Cavity Multiplexer Coupler Structure for Wideband Low-Loss Filtering
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current multiplexers and small size filters face challenges with edge loss, group delay, and limited bandwidth, especially in high frequency bands, due to the reflection of adjacent channels and the need for additional volume to integrate low pass filters.
Innovation Solution
A communication device with a wideband coupling structure is proposed, featuring a housing with a common port and multiple secondary ports, cavity filters with resonators, and a coupler that forms a low pass filter by using a conductive bar with varying resistance portions and a metal sheet comb structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If traditional small size filters are used, then the filter size and weight are reduced, but the bandwidth is limited and high frequency performance is poor
Solution Approach 1:
The patent transitions from traditional single-dimension coupling structures to a three-dimensional coupling structure where the coupler extends into the cavity space. This dimensional change allows for increased coupling bandwidth without increasing the overall filter footprint, effectively resolving the contradiction between compact size and wide bandwidth capability
Solution Approach 2:
The coupler is nested within the cavity structure, with the conductive bar positioned inside the cavity volume. This nesting approach maximizes the use of available internal space to achieve wideband coupling without increasing the external dimensions of the filter, maintaining compact size while improving bandwidth
2Reliability
If directional or isolating elements (Isolator or hybrid) are added to multiplexers, then performance is improved, but additional insertion losses occur
Solution Approach 1:
The patent removes the need for separate directional or isolating elements by integrating their functionality directly into the coupler structure. The coupler is designed with asymmetric coupling characteristics that provide isolation and directionality inherently, eliminating additional components that would contribute to insertion loss while maintaining the required performance
3Device complexity
If multiple cavity filters are combined without directional elements, then device complexity is reduced, but edge loss and group delay vary greatly due to reflection
Solution Approach 1:
The patent merges the functions of multiple cavity filters through a unified coupler structure that provides both coupling and isolation functionality. The conductive bar couples all cavity filters to the common port while its specific geometry and positioning provide inherent isolation between cavities, reducing reflections and stabilizing group delay without requiring additional directional elements
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 provides effective suppression of high frequency harmonics, supports multiple channels with a relative bandwidth of over 7%, and allows for flexible channel merging, while maintaining low loss and compact, lightweight design.
Implementation Method 1
a resonator arranged in each cavity
Implementation Method 2
The coupler comprises at least one low resistance portion and at least one high resistance portion
Data Source
AI summary
The present disclosure relates to a communication device such as a multiplexer or a demultiplexer, comprising: a housing comprising a common first port and a plurality of second ports; a plurality of cavity filters for transmitting a wireless signal between the first port and a corresponding one of the second ports, each of the plurality of cavity filters comprising one or more cavities formed in the housing and a resonator arranged in each cavity; and a coupler for coupling the first port to each cavity filter. The coupler is arranged in one cavity of each cavity filter, and is coupled to the resonator in the one cavity.