High Frequency Module Duplexer Isolation via Receive-Only Filter Placement
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Solution Overview
Problem
In high-density mounted mobile communication terminals, achieving sufficient isolation between transmission and reception signals is challenging due to electromagnetic coupling, especially in miniaturized designs where physical separation is difficult.
Innovation Solution
A high frequency module is designed with a duplexer having transmission and reception filters, a receive-only filter, and a power amplifier, where the receive-only filter is strategically placed between the power amplifier and the duplexer to enhance isolation characteristics between transmission and reception signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If physical distance is increased between components to reduce electromagnetic coupling, then isolation characteristics improve, but device area increases
Solution Approach 1:
A ground wall structure is introduced as an intermediary element between the power amplifier and duplexer components. This ground wall acts as a shield that blocks electromagnetic coupling paths without requiring increased physical separation between components, thereby improving isolation characteristics while maintaining compact device area
Solution Approach 2:
The harmful electromagnetic coupling effect is extracted and redirected by introducing a ground wall that captures and grounds the interfering signals. This separates the transmission and reception signal paths by providing a dedicated grounding structure that prevents mutual interference without increasing overall device dimensions
2Area of stationary object
If high-density mounting is implemented to reduce device size, then device miniaturization is achieved, but electromagnetic coupling between components increases
Solution Approach 1:
The ground wall serves as a mediating structure that enables high-density mounting by providing localized electromagnetic shielding between closely-spaced components. This allows components to be mounted in high-density configurations while the ground wall prevents harmful electromagnetic coupling from developing
Solution Approach 2:
Instead of uniformly increasing distance between all components, the ground wall provides localized electromagnetic shielding precisely where needed between the power amplifier and duplexer. This enables high-density mounting in areas not requiring shielding while maintaining isolation where electromagnetic coupling would be problematic
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 solution effectively improves the isolation characteristics between transmission and reception signals by about 2 dB, mitigating electromagnetic coupling issues in compact designs, thereby maintaining signal integrity in multi-frequency band and multi-mode communication systems.
Implementation Method 1
a receive-only filter, a frequency band of a second reception signal having a frequency band different from the frequency band of the first reception signal being defined as a pass band of the receive-only filter
Implementation Method 2
a transmission filter, a frequency band of a transmission signal being defined as a pass band of the transmission filter and a frequency band of a first reception signal being defined as a stop band of the transmission filter
Implementation Method 3
a reception filter, the frequency band of the transmission signal being defined as a stop band of the reception filter and the frequency band of the first reception signal being defined as a pass band of the reception filter
Implementation Method 4
a power amplifier that power-amplifies the transmission signal
Data Source
AI summary
A high frequency module includes a duplexer that includes a transmission filter, a receive-only filter, and a power amplifier that power-amplifies a transmission signal. In order to improve the isolation characteristics between a transmission signal and a reception signal at the duplexer, the receive-only filter is arranged between the power amplifier and the duplexer.