Orthogonal Inductor Filter Device for Multi-Mode Cellular Attenuation
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Solution Overview
Problem
Existing filter devices for multi-band and multi-mode cellular phones face challenges in improving attenuation characteristics while maintaining a compact size, as the arrangement of inductors on a rectangular substrate increases the device's area, making it difficult to reduce size effectively.
Innovation Solution
A filter device with a ladder filter and inductors is designed using a multilayer substrate, where the first and second inductors are mounted adjacent to each other with orthogonal coil axes, and the third inductor is incorporated within the substrate, allowing for size reduction and improved attenuation characteristics by controlling coupling coefficients between inductors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two chip inductors are arranged in the vicinity of different side surfaces of the filter chip to adjust coupling degree, then attenuation characteristics are improved, but the area of the substrate becomes large
Solution Approach 1:
The patent transitions from a two-dimensional planar arrangement of inductors on the substrate surface to a three-dimensional configuration where inductors are embedded within the multilayer substrate structure. This vertical integration allows inductors to be positioned closer together while maintaining proper coupling, thereby reducing the overall substrate area required.
Solution Approach 2:
The patent embeds inductors within the multilayer substrate structure, nesting them inside the filter device housing rather than placing them externally on the substrate surface. This nesting approach consolidates the device footprint by utilizing the internal volume of the substrate layers.
2Reliability
If chip inductors are mounted on the substrate to improve filter performance, then attenuation characteristics are improved, but the device complexity increases
Solution Approach 1:
The patent combines multiple inductor functions into a single integrated multilayer substrate structure. Rather than using separate discrete chip inductors mounted on the substrate, the inductors are formed as integral parts of the substrate layers, merging the substrate and inductor components into one unified structure.
Solution Approach 2:
The multilayer substrate serves multiple functions simultaneously: it provides mechanical support, electrical connections, and hosts the inductor structures. This multi-functionality reduces the need for separate components and simplifies the overall device architecture while maintaining the required attenuation characteristics.
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 enhances attenuation characteristics outside the passband, ensures isolation between filters, and reduces the overall size of the filter device, enabling efficient performance in multi-band and multi-mode communication systems.
Implementation Method 1
the first inductor and the second inductor are not inductively coupled to each other because the coil axis of the first inductor and the coil axis of the second inductor are orthogonal or substantially orthogonal to each other
Implementation Method 2
a third inductor which is provided in series in a channel connecting the parallel resonator and ground, wherein the third inductor is incorporated in a multilayer substrate
Data Source
AI summary
A filter device includes a first filter including series resonators and parallel resonators, a first inductor connected in parallel between a first terminal and the first filter, a second inductor provided in series between the first filter and a second terminal, and a third inductor provided in series in a channel connecting the parallel resonator and ground, the third inductor is incorporated in a multilayer substrate, the first filter is mounted on a main surface of the multilayer substrate and incorporated in a filter chip, and the first inductor and the second inductor are chip inductors including coil conductors and are mounted on the main surface of the multilayer substrate beside the filter chip so as to be adjacent to each other and such that coil axes thereof are orthogonal or substantially orthogonal to each other.