Tunable filter arrangement comprising resonators with reflection layers

• US 6,583,688 B2
• Filed: 04/05/2001
• Issued: 06/24/2003
• Est. Priority Date: 04/06/2000
• Status: Expired due to Term

• Current Assignee: Qorvo US, Inc. (Qorvo, Inc.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Mackens, Uwe, Kiewitt, Rainer, Lobl, Hans Peter, Milsom, Robert Frederick, Klee, Mareike Katharine, Wunnicke, Olaf, Hermann, Wilhelm Georg, Van Delden, Martinus Hermanus Wilhemus Maria
• Primary Examiner(s): Summons, Barbara
• Application Number:
  US09/826,684
• Publication Number:
  US 20010028285A1
• Time in Patent Office: 810 Days
• Field of Search: 333/186-196, 333/133, 310/358
• US Class Current: 333/188
• CPC Class Codes: H03H 3/04 for obtaining desired frequency or temperature coefficient
• CPC Class Codes: H03H 9/02094 of adherence
• CPC Class Codes: H03H 9/02149 of ageing changes of characteristics, e.g. electro-acousto-migration
• CPC Class Codes: H03H 9/562 comprising a ceramic piezoelectric layer
• CPC Class Codes: H03H 9/566 Electric coupling means therefor H03H9/0095 takes precedence

Abstract

The invention describes a tunable filter arrangement with a plurality of resonators which are coupled to one another and of which there is at least one which comprises a piezoelectric component made of a ferroelectric material and to which a DC voltage source is connected. The application of a DC voltage to the resonator renders it possible to change its electrical properties and thus the overall filter characteristic. Furthermore, a transmitter, a receiver device, and a mobile telephone device with such a filter arrangement are disclosed, aswell as a tunable bulk acoustic wave resonator.

Claims

1. A tunable filter arrangement which comprises a substrate and provided thereon an arrangement of at least two resonators coupled to one another, of which resonators there is at least one which contains a piezoelectric component of a ferroelectric material and to which a DC voltage source is connected, the arrangement further comprising lower and upper electrodes, a reflection element said lower electrode and a second reflection element above said upper electrode.

2. A tunable filter arrangement as claimed in claim 1, characterized in that the ferroelectric material is chosen from the group consisting of PbTi₁₋

xZr_xO₃ (0≦

x≦

1), LiNbO₃, LiTaO₃, PbNb₂O₆, Pb<sub>1−

x</sub>Ca_xTiO₃ (0≦

x≦

1), [Pb(Mg_⅓

Nb_⅔

)O₃]—

[PbTiO₃]<sub>1−

x</sub> (0≦

x≦

1), BaTiO₃, Ba<sub>1−

x</sub>Sr_xTiO₃ (0≦

x≦

1), Ba<sub>1−

x</sub>Sr_xTiO₃ (0≦

x≦

1) (1≦

x≦

2.5), [Ba<sub>1−

x</sub>Sr_xTiO₃]—

[Pb<sub>1−

x</sub>Ca_yTiO₃] (0≦

x≦

1, 0≦

y≦

1), Ba<sub>1−

x</sub>Sr_xZr_yTi<sub>1−

y</sub>O₃ (0≦

x≦

1, 0≦

y≦

1), Ba<sub>1−

x</sub>Pb_xTiO₃ (0≦

x≦

1), Ba<sub>1−

x</sub>Ca_xTiO₃ (0≦

x≦

1), (Pb,Ba,Sr) (Mg_⅓

Nb_⅔

)_xTi_y(Zn_⅓

Nb_⅔

)<sub>1−

x−

y</sub>O₃ (0≦

x≦

1, 0≦

y≦

1), K<sub>1−

x</sub>Na_xNbO₃ (0≦

x≦

1), (Cd,Na)NbO₃, (Bi,Na)TiO₃, (Bi,Na,Pb,Ba)TiO₃, Bi₇Ti₄NbO₂₁, (Ba<sub>1−

x</sub>Sr_x)₂NaNb₅O₁₅ (0≦

x≦

1), (Ba<sub>1−

x</sub>Sr_x)₂KNb₅O₁₅ (0≦

x≦

1), (Ba<sub>1−

x+y/8</sub>Sr_x+y/8)₂Na<sub>1−

y</sub>Nb₅O₁₅ (0≦

x≦

1, 0≦

y≦

1), (B<sub>1−

x+y/8</sub>Sr_x+y/8)₂K<sub>1−

y</sub>Nb₅O₁₅ (0≦

x≦

1, 0≦

y≦

1), (Ba<sub>1−

x</sub>Sr_x)₂K<sub>1−

3y</sub>SE_yNb₅O₁₅ (0≦

x≦

1, 0≦

y≦

1, SE=ion from the group of rare earths), Sr₂Ba₄Ti₂Nb₈O₃₀,

a) Pb(Mg_½

W_½

)O₃,

b) Pb(Fe_½

Nb_½

)O₃,

c) Pb(Fe_⅔

W_⅓

)O₃,

d) Pb(Ni_⅓

Nb_⅔

)O₃,

e) Pb(Zn_⅓

Nb_⅔

)O₃,

f) Pb(Sc_½

Ta_½

)O₃ and combinations of the compounds a) to f) with PbTiO₃ and/or Pb(Mg_⅓

Nb_⅔

)O₃.

3. A tunable filter arrangement as claimed in claim 1, characterized in that the resonators are bulk acoustic wave resonators.

4. A tunable filter arrangement as claimed in claim 3, characterized in that the resonators are constructed in the thin film technology.

5. A tunable filter arrangement as claimed in claim 3, characterized in that the chosen resonators are bulk acoustic wave resonators that each comprise a resonator unit of a lower and upper electrode and a piezoelectric layer arranged therebetween and a reflection element which is positioned between the substrate and the resonator unit.

6. A mobile telephone device provided with a tunable filter arrangement which comprises a substrate and provided thereon an arrangement of at least two resonators which are coupled to one another, of which resonators there is at least one which has a piezoelectric component made of a ferroelectric material and to which a DC voltage source is connected, the arrangement further comprising lower and upper electrodes, a reflection element below said lower electrode and a second reflection element above said upper electrode.

7. A transmitter provided with a tunable filter arrangement which comprises a substrate and provided thereon an arrangement of at least two resonators which are coupled to one another, of which resonators there is at least one which has a piezo electric component made of a ferroelectric material and to which a DC voltage source is connected, said transmitter comprising at least two reflection layers separated by at least one electrode.

8. A receiver provided with a tunable filter arrangement which comprises a substrate and provided thereon an arrangement of at least two resonators which are coupled to one another, of which resonators there is at least one which has a piezoelectric component made of a ferroelectric material and to which a DC voltage source is connected, and wherein a layer of said resonator separates two reflective layers.