NZ248624A

NZ248624A - Radiophone handset: radiation directed away from user's head

Info

Publication number: NZ248624A
Application number: NZ248624A
Authority: NZ
Inventors: Claudio Maggio; Luigi Panico
Original assignee: Alcatel Australia
Priority date: 1992-09-18
Filing date: 1993-09-09
Publication date: 1996-01-26
Also published as: EP0588271B1; AU4607593A; EP0588271A1; ITMI922146A1; DE69318361T2; IT1255602B; ES2116378T3; AU668748B2; ATE165942T1; ITMI922146A0; DK0588271T3; DE69318361D1

Abstract

The present invention relates to a portable transceiver apparatus, in particular a radiomobile telephone set, with low irradiation of the user, comprising a handset and an antenna, having an asymmetric radiation pattern, applied to said handset. Since such apparatuses, when in use, are placed alongside the user's head, a great amount of electromagnetic waves pass through it, in particular with the continuous increase in the transmission frequency and the consequent decrease in the dimension of the antenna the irradiation of the user's head is and will become a serious problem. The aim of the invention is to provide a portable transceiver apparatus so as to minimize the irradiation of its user. By using an antenna having an asymmetric irradiation pattern such as to be extremely limited in the directions of the user's head, a greatly reduced irradiation can be obtained. <IMAGE>

Description

<div class="application article clearfix" id="description"> 24 86 24 Priority Date(s) Complete Specification Filed: Class: (6) /kftfijJ^.9:./../&/.$. Publication Date: 1336. P.O. Journal No: . ......:../!'fr£?..<rr? ORIGINAL NEW ZEALAND PATENTS ACT 1953 COMPLETE SPECIFICATION "MOBILE RADIOTELEPHONE HAVING ASYMMETRIC RADIATION PATTERN" WE, ALCATEL AUSTRALIA LIMITED, qoo 005 3^ A Company of the State of New South Wales, of 280 Botany Road, Alexandria, New South Wales, 2015, Australia, hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: 1 24 86 2 4 This invention relates to mobile radio telephone sets having a handset and an antenna attached to said handset, and in particular to a mobileradio telephone with low irradiation of the user by energy radiated from the antenna. In Figs. 1 and 2 of the accompanying drawings, there are illustrated 5 schematicallyu in a side view two known mobileradio apparatuses; Fig. 1 shows the Motorola 8800X model and Fig. 2 shows the 9800X model. The schematic side view of Fig. 1 is typical of all the protable transceiver apparatuses. Such apparatuses basically comprise a handset AC and an antenna AA attached to the handset. Located inside said handset generally are a loudspeaker AL, a 10 microphone AM, a control panel AK and the circuitry for operating the apparatus. The antenna AA of a radiomobile telephone set is placed in the upper portion of the handset AC; several models, all of the retractile and fixed whip type are available. 15 Since such apparatuses, when in use, are placed alongside the user's head, a substantial amount of electromagnetic waves pass through the head. With the continuous increase in the frequency used for transmission, at present a 900 MHz frequency is used but the trend is to achieve 60 GHz in the future, the dimensions of the antenna decrease and therefore the distance between the 20 antenna and the user's head will become practically nil. Irradiation of the user's head is and will become a serious problem, particularly if the increase in transmission frequency is taken into account. It is an object of the present invention to provide a portable transceiver 2 24 86 24 apparatus arranged to minimize the irradiation of its user. According to the invention there is provided a portable transceiver apparatus, including a handset and an antenna attached to said handset. Wherein said antenna is arranged such that its radiation pattern is extremely 5 limited in the direction of the heads or a user using the said apparatus. By using an antenna having a suitable asymmetric radiation pattern, such as to be extremely limited in the direction of the user's head, a considerable reduction in the irradiation can be obtained. In order that the invention may be readily carried into effect, embodiments 10 thereof will now be described in relation to the accompanying drawings, in which: Figs. 1 and 2 represent schematic side views of two prior art appasratuses, and Fig. 3 is a possible radiation pattern of the handset-antenna assembly in accordance with the present invention, represented in overlap to an apparatus 15 and to the user's head. From Figs. 1 and 2 two schematic side views of two prior art portable transceiver apparatuses can be seen; for the purpose of describing the present invention it will suffice to say that such apparatuses comprise a handset AC and an antenna AA applied to the handset AC. 20 As already said, the solution, in accordance with the present invention, for limited the irradiation of the user;s head caused by a portable transceiver apparatus consists in using an antenna AA having a suitable asymmetric radiation pattern, such as to be extremely limited in the direction of the user;s 3 2 4 8 6 2 4 head. Naturally the radiation pattern of antenna AA is modified by the handset AC and its content and therefore, for precision's sake, it would be necessary to consider the overall radiation pattern; very often, the contribution from handset 5 AC can be, at least in a first approximation, neglected or made negligible by screening the handset AC itself. In Fig. 3, e.g., there is shown one of may possible radiation patterns RD of the assembly formed by handset AC and antenna AA in accordance with the present invention, represented in overlap to an apparatus and to the head U of its user. 10 Such radiation patterns having special shape can be obtained through suitable choice of the type and shape of antenna AA. A first possibility consists in using a screened whip antenna. Another possibility is to use high frequency antenna arrays. An exhaustive treatment of this topic can be obtained from H. Jasik, 15 Antenna Engineering Handbook, McGraw-Hill, in particular chap. 21 (High-Frequency Arrays) and from section 30.6 (Strip Transmission Lines). Such arrays basically comprise at least one horizontal-dipole radiator located at a suitable distance from a horizontal conducting plane. Several dipoles may be placed in parallel to form bays and several bays 20 can be associated to form curtains. Depending on the number and position, the radiation pattern assumes special shapes respectively increasing the vertical and horizontal directivity. In addition to the radiators(s) at least one reflector can be placed in the 4 24 8 6 24 back zone to limit the radiation pattern in suitable directions; such reflectors can be constituted by tuned dipoles operating in a passive manner, or by a vertical relecting screen, composed of densely-spaced horizontal turns. Other types of antennas usable individually or in array fashion are, e.g., 5 horizontal rhombic antennas, long singlewire antennas, horizontal V antennas both resonant and terminated. It is clear that in order to implement advantageously such types of angtennas for use on portable transceiver apparatuses one must be able to reduce at the maximum extent their overall dimensions. Variously-shaped 10 microstrip structures and, in addition, metal conducting planes are then used, if required; all being arranged on a substrate. An exhaustive treatment on microstrip antennas can be found bothe in the above-mentioned antenna engineering hand boom and in Collin, Robert "Antennas and Radiowave Propagation" McGraw-Hill, in particular at section 15 4.14 (Microstrip Antennas). If the antenna is mounted on a board, when the apparatus is not in use, the antenna can be located inside it and, when the apparatus is to be used, it can be drawn out by sliding or by turning over; this in order to reduce the overall dimensions and the handiness of the apparatus when not in use, of course. 20 The possible conformations of the microstrip structures which form the antenna are very many and those skilled in the art will be able to find the one which is best suitable for his needs in terms of operating frequency band, of directivity and of gain. 5 </div>

Claims

<div class="application article clearfix printTableText" id="claims"> What we claim is:

1. A portable transceiver apparatus, including a handset having a mouthpiece means and an earpiece means, said earpiece means comprising a transducer for producing acoustic energy that is radiated from the earpiece means, and an antenna 5 attached to said handset, wherein said antenna is arranged such that its electromagnetic radiation pattern is extremely limited in the direction of the acoustic energy radiation from the earpiece means, whereby, during use, irradiation of the head of a user by said electromagnectic radiation from the antenna is therefore extremely limited. 10

2. An apparatus as claimed in claim 1, wherein said antenna comprises a screened whip antenna.

3. An apparatus as claimed in claim 1, wherein said antenna comprises at least one horizontal dipole radiator disposed at a suitable distance from a horizontal conducting plane. 15

4. An apparatus as claimed in claim 3, wherein said antenna further comprises at least one reflector placed behind said radiator.

5. An apparatus as claimed in claim 1, wherein said antenna is a rhombic antenna.

6. An apparatus as calimed in claim 1, wherein said antenna is a long single-20 wire antenna.

7. An apparatus as claimed in claim 1, wherein said antenna is a resonant or terminated V antenna.

8. An apparatus as claimed in claim 1, wherein said antenna comprises variously conformed microstrip structures. 25

9. An apparatus as claimed in claim 8, wherein said antenna further comprises metallic conducting planes.

10. An apparatus as claimed in claim 8, wherein said antenna is housed on a j- II ny ■■■■! iinii^u N.Z. PATENT OFFICE- 1 0 NOV 1995 RECEIVED I 4 8 6 2 4 board that is located inside the apparatus when the latter is not used and can be drawn out by sliding or by turning over when the apparatus is to be used.

11. An apparatus substantially as herein described with reference to Figure 3 of the accompanying drawings. ALCATEL AUSTRALIA LIMITED (ACN 000 005 363) B. O'Connor Authorised Agent P5/1/1703 f -^"^ATE^OFr;cE "| ! "9 SEP 1993 .m </div>