RF Module Grounded Shield Plate for Electromagnetic Isolation
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Solution Overview
Problem
Electromagnetic coupling between circuit components in radio-frequency modules of mobile communication devices leads to signal quality deterioration, reduced isolation, and interference, particularly due to harmonic and spurious waves.
Innovation Solution
A radio-frequency module design incorporating a module substrate with a metal shield plate and via-conductor, connected to a ground potential, to reduce electromagnetic coupling between circuit components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If circuit components are disposed in transmit path, receive path, and transmit/receive path without additional shielding, then device complexity is reduced, but electromagnetic coupling occurs between components leading to signal quality deterioration
Solution Approach 1:
A metal shield plate is introduced as an intermediary component between the transmit path components (power amplifier, transmit filter) and receive path components (low-noise amplifier, receive filter). This shield plate, connected to ground potential, acts as a mediator that blocks electromagnetic coupling between the transmit and receive paths, preventing harmonic waves and spurious signals from interfering with receive signals while maintaining the integrated circuit arrangement.
Solution Approach 2:
The radio-frequency module is segmented into distinct electromagnetic zones using the metal shield plate, which divides the circuit board into transmit path regions and receive path regions. This segmentation isolates high-power transmit components from sensitive receive components, allowing each path to operate independently without mutual interference, thus resolving the electromagnetic coupling issue while maintaining component integration.
2Power
If power amplifier operates at high output power, then transmit signal strength is improved, but harmonic wave components are generated that deteriorate signal quality
Solution Approach 1:
The metal shield plate, connected to ground potential, converts the harmful electromagnetic energy from harmonic waves and spurious signals generated by the high-power amplifier into harmless ground current. By providing a low-impedance ground path, the shield plate directs the harmful electromagnetic radiation away from sensitive receive components, effectively neutralizing the harmful effects while allowing the power amplifier to operate at high output power for strong transmit signals.
3Area of stationary object
If transmit and receive components are placed close together, then device area is reduced, but isolation between transmit and receive sides decreases allowing signal leakage
Solution Approach 1:
The metal shield plate serves as a ground-connected intermediary barrier placed between closely spaced transmit and receive components. This thin metallic barrier, when connected to ground potential, effectively blocks electromagnetic field coupling between adjacent circuits, maintaining high isolation between transmit and receive paths even when components are positioned close together to minimize the overall module area.
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
Enhances signal isolation and reduces signal interference, improving the quality of transmit and receive signals by minimizing electromagnetic coupling and leakage.
Implementation Method 1
a metal shield plate 70 that is disposed over the major face 91a and, with the module substrate 91 seen in plan view, located between the first circuit component and the second circuit component
Data Source
AI summary
A radio-frequency module includes: a module substrate having a major face; a first circuit component and a second circuit component that are disposed over the major face; a resin component that covers the first circuit component and the second circuit component; a metal shield layer that covers a surface of the resin component; a metal shield plate that is disposed over the major face and, with the module substrate seen in plan view, located between the first circuit component and the second circuit component; and a via-conductor disposed in the module substrate and set to a ground potential. The metal shield plate is in contact with the metal shield layer, and connected at the major face with the via-conductor. The metal shield plate has a thickness greater than a thickness of the metal shield layer and less than or equal to an outside diameter (of the via-conductor.