Acoustic Wave Filter Circuitry for High Second Harmonic Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing radio frequency front-end circuitry faces challenges in achieving high second harmonic suppression and minimizing losses in transmit and receive paths, particularly in mid-band filters, which affect efficiency and noise figure, and require additional components that increase layout area and cost.
Innovation Solution
Incorporating a blocking inductor coupled with an acoustic wave resonator in parallel configuration to attenuate harmonics, combined with an acoustic wave filter bank having multiplexed filter ports, provides enhanced harmonic suppression and reduced losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a second harmonic trap is included at the post-antenna switch to suppress harmonics, then harmonic suppression is improved, but loss in higher frequencies increases degrading efficiency and noise figure
Solution Approach 1:
The solution divides the harmonic suppression function into separate segments for each mid-band transmit filter rather than using a single common trap. Each filter gets its own dedicated H2 trap circuitry, allowing independent optimization of suppression performance without affecting other frequency bands.
Solution Approach 2:
The H2 trap circuitry is customized for each specific filter location and frequency band requirements. By placing traps locally at each filter output rather than globally at the antenna switch, the solution provides targeted harmonic suppression only where needed, avoiding unnecessary loss in other paths.
2Loss of energy
If individual H2 traps are used in front of MB TX filters, then loss and multiplexing impact are reduced, but suppression may be insufficient and sensitivity to tolerances increases
Solution Approach 1:
The H2 trap circuitry is merged with the existing mid-band transmit filter assembly rather than being implemented as separate discrete components. The trap inductors and capacitors are integrated into the filter structure, combining multiple functions (filtering and harmonic suppression) into a unified circuit that reduces sensitivity to component tolerances.
Solution Approach 2:
The solution uses composite circuit structures combining resistive, inductive, and capacitive elements in specific configurations. The H2 traps utilize composite RLC circuits with carefully selected component values that provide robust suppression performance across manufacturing tolerances, rather than relying on simple parallel LC resonators.
3Object-generated harmful factors
If individual H2 traps with multiple surface-mount devices are used, then harmonic suppression is achieved, but layout area usage and cost increase
Solution Approach 1:
Multiple H2 trap circuits are merged into a shared inductor structure where a single common inductor serves multiple filter outputs. This consolidation dramatically reduces the number of discrete surface-mount devices required and minimizes the overall layout area while maintaining suppression effectiveness for each individual filter.
Solution Approach 2:
The common inductor structure serves multiple functions simultaneously - it acts as the H2 trap for multiple different mid-band transmit filters at once. This universal component performs harmonic suppression across several frequency bands without requiring separate dedicated components for each band, reducing both area and cost.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution achieves improved harmonic suppression and reduced losses in both mid-band and high-band filters, simplifying multiplexer networks and reducing layout area and cost while maintaining efficient complex conjugate matching.
Implementation Method 1
an acoustic wave resonator coupled in parallel with the first blocking inductor, wherein the first blocking inductor and first acoustic resonator are configured to substantially attenuate harmonics
Data Source
AI summary
Filter circuitry having harmonic blocking circuitry with a first blocking inductor coupled between a first blocking terminal and a second blocking terminal, and a first acoustic wave resonator coupled in parallel with the first blocking inductor, wherein the first blocking inductor and first acoustic resonator are configured to substantially attenuate harmonics of signals that pass between the first blocking terminal and the second blocking terminal. Further included is an acoustic wave filter bank having a plurality of first filter ports and a plurality of second filter ports. In some embodiments, the acoustic wave filter bank has at 10 least two second filter ports of the plurality of second filter ports multiplexed together and coupled to the first blocking terminal.