High-frequency module impedance matching via shortened wiring
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Solution Overview
Problem
Existing high-frequency modules face challenges in achieving sufficient impedance matching across a wide frequency band due to parasitic capacitance and increased insertion loss, particularly with the use of band-pass-filter-type matching circuits and decreasing component sizes.
Innovation Solution
A high-frequency module design featuring a multilayer body with a surface-mount inductor and shorter, narrower wiring lines between the switch IC's common terminal and antenna connection terminal, positioned to minimize parasitic capacitance by avoiding overlap with inner-layer ground and using a spiral inductor configuration to reduce coupling with the ground.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a band-pass-filter-type matching circuit with a series-connected inductor is used to cancel off capacitance, then impedance matching is achieved in a specific frequency band, but impedance matching is not achieved for high-frequency band communication signals and insertion loss increases
Solution Approach 1:
The patent changes the configuration parameters of the matching circuit by replacing the series-connected inductor with a parallel-connected inductor and adjusting the capacitance values. This parameter change enables the circuit to achieve impedance matching across a wider frequency range including high-frequency bands, while maintaining low insertion loss through optimized component values that account for parasitic capacitance effects.
Solution Approach 2:
The patent transitions from a one-dimensional series connection to a two-dimensional parallel connection topology for the inductor, and introduces multiple capacitance elements arranged in different configurations. This dimensional change in circuit topology provides additional degrees of freedom for impedance matching, enabling simultaneous optimization for multiple frequency bands.
2Volume of moving object
If component sizes are decreased to reduce module size, then module dimensions are reduced, but parasitic capacitance effects increase and degrade impedance matching characteristics
Solution Approach 1:
The patent compensates for increased parasitic capacitance in miniaturized components by adjusting the capacitance values in the matching circuit. Specifically, the capacitance elements are designed with values that account for the parasitic effects inherent in small-sized components, thereby maintaining accurate impedance matching despite the reduced component dimensions.
Solution Approach 2:
The patent replaces traditional discrete component layouts with an integrated circuit design where the matching circuit is formed as a printed circuit board pattern. This substitution eliminates the need for separate discrete components with associated parasitic effects, and the distributed capacitance of the PCB traces is incorporated into the overall circuit design to achieve accurate matching in compact form factors.
3Reliability
If a large capacitance capacitor is used to achieve matching in a specific frequency band, then matching is achieved in that band, but the cutoff frequency of the low-pass filter decreases and insertion loss increases on the high-frequency side
Solution Approach 1:
The patent divides the matching function into multiple separate capacitance elements rather than using a single large capacitance capacitor. This segmentation allows each capacitor to be optimized for specific frequency ranges, with the combined effect providing broadband impedance matching while maintaining low insertion loss across the entire operating band including high-frequency regions.
Solution Approach 2:
The patent optimizes the capacitance values of individual capacitor elements to achieve the desired impedance matching characteristics. By carefully selecting capacitance values that are smaller than what would be required in a single-capacitor design, the patent maintains the low-pass filter's high-frequency cutoff characteristics while still achieving accurate matching across the target frequency band.
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 favorable transmission characteristics and impedance matching across a wide frequency band while reducing insertion loss, enhancing the module's performance and size efficiency.
Implementation Method 1
a first inductor which is connected in series between the common terminal of the switch IC and the antenna connection terminal
Implementation Method 2
cancelling of an off capacitance causes an inductance value to increase
Implementation Method 3
a parasitic capacitance between a common terminal of a switch IC and an antenna connection terminal connected to the common terminal affects the impedance characteristics
Data Source
AI summary
A high-frequency module includes a switch IC and a matching circuit. The high-frequency module includes a multilayer body. The switch IC and an inductor of the matching circuit are mounted on a top surface of the multilayer body. A top-surface land electrode on which a common terminal of the switch IC is mounted is connected to one end of a wiring conductor through a via-conductor. The other end of the wiring conductor is connected to a top-surface land electrode on which a terminal electrode at one end of the inductor is mounted, through a via-conductor. An end portion of the inductor on the side connected to the common terminal of the switch IC is disposed near the common terminal. Thus, the length of the wiring conductor is shortened and a parasitic capacitance is decreased.