OTA Shield Box Ventilation for Stable Multi-Antenna Testing

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Solution Overview

Problem

Existing shield boxes for testing mobile telecommunication terminals with multiple antennas suffer from poor versatility and temperature rise during tests due to their closed structure, affecting signal consistency and stability, especially in Over The Air (OTA) methods.

Innovation Solution

A shield box with vent holes, ventilation fans, and a heat dissipation system to maintain a constant temperature, combined with non-contact wireless connection parts and RF couplers for stable signal transmission and reception, ensuring minimal variability and consistent performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a closed shield box structure is used to block external radio interference, then signal interference is reduced, but temperature rises continuously during testing

Engineering Contradiction:
Improveradio interferenceVSAvoidtemperature inside shield box
Core Design Contradiction:
Object-affected harmful factorsVSTemperature

Solution Approach 1:

The patent applies porous foam material filled in the shield box to absorb electromagnetic waves and reduce radio interference. The porous structure provides both EMI shielding and thermal management by allowing heat dissipation while maintaining signal isolation.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The patent introduces a non-contact wireless connection system using magnetic coupling between the shield box and external equipment. This intermediary magnetic field transmission method allows signal communication while maintaining the closed shield structure for thermal and EMI control.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If the shield box maintains a closed structure for EMI shielding, then external interference is blocked, but signal consistency deteriorates due to temperature rise

Engineering Contradiction:
Improveexternal interferenceVSAvoidsignal consistency
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

Porous foam material is used to line the shield box interior, providing both EMI absorption and thermal regulation. This maintains signal consistency by preventing temperature-induced signal variations while blocking external interference.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The patent replaces traditional mechanical contact-based signal transmission with non-contact wireless magnetic coupling. This eliminates mechanical wear and contact instability, improving signal consistency while maintaining EMI shielding.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If non-contact wireless connection is used for testing, then versatility is improved, but temperature control becomes more difficult

Engineering Contradiction:
Improvetesting versatilityVSAvoidtemperature control
Core Design Contradiction:
Adaptability or versatilityVSTemperature

Solution Approach 1:

Magnetic field coupling serves as an intermediary for wireless signal transmission between the shield box and external testing equipment. This non-contact method enables versatile testing of different devices while the porous foam interior maintains temperature control.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The porous foam material provides thermal management within the shield box, enabling temperature control during versatile non-contact wireless testing of various mobile communication terminals.

Inventive Principle:
Principle #31Porous materials

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 shield box maintains a constant temperature and signal consistency, enabling long-duration 5G interworking tests without network switching, while supporting MIMO channels with high coupling performance and minimal crosstalk.

Implementation Method 1

a ventilation fan mounted on the upper vent or the rear vent

Methodology Applied
Scientific EffectForced Convection: Forced Convection

Implementation Method 2

a probe antenna embedded in a metal box, located directly above or directly below the antenna part of a mobile telecommunication terminal housed in the metal box, to receive signals from a mobile telecommunication terminal antenna in a non-contact manner

Methodology Applied
Scientific EffectElectromagnetic Induction: Electromagnetic Induction

Implementation Method 3

a first radio wave absorber that is attached to the entire inner surface of a metal box except for the terminal storage space of the same size as the mobile telecommunication terminal and prevents radio waves emitted from the mobile telecommunication terminal antenna from being reflected inside the metal box

Methodology Applied
Scientific EffectElectromagnetic Absorption: Absorption (EM radiation)

Data Source

PatentEP4224175B1Shield box for testing mobile telecommunication terminal
Publication Date: 2025.10.15 INNOWIRELESS
  • EP4224175B1 patent drawingFigure 1
  • EP4224175B1 patent drawingFigure 2A~2B
  • EP4224175B1 patent drawingFigure 3

AI summary

The present disclosure relates to a shield box for testing a mobile telecommunication terminal in which an increase in temperature in a shield box is prevented in performing various tests on a mobile telecommunication terminal having multiple antennas in an Over The Air (OTA) method to perform a stable test. The shield box for testing a communication terminal of the present disclosure includes a shield box main body (180) made of metal, having a jig entrance (180a) formed on the front side, and equipped with a vent (120b, 160a) which a plurality of vent holes of 1 to 10 mm in size are formed on the upper and rear sides, respectively; a test jig assembly (200) installed to be able to enter and exit through the jig entrance (180a) while mounting a PCB for non-contact wireless connection in which a plurality of non-contact wireless connection parts that are wirelessly connected to a mobile telecommunication terminal and transmit and receive signals are arranged; and a ventilation fan mounted on the upper vent or the rear vent.