Wide bandwidth bandpass filter comprising parallel connected piezoelectric resonators
First Claim
1. A wide bandwidth bandpass filter comprising:
- an input inductor having a first terminal coupled to an input terminal of the bandpass filter, and a second terminal coupled to a common terminal of the bandpass filter;
an output inductor having a first terminal coupled to an output terminal of the bandpass filter, and a second terminal coupled to the common terminal of the bandpass filter;
a first stacked piezoelectric resonator having a first input coupled to the input terminal, a first output coupled to the output terminal, and a first common electrode coupled to the common terminal wherein the first stacked piezoelectric resonator has a first odd overtone frequency that is within a passband of the bandpass filter;
a second stacked piezoelectric resonator having a second input coupled to the input terminal, a second output, and a second common electrode coupled to the common terminal wherein the second stacked piezoelectric resonator has a second odd overtone frequency that is displaced from the first odd overtone frequency; and
a third stacked piezoelectric resonator having a third input coupled to the second output of the second piezoelectric resonator, a third output coupled to the output terminal, and a third common electrode coupled to the common terminal wherein the third stacked piezoelectric resonator has a third odd overtone frequency that is substantially equal to the second odd overtone frequency.
1 Assignment
0 Petitions
Accused Products
Abstract
A plurality of piezoelectric resonators (10,32,37,57,62,66,79,88,93) are utilized to form a bandpass filter (31,56,78). The resonators (10,32,37,57,62,66,79,88,93) are connected in parallel to form a plurality of parallel paths between an input (43,73,81) and an output (47,74,82) of the filter (31,56,78). A predetermined number of the piezoelectric resonators (10,32,37,57,62,66,79,88,93) provide a phase shift of approximately 180 degrees. Each parallel path has a passband and center frequency that is displaced from the passband and center frequency of other paths. Consequently, the passband of each parallel path algebraically sums and creates a filter passband that is wider than the passband of each of the filter'"'"'s individual parallel paths.
165 Citations
18 Claims
-
1. A wide bandwidth bandpass filter comprising:
-
an input inductor having a first terminal coupled to an input terminal of the bandpass filter, and a second terminal coupled to a common terminal of the bandpass filter; an output inductor having a first terminal coupled to an output terminal of the bandpass filter, and a second terminal coupled to the common terminal of the bandpass filter; a first stacked piezoelectric resonator having a first input coupled to the input terminal, a first output coupled to the output terminal, and a first common electrode coupled to the common terminal wherein the first stacked piezoelectric resonator has a first odd overtone frequency that is within a passband of the bandpass filter; a second stacked piezoelectric resonator having a second input coupled to the input terminal, a second output, and a second common electrode coupled to the common terminal wherein the second stacked piezoelectric resonator has a second odd overtone frequency that is displaced from the first odd overtone frequency; and a third stacked piezoelectric resonator having a third input coupled to the second output of the second piezoelectric resonator, a third output coupled to the output terminal, and a third common electrode coupled to the common terminal wherein the third stacked piezoelectric resonator has a third odd overtone frequency that is substantially equal to the second odd overtone frequency. - View Dependent Claims (2, 3, 4, 5, 6, 7)
-
-
8. A bandpass filter comprising:
-
an input terminal; an output terminal; a common terminal; a first stacked piezoelectric resonator having a first input coupled to the input terminal, a first output coupled to the output terminal, and a first common electrode coupled to the common terminal; and a second stacked piezoelectric resonator having a second input coupled to the input terminal, a second common electrode coupled to the common terminal, and a second output coupled to the output terminal, wherein the bandpass filter has a passband.
-
-
9. A bandpass filter comprising:
-
an input terminal; an output terminal; a common terminal; a first piezoelectric resonator having a first input coupled to the input terminal, a first output coupled to the output terminal, and a first common electrode coupled to the common terminal wherein the first piezoelectic resonator has a fundamental frequency that is within a passband of the bandpass filter; and a second piezoelectric resonator having a second input coupled to the input terminal, a second common electrode coupled to the common terminal, and a second output coupled to the output terminal wherein the second piezoelectric resonator has an odd overtone frequency that is within a percentage value of the fundamental frequency. - View Dependent Claims (10)
-
-
11. A bandpass filter comprising:
-
an input terminal; an output terminal; a common terminal; a first piezoelectric resonator having a first input coupled to the input terminal, a first output coupled to the output terminal, and a first common electrode coupled to the common terminal; a second piezoelectric resonator having a second input coupled to the input terminal and and a second output; and a phase shift network having a first terminal coupled to the second output of the second piezoelectric resonator and a second terminal coupled to the output terminal wherein the phase shift network provides a phase shift of approximately one hundred eighty degrees (180°
) and wherein the first piezoelectric resonator has a first fundamental frequency that is within a passband of the bandpass filter and the second piezoelectric resonator has a second fundamental frequency that is within a percentage value of the first fundamental frequency. - View Dependent Claims (12)
-
-
13. A bandpass filter comprising:
-
an input terminal; an output terminal; a common terminal; a first piezoelectric resonator having a first input coupled to the input terminal, a first output coupled to the output terminal, and a first common electrode coupled to the common terminal; a second piezoelectric resonator having a second input coupled to the input terminal, a second common electrode coupled to the common terminal, and a second output; and a third piezoelectric resonator having a third input coupled to the second output of the second piezoelectric resonator, a third output coupled to the output terminal, and a third common electrode coupled to the common terminal. - View Dependent Claims (14, 15)
-
-
16. A method of forming a wide bandwidth bandpass filter comprising:
coupling a plurality of piezoelectric resonators in parallel between an input terminal of the filter and an output terminal of the filter and having at least one piezoelectric resonator of the plurality of piezoelectric resonators creating a phase shift of approximately one hundred eighty degrees (180°
).- View Dependent Claims (17, 18)
Specification