Patent ID: 7944328

Claim:
A low-pass filter comprising: a first curved microstrip in an n-shape and defining a first receiving space therein, wherein one end of the first curved microstrip is defined as an input portion of the low-pass filter; a second curved microstrip in an n-shape and defining a second receiving space therein, wherein two opposite sides of the second curved microstrip are parallel to those of the first curved microstrip, and one end of the second curved microstrip is connected to a side of the first curved microstrip close to the second curved microstrip; a first flat microstrip, received in the first receiving space, and connected to a topside of the n shape of the first curved microstrip; a second flat microstrip, received in the first receiving space along with the first flat microstrip, and connected to the other end of the first curved microstrip; and a third flat microstrip, received in the second receiving space, and connected to the other end of the second curved microstrip; wherein the third flat microstrip defines an output portion of the low-pass filter.