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CN-114902561-B - Band-pass filter

CN114902561BCN 114902561 BCN114902561 BCN 114902561BCN-114902561-B

Abstract

A band-pass filter (100) is provided with filter circuits (FC 1, FC 2), intermediate circuits (MC 1, MC 2), and a capacitor (C51). The intermediate circuit (MC 1) has an inductor (L31) connected between the capacitor (C31) and the capacitor (C32). The intermediate circuit (MC 2) has an inductor (L41) connected between the capacitor (C41) and the capacitor (C42). The resonance circuits (RC 1, RC 2) included in the filter circuit (FC 1) are grounded via a common capacitor (C61). The resonance circuits (RC 3, RC 4) included in the filter circuit (FC 2) are grounded via a common capacitor (C62). The capacitor (C51) is connected between the intermediate circuit (MC 1) and the intermediate circuit (MC 2).

Inventors

  • TANIGUCHI TETSUO

Assignees

  • 株式会社村田制作所

Dates

Publication Date
20260505
Application Date
20210114
Priority Date
20200124

Claims (5)

  1. 1. A band-pass filter is provided with: A first filter circuit including a first resonant circuit having a first inductor, a third inductor, and a first capacitor, a second resonant circuit having a second inductor, the third inductor, and a second capacitor, and a first common capacitor; A second filter circuit including a third resonant circuit, a fourth resonant circuit, and a second common capacitor, the third resonant circuit having a fourth inductor, a sixth inductor, and a third capacitor, the fourth resonant circuit having a fifth inductor, the sixth inductor, and the fourth capacitor; A first intermediate circuit having a fifth capacitor connected to ground, a sixth capacitor connected to ground, and a seventh inductor connected between the fifth capacitor and the sixth capacitor; A second intermediate circuit having a grounded seventh capacitor, a grounded eighth capacitor, and an eighth inductor connected between the seventh capacitor and the eighth capacitor, and A ninth one of the capacitors is provided with a capacitor, The first resonant circuit and the second resonant circuit are grounded via the first common capacitor, The third resonant circuit and the fourth resonant circuit are grounded via the second common capacitor, The seventh inductor is electromagnetically coupled to the first to third inductors, respectively, the eighth inductor is electromagnetically coupled to the fourth to seventh inductors, respectively, The ninth capacitor is connected between the first intermediate circuit and the second intermediate circuit, The ninth capacitor is connected between a connection point of the fifth capacitor and the seventh inductor and a connection point of the seventh capacitor and the eighth inductor.
  2. 2. The bandpass filter according to claim 1, wherein, A tenth capacitor is also provided, which is provided, The tenth capacitor is connected between a connection point of the sixth capacitor and the seventh inductor and a connection point of the eighth capacitor and the eighth inductor.
  3. 3. A band-pass filter is provided with: A plurality of stacked dielectric layers; A first filter circuit and a second filter circuit arranged in a direction orthogonal to a stacking direction of the plurality of dielectric layers; A first intermediate circuit and a second intermediate circuit arranged between the first filter circuit and the second filter circuit, the first intermediate circuit being electromagnetically coupled to the first filter circuit, the second intermediate circuit being electromagnetically coupled to the second filter circuit and the first intermediate circuit, respectively; A first ground electrode, and A first intermediate capacitor electrode is provided which, The first filter circuit and the second filter circuit each include: a first line electrode extending in a direction perpendicular to the stacking direction; A common electrode disposed opposite to the first ground electrode; a first capacitor electrode disposed opposite to the common electrode; a second capacitor electrode disposed opposite to the common electrode; A first conductive conductor passing through the lamination direction and connecting the first line electrode and the first capacitor electrode; A second conductive conductor passing through the lamination direction and connecting the first line electrode and the second capacitor electrode, and A common conductive conductor arranged between the first conductive conductor and the second conductive conductor, passing through the first conductive conductor in the lamination direction, and connecting the first line electrode and the common electrode, The first intermediate circuit and the second intermediate circuit each include: A second line electrode extending in the vertical direction; a second ground electrode; a ground conductive conductor connecting the first ground electrode and the second ground electrode; a third capacitor electrode disposed opposite to the second ground electrode; A fourth capacitor electrode disposed opposite to the second ground electrode; A third conductive conductor passing through the lamination direction and connecting the second line electrode and the third capacitor electrode, and A fourth conductive conductor passing through the lamination direction and connecting the second line electrode and the fourth capacitor electrode, The first intermediate capacitor electrode is disposed so as to face the third capacitor electrode of the first intermediate circuit and the third capacitor electrode of the second intermediate circuit.
  4. 4. A bandpass filter as claimed in claim 3, wherein, There is also a second intermediate capacitor electrode, The second intermediate capacitor electrode is disposed so as to face the fourth capacitor electrode of the first intermediate circuit and the fourth capacitor electrode of the second intermediate circuit.
  5. 5. The bandpass filter according to claim 3 or 4, wherein, The common electrode and the second ground electrode are disposed apart from each other.

Description

Band-pass filter Technical Field The present invention relates to a bandpass filter, and more particularly to a bandpass filter including a plurality of resonant circuits each including an inductor and a capacitor. Background A plurality of resonant circuits each including a capacitor and an inductor are formed in a laminate including a dielectric layer, a pattern conductor, and a conductive conductor, thereby forming a high-frequency band-pass filter suitable for miniaturization and cost reduction. An example of such a bandpass filter is a bandpass filter described in japanese patent application laid-open No. 2014-57277 (patent document 1). The bandpass filter of patent document 1 has three or more resonant circuits each composed of an inductor and a capacitor, and a floating conductor arranged so as not to contact other line conductors and so as to cross each inductor. The capacitance formed by the floating conductor and the predetermined line conductor is larger than the sum of the resonance capacitances of the constituent capacitors. Patent document 1 Japanese patent application laid-open No. 2014-57277 In a band-pass filter, both maintenance of a pass band and change of attenuation of an attenuation pole are required. In the bandpass filter of patent document 1, the above-described configuration causes non-adjacent resonant circuits to be capacitively coupled, thereby obtaining a desired passband. In this case, when the passband is changed, the attenuation amount of the attenuation pole may also vary. That is, it may be difficult to change the attenuation amount of the attenuation pole while maintaining the passband. Disclosure of Invention That is, an object of the present invention is to provide a bandpass filter capable of generating attenuation poles of a required attenuation amount on at least one of a high-frequency side and a low-frequency side of a passband while maintaining the passband. In the band-pass filter of the present invention, an improvement in the coupling structure of a plurality of resonance circuits is achieved. The first aspect of the band-pass filter of the present invention includes a first filter circuit, a second filter circuit, a first intermediate circuit, a second intermediate circuit, and a ninth capacitor. The first filter circuit includes a first resonant circuit, a second resonant circuit, and a first common capacitor. The first resonant circuit has a first inductor, a third inductor, and a first capacitor. The second resonant circuit has a second inductor, a third inductor, and a second capacitor. The first resonant circuit and the second resonant circuit are grounded via a first common capacitor. The second filter circuit comprises a third resonant circuit, a fourth resonant circuit and a first common capacitor. The third resonant circuit has a fourth inductor, a sixth inductor, and a third capacitor. The fourth resonant circuit has a fifth inductor, a sixth inductor, and a fourth capacitor. The third resonant circuit and the fourth resonant circuit are grounded via a second common capacitor. The first intermediate circuit has a fifth capacitor connected to ground, a sixth capacitor connected to ground, and a seventh inductor connected between the fifth capacitor and the sixth capacitor. The second intermediate circuit has a seventh capacitor connected to ground, an eighth capacitor connected to ground, and an eighth inductor connected between the seventh capacitor and the eighth capacitor. The seventh inductor is coupled with the first to third inductors by electromagnetic fields respectively. The eighth inductor is electromagnetically coupled with the fourth to seventh inductors, respectively. Further, a ninth capacitor is connected between the first intermediate circuit and the second intermediate circuit. A second aspect of the band-pass filter of the present invention includes a plurality of stacked dielectric layers, a first filter circuit and a second filter circuit, a first intermediate circuit and a second intermediate circuit, a first ground electrode, and a first intermediate capacitor electrode. The first filter circuit and the second filter circuit are arranged in a direction orthogonal to the stacking direction of the plurality of dielectric layers. The first intermediate circuit and the second intermediate circuit are arranged between the first filter circuit and the second filter circuit. In addition, the first intermediate circuit is electromagnetically coupled to the first filter circuit. The second intermediate circuit is electromagnetically coupled with the second filter circuit and the first intermediate circuit, respectively. The first filter circuit and the second filter circuit respectively comprise a first line electrode, a common electrode, a first capacitor electrode, a second capacitor electrode, a first conducting conductor, a second conducting conductor and a common conducting conductor. The first line electrode extends in a direction p