US 2009/0243760 A1 · Second-Order Band-Pass Filter and Wireless Apparatus Using the Same

Abstract

A second-order band-pass filter for generating at least two transmission zeros includes a first signal terminal, a second signal terminal, a first transmission line resonator, a second transmission line resonator and an impedance inverter. The first transmission line resonator and the second transmission line resonator are symmetric to each other and coupled to the first signal terminal and the second signal terminal, which are formed by bending two quarter-wavelength open stubs and have an open circuit gap between the two terminals. The impedance inverter includes an inductor, a first micro strip line and a second micro strip line. The first micro strip line and the second micro strip line are symmetric to each other, and are coupled to the first signal terminal and the second signal terminal and coupled to a ground through the inductor, respectively.

Claims18

Dependent claims

A second-order band-pass filter comprising:

a first signal terminal;
a second signal terminal;
a first transmission line resonator, formed with a plurality of bendings, having one end coupled to the first signal terminal and another end open-circuited in a first direction;
a second transmission line resonator, symmetric to the first transmission line resonator and formed with a plurality of bendings, having one end coupled to the second signal terminal and another end open-circuited in a second direction opposite the first direction;
and
an impedance inverter, coupled between the first transmission line resonator and the second transmission line resonator, comprising:
an inductor;
a first micro strip line having one end coupled to the first signal terminal and another end coupled to a ground through the inductor;
and
a second micro strip line, symmetric to the first micro strip line, having one end coupled to the second signal terminal and another end coupled to the ground through the inductor.

7 more elements

A wireless apparatus comprising:

a transceiver for receiving or transmitting a radio signal;
and
a second-order band-pass filter, coupled to the transceiver, for filtering the radio signal, the second-order band-pass filter comprising:
a first signal terminal;
a second signal terminal;
a first transmission line resonator, formed with a plurality of bendings, having one end coupled to the first signal terminal and another end open-circuited in a first direction;
a second transmission line resonator, symmetric to the first transmission line resonator and formed with a plurality of bendings, having one end coupled to the second signal terminal and another end open-circuited in a second direction opposite the first direction;
and
an impedance inverter, coupled between the first transmission line resonator and the second transmission line resonator, comprising:
an inductor;
a first micro strip line having one end coupled to the first signal terminal and another end coupled to a ground through the inductor;
and
a second micro strip line, symmetric to the first micro strip line, having one end coupled to the second signal terminal and another end coupled to the ground through the inductor.

10 more elements

Dependencies are inferred from the claim text.

Second-Order Band-Pass Filter and Wireless Apparatus Using the Same

Life of this patent

Second-Order Band-Pass Filter and Wireless Apparatus Using the Same

Life of this patent

Abstract

Claims18