RF Protection Coupler with Dynamic Switching for ESD Hazard Mitigation

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Solution Overview

Problem

Existing RF systems face hazards from electrostatic discharge (ESD) and reflected RF power when external RF loads are disconnected, leading to potential harm to personnel and equipment, and current mitigation techniques reduce transmission efficiency.

Innovation Solution

A radio frequency (RF) protection coupler with a source side and load side RF switch that toggles between states based on the mating status of the external RF load, establishing an electrically conductive path when mated and coupling the RF source circuit to an impedance load and ground when un-mated, thereby isolating the RF source circuit and preventing ESD and reflected power.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a diode is installed at the transmitter output to shunt ESD and reflected RF power to ground, then protection against ESD and reflected power is improved, but transmission efficiency deteriorates due to introduced capacitance

Engineering Contradiction:

Improveprotection against ESD and reflected powerVSAvoidtransmission efficiency

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent employs dynamic switching using RF switches that change the circuit configuration based on whether an antenna is connected or disconnected. When disconnected, the switches connect protection elements (resistors and diodes) to ground; when connected, they disconnect these elements from the signal path. This dynamic reconfiguration allows the system to provide protection only when needed, avoiding the continuous capacitance penalty that would reduce transmission efficiency during normal operation.

Inventive Principle:

Principle #15Dynamics

2Device complexity

If the antenna port is left open when the antenna is decoupled, then equipment simplicity is maintained, but hazards from electrostatic discharge and reflected RF power increase

Engineering Contradiction:

Improveequipment simplicityVSAvoidhazards from ESD and reflected RF power

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces protection elements (resistors and diodes) as intermediary components between the transmitter output and the open antenna port. These intermediaries provide a safe discharge path for electrostatic charges and absorb reflected RF power when the antenna is disconnected. The elements are coupled through RF switches that connect them to ground only when needed, allowing the system to maintain simplicity during normal operation while providing protection when the antenna is decoupled.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If protection elements are continuously connected to the antenna port, then protection against hazards is improved, but transmission efficiency deteriorates due to capacitance and impedance mismatch

Engineering Contradiction:

Improveprotection against hazardsVSAvoidtransmission efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent uses RF switches to dynamically reconfigure the circuit, connecting protection elements to the antenna port only when the antenna is disconnected and disconnecting them when the antenna is connected. This dynamic approach ensures protection is available when needed while eliminating the continuous capacitance and impedance mismatch that would otherwise reduce transmission efficiency during normal operational conditions.

Inventive Principle:

Principle #15Dynamics

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

The RF protection coupler effectively protects both personnel and equipment from ESD and reflected RF power hazards while maintaining transmission efficiency by grounding the external load and matching impedance, minimizing reflected power and dissipating heat safely.

Implementation Method 1

an air gap between the source side RF switch and the load side RF switch electrically isolates the first port from the second port

Methodology Applied

Scientific EffectElectrical insulation: Dielectric

Implementation Method 2

the impedance load is impedance matched to the output of the RF source circuit

Methodology Applied

Scientific EffectImpedance matching: Electrical Impedance Tomography

Implementation Method 3

the load side RF switch couples the second port to an electrical ground

Methodology Applied

Scientific EffectElectrostatic discharge: Electrostatic Discharge

Data Source

PatentUS11563458B2Systems and methods for radio frequency hazard protection for external load connections

Publication Date: 2023.01.24 OUTDOOR WIRELESS NETWORKS LLC

AI summary

Systems and methods for RF hazard protection are provided. In one embodiment, a RF protection coupler comprises: a first port to couple to an output of an RF source circuit; a second port to couple to an external RF load; a source side and load side RF switches, wherein the source side RF switch and the load side RF switch are each switch between a first and second states in response to a detected matting. In the first state the source and load side RF switches establish an electrical path between the first and second ports. In the second state: the source side RF switch couples the first port to an impedance load that is impedance matched to the output of the RF source circuit; the load side RF switch couples the second port to an electrical ground; and a gap between the switches electrically isolates the ports.