RF Module Bonding Wire Shielding for Magnetic Coupling
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Solution Overview
Problem
The increasing complexity of radio-frequency module layouts in mobile communication devices leads to magnetic coupling between transmitting and receiving circuits, causing degradation in reception sensitivity due to high-power radio-frequency signals, harmonic components, and intermodulation distortion.
Innovation Solution
Incorporating a bonding wire connected to the ground that bridges over the first inductor in the transmitting circuit, providing a shielding effect to suppress magnetic coupling between the inductance components of the transmitting and receiving circuits, thereby improving isolation characteristics and maintaining reception sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the transmitting circuit and receiving circuit are disposed close to each other to achieve compact module size, then the module area is reduced, but magnetic coupling occurs between inductance components causing reception sensitivity degradation
Solution Approach 1:
A bonding wire connected to ground is introduced as an intermediary element between the transmitting and receiving circuits. This bonding wire acts as a magnetic shield that intercepts and redirects magnetic field lines, preventing direct magnetic coupling between the inductance components of the transmitting and receiving circuits while allowing the circuits to remain in close proximity
Solution Approach 2:
The bonding wire, which is necessarily present for electrical connections in the compact module layout, is strategically positioned to bridge over the inductor in the receiving circuit. This converts the bonding wire from a mere electrical connector into a dual-function element that also provides magnetic shielding, turning a potential source of interference into a protective element
2Reliability
If magnetic shielding is added to suppress magnetic coupling, then reception sensitivity is maintained, but device complexity increases
Solution Approach 1:
The bonding wire is designed to serve multiple functions simultaneously: it provides necessary electrical grounding connections and also acts as a magnetic shield. This multi-functional design eliminates the need for separate shielding structures, maintaining reception sensitivity without increasing overall device complexity
Solution Approach 2:
The bonding wire performs self-service by using its own physical presence and ground connection to provide magnetic shielding functionality. The same structural element that is required for electrical connectivity automatically provides electromagnetic interference protection, requiring no additional components or complex shielding mechanisms
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 configuration effectively reduces magnetic coupling, enhancing the isolation between the transmitting and receiving circuits and preventing signal interference, thus maintaining or improving the reception sensitivity of the radio-frequency module.
Implementation Method 1
The bonding wire bridges over the first inductor. The configuration effectively reduces magnetic coupling, enhancing the isolation between the transmitting and receiving circuits
Data Source
AI summary
A radio-frequency module includes: a transmitting circuit disposed on a mounting substrate to process a radio-frequency signal input from a transmission terminal and to output a resultant signal to a common terminal; a receiving circuit disposed on the mounting substrate to process a radio-frequency signal input from the common terminal and to output a resultant signal to a reception terminal; a first inductor included in a first transmitting circuit; and a bonding wire connected to the ground and bridging over the first inductor.