Bulk Wave Band Elimination Filter for Intermodulation Noise Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional communication devices experience noise due to intermodulation distortion when transmitting signals in multiple frequency bands simultaneously, as transmission signals from one band can interfere with duplexers or triplexers handling other bands, leading to unwanted signal intrusion and noise.
Innovation Solution
A communication device is equipped with a band elimination filter featuring a bulk wave element and a ladder circuit configuration, connected between the antenna terminal and a multiplexer, which eliminates signals from different frequency bands, thereby reducing intermodulation distortion by ensuring that transmission and reception signals in one band do not intrude into another.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple transmission signals are transmitted at the same time in different frequency bands, then communication capability in multiple frequency bands is improved, but intermodulation noise occurs between transmission signals
Solution Approach 1:
A band elimination filter is introduced as an intermediary component between the antenna terminal and the duplexer/triplexer. This filter selectively eliminates transmission signals from specific frequency bands before they can enter other duplexers or triplexers, thereby preventing intermodulation noise while allowing simultaneous multi-band communication to proceed
Solution Approach 2:
The frequency spectrum is segmented into different bands, and a dedicated band elimination filter is used to separate and eliminate signals from specific frequency bands. This segmentation approach allows the system to handle multiple frequency bands simultaneously while preventing harmful interactions between them
2Object-generated harmful factors
If a band elimination filter using a surface acoustic wave element is connected to eliminate signals of other frequency bands, then noise suppression is improved, but the filter size increases and manufacturing complexity increases
Solution Approach 1:
The patent replaces the conventional surface acoustic wave element with a bulk wave element (such as a bulk acoustic wave resonator or filter). This substitution maintains the band elimination function while reducing the physical size and simplifying the manufacturing process, as bulk wave elements can be integrated more easily into compact device structures
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 effectively reduces or prevents intermodulation noise, enhancing the quality of reception signals by ensuring that signals from other frequency bands are eliminated, thus minimizing interference and improving communication quality.
Implementation Method 1
A band elimination filter is provided with a filter circuit including a bulk wave element. The band elimination filter eliminates signals of a frequency band different from a frequency band of signals transmitted and received in the first multiplexer.
Implementation Method 2
The band elimination filter preferably includes a ladder circuit.
Data Source
AI summary
A communication device is provided with a band elimination filter that has one end connected to an antenna terminal, and a first multiplexer that is connected to the other end of the band elimination filter. The band elimination filter is configured to eliminate signals of a frequency band that is different from the frequencies of signals transmitted and received in the first multiplexer, and is configured from a filter circuit that includes a bulk wave element.