Antenna Device Septum Phase Plate Asymmetry Correction
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Solution Overview
Problem
Conventional antenna devices with septum phase plates suffer from degradation in axial ratio characteristics due to asymmetrical structures, which cannot be sufficiently improved by adjusting the size and thickness of the stair-stepped portion of the septum phase plate.
Innovation Solution
The antenna device incorporates two projecting portions on the inner walls parallel to the septum phase plate within the rectangular waveguide, positioned centrally and not overlapping with the septum, to adjust the electric field strength ratio, thereby reducing asymmetry-induced degradation and enhancing the axial ratio characteristic.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the size and board thickness of the stair-stepped portion of the septum phase plate are adjusted to improve axial ratio characteristic, then the axial ratio characteristic can be improved, but the asymmetrical shape of the septum phase plate causes degradation in axial ratio characteristic
Solution Approach 1:
The patent applies asymmetry principle by introducing first and second projecting portions on opposite inner walls of the rectangular waveguide. These projecting portions create a controlled asymmetrical structure that compensates for the inherent asymmetry of the septum phase plate, thereby improving the axial ratio characteristic despite the asymmetrical shape of the septum phase plate
2Productivity
If projecting portions are disposed on inner walls to shift resonance frequency, then band broadening is achieved, but asymmetry in the structure degrades axial ratio characteristic
Solution Approach 1:
The patent applies counterweight principle by placing first and second projecting portions symmetrically on opposite inner walls of the waveguide. These projecting portions act as counterbalancing elements that offset the asymmetrical influence of the septum phase plate, thereby maintaining good axial ratio characteristics while achieving band broadening through resonance frequency shifting
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 effectively improves the axial ratio characteristic by balancing electric field strengths, reducing asymmetry-related degradation and achieving a better frequency range performance.
Implementation Method 1
an antenna device that includes a septum phase plate inside a rectangular waveguide in order to convert an inputted circularly polarized wave into a linearly polarized wave
Implementation Method 2
a projecting portion is disposed on an inner wall of the rectangular waveguide in order to shift a resonance frequency in a TM11 mode toward a high frequency
Data Source
Figure 1A~1C
Figure 2A~3
Figure 4A~4C
AI summary
Disclosed is an antenna device including a rectangular waveguide (1) having a first opening end (2a) and a second opening end (2b), a septum phase plate (3) disposed inside the rectangular waveguide (1) in such a way as to partition the first opening end (2a) into two parts along a first direction perpendicular to a waveguide axial direction of the rectangular waveguide (1), a width of the septum phase plate in a second direction perpendicular to both the waveguide axial direction of the rectangular waveguide (1) and the first direction becoming narrower stepwise with advancing from the first opening end (2a1, 2a2) toward the second opening end (2b), and first projecting portions (4a, 4b) disposed on two respective first inner walls (1a, 1b) parallel to the septum phase plate (3), out of four inner walls of the rectangular waveguide (1), in such a way as to project toward an inside of the rectangular waveguide (1).