Non-reciprocal Circuit Device Thickness Reduction via Ferrite Integration
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Solution Overview
Problem
The challenge is to reduce the thickness and cost of non-reciprocal circuit devices such as isolators and circulators while maintaining their electric characteristics, as existing designs face limitations in size reduction due to the stacking of planar microwave ferrite members, strip line members, and permanent magnets, leading to increased insertion loss and narrowed passband width.
Innovation Solution
The solution involves a non-reciprocal circuit device structure with a metal case, a ground plate, a resin member, a planar microwave ferrite member, and a permanent magnet, where the permanent magnet is positioned directly on the strip line member without an additional ferrite member, using a partition member for precise magnetic field distribution and a gap adjustment to minimize dielectric loss, and incorporating microstrip lines and a grounded capacitor for impedance matching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple planar microwave ferrite members are stacked to achieve non-reciprocal function, then the electric characteristics (isolation, passband width) are maintained, but the device thickness increases
Solution Approach 1:
The patent combines the functions of multiple ferrite members into a single planar microwave ferrite member by integrating the non-reciprocal function directly into the strip line member structure. The strip line member itself serves as the ferrite component with non-reciprocal characteristics, eliminating the need for separate stacked ferrite members and reducing overall device thickness.
Solution Approach 2:
The strip line member is designed to perform multiple functions simultaneously: it serves as both the transmission line structure and the non-reciprocal ferrite component. This multi-functional design integrates the resonator, impedance transformer, and non-reciprocal element into a single component, reducing the number of stacked layers required.
2Reliability
If multiple components are stacked to achieve non-reciprocal function, then the desired isolation and passband characteristics are obtained, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent merges the strip line member and ferrite member into a single integrated component. The strip line member is constructed with a specific three-layer structure (conductor layers separated by dielectric layers) that inherently provides both the transmission line function and the non-reciprocal ferrite function, eliminating the need for separate components and simplifying the overall device structure.
Solution Approach 2:
The strip line member is segmented into three functional layers (first conductor layer, dielectric layer, second conductor layer) where each layer contributes to the overall non-reciprocal function. This segmentation allows the non-reciprocal characteristics to be distributed across multiple layers within a single component rather than requiring multiple separate stacked components.
3Reliability
If multiple planar microwave ferrite members are stacked, then non-reciprocal function is achieved, but the insertion loss increases
Solution Approach 1:
By combining the non-reciprocal function into the strip line member itself rather than using separate stacked ferrite members, the patent reduces the number of interfaces and connections between components. This integration minimizes signal reflection and insertion loss while maintaining the non-reciprocal function, as there are fewer discrete components for the signal to pass through.
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 a reduced thickness without compromising electric characteristics, such as insertion loss, passband width, and isolation, while allowing for cost-effective production due to a simpler structure.
Implementation Method 1
a permanent magnet disposed on the strip line member with a certain distance therebetween without another planar microwave ferrite member therebetween
Implementation Method 2
the polarization plane of the high-frequency magnetic field rotates when passing through the planar microwave ferrite members 7, 7, giving an output only to a predetermined branched line 8a, 8b, 8c (exhibiting non-reciprocality)
Implementation Method 3
When current is supplied to the strip line member 8, a high-frequency magnetic field is generated from the disc-shaped microwave ferrite members 7, 7 such that it surrounds the strip line member 8
Data Source
Figure 1~14
Figure 2~3
Figure 4~6
AI summary
A non-reciprocal circuit device comprising a metal case (9), a ground plate (6) disposed on an inner bottom surface of the metal case (9), a resin member (10) disposed on the ground plate (6) and having an opening from which the ground plate (6) is exposed, a planar microwave ferrite member (7) disposed in the opening of the resin member (10), a strip line member (8) disposed on the planar microwave ferrite member (7), and a permanent magnet (4) disposed with distance on the strip line member (8) without another planar microwave ferrite member (7) therebetween, the strip line member (8) comprising a connecting portion constituted by strip electrodes radially extending from a center portion, and branch lines radially extending from the center portion between the strip electrodes.