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Emergency cellular RF link for metal elevators

IP.com Disclosure Number: IPCOM000008505D
Original Publication Date: 2002-Jun-18
Included in the Prior Art Database: 2002-Jun-18
Document File: 6 page(s) / 68K

Publishing Venue

Motorola

Related People

Gadi Shirazi: AUTHOR [+2]

Abstract

This paper is about enabling a cellular communication in elevators. Since elevator is usually build as a big metal box, it forms a "Faraday electromagnetic cage" in which electromagnetic radiation can not penetrate. Therefore loosing the cellular connection in an elevator is a common phenomenon. Usually, this is not an important problem, but when a miss-function of the elevator occurs, a real problem arises. The situation where a person is trapped in a stuck elevator is well known and very unpleasant. Nowadays, when a cellular telephone is very common, it would be very convenient and sometimes crucially important to allow the use of a cellular telephone inside a stuck elevator in order to call for rescue.

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Emergency cellular RF link for metal elevators.

By: Gadi Shirazi, Yerach Krupnik

1. Introduction

This paper is about enabling a cellular communication in elevators.

Since elevator is usually build as a big metal box, it forms a "Faraday electromagnetic cage" in which electromagnetic radiation can not penetrate. Therefore loosing the cellular connection in an elevator is a common phenomenon. Usually, this is not an important problem, but when a miss-function of the elevator occurs, a real problem arises. The situation where a person is trapped in a stuck elevator is well known and very unpleasant. Nowadays, when a cellular telephone is very common, it would be very convenient and sometimes crucially important to allow the use of a cellular telephone inside a stuck elevator in order to call for rescue.

2. The problem to be solved

As said, The common structure of elevators crucially attenuates the cellular signal. A method to couple the radio signal of the cellular telephone inside and outside of the elevator is needed.

3. Known solutions to the problem

There are few methods of communicating from stuck elevators such as elevator alarm, internal microphone and even shouting. But all these old fashion methods pale compering to the opportunity to simply talk with a cellular telephone, which is so common. 

4. The proposed solution

The proposed solution is a RF coupler from the inner volume of the elevator to the outside as shown in Fig. 1. The radio antenna is inserted into the coup...