Millimeter Waveband Filter With Leakage-Preventing Groove
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Solution Overview
Problem
Conventional millimeter waveband filters face challenges in achieving high-sensitivity and high-precision measurements above 100 GHz due to noise levels and frequency precision issues, with difficulties in separating harmonics and preventing electromagnetic wave leakage, which affects resonance characteristics and frequency tuning.
Innovation Solution
A millimeter waveband filter design featuring a first square waveguide and a second ridge waveguide with adjustable gap and groove structures to prevent electromagnetic wave leakage, allowing for variable resonance frequencies and maintaining resonance characteristics by aligning groove length with waveguide transmission line direction, and using slits with varying heights to optimize transmittance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the second waveguide is made thinner to widen the low frequency band, then the propagatable frequency range is extended, but electromagnetic waves leak from the gap between waveguides causing deterioration of resonance characteristics
Solution Approach 1:
A groove structure is introduced as an intermediary element between the first and second waveguides. This groove acts as a mediator that prevents electromagnetic wave leakage from the gap while allowing the thin second waveguide to maintain its size for wide frequency coverage. The groove structure effectively blocks the harmful leakage without requiring the waveguide to be thicker.
Solution Approach 2:
The groove structure extracts the leakage prevention function from the waveguide body itself. Instead of making the waveguide thicker to prevent leakage, the groove structure separately handles the leakage prevention task, allowing the waveguide to remain thin for wide frequency operation.
2Reliability
If the groove depth is increased to 1/4 wavelength for leakage prevention, then electromagnetic wave leakage is reduced, but the waveguide thickness becomes excessive and low frequency band is lost
Solution Approach 1:
The groove structure is positioned locally at the gap region between waveguides rather than requiring the entire waveguide to be thick. This localized approach provides leakage prevention exactly where needed (at the gap) without unnecessarily increasing the overall waveguide thickness, thereby preserving low frequency band operation.
Solution Approach 2:
Instead of solving leakage prevention by increasing the thickness dimension of the entire waveguide, the groove structure introduces a localized dimensional feature only at the gap region. This dimensional change is applied selectively in another dimension (depth at the gap) without affecting the overall waveguide thickness, thus preventing leakage while maintaining low frequency capability.
3Ease of operation
If waveguides of different sizes are connected for frequency tuning, then variable resonance frequency is achieved, but electromagnetic waves leak from the gap causing resonance characteristic deterioration
Solution Approach 1:
The groove structure serves as an intermediary element at the gap between differently sized waveguides. It mediates the interaction between the waveguides by preventing electromagnetic wave leakage from the gap, allowing frequency tuning through size variation while maintaining resonance characteristics.
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 design enables wideband frequency tuning without deteriorating resonance characteristics, effectively preventing electromagnetic wave leakage and maintaining low-frequency band propagation, thus enhancing measurement precision and sensitivity.
Implementation Method 1
electromagnetic waves which enter the gap and reach the groove and electromagnetic waves which are phase-inverted while reciprocating in the groove are cancelled
Implementation Method 2
electromagnetic waves which enter the gap and reach the groove and electromagnetic waves which are phase-inverted while reciprocating in the groove are cancelled
Implementation Method 3
desired frequency components of the millimeter waves are selectively transmitted by a resonance action between a pair of electric wave half mirrors
Data Source
AI summary
To provide a millimeter waveband filter which can vary a resonance frequency in a wider band without causing deterioration of resonance characteristics due to leakage of electromagnetic waves. In a millimeter waveband filter 20, a first waveguides 22 and a second waveguide 24 are relatively moved to vary the interval between the electric wave half mirrors 30A and 30B, and the resonance frequency of a resonator formed between the mirrors varies to selectively transmit resonance frequency components. A groove 60 which has a length p along a longitudinal direction of the transmission line corresponding to a ¼ wavelength of electromagnetic waves to be a leakage prevention target is provided on the outside of the second waveguide 24 facing the inside of the first waveguide 22, thereby preventing leakage of electromagnetic waves from the gap between the first waveguide 22 and the second waveguide 24.