Broad-band Circularly Polarized Antenna with Four Monopole Elements
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Solution Overview
Problem
Traditional circularly-polarized antennas, such as microstrip patches or helix antennas, fail to maintain a good axial ratio at low elevation angles, requiring complex mechanical engineering to ensure precise dipole orientation and assembly, which is difficult to maintain over time.
Innovation Solution
A broad-band circularly-polarized antenna design featuring four monopole antenna elements arranged around a vertical axis, with each element driven at specific phase angles to achieve right-hand or left-hand circular polarization across a wide range of elevation angles, eliminating the need for precise dipole orientation and simplifying assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional microstrip patches or helix antennas are used, then the antenna structure is simple, but the axial ratio performance is poor at low elevation angles
Solution Approach 1:
The antenna is divided into four separate dipole elements arranged in a specific three-dimensional configuration. Each dipole is oriented at 45 degrees to the horizontal plane, with opposing pairs being mutually perpendicular. This segmentation allows each element to contribute to circular polarization while maintaining simple individual structures.
Solution Approach 2:
The patent transitions from traditional two-dimensional planar arrangements to a three-dimensional spatial structure. The dipoles are positioned in 3D space with specific orientations and spacing, creating a volumetric radiation pattern that maintains circular polarization from zenith to horizon, overcoming the limitations of flat antenna designs.
2Reliability
If four dipoles are arranged at precise 45 degree orientation with mutual perpendicularity, then circular polarization is achieved, but mechanical engineering complexity increases significantly
Solution Approach 1:
The patent employs a feed network with hybrid couplers that can drive multiple dipoles with precise phase relationships. This universal feeding mechanism simplifies the assembly process by providing a standardized interface for connecting dipoles, reducing the need for custom mechanical fixtures for each specific orientation configuration.
Solution Approach 2:
The antenna uses four identical dipole elements with the same structural design, each oriented at 45 degrees. This copying approach allows for standardized manufacturing and assembly, where identical components can be produced and installed using the same procedures, reducing mechanical complexity despite the precise spatial requirements.
3Manufacturing precision
If precise perpendicular orientation between opposite dipole pairs is maintained, then axial ratio is improved, but long term quality requires significant mechanical engineering
Solution Approach 1:
The patent incorporates preliminary alignment features and rigid mounting structures that establish the precise 45-degree orientations and perpendicular relationships during assembly. By pre-configuring the mechanical supports to enforce the correct geometry, the need for complex real-time adjustment mechanisms is eliminated, ensuring long-term stability without ongoing mechanical 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
The design achieves a wider operating frequency band and maintains circular polarization from vertical to horizontal angles, improving axial ratio performance and reducing mechanical complexity, thus enhancing the antenna's operational efficiency and stability.
Implementation Method 1
A broad-band circularly-polarized antenna includes four monopole antenna elements having four respective radiating surfaces. When the broad-band circularly-polarized antenna is operational, the electromagnetic fields are emitted from the radiating surfaces
Implementation Method 2
When the phase is driving the first, second, third, and fourth monopole antenna elements at 0°, -90°, -180°, and -270° phase angle, respectively, the electric fields radiated from the circularly polarized antenna are right-hand-circular-polarization (RHCP) for elevation angles above the horizon
Data Source
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AI summary
A broad-band circularly- polarised antenna is presented. The circularly-polarised antenna includes at least four monopole antenna elements having respective at least four radiating surfaces with respective at least four normals. The monopole antenna elements are arranged around a vertical axis. The normals of the respective radiating surfaces are perpendicular to and point away from the vertical axis. The broad-band circularly-polarized antenna include s at least one feed network communicatively coupled to edge portions of the at least four mono pole antenna elements. A first antenna element is driven with a first driving phase offset by 90 degrees from a second driving phase used to drive a second antenna element. Tie second driving phase is offset by 90 degrees from a third driving phase used to drive a third monopole antenna element. The third driving phase is offset by 90 degrees from a fourth driving phase used to drive a fourth antenna element.