Feed Horn Phase Center Design for Dual-Band Subreflector Tracking
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Solution Overview
Problem
Existing satellite communication systems with large reflector antennas face challenges in maintaining precise alignment and signal stability across different frequency bands due to the weight and complexity of tracking mounts, particularly for uplink signals, as the phase center of the feed horn shifts significantly with frequency, affecting the optimal subreflector height for both downlink and uplink signals.
Innovation Solution
A dual-reflector earth station antenna system with a feed horn optimized for a near-constant phase center across a range of frequencies, combined with a subreflector tracking assembly capable of movement in the X, Y, and Z axes, and a control system that adjusts the subreflector to maximize signal gain for both uplink and downlink frequencies, using feedback sensors to monitor and adjust the subreflector position to maintain optimal alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a tracking mount is used to align the entire antenna assembly, then alignment precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent divides the alignment function into two segments: the main antenna structure remains stationary while only the subreflector is made movable on three axes. This segmentation allows precise alignment to be achieved through small subreflector adjustments rather than moving the entire heavy antenna assembly, thereby reducing device complexity while maintaining alignment precision.
Solution Approach 2:
The patent introduces dynamic adjustment capability to the subreflector position on three axes (X, Y, and Z), allowing the system to adapt and maintain precise alignment without requiring the entire antenna to be movable. This localized dynamics approach achieves tracking precision while avoiding the complexity of moving the complete antenna structure.
2Reliability
If the phase center of the feed horn is optimized for one frequency band, then signal stability is improved, but performance degrades in other frequency bands
Solution Approach 1:
The patent applies local quality by optimizing the feed horn's phase center characteristics specifically for the uplink frequency band while maintaining adequate performance in the downlink band. The feed horn geometry is tailored to provide a near-constant phase center for uplink frequencies, creating localized optimization rather than attempting uniform performance across all bands.
Solution Approach 2:
The patent utilizes parameter changes by adjusting the feed horn's physical dimensions and geometry to achieve a near-constant phase center over the uplink frequency range. By modifying the feed horn's structural parameters (length, diameter, flare angle), the system achieves improved signal stability in the uplink band while maintaining functional performance in the downlink band.
Data Source
AI summary
A dual reflector earth station antenna (ESA) system for transmitting uplink in a first frequency band and receiving downlink in a second frequency band, the ESA system comprises a reflector; a reflector tracking assembly coupled to the reflector and configured to control the direction of the reflector; a feed horn coupled to the reflector and optimized for a near-constant phase center for both the first frequency band and the second frequency band; a subreflector tracking assembly including a subreflector, configured for tracking in the X, Y and Z-axes and supported proximate a focal point of the reflector; and a control system in communication with the subreflector tracking assembly and comprising at least one processor. The processor is configured to adjust the subreflector of the subreflector tracking assembly along X, Y and Z axes of the reflector until a signal gain of the reflector antenna is maximized for the second frequency band; and wherein a signal gain of the reflector antenna is also simultaneously maximized for the first frequency band due to the optimization of the feed horn for a near-constant phase center for both the first frequency band and the second frequency band.