Patent ID: 7102470
Filing Date: 2006-09-05
Classification: H01P

Abstract:
1. A dual-band bandpass filter equipped with stepped-impedance resonators for filtering a signal, comprising: a circuit board; an input end located on the circuit board for receiving the signal; an output end located on the circuit board to transmit the filtered signal; and at least two resonators located on the circuit board, each of the resonators including a connecting section and two coupling sections; the connecting section connecting two coupling sections; one coupling section of the first resonator being coupled with one coupling section of the second resonator and the other coupling section of the first resonator being coupled with the input end or the output end; wherein the circuit board is a multi-layer circuit board, including at least a first layer, a second layer and a third layer, the resonators being located at least on the second layer, the input end and the output end being located respectively on the first layer and the third layer; wherein an impedance of the connecting section and the coupling sections satisfies the condition: wherein f