Dual-Band Multimode Antenna Feed With Integrated Frequency Filter
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Solution Overview
Problem
Existing dual-frequency band antenna feeds are bulky, require external support struts and de-icing equipment, and suffer from increased side-lobe levels due to long waveguides and external feed arrangements, making them inefficient for compact reflector antenna systems.
Innovation Solution
A dual-band multimode antenna feed with four high-frequency waveguide ports and one low-frequency waveguide port, featuring a filter that is transparent to lower frequencies and reflective to higher frequencies, and inductive diaphragms to reduce aperture sizes and enhance mode mixing, eliminating the need for external equipment and long waveguides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If external feed arrangements with support struts are used, then the antenna can provide dual-frequency band operation, but the antenna becomes bulky and side-lobe levels increase
Solution Approach 1:
The patent combines high-frequency and low-frequency waveguide ports and their associated waveguides into a single integrated feed structure. The high-frequency waveguides and low-frequency waveguide share the same physical space and structural support, eliminating the need for separate external feed arrangements and support struts for each frequency band.
Solution Approach 2:
The feed structure is designed to serve multiple functions: it provides waveguide apertures for both high-frequency and low-frequency bands, supports mode mixing sections for both frequency ranges, and uses a single filter structure to differentiate between frequency bands. This multi-functional design replaces what would traditionally require separate specialized components.
2Adaptability or versatility
If long waveguides are used for external feed arrangements, then dual-frequency band operation is achieved, but side-lobe levels increase and device complexity increases
Solution Approach 1:
The patent merges the waveguide paths for high and low frequencies into a compact integrated structure, significantly reducing the overall waveguide length compared to separate external feed arrangements. This reduction in length directly decreases the harmful side-lobe levels while maintaining dual-frequency functionality.
3Strength
If external support struts and de-icing equipment are added, then the antenna structure is supported, but device complexity and side-lobe levels increase
Solution Approach 1:
The patent integrates the support function into the feed structure itself, where the feed housing and waveguide arrangements provide mutual structural support. This eliminates the need for separate external support struts and associated de-icing equipment, reducing device complexity while maintaining structural integrity.
4Adaptability or versatility
If a filter is added to separate frequency bands in the first section, then frequency band separation is achieved, but device complexity increases
Solution Approach 1:
The patent introduces a filter as an intermediary element within the first mode mixing section that selectively transmits or reflects specific frequency bands. This single filter component mediates between the high-frequency and low-frequency waveguides, achieving frequency separation without requiring complex active control systems or multiple separate filtering stages.
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 enables a compact reflector antenna system with improved side-lobe performance and reduced complexity, allowing for efficient operation across both high and low-frequency bands without external support struts or de-icing equipment.
Implementation Method 1
A filter is arranged inside the first section, where the filter is arranged to be transparent for plane wave modes exhibited at lower frequencies and reflecting for plane wave modes exhibited at higher frequencies
Implementation Method 2
Each high-frequency input/output waveguide has a high-frequency waveguide aperture facing a first section for mixing electromagnetic modes in the E-plane
Implementation Method 3
The first section is connected to a second section for mixing electromagnetic modes in the H-plane
Data Source
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AI summary
The invention relates to a dual-band multimode antenna feed (1) for a high-frequency band and a low-frequency band. The feed comprises four high-frequency waveguide ports (8a, 8b, 8c, 8d), where each high-frequency waveguide port (8a, 8b, 8c, 8d) is connected to a respective high-frequency input/output waveguide (9a, 9b, 9c, 9d). Each high-frequency input/output waveguide (9a, 9b, 9c, 9d) comprises a high-frequency waveguide aperture (10a, 10b, 10c, 10d) facing a first section (11) for mixing electromagnetic modes in the E-plane. The first section (11) is connected to a second section (12) for mixing electromagnetic modes in the H-plane. The feed further comprises a low-frequency waveguide port (13) connected to a low-frequency input/output waveguide (14), wherein a low-frequency waveguide aperture (15) faces the first section (11). A filter (16) is arranged inside the first section (11). The filter (16) is arranged to be transparent for plane wave modes exhibited at lower frequencies and reflecting for plane wave modes exhibited at higher frequencies.