Diplexer Filter Resonator Layout for Non-Passband Attenuation
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Solution Overview
Problem
Existing diplexers face challenges in achieving sufficient attenuation characteristics in the non-passband, particularly when the passbands of the high-band and low-band filters are proximate to each other.
Innovation Solution
The filter apparatus includes a first filter with a closed-loop resonator in the high-band filter and a non-loop resonator in the low-band filter, each with multiple stages, connected between two ground electrodes, to enhance attenuation characteristics in the non-passband.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional LC resonance circuits are used in both high-band and low-band filters, then the device complexity is reduced and ease of manufacture is improved, but the attenuation characteristics in the non-passband deteriorate when passbands are proximate
Solution Approach 1:
The patent applies different resonator configurations to different frequency bands: the high-band filter uses closed-loop resonators while the low-band filter uses non-loop resonators. This local differentiation optimizes attenuation characteristics for each specific frequency range without requiring complete redesign of the entire filter system, thus improving reliability while maintaining reasonable manufacturing complexity.
Solution Approach 2:
The filter system is segmented into distinct high-band and low-band filters with different resonator topologies. Each band is independently optimized with appropriate resonator types, allowing the system to achieve superior attenuation characteristics in the non-passband region between the two passbands while maintaining ease of manufacture for each individual filter section.
2Reliability
If closed-loop resonators are used in the high-band filter and non-loop resonators in the low-band filter, then the attenuation characteristics in the non-passband are improved, but the device complexity increases
Solution Approach 1:
Different resonator configurations are applied locally to specific frequency bands where they are most effective. The closed-loop resonators are used only in the high-band filter where they provide superior attenuation, while non-loop resonators are used in the low-band filter. This targeted approach improves overall system reliability without requiring all components to be complex, thus limiting the increase in device complexity.
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 improves attenuation in the non-passband on both the lower and higher frequency sides of the passband, enhancing the overall performance of the diplexer.
Implementation Method 1
Each of the first filter and the second filter includes resonators in a plurality of stages between the first ground electrode and the second ground electrode
Implementation Method 2
A resonator in a first stage connected to the input terminal in the first filter includes a first capacitor connected to the second ground electrode
Implementation Method 3
a first inductor connected between the first capacitor and the first ground electrode
Data Source
AI summary
A filter apparatus includes an input terminal, first and second ground electrodes opposed to each other, and first and second filters connected to the input terminal. The first filter has a first passband. The second filter has a second passband higher than the first passband. Each of the first and second filters includes resonators in stages between the first and second ground electrodes. A resonator in the first stage in the first filter includes a capacitor connected to the second ground electrode and an inductor connected between the capacitor and the first ground electrode. A resonator in the first stage in the second filter includes a capacitor connected between the input terminal and the second ground electrode and an inductor connected between the capacitor and the second ground electrode.