Multi-beam Antenna with Amplifying Lens for Ka-band Gain
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Solution Overview
Problem
Current Ka-band multi-beam antennas for geostationary spacecraft face challenges in achieving the required gain and beam width with minimal grating lobes and aberration effects, while also managing power consumption and thermal issues, especially due to the limitations of phase shifters and traditional phased arrays.
Innovation Solution
The use of a multi-beam antenna system with a focusing system designed as an amplifying lens, featuring a two-dimensional array of feeders that form non-planar wave fronts equidistant to plane wave fronts, allowing for simpler beamforming and power management, and incorporating low-power amplifiers and optical modulation to reduce thermal issues and grating lobes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If traditional phased arrays with highly directional partial feeders are used to achieve required gain, then gain is improved, but grating lobes become unacceptably powerful and beam width increases at edges of service area
Solution Approach 1:
The antenna aperture is divided into multiple subarrays, each with its own lower-power amplifier. This segmentation allows each subarray to operate independently with optimized feeder spacing, reducing grating lobe levels while maintaining overall gain through coherent combination of subarray outputs.
Solution Approach 2:
Different regions of the antenna aperture are assigned different feeder spacing and amplification characteristics. Central regions use tighter spacing for high gain, while edge regions use wider spacing to control grating lobes, with each region optimized for its local performance requirements.
2Object-generated harmful factors
If lattice spacing is reduced to eliminate grating lobes, then grating lobe level is improved, but the number of partial feeders increases to about 36 thousand which is almost impossible with current technology
Solution Approach 1:
The large aperture is divided into multiple smaller subarrays, each handling a portion of the total feeders. This reduces the complexity of controlling each individual feeder while maintaining the overall effect of reduced grating lobes through coordinated operation of subarrays.
Solution Approach 2:
Instead of uniformly reducing spacing across the entire aperture with all feeders, only certain subarrays with specific spacing configurations are activated for each beam position, reducing the effective number of feeders that need to be controlled at any given time.
3Adaptability or versatility
If beam hopping is used to service multiple beam positions with limited active channels, then adaptability is improved, but beam switching speed must be increased to maintain voice transmission quality
Solution Approach 1:
Multiple subarrays are pre-configured with different amplitude and phase settings corresponding to different beam positions. The beamforming system can rapidly switch between pre-configured subarray combinations, eliminating the need for real-time recalculation and enabling fast beam hopping while maintaining service to multiple positions.
Solution Approach 2:
The system dynamically reconfigures which subarrays are active and their respective weighting coefficients based on the current beam position and service requirements. This dynamic subarray selection enables rapid beam switching while maintaining adaptability to different coverage scenarios.
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 solution simplifies the beamforming system, reduces antenna size, maintains high gain and beam quality, provides flexible coverage, and improves thermal management, enabling efficient operation with reduced power consumption and minimal grating lobe interference.
Implementation Method 1
the focusing system is designed as an amplifying lens, and for each such beam, the beamforming system provides such amplitude-time parameters of the transmitted radio signal for each partial feeder in its sub-array, to form a non-planar wave front, equidistant through the amplifying lens to the plane wave front of such a beam
Data Source
AI summary
A multi-beam telecommunications antenna system with a focusing device including a two-dimensional radiator array generating a plurality of beams simultaneously by setting amplitude-time parameters of the signals for each radiator. The antenna includes: a focusing system having an amplifying lens; a radiating device, for irradiating the amplifying lens and having a two-dimensional radiator array, is disposed at a distance from the amplifying lens and covers a projection area of beams at this distance; and a beam forming system. At least one sub-array of the radiators provides a beam in a set direction. For each beam, the beam forming system provides, for each radiator in the corresponding sub-array, amplitude-time parameters of the signal being transmitted to form a non-planar wavefront, which is equidistant across the amplifying lens to a planar wavefront of the beam. The radiating surface of the radiator array is outside a region of self-intersection of the non-planar wavefronts.