Integrated Microwave Filter-Balun Coupling for Sharp Attenuation
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Solution Overview
Problem
Existing passive components for microwave bands face challenges in reducing size while maintaining sharp attenuation characteristics, especially when integrating unbalanced to balanced converters with filters in dielectric substrates, due to limitations in signal input/output systems and layout constraints.
Innovation Solution
A passive component with a simple structure that integrates a filter and an unbalanced to balanced converter in a dielectric substrate, using capacitive coupling between the filter and converter stages to prevent unwanted matching, allowing adjustable attenuation characteristics and reduced size through the use of ¼-wavelength resonators and strategically positioned capacitors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the filter and unbalanced to balanced converter are directly connected, then the structure is simpler, but unwanted matching occurs in the attenuation range producing unwanted peaks
Solution Approach 1:
A capacitor is introduced as an intermediary component between the filter output stage and the unbalanced to balanced converter input stage. This capacitor prevents direct connection while maintaining signal coupling, thereby eliminating unwanted matching and peaks in the attenuation range without significantly increasing structural complexity.
2Volume of moving object
If the filter and unbalanced to balanced converter are integrally combined in a dielectric substrate, then the component size is reduced, but the attenuation characteristics become less sharp
Solution Approach 1:
The capacitor serves as a mediator that enables integral combination of the filter and converter in a compact dielectric substrate while maintaining sharp attenuation characteristics. By controlling the capacitor's impedance and placement, the unwanted matching is prevented even in the integrated compact structure.
Solution Approach 2:
The impedance of the capacitor is specifically designed and adjusted to achieve the desired balance between compact size and sharp attenuation characteristics. By optimizing the capacitor's electrical parameters (capacitance value, impedance), the system achieves both small size and reliable attenuation performance.
3Adaptability or versatility
If a balun is used to connect balanced-input semiconductor component to unbalanced passage component, then the connection is enabled, but the size of the passage component increases
Solution Approach 1:
The unbalanced to balanced converter is merged with the filter into a single integrated component. This combination eliminates the need for separate balun components, enabling connection of balanced-input semiconductor components while keeping the overall passage component size reduced.
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
Enables flexible frequency characteristics, including gradual and sharp attenuation, and wide or narrow passbands, while reducing component size and loss, with increased design freedom for impedance settings, thus improving performance and adaptability across various environments.
Implementation Method 1
the filter and the unbalanced to balanced converter are connected to each other through a first capacitor, and the input stage of the filter and the input stage of the unbalanced to balanced converter are connected to each other through a second capacitor
Implementation Method 2
having at least one resonator
Data Source
AI summary
A passive component is provided with a filter section employing a nonequilibrium input/output system, which has an input side resonator connected to a nonequilibrium input terminal, and an output side resonator coupled with the input side resonator; and a converting section having two double line coupled lines. An output stage of the filter section is connected with an input stage of the converting section through a first capacitor, and an input stage of the filter section is connected with the input stage of the converting section through a second capacitor. Namely, the second capacitor functions as a jump capacitor. The position of an attenuation pole is permitted to be adjusted by a second capacitor in a region low in frequency characteristics.