Millimeter Waveband Filter Resonator with Variable Curvature
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional millimeter waveband filters face challenges in achieving high-sensitivity and high-precision measurements above 100 GHz due to increased noise and conversion loss, difficulty in separating harmonics, and limitations in frequency variability, particularly with Fabry-Perot resonators which suffer from reduced Q-factor and design inflexibility when tuning the passband.
Innovation Solution
A millimeter waveband filter structure featuring a pair of flat electric wave half mirrors arranged in a waveguide transmission line, with a high-pass filter and band rejection filter, allowing for variable resonance frequency and enhanced rejection band attenuation, reducing space emission loss and improving design flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a confocal Fabry-Perot resonator is used to achieve high Q, then the Q-factor is improved, but the focus shifts when tuning the passband and Q is significantly lowered
Solution Approach 1:
The resonator is divided into multiple sections with different curvature radii (first resonator section with radius R1, second resonator section with radius R2). This segmentation allows each section to contribute differently to the overall resonance, enabling frequency tuning while maintaining stable Q-factor characteristics without the focus shift problem of confocal resonators.
Solution Approach 2:
Different sections of the resonator are given different local properties (different curvature radii R1 and R2). The first resonator section has curvature radius R1 and the second has curvature radius R2, where these radii are specifically designed to achieve both frequency variability and Q-factor stability simultaneously.
2Adaptability or versatility
If parallel-plate half mirrors are used to maintain Q during tuning, then frequency variability is improved, but the filter size increases and plane wave input is required
Solution Approach 1:
The resonator incorporates variable geometric parameters (curvature radii R1 and R2, length L) that can be adjusted to change the resonance frequency. This dynamic capability allows frequency tuning while maintaining compact dimensions, avoiding the need for large parallel-plate structures.
3Adaptability or versatility
If open-type filter structure is used, then design flexibility is improved, but loss by space emission is large
Solution Approach 1:
The resonator is nested within the waveguide structure, with the resonator cavity positioned inside the waveguide. This nesting configuration contains the electromagnetic fields within the waveguide boundaries, preventing space emission losses while preserving the design flexibility of the resonator structure.
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 proposed filter design achieves high selection characteristics, suppresses wavefront conversion, and significantly increases rejection band attenuation without affecting passband characteristics, enabling precise measurements in the millimeter waveband.
Implementation Method 1
a waveguide (21, 21A, 21B) which has a transmission line allowing electromagnetic waves in a predetermined frequency range of a millimeter waveband to propagate from one end to the other end in a TE10 mode
Implementation Method 2
a pair of electric wave half mirrors (40A, 40B) which have characteristics to transmit a part of the electromagnetic waves in the predetermined frequency range and to reflect a part of the electromagnetic waves
Implementation Method 3
frequency components centering on the resonance frequency of a resonator formed between the pair of electric wave half mirrors are selectively transmitted
Implementation Method 4
a high-pass filter (30) which is provided in the transmission line between the end of the waveguide and the electric wave half mirror, and has a transmission line reduced in size so as to have a cutoff frequency at a frequency close to the lower limit of the filter passband in a rejection band lower than a filter passband
Implementation Method 5
a band rejection filter (35) which has a choke groove (36) having a predetermined depth formed around the inner wall of the high-pass filter, and attenuates components of a rejection band higher than the filter passband
Data Source
AI summary
A millimeter waveband filter is provided with a resonator formed by a pair of electric wave half mirrors in a transmission line of a waveguide allowing electromagnetic waves in a predetermined frequency range of a millimeter waveband to propagate in a TE10 mode, and allows frequency components centering on the resonance frequency of the resonator to pass therethrough. A high-pass filter which has a transmission line reduced in size so as to have a cutoff frequency matching an upper limit of a lower rejection band of a filter passband is formed in a transmission line between the end of the waveguide and the electric wave half mirror, thereby increasing the attenuation of the lower rejection band.