Acoustic Wave Filter Layout for High Isolation With Low Insertion Loss
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Solution Overview
Problem
Existing acoustic wave devices face challenges in miniaturization and require improved isolation characteristics without increasing insertion loss or adding additional elements, as current solutions compromise on miniaturization due to increased insertion loss.
Innovation Solution
The acoustic wave device incorporates a band pass filter with a combination of series and parallel resonators, featuring specific attenuation poles to enhance isolation characteristics while maintaining minimal insertion loss, utilizing a multilayer LTCC substrate and flip-chip bonding for compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a capacitive element is connected in parallel with a reception filter to improve isolation characteristics, then isolation characteristics are improved, but insertion loss increases and device miniaturization is hindered
Solution Approach 1:
The invention changes the parameters of existing resonators by strategically positioning attenuation poles at specific frequency points. By adjusting the attenuation pole positions and values in series resonators, the invention achieves improved isolation characteristics without adding external components, thereby avoiding the insertion loss penalty associated with parallel capacitive elements.
Solution Approach 2:
The invention uses the existing resonator structures within the bandpass filter to achieve the isolation function. Instead of adding a separate capacitive element, the invention modifies the existing series resonators to provide the necessary attenuation, effectively using the existing filter structure to serve dual purposes: signal filtering and isolation.
2Reliability
If additional elements are added to improve isolation characteristics, then isolation characteristics are improved, but device size increases and miniaturization is hindered
Solution Approach 1:
The series resonators in the bandpass filter are designed to perform multiple functions: they provide the primary signal filtering function of the bandpass filter and simultaneously provide isolation characteristics through strategically positioned attenuation poles. This multi-functionality eliminates the need for additional isolation components, maintaining compact device size while achieving improved isolation.
Solution Approach 2:
By modifying the attenuation pole parameters of existing series resonators, the invention achieves improved isolation characteristics without adding physical components. The attenuation pole positions are strategically set to provide adequate isolation while maintaining the compact form factor required for device miniaturization.
3Reliability
If attenuation poles are positioned to improve isolation characteristics, then isolation characteristics with steep attenuation are achieved, but device complexity increases
Solution Approach 1:
The invention optimizes the attenuation pole parameters of series resonators to achieve steep attenuation and improved isolation characteristics. By carefully selecting the attenuation pole positions and values, the invention achieves superior isolation performance while maintaining a relatively simple filter structure that does not require additional components or complex circuit topologies.
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
This configuration achieves improved isolation characteristics with steep attenuation without increasing insertion loss and eliminates the need for additional elements, enabling more compact and efficient acoustic wave devices.
Implementation Method 1
a band pass filter with a plurality of series resonators and a plurality of parallel resonators
Implementation Method 2
an acoustic wave device includes a band pass filter having a plurality of series resonators and a plurality of parallel resonators
Data Source
AI summary
An acoustic wave device includes a band pass filter having a plurality of series resonators and a plurality of parallel resonators. The plurality of series resonators include a first series resonator and a second series resonator. The first series resonator has a first attenuation pole and a second attenuation pole having an attenuation amount that is less than or equal to half of that of the first attenuation pole. The second series resonator includes a third attenuation pole and a fourth attenuation pole. The third attenuation pole and the fourth attenuation pole has an attenuation amount less than that of the first attenuation pole and greater than that of the second attenuation pole.