Integrated Balun Filter Resonator Design for RF Impedance Matching
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Solution Overview
Problem
In RF systems, the individual design and series connection of balun converters and band pass filters lead to impedance matching issues, increased transmission loss, and a larger required circuit area, reducing antenna gain.
Innovation Solution
A balun filter that integrates both balun conversion and filtering functions, utilizing a fence-type band pass filter with resonators and line segments to achieve impedance matching and balanced signal conversion, allowing for a single functional block that reduces circuit area and transmission loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the balun converter and band pass filter are designed individually and connected in series, then each component can be optimized independently, but the impedance matching problem occurs and the system performance is reduced
Solution Approach 1:
The patent combines the balun converter and band pass filter into a single integrated device where the resonators perform both filtering and balun conversion functions simultaneously, eliminating the impedance matching problems that occur when separate components are connected in series
Solution Approach 2:
The resonators in the integrated device serve multiple functions: they act as filtering elements for the band pass filter and simultaneously provide balun conversion capability, allowing one component to perform what previously required two separate components
2Adaptability or versatility
If the balun converter and band pass filter are connected in series, then both functions are achieved, but the circuit area is expanded
Solution Approach 1:
The patent merges the balun converter and band pass filter into a single integrated structure that occupies a smaller circuit area compared to having two separate components connected in series
Solution Approach 2:
The resonators are designed to provide both filtering and balun conversion functions within a single component footprint, reducing the overall circuit area required
3Ease of operation
If the transmission line between balun converter and band pass filter is too long, then the components can be connected, but the loss on transmission is increased and antenna gain is reduced
Solution Approach 1:
By integrating the balun converter and band pass filter into a single device, the patent eliminates the need for a transmission line connecting separate components, thereby removing the transmission loss that would occur over a long connection line
4Ease of manufacture
If the balun converter and band pass filter are designed individually, then each component can be optimized, but the device complexity is increased
Solution Approach 1:
The patent combines two separate components into one integrated device, reducing the overall system complexity and the number of interconnections required, while still allowing optimization of the resonator design to achieve both filtering and balun conversion performance
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 integrated balun filter effectively converts single-end signals to differential signals with reduced reflection loss and enhanced impedance matching, minimizing the required circuit area and improving antenna gain.
Implementation Method 1
the band pass filter including a plurality of resonators, each resonator including a surrounding line
Data Source
AI summary
A balun filter utilized for a radio-frequency (RF) system includes a first terminal coupled to an antenna of the RF system for delivering an RF signal; a differential port has a second terminal and a third terminal for delivering a differential signal; a band pass filter coupled between the first terminal and the differential port has a plurality of resonators, each including a surrounding line substantially surrounding an area and forming a loophole on a side of the each resonator; and at least a line segment connected to the surrounding line and disposed separately within the area surrounded by the surrounding line.