Satellite Ground Terminal FSS Duplexer Signal Isolation

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Solution Overview

Problem

Satellite ground terminals face challenges in separating uplink and downlink signals efficiently without using expensive and heavy waveguide devices, which are necessary to prevent crosstalk interference and meet regulatory standards, while also optimizing each communication path independently.

Innovation Solution

A frequency-selective surface module is placed within the optical path between the reflector and the focal point of the reflector dish to act as a frequency duplexer, separating the uplink and downlink signals, allowing for independent optimization of each communication path without the need for waveguide devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If waveguide devices are used to separate uplink and downlink signals, then signal isolation is improved, but weight and cost increase

Engineering Contradiction:

Improvesignal isolationVSAvoidterminal weight

Core Design Contradiction:

ReliabilityVSWeight of stationary object

Solution Approach 1:

The patent changes the operating parameters by using a frequency-selective surface that operates at specific frequency bands (e.g., 20 GHz for downlink, 30 GHz for uplink) to achieve signal separation. This frequency-based parameter change eliminates the need for heavy waveguide devices while maintaining signal isolation through selective frequency reflection and transmission properties of the FSS.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical waveguide separation system with an electromagnetic field-based frequency-selective surface. Instead of using physical waveguide structures to separate signals, the FSS uses its electromagnetic properties to selectively reflect or transmit signals based on frequency, thereby substituting a mechanical system with an electromagnetic field-based solution that reduces weight.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If waveguide devices are used to separate uplink and downlink signals, then signal isolation is improved, but manufacturing cost increases

Engineering Contradiction:

Improvesignal isolationVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent employs a frequency-selective surface that can be manufactured using cost-effective techniques such as printing or coating methods on a substrate, replacing expensive precision-machined waveguide devices. The FSS structure, while providing the same signal isolation function, uses cheaper materials and manufacturing processes, reducing overall system cost.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Device complexity

If a single feed horn antenna is used for both uplink and downlink, then device complexity is reduced, but independent optimization of communication paths is limited

Engineering Contradiction:

Improveantenna system complexityVSAvoidcommunication path optimization

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent applies local quality by positioning the frequency-selective surface at specific locations within the antenna system where it can selectively affect different frequency bands. The FSS is placed in the optical path between the reflector and focal point, creating localized frequency separation that allows independent optimization of uplink and downlink paths while maintaining a single feed horn antenna structure.

Inventive Principle:

Principle #3Local quality

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 reduces the weight and cost of the terminal by eliminating the need for waveguide devices, enhances signal isolation, and optimizes each communication path for improved efficiency and compliance with regulatory standards.

Implementation Method 1

a frequency-selective surface module including a frequency-selective surface placed within the optical path between the reflector and the focal point of the reflector

Methodology Applied

Scientific EffectFrequency-selective surface: Filter (optical)

Data Source

PatentEP3311448B1Satellite ground terminal utilizing frequency-selective surface duplexer

Publication Date: 2023.08.02 HUGHES NETWORK SYST

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AI summary

Systems and methods are provided for separating the uplink signal from the downlink signal in a satellite communication system. A communication terminal for satellite communications is provided, comprising a reflector having a prime focus; a first feed located at the prime focus of the reflector and in optical communication with the reflector; a frequency-selective surface module having a reflected focus and located at a point along a communication path between the main reflector and the first feed; and a second feed located at the reflected focus of the frequency- selective surface module and in optical communication with the frequency-selective surface module.