Full-Duplex Reflector Antenna Layout for Loopback Noise Isolation

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Solution Overview

Problem

Existing full-duplex communication systems suffer from loopback noise due to self-interference, limiting channel capacity and communication rate, and existing full-duplex technologies face challenges in effectively reducing loopback noise and maintaining signal transmission precision.

Innovation Solution

A full-duplex antenna apparatus with a primary reflector, isolation plate, and secondary reflectors, separated by feeds, where the isolation plate blocks transmission between the feeds, and the secondary reflectors facilitate signal reflection to reduce loopback noise, allowing co-frequency co-time signal transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If full-duplex technology is applied to enable co-frequency co-time transmission, then channel capacity and communication rate are doubled, but loopback noise power becomes far greater than wanted signal power causing radio frequency module to exceed linear working range

Engineering Contradiction:
Improvechannel capacityVSAvoidloopback noise
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The antenna apparatus divides the reflective surface into two separate reflection zones using an isolation plate, creating spatial separation between transmit and receive signal paths. This segmentation prevents the transmitted signal from directly coupling back to the receive antenna, thereby reducing loopback noise while maintaining full-duplex operation

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The isolation plate acts as an intermediary element positioned between the transmit and receive feeds. It blocks the direct path of transmitted signals from reaching the receive antenna, serving as a physical barrier that mediates the interaction between the two signal paths and eliminates the harmful loopback effect

Inventive Principle:
Principle #24Intermediary (Mediator)

2Volume of moving object

If transmit and receive antennas are placed close together for compact design, then device size is reduced, but loopback noise power becomes far greater than wanted signal power

Engineering Contradiction:
Improveantenna device sizeVSAvoidloopback noise
Core Design Contradiction:
Volume of moving objectVSObject-affected harmful factors

Solution Approach 1:

Instead of increasing physical distance between antennas in the horizontal plane, the invention introduces a vertical dimension by placing the isolation plate between the feeds along the signal path. This dimensional approach allows compact lateral arrangement while maintaining signal isolation through the intermediate blocking structure

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Measurement precision

If isolation measures are implemented to reduce loopback noise, then signal transmission precision is improved, but device complexity increases with additional components

Engineering Contradiction:
Improvesignal transmission precisionVSAvoidantenna structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The isolation plate serves multiple functions simultaneously: it acts as a signal blocking barrier to reduce loopback noise, provides structural support for mounting the secondary reflector, and helps define the radiation pattern. This multi-functionality reduces the need for additional separate isolation components, thereby limiting the increase in device complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

Significantly reduces loopback noise and improves signal transmission precision, enabling high-gain beam formation and increased channel bandwidth without wasting spectrum or time resources.

Implementation Method 1

The isolation plate is configured to block transmission of electromagnetic wave signals between the two feeds

Methodology Applied
Scientific EffectElectromagnetic wave blocking: Absorption (EM radiation)

Implementation Method 2

the signal is reflected by the secondary reflector corresponding to the reflection zone, and then is transmitted to the outside by using the primary reflector

Methodology Applied
Scientific EffectElectromagnetic wave reflection: Reflection

Implementation Method 3

the primary reflector sends the to-be-transmitted electromagnetic wave signal to the remote end

Methodology Applied
Scientific EffectElectromagnetic wave reflection and direction: Reflection

Data Source

PatentEP4625703A1Full duplex antenna device and communication system
Publication Date: 2025.10.01 HUAWEI TECH CO LTD
  • EP4625703A1 patent drawingFigure 1~3
  • EP4625703A1 patent drawingFigure 4~5
  • EP4625703A1 patent drawingFigure 6~7

AI summary

This application provides a full-duplex antenna apparatus and a communication system. The full-duplex antenna apparatus includes a primary reflector, an isolation plate, two secondary reflectors, and two feeds. The primary reflector has a first reflective surface. The isolation plate is disposed on one side of the first reflective surface and fastened to the first reflective surface, and divides the first reflective surface into two reflection zones. The two secondary reflectors are respectively disposed on two sides of the isolation plate. The two feeds are disposed on one side of the first reflective surface, and the two feeds are respectively located on two sides of the isolation plate. One of the two feeds is configured to transmit an electromagnetic wave signal to a receive end of a remote end, and the other feed is configured to receive an electromagnetic wave signal sent by a transmit end of the remote end. The isolation plate is configured to block transmission of electromagnetic wave signals between the two feeds. The full-duplex antenna apparatus has a feature of low loopback noise.