Tunable Band-Pass Filter With Movable Dielectric Plate
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Solution Overview
Problem
Tunable band-pass filters experience significant fluctuations in bandwidth when the center frequency of the passband is changed, which is a common issue among existing designs.
Innovation Solution
A tunable band-pass filter design that includes a waveguide with resonators and a dielectric plate with metal patterns for coupling adjustment, allowing the distance between the dielectric plate and resonators to be variable, thereby controlling the coupling coefficient to maintain a constant bandwidth across different center frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the center frequency of the passband is changed in a conventional tunable band-pass filter, then the frequency selectivity is improved, but the bandwidth fluctuates significantly
Solution Approach 1:
The patent employs a movable dielectric plate that can be dynamically adjusted in position along the longitudinal direction of the waveguide. This dynamic structure allows the filter to maintain optimal coupling between the dielectric plate and resonators across different center frequencies, thereby stabilizing bandwidth while enabling frequency tuning. The movable configuration transforms a static filter into an adaptable system that preserves performance characteristics during operation.
Solution Approach 2:
The invention changes the positional parameter of the dielectric plate relative to the resonators to simultaneously control both the center frequency and bandwidth characteristics. By adjusting the distance between the dielectric plate and resonators, the coupling coefficient is modified in a controlled manner, allowing the system to maintain constant bandwidth while tuning the center frequency through parameter optimization.
2Speed
If the distance between the dielectric plate and resonators is increased to tune the center frequency, then the frequency response shifts, but the coupling coefficient decreases causing bandwidth reduction
Solution Approach 1:
The patent utilizes a dynamically adjustable dielectric plate positioned at a movable distance from the resonators. This dynamic configuration enables the system to optimize the coupling coefficient at each tuned frequency point, ensuring that bandwidth remains stable even as the center frequency changes. The movable design allows real-time adaptation of the electromagnetic coupling to maintain consistent filter performance.
Solution Approach 2:
The invention replaces fixed mechanical structures with a movable dielectric plate system that can be repositioned along the waveguide. This substitution allows for continuous adjustment of the coupling coefficient without requiring mechanical redesign of the entire filter structure, enabling frequency tuning while maintaining bandwidth consistency through optimized positioning.
3Ease of manufacture
If a conventional fixed structure is used, then the manufacturing is simple, but the passband cannot be changed from the outside
Solution Approach 1:
The patent introduces a movable dielectric plate that can be repositioned along the longitudinal direction of the waveguide, transforming a fixed filter into a tunable system. This dynamic element allows the passband to be adjusted from the outside without complicating the overall manufacturing process, as the movable plate can be integrated into existing waveguide structures using standard positioning mechanisms.
Solution Approach 2:
The invention creates a multi-functional filter structure where the same basic design serves both as a fixed filter during initial operation and as a tunable filter when the dielectric plate is repositioned. This universal design allows the filter to adapt to different frequency requirements while maintaining compatibility with conventional manufacturing processes and waveguide configurations.
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 effectively suppresses bandwidth fluctuations when changing the center frequency, improving the stability and performance of the tunable band-pass filter.
Implementation Method 1
a metal pattern for coupling adjustment formed on the dielectric plate at a position corresponding to an interstage of the resonators
Implementation Method 2
The resonance plates 121-1 to 121-3 operate to resonate at a resonance frequency determined by the shape, the length (the y-direction) and the like
Data Source
AI summary
A tunable band-pass filter (10) according to the present disclosure includes: a waveguide (11); a plurality of resonators (121) configured to be accommodated in the waveguide (11) and aligned in a longitudinal direction of the waveguide (11); a dielectric plate (13) configured to extend in the longitudinal direction of the waveguide (11) so to be arranged adjacent to the plurality of resonators (121); and a metal pattern (15) for coupling adjustment formed on the dielectric plate (13) at a position corresponding to an interstage of the resonators (121), in which a distance between the dielectric plate (13) and the resonators (121) is variable.