Diplexer including two bandpass filters

Patent metadata

Field	Value
Publication number	US-9413328-B2
Application number	US-201414325775-A
Country	US
Kind code	B2
Filing date	Jul 8, 2014
Priority date	Jul 23, 2013
Publication date	Aug 9, 2016
Grant date	Aug 9, 2016

Abstract

A diplexer includes a first bandpass filter provided between an input terminal and a first output terminal and selectively passing a signal in a first frequency band, and a second bandpass filter provided between the input terminal and a second output terminal and selectively passing a signal in a second frequency band. The first bandpass filter includes a plurality of first resonators. The second bandpass filter includes a second resonator and a series resonant circuit. The series resonant circuit is composed of a capacitor provided between the input terminal and the second resonator, and an inductance component of a line that connects the input terminal and the second resonator via the capacitor.

First claim

What is claimed is:

1. A diplexer comprising:
an input terminal to receive a first signal of a frequency within a first frequency band and a second signal of a frequency within a second frequency band higher than the first frequency band;
a first output terminal for outputting the first signal;
a second output terminal for outputting the second signal;
a first bandpass filter provided between the input terminal and the first output terminal and selectively passing the first signal; and
a second bandpass filter provided between the input terminal and the second output terminal and selectively passing the second signal, wherein
the first bandpass filter includes a plurality of first resonators,
the second bandpass filter is directly connected to the second output terminal and is composed only of a second resonator and a series resonant circuit, the series resonant circuit connecting the input terminal and the second resonator, and
the series resonant circuit is composed of a capacitor provided between the input terminal and the second resonator, and an inductance component of a line that connects the input terminal and the second resonator via the capacitor.

2. The diplexer according to claim 1 , wherein the second resonator has a first end connected to the second output terminal and a second end connected to a ground, and is configured to produce parallel resonance.

3. The diplexer according to claim 1 , wherein each of the second resonator and the series resonant circuit has a resonant frequency within the second frequency band.

4. The diplexer according to claim 1 , further comprising an inductor provided between the input terminal and the first bandpass filter.

5. A diplexer comprising:
an input terminal to receive a first signal of a frequency within a first frequency band and a second signal of a frequency within a second frequency band higher than the first frequency band;
a first output terminal for outputting the first signal;
a second output terminal for outputting the second signal;
a first bandpass filter provided between the input terminal and the first output terminal and selectively passing the first signal;
an inductor provided between the input terminal and the first bandpass filter; and
a second bandpass filter selectively passing the second signal of the first and second signals received at the input terminal and allowing the second signal to be output from the second output terminal, wherein
the first bandpass filter includes a plurality of first resonators,
each of the plurality of first resonators has an end connected to a ground, and is configured to produce parallel resonance,
the inductor has an inductance component and a stray capacitance,
the inductance component and the stray capacitance of the inductor constitute a parallel resonant circuit, and
the second bandpass filter includes the parallel resonant circuit, and a second resonator provided between the input terminal and the second output terminal.

6. The diplexer according to claim 5 , wherein the second resonator has a first end connected to the second output terminal and a second end connected to the ground, and is configured to produce parallel resonance.

7. The diplexer according to claim 5 , wherein
the second bandpass filter further includes a capacitor provided between the input terminal and the second resonator, and
the capacitor capacitively couples the parallel resonant circuit and the second resonator to each other.

Assignees

• Tdk Corp

Inventors

• Tsukamoto Kazuhiro
• Tsutsumi Masanori

Classifications

• H03H7/175

  Series LC in series path (H03H7/1783 takes precedence) · CPC title

• H03H7/1766

  Parallel LC in series path (H03H7/1783 takes precedence) · CPC title

• H03H7/461 Primary

  particularly adapted for use in common antenna systems · CPC title

• H03H7/1775

  Parallel LC in shunt or branch path (H03H7/1791 takes precedence) · CPC title