Multilayer Balanced Filter Layout for Compact Impedance Conversion
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Solution Overview
Problem
Conventional multilayer band pass filters with balanced-unbalanced conversion functions face challenges in reducing size and achieving easy impedance conversion between unbalanced and balanced terminals, requiring additional space for impedance conversion circuits.
Innovation Solution
A multilayer balanced filter design featuring a stack of dielectric and electrode layers with specific configurations of straight-line electrodes, coils, and capacitors, allowing for vertical conduction electrodes and adjustable coupling between electrodes to facilitate balanced-unbalanced conversion and impedance matching, thereby reducing size and enhancing design flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional multilayer band pass filter uses 1/2-wavelength resonators arranged on the same surface to achieve balanced-unbalanced conversion, then the filter can realize balanced-unbalanced conversion function, but the device size cannot be easily reduced and additional area is required for impedance conversion circuits
Solution Approach 1:
The patent transitions from planar arrangement of resonators to a three-dimensional stacked configuration. Multiple resonators are arranged in different layers vertically, allowing electromagnetic coupling through vertical vias. This dimensional change enables compact integration of balanced-unbalanced conversion functionality without requiring additional planar area, directly resolving the contradiction between functional versatility and device size.
Solution Approach 2:
The patent combines the resonator structures with impedance conversion functionality into a single integrated system. The resonators in different layers are electromagnetically coupled through vertical conduction electrodes, merging the signal processing and impedance transformation functions into one compact structure, eliminating the need for separate impedance conversion circuits and reducing overall device area.
2Ease of operation
If a conventional multilayer band pass filter uses additional impedance conversion circuits to achieve appropriate impedance conversion between unbalanced and balanced terminals, then the filter can realize impedance matching, but the device size increases due to additional circuit area
Solution Approach 1:
The resonator structures serve multiple functions simultaneously: they provide signal resonance, enable balanced-unbalanced conversion through electromagnetic coupling, and perform impedance transformation. This multi-functionality eliminates the need for dedicated impedance conversion circuits, achieving ease of operation for impedance matching while avoiding the area penalty of additional components.
Solution Approach 2:
The patent merges impedance conversion functionality into the resonator coupling structure itself. The vertical conduction electrodes and dielectric layers that form the resonators also serve as the impedance transformation path between unbalanced and balanced terminals, combining multiple functions into a single integrated structure.
3Reliability
If a conventional multilayer band pass filter uses multiple 1/2-wavelength resonators arranged in a line to achieve filter characteristics, then the filter can realize band pass characteristics, but the device complexity increases and design flexibility for impedance conversion is limited
Solution Approach 1:
The patent arranges resonators in a three-dimensional stacked configuration rather than a linear planar arrangement. This vertical stacking with electromagnetic coupling through layers simplifies the interconnection structure and provides greater design flexibility for impedance conversion, while maintaining the necessary filter characteristics through controlled electromagnetic interaction between layers.
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 design achieves compact size and precise impedance conversion, allowing for a wider passband and easier adjustment of coupling strength, while reducing the number of ground electrodes and stack height, thus enabling efficient balanced-unbalanced signal processing.
Implementation Method 1
the ground electrode and the first capacitor electrode constitute a first capacitor, the ground electrode and the second capacitor electrode constitute a second capacitor, and the ground electrode and the third capacitor electrode constitute a third capacitor
Implementation Method 2
an LC parallel resonator is defined by the first coil and the first capacitor; a second coil is connected to a first end of the second straight line electrode via the vertical conduction electrode, and a third coil is connected to a second end of the second straight line electrode via the vertical conduction electrode
Data Source
AI summary
A multilayer balanced filter includes a first coil including a first straight line electrode and via electrodes. A first capacitor, a second capacitor, and a third capacitor are provided respectively between a ground electrode and a first capacitor electrode, between the ground electrode and a second capacitor electrode, and between the ground electrode and a third capacitor electrode. The first coil and the first capacitor constitute an LC resonator. A second straight line electrode is arranged in parallel or substantially in parallel with the first straight line electrode, and a second coil and a third coil, each having a loop plane perpendicular or substantially perpendicular to the loop plane of the first coil, are provided. A second capacitor and a third capacitor are respectively connected between balanced output terminals and the ground.