Dispersive delay line with lamb wave propagation
Dispersive delay lines are disclosed. The dispersive delay line can include a piezoelectric substrate having a first interdigital transducer electrode on a first region of the piezoelectric substrate and a second interdigital transducer electrode on a second region of the piezoelectric substrate. The dispersive delay line is arranged such that an acoustic wave is configured to propagate from the first interdigital transducer electrode to the second interdigital transducer electrode though a third region of the piezoelectric substrate. An additional material positioned on the third region of the piezoelectric substrate can impact acoustic wave propagation velocity. Related radio frequency modules, wireless communications devices, and methods are disclosed.
1. A dispersive delay line comprising:
a piezoelectric substrate including a first region, a second region, and a third region;
a first interdigital transducer electrode on the first region of the piezoelectric substrate;
a second interdigital transducer electrode on the second region of the piezoelectric substrate; and
an additional material on the third region of the piezoelectric substrate, the additional material configured to adjust acoustic wave propagation velocity in the third region of the piezoelectric substrate, the dispersive delay line arranged such that a Lamb wave of wavelength λ is configured to propagate from the first interdigital transducer electrode to the second interdigital transducer electrode though the third region of the piezoelectric substrate with a group delay that depends on frequency.
2. The dispersive delay line of claim 1 wherein the additional material is positioned on both a top surface and a bottom surface of the piezoelectric substrate in the third region.
3. The dispersive delay line of claim 1 wherein the additional material includes silicon dioxide.
4. The dispersive delay line of claim 1 wherein the additional material includes gallium nitride.
5. The dispersive delay line of claim 1 wherein the additional material includes silicon nitride.
6. The dispersive delay line of claim 1 wherein the piezoelectric substrate has a substantially constant thickness in the first region, the second region, and the third region.
7. The dispersive delay line of claim 1 wherein the group delay has a non-linear relationship with frequency.
8. The dispersive delay line of claim 1 wherein the group delay has a linear relationship with frequency.
9. The dispersive delay line of claim 1 wherein the dispersive delay line has a passband bandwidth in a range from 0.5 gigahertz to 2 gigahertz.
10. The dispersive delay line of claim 1 wherein the dispersive delay line has a passband bandwidth of more than 1 gigahertz.
11. The dispersive delay line of claim 1 wherein the group delay is in a range from 20 nanoseconds to 100 nanoseconds.
12. The dispersive delay line of claim 1 wherein the dispersive delay line has an operating frequency in range from 5 gigahertz to 10 gigahertz.
13. The dispersive delay line of claim 1 wherein the dispersive delay line has an operating frequency in Frequency Range 2 defined by a New Radio standard.
14. The dispersive delay line of claim 1 wherein the piezoelectric substrate includes aluminum nitride.
15. The dispersive delay line of claim 14 wherein the Lamb wave is a lowest order symmetric mode Lamb wave.
16. The dispersive delay line of claim 1 wherein the Lamb wave is a lowest order symmetric mode Lamb wave.
17. A radio frequency module comprising:
a dispersive delay line including a piezoelectric substrate, a first interdigital transducer electrode on a first region of the piezoelectric substrate, a second interdigital transducer electrode on a second region of the piezoelectric substrate, and an additional material on a third region of the piezoelectric substrate, the additional material configured to adjust acoustic wave propagation velocity in the third region of the piezoelectric substrate, the dispersive delay line arranged such that a Lamb wave of wavelength λ is configured to propagate from the first interdigital transducer electrode to the second interdigital transducer electrode though the third region of the piezoelectric substrate with a group delay that depends on frequency;
a radio frequency circuitry coupled to the dispersive delay line; and
packaging structure enclosing the dispersive delay line and the radio frequency circuitry.
18. The radio frequency module of claim 17 wherein the radio frequency circuitry includes a radio frequency amplifier.
19. A wireless communication device comprising:
a dispersive delay line including a piezoelectric substrate, a first interdigital transducer electrode on a first region of the piezoelectric substrate, a second interdigital transducer electrode on a second region of the piezoelectric substrate, and an additional material on a third region of the piezoelectric substrate, the additional material configured to adjust acoustic wave propagation velocity in the third region of the piezoelectric substrate, the dispersive delay line arranged such that a Lamb wave of wavelength λ is configured to propagate from the first interdigital transducer electrode to the second interdigital transducer electrode though the third region of the piezoelectric substrate with a group delay that depends on frequency; and
an antenna in communication with the dispersive delay line.
20. The wireless communication device of claim 19 wherein the wireless communication device is a mobile phone.