Modular Antenna System with Nested Waveguide Feeding
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Solution Overview
Problem
Current antenna systems for mobile and aeronautical satellite communications face challenges in achieving small size, low weight, high efficiency, and regulatory compliance, particularly in the Ka band, due to issues with parasitic side lobes, frequency bandwidth support, and feed network efficiency.
Innovation Solution
The antenna system consists of modular design with microstrip line networks and waveguide networks, where individual radiators support orthogonal polarizations, and are arranged to minimize parasitic side lobes, with dielectric filling and geometric constrictions to enhance bandwidth and efficiency, and frequency diplexers for signal separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If horn radiators are densely packed to eliminate parasitic side lobes, then grating lobes are suppressed, but the aperture area becomes too small to support the reception band
Solution Approach 1:
The patent implements a nested structure where a first waveguide network is positioned inside a second waveguide network, with different orientations (first network parallel to x-axis, second network parallel to y-axis). This nested arrangement allows dense packing of radiating elements while maintaining sufficient aperture area by utilizing spatial nesting rather than simple linear densification.
Solution Approach 2:
The patent transitions from two-dimensional planar arrays to three-dimensional nested structures. By stacking waveguide networks at different levels and orientations within the same aperture footprint, the system achieves higher element density without proportionally reducing the aperture area, effectively utilizing the third dimension (depth/height) to resolve the contradiction.
2Loss of energy
If waveguide networks are used to feed horn radiators, then feed network efficiency is high, but parasitic side lobes occur due to large beam center distances
Solution Approach 1:
The nested waveguide network configuration allows the system to maintain efficient waveguide feeding while achieving smaller beam center distances. The inner waveguide network operates at one frequency band and the outer network at another, with both networks sharing the same spatial envelope. This nesting enables dense element spacing without increasing the overall feed network complexity or loss.
Solution Approach 2:
The patent makes the waveguide feed system multi-functional by implementing two separate waveguide networks that can independently feed different frequency bands (reception and transmission). Each network is optimized for its respective band, allowing the system to achieve low losses at both frequencies while maintaining the spatial configuration needed to suppress grating lobes.
3Loss of energy
If conventional waveguides are used, then feed network efficiency is high, but they cannot support large frequency bandwidths
Solution Approach 1:
The patent implements a dual-band waveguide feed system where the first waveguide network supports the reception frequency band and the second waveguide network supports the transmission frequency band. Both networks use conventional waveguide structures optimized for their respective bands, achieving low losses while collectively providing broad frequency coverage that a single conventional waveguide could not support.
Solution Approach 2:
The feed network is segmented into multiple specialized waveguide networks, each optimized for a specific frequency band. Rather than using a single broadband waveguide with compromised performance, the system divides the frequency support function across multiple narrowband-optimized waveguide networks, achieving both high efficiency and broad overall bandwidth.
4Weight of stationary object
If antenna size is reduced for mobile applications, then weight and air resistance decrease, but regulatory compliance becomes difficult to achieve
Solution Approach 1:
The nested waveguide network configuration allows the antenna to achieve the element density required for regulatory compliance within a compact aperture. By nesting the first and second waveguide networks within each other, the system maintains sufficient radiating element density to control sidelobes and meet spectral power density requirements, while keeping the overall antenna size and weight minimized for mobile applications.
Solution Approach 2:
The patent employs a composite feed network structure combining two different waveguide network configurations (with different orientations and frequency optimizations) within a single antenna system. This composite approach allows the antenna to simultaneously optimize for multiple frequency bands and meet regulatory requirements across both reception and transmission bands while maintaining a compact form factor.
Data Source
Figure 1a~1b
Figure 2a~2b
Figure 3a~3c
AI summary
The invention relates to an antenna system consisting of at least two modules, each of which includes at least two individual radiators. Said antenna system comprises microstrip conductor arrangements for feeding the individual radiators within a module, and hollow conductor arrangements for feeding the modules. The modular design of antennas according to the invention has the advantage that microstrip conductors are used where the available mounting space is very limited. Although microstrip conductors have significantly greater dissipation losses than hollow conductors, they require much less mounting space. Moreover, the losses can be greatly reduced by combining only as many primary horn antennas in the modules as needed to create enough mounting space for hollow conductor components. The microstrip conductors are therefore kept comparatively short. The inter-modular feeding arrangements are thus designed as very low-loss hollow conductors. The individual radiators advantageously support two polarizations.