Multiband Coupling Circuit Using Identical Distributed Elements
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Solution Overview
Problem
Multiband radio transceiver systems face challenges in manufacturing complexity and directivity variations due to the need for different coupler sizes for various frequency bands, leading to stray reflections and measurement errors.
Innovation Solution
A distributed multiband coupling circuit with identical couplers sized for the highest frequency band, using resistive splitters and attenuators to maintain consistent directivity across all bands, and a common circuit for measuring information sampled from the third port.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If different sized couplers are used for each frequency band, then each coupler can be optimized for its specific band, but manufacturing complexity increases and directivity varies across bands
Solution Approach 1:
The patent employs a single universal coupler design that operates across multiple frequency bands (e.g., GSM 900, GSM 1800, UMTS 2100) without requiring separate optimized couplers for each band. This universal coupler maintains consistent directivity performance across all bands, eliminating the need for multiple band-specific coupler designs and their associated manufacturing complexities.
2Ease of manufacture
If coupler size is reduced for lower frequency bands, then manufacturing becomes easier, but directivity performance deteriorates
Solution Approach 1:
The patent utilizes variable electrical length parameters within the coupler design to adapt its performance across different frequency bands. By adjusting the electrical length of transmission lines and reactive elements, the coupler maintains optimal directivity performance across a wide frequency range without requiring physical size changes, thus preserving both manufacturing simplicity and performance.
3Object-generated harmful factors
If port matching is improved, then stray reflections are reduced, but measurement precision requirements increase
Solution Approach 1:
The patent introduces resistive splitters as intermediary elements between the coupler ports and the measurement system. These resistive splitters provide impedance transformation and isolation, improving port matching and reducing stray reflections without requiring extremely precise matching conditions. The resistive elements act as mediators that tolerate broader manufacturing tolerances while still achieving low reflection levels.
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 reduces manufacturing complexity, improves measurement reliability by minimizing the impact of matching variations, and achieves consistent directivity across multiple frequency bands, reducing stray reflections and enhancing signal integrity.
Implementation Method 1
a distributed multiband coupling circuit comprising: a number n of first and of second terminals equal to the number of frequency bands; a third terminal and a fourth terminal; a number n of distributed couplers equal to the number of frequency bands, all couplers being identical and sized according to the highest frequency band, and each coupler comprising a first conductive line between first and second ports intended to convey a signal to be transmitted in the concerned frequency band, and a second conductive line coupled to the first one between third and fourth ports
Data Source
AI summary
A distributed multiband coupling circuit including: a number n of first and of second terminals equal to the number of frequency bands; a third terminal and a fourth terminal; a number n of distributed couplers equal to the number of frequency bands, all couplers being identical and sized according to the highest frequency band, and each coupler including a first conductive line between first and second ports intended to convey a signal to be transmitted in the concerned frequency band, and a second conductive line coupled to the first one between third and fourth ports; a first set of resistive splitters in cascade between the third ports of the couplers, a terminal of the splitter associated with the first coupler being connected to the third terminal of the coupling circuit; and a second set of resistive splitters in cascade between the fourth ports of the couplers, a terminal of the splitter associated with the first coupler being connected to the fourth terminal of the coupling circuit.