High-Frequency Module Layout for Terminal Isolation in Compact RF Front Ends
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Solution Overview
Problem
The challenge is to maintain the degree of isolation between outer terminals in high-frequency modules, particularly in small-size and multi-band mobile communication devices, where reducing terminal spacing leads to decreased isolation.
Innovation Solution
A high-frequency module design featuring a multilayer board with strategically placed earth terminals and a ground electrode between transmission and reception filters, along with a switch that can simultaneously transmit and receive signals, while being integrated into the board to reduce size and maintain isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the distances between outer terminals are reduced to downsize the high-frequency module, then the module size is reduced, but the degree of isolation between outer terminals decreases
Solution Approach 1:
The patent utilizes the vertical dimension by providing a ground electrode between the transmission filter and reception filter in the thickness direction of the multilayer board. This three-dimensional arrangement allows terminals to be positioned closer in the planar direction while maintaining isolation through the added ground electrode layer, effectively resolving the contradiction between reduced module size and maintained terminal isolation.
2Quantity of substance
If the distances between outer terminals are reduced to increase packing density, then the packing density is improved, but the degree of isolation between outer terminals decreases
Solution Approach 1:
By introducing a ground electrode in the vertical dimension between the transmission and reception filters, the patent enables higher packing density in the planar direction without compromising isolation. The ground electrode acts as an additional isolation barrier that compensates for the reduced lateral spacing between terminals.
3Reliability
If a ground electrode is added between transmission filter and reception filter, then isolation between filters is improved, but device complexity increases
Solution Approach 1:
The ground electrode is integrated into the multilayer board structure itself, merging the isolation function with the existing board architecture. This approach provides filter isolation without requiring separate external components or complex additional structures, thus minimizing the increase in device complexity while achieving improved isolation.
Data Source
AI summary
A high-frequency module includes an antenna terminal, a transmission signal terminal, a reception signal terminal, a plurality of earth terminals, a switch, a transmission filter, a reception filter, and a multilayer board. The multilayer board includes a ground electrode arranged between the transmission filter and the reception filter. The plurality of earth terminals include a first earth terminal and a second earth terminal. When the high-frequency module is viewed in a direction perpendicular to a principal surface of the multilayer board, the reception signal terminal is provided between the antenna terminal and the transmission signal terminal, the first earth terminal is provided between the antenna terminal and the reception signal terminal, and the second earth terminal is provided between the reception signal terminal and the transmission signal terminal.