Switch Module Isolation via Multilayer Ground Shielding
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Solution Overview
Problem
In switch modules that use a common antenna for transmitting and receiving multiple communication signals, electromagnetic field coupling between the lead wiring lines of the common-port-side circuit and the switching-port-side circuits degrades isolation characteristics and attenuates harmonic components, particularly due to the close arrangement of circuit elements and lead wiring lines.
Innovation Solution
A switch module design that includes a multilayer substrate with a second wiring portion between the common-port-side circuit and the filter circuit, which reduces or prevents electromagnetic field coupling by spacing the common-port-side circuit and the first wiring portion apart, improving isolation and attenuation characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If circuit elements and lead wiring lines are arranged closely to reduce module size, then area is reduced, but electromagnetic field coupling increases causing degraded isolation characteristics
Solution Approach 1:
A ground electrode is introduced as an intermediary element positioned between the common-port-side circuit and switching-port-side circuits. This ground electrode acts as a shield that blocks electromagnetic field coupling between the circuits, allowing them to be arranged closely without degrading isolation characteristics
Solution Approach 2:
The solution moves from two-dimensional planar arrangement to three-dimensional spatial configuration by utilizing vertical layering in a multilayer substrate. Circuit elements are distributed across multiple layers with ground electrodes positioned in intermediate layers, enabling close integration while maintaining isolation through spatial separation
2Device complexity
If lead wiring lines are arranged closely to improve integration, then device complexity is reduced, but attenuation of harmonic components decreases
Solution Approach 1:
The ground electrode serves as a protective intermediary that prevents electromagnetic interference from affecting the filter circuit's ability to attenuate harmonic components, ensuring reliable signal filtering even in closely integrated configurations
Solution Approach 2:
The ground electrode is positioned in advance between the circuits to preemptively block electromagnetic field paths, preventing coupling before it can degrade the filter circuit's attenuation performance
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 significantly reduces electromagnetic field coupling, enhancing the isolation and attenuation performance of the switch module, thereby improving the overall efficiency of signal transmission and reception.
Implementation Method 1
electromagnetic field coupling between the lead wiring line of a common-port-side circuit and switching-port-side circuits
Implementation Method 2
The switching-port-side circuit 107A, which is connected to the low-frequency-side transmission terminal LTx, is formed as a low pass filter that removes the harmonic components of a low-frequency-side transmission signal
Data Source
AI summary
A switch module includes a multilayer substrate including an antenna terminal, a ground terminal, and a high-frequency-side transmission signal terminal, as external connection terminals. A common-port-side circuit, a switch circuit, and a switching-port-side circuit are provided between the antenna terminal and the high-frequency-side transmission signal terminal. A first wiring portion connects a second inductor that defines a portion of the switching-port-side circuit to the high-frequency-side transmission signal terminal. When the multilayer substrate is viewed in plan, a first inductor, the second inductor, and via electrodes connected to the ground terminal are arranged between the first wiring portion, and second and third wiring portions and a capacitor which are connected to the antenna terminal.