RF filter with increased bandwidth and filter component
An RF filter (BPF) with an increased bandwidth is provided. The filter comprises a half-lattice topology and a phase shifter (PS) comprising inductively coupled inductance elements in a parallel branch parallel to a first segment (S 1 ) of a signal path (SP) between a first port (P 1 ) and a second port (P 2 ) of the filter.
1. A half lattice filter, comprising:
an input port, an output port and a signal path between the input port and the output port,
a first segment in the signal path,
a parallel branch that is electrically connected in parallel to the first segment of the signal path,
a first electro acoustic resonator in the first segment,
an impedance element in the parallel branch, and
a phase shifter having a first and second terminal, the phase shifter electrically connected in the parallel branch in series to the impedance element,
wherein the phase shifter comprises two inductively coupled inductance elements and a first capacitance element electrically connected to at least one of the first terminal and the second terminal.
2. The half lattic filter of claim 1 , wherein the impedance element is selected from a capacitance element and an electro acoustic resonator.
3. The half lattic filter of claim 1 , where each of the two inductively coupled inductance elements has one connection coupled to ground.
4. The half lattic filter of claim 1 , wherein the phase shifter comprises a second capacitance element electrically connected to a second terminal of the phase shifter.
5. The half lattic filter of claim 4 , wherein the phase shifter comprises a third capacitance element electrically connecting the two inductively coupled inductance elements to ground.
6. The half lattic filter of claim 1 , further comprising a second electro acoustic resonator electrically connected in a signal path between the first electro acoustic resonator and a second port.
7. The half lattic filter of claim 1 , further comprising
a second capacitance element electrically connected in the parallel branch between the first capacitance element and a second port and
a third capacitance element electrically connected in the parallel branch between the second capacitance element and the second port.
8. The half lattic filter of claim 5 , further comprising a fourth capacitance element electrically connected between the parallel branch and ground.
9. The half lattic filter claim 1 , further comprising
a first impedance matching circuit electrically connected in a signal path between a first port and the first electroacoustic resonator and/or
a second impedance matching circuit electrically connected in a signal path between the first electroacoustic resonator and a second port.
10. A half lattic filter comprising:
an input port, an output port and a signal path between the input port and the output port;
a first segment in the signal path;
a parallel branch that is electrically connected in parallel to the first segment of the signal path;
a first electro acoustic resonator in the first segment;
an impedance element in the parallel branch;
a phase shifter having two inductively coupled inductance elements, the phase shifter electrically connected in the parallel branch in series to the impedance element; and
a plurality of capacitance elements, wherein the plurality of capacitance elements are combined with the electro acoustic resonator in an acoustic package.
11. The half lattic filter claim 1 , being a band pass filter with a relative bandwidth Δf with 13%<=Δf<=24%.
12. The half lattic filter of claim 1 , wherein the two inductively coupled inductance elements are established in a multilayer carrier substrate.
13. The half lattic filter of claim 12 , wherein the multilayer carrier substrate is selected from a LTCC substrate, a HTCC substrate, a laminate, a substrate for integrated passive devices.
14. The half lattic filter of claim 1 , wherein the electro acoustic resonator is selected from a BAW resonator, a SAW resonator, a GBAW resonator, a TF-SAW resonator, or a TC-SAW resonator.