Tunable filter arrangement

• US 20010048352A1
• Filed: 04/05/2001
• Published: 12/06/2001
• Est. Priority Date: 04/06/2000
• Status: Active Grant

• Current Assignee: Qorvo US, Inc. (Qorvo, Inc.)
• Original Assignee: Koninklijke Philips N.V.
• Inventors: Wunnicke, Olaf, Kiewitt, Rainer, Mackens, Uwe, Milsom, Robert Frederick, Klee, Mareike Katharine, Lobl, Hans Peter, Van Delden, Martinus Hermanus Wilhemus Maria, Hermann, Wilhelm Georg
• Granted Patent: US 6,653,913 B2
• Time in Patent Office: Days
• 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 9/0542 consisting of a lateral arrangement H03H9/0566 takes precedence
• 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 at least two resonators which are coupled to one another and of which at least one is connected to a capacitor with tunable capacitance. The electrical properties of the resonator, and thus the overall filter characteristic, can be changed through a change in the capacitance of the capacitor.

Furthermore, a transmitter, a receiver, a mobile telephone device, and a wireless data transmission system comprising such a filter arrangement are disclosed, as is a tunable bulk acoustic wave resonator.

Claims

1. A tunable filter arrangement which comprises a substrate (1) and provided thereon an arrangement of at least two mutually coupled resonators of which at least one is connected to a capacitor with tunable capacitance.

2. A tunable filter arrangement as claimed in

claim 1

, characterized in that the capacitor comprises a dielectric (8) made of a material having EL voltage-dependent relative dielectric constant ε

_r.

3. A tunable filter arrangement as claimed in

claim 2

, characterized in that the material with a voltage-dependent relative dielectric constant ε

_r is chosen from the group comprising PbTi<sub>1−

x</sub>Zr_xO₃ (0≦

x≦

1) with and without dopants of La, Nb or Mn with and without excess lead, BaTiO₃ with and without dopants, SrTiO₃ with and without dopants, Ba<sub>1−

x</sub>Sr_xTiO₃ (0≦

x≦

1) with and without dopants of Ca and Pb, Ba<sub>1−

x</sub>Sr_xTiO₃ (0≦

x≦

1)+MgO,

Ba<sub>1−

x</sub>Sr_xTiO₃—

Pb<sub>1−

y</sub>Ca_yTiO₃ (0≦

x≦

1, 0≦

y≦

1), CaTiO₃ doped with Bi, Sr_n+1Ti_nO_3n+1 (1≦

n≦

5), Pb<sub>1−

x</sub>Ca_xTiO₃ (0≦

x≦

1), Ba<sub>1−

x</sub>Sr_xTiO₃ (0≦

x≦

1) with and without added VO_x (1≦

x≦

2.5) and/or SiO₂, Ba<sub>1−

x</sub>Sr_xZr_yTi<sub>1−

y</sub>O₃ (0≦

x≦

1, 0≦

y≦

1) with and without dopants, Ba<sub>1−

x</sub>Pb_xTiO₃ (0≦

x≦

1) with and without excess lead, Ba<sub>1−

x</sub>Ca_xTiO₃ (0≦

x≦

1), SrZr_xTi<sub>1−

x</sub>O₃ (0≦

x≦

1) with and without dopants, [PbMg_⅓

Nb_⅔

O₃]_x—

[PbTiO₃]<sub>1−

x</sub> (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), Pb<sub>1−

x</sub>Ca_xTiO₃ (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) with and without excess Na⁺, (Ba<sub>1−

x+y/8</sub>Sr_x+y/8)₂K<sub>1−

y</sub> Nb₅O₁₅ (0≦

x≦

1, 0≦

y≦

1) with and without excess K⁺, (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, BiNbO₄ with and without VO_x (1≦

x≦

2.5) and/or CuO dopants, (Bi<sub>2−

x</sub>Zn_x)(Nb<sub>2−

y</sub>Zn_y)O_x,

Bi₂(Zn_⅓

Nb_⅔

)₂O₇,

a) Pb(Mg_½

WI_½

)O₃,

b) Pb(Fe_½

Nb_½

)O₃,

c) Pb(Fe_⅔

WI_⅓

)O₃,

d) Pb(Ni_⅓

Nb_⅔

)O₃,

e) Pb(Zn_⅓

Nb_⅔

)O₃,

f) Pb(Sc_½

Ta_½

)O₃,

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

Nb_⅔

)O₃ with and without excess lead and Ba<sub>1−

x</sub>Zr_xTiO₃ (0≦

x≦

1).

4. A tunable filter arrangement as claimed in

claim 1

, characterized in that the resonators are chosen from the group comprising bulk acoustic wave resonators, surface acoustic wave resonators, and LC resonators.

5. A tunable filter arrangement as claimed in

claim 4

, characterized in that the resonators are constructed in a thin-film technology process.

6. A tunable filter arrangement as claimed in

claim 4

, characterized in that a bulk acoustic wave resonator comprises a resonator unit of a lower and an upper electrode (5, 7) as well as a piezoelectric layer (6) arranged therebetween and a reflection element (2) arranged between the substrate (1) and the resonator unit.

7. A tunable filter arrangement as claimed in

claim 1

, characterized in that the resonator connected to a capacitor of tunable capacitance is also connected to a further capacitor.

8. A tunable filter arrangement as claimed in

claim 7

, characterized in that at least one capacitor is connected in series with and at least one capacitor is connected in parallel to the resonator.

9. A mobile telephone device provided with a tunable filter arrangement which comprises a substrate and provided thereon an arrangement of at least two mutually coupled resonators of which at least one is connected to a capacitor with tunable capacitance.

10. A transmitter provided with a tunable filter arrangement which comprises a substrate and provided thereon an arrangement of at least two mutually coupled resonators of which at least one is connected to a capacitor with tunable capacitance.

11. A receiver provided with a tunable filter arrangement which comprises a substrate and provided thereon an arrangement of at least two mutually coupled resonators of which at least one is connected to a capacitor with tunable capacitance.

12. A wireless data transmission system provided with a tunable filter arrangement which comprises a substrate and provided thereon an arrangement of at least two mutually coupled resonators of which at least one is connected to a capacitor with tunable capacitance.

13. A tunable bulk acoustic wave resonator which comprises a substrate and provided thereon a resonator unit with a lower and an upper electrode as well as a piezoelectric layer arranged therebetween, and a reflection element which is arranged between the substrate and the resonator unit, which resonator is connected to a capacitor having a tunable capacitance value.