respect to the interstage coupling element, wherein the first inductor and the third inductor are arranged in symmetrical positions with respect to the interstage coupling element, and wherein the second inductor and the fourth inductor are arranged in symmetrical positions with respect to the interstage coupling element.