FR2724772A1 - MULTI-POSITION RIBBON ANTENNA AND METHOD FOR PRODUCING THE SAME - Google Patents

Abstract

A radio communications device (100) comprising high frequency circuits (415) positioned in the first part of the housing (101). A second housing portion (103) is movably supported on the first housing portion so as to be movable between an open, deployed position and a collapsed position, with the second housing portion projecting outwardly from the first portion. housing in the open position. An antenna assembly (107) is positioned in the second part of the housing. The antenna assembly includes an antenna conductor (542), a flexible dielectric layer (544), and a ground element (446), the ground element being positioned between the antenna conductor and the high circuits. frequency when the first and second housing parts are in the folded position.

Description

Title: Multi-position ribbon antenna and method

realization of it.

  Field of the Invention The present invention applies to antennas for communication devices. Technological background of the invention Radiocommunication devices comprise a transmitter and / or a receiver coupled to an antenna

  which emits and / or detects high frequency signals.

  The device may include a microphone to provide audio signals to a transmitter or a speaker to output signals received by a transmitter. Examples of such radiocommunication devices include unidirectional radios, two-way radios, radiotelephones, personal communication devices, and several other types of equipment. These communication devices often have a standby configuration in which the device is folded for storage, and an active communication configuration in which the antenna is deployed so as to

obtain optimal performance.

  With radiotelephones and two-way radios, it is typically desirable for these devices to have a reduced size when they are in standby mode in order to facilitate their storage and transport. For example, users prefer that the size of radiotelephones be reduced enough in the standby mode to allow them to be stored in a shirt or jacket pocket. In the active communication state, it is desirable that the device is

  long enough to position the top

  speaker so that it is adjacent to the user's ear, with the microphone near the user's mouth and the antenna remote from the user's body. It is desirable that the antenna is positioned distant from the body of the user because the body of the user constitutes a ground plane which

  disrupts reception of high frequency signals.

  One particularly effective way of positioning the antenna remote from the body of the user is to deploy the antenna from the body of the device during commissioning. By providing an antenna which folds up for storage and which is deployed for active communication, an antenna ensuring optimal active mode operation is provided in a

easy to store device.

  One difficulty encountered with such reconfigurable communication devices consists in providing a high performance antenna in the standby mode. For example, radio telephones are known to receive paging signals, e-mail, and alert call signals in the standby mode. However, the device body, including the internal electronic circuits inside the body, is typically in the near reactive field of the antenna in the storage position. This mass in the reactive near field decreases the performance of the antenna, which disadvantages reception of signals in the standby mode. Therefore, it is desirable to provide an antenna system having high performance characteristics when the communication device is deployed in an active communication mode and when the communication device is

  folded back into a waiting procedure.

Brief description of the drawings

  Figure 1 is a front perspective view showing a deployed radiotelephone comprising an antenna system according to the invention; Figure 2 is a front perspective view showing a folded radiotelephone according to Figure 1 in the standby configuration; Figure 3 is an exploded top perspective view showing the front housing, the high frequency (H.F.) printed circuit board, the logic printed circuit board, and the rear housing section; Figure 4 is a fragmentary view showing the interior of the radiotelephone housing according to the

  Figure 1 and schematically showing a transmitter-

  receiver; Figure 5 is a plan view of a radiotelephone cover according to Figure 1, with the front cover housing section removed and representing a first antenna; Figure 6 is a side view of the antenna

hood.

  Figure 7 is a perspective view from above

exploded view of the hood.

  Figure 8 is a perspective view from below

exploded view of the hood.

  Figure 9 is a top plan view

representing a ribbon antenna.

  Figure 10 is a top plan view

representing a ribbon antenna.

  Fig. 11 is a side view schematically showing a radiotelephone hood antenna in the open position; and Figure 12 is a cross-sectional view showing the cover according to the plane XII-XII on the

figure 11.

Detailed description of the drawings

  High frequency radio communication device circuits are positioned in the first part of the housing. A second part of the housing is movably supported on the first part of the housing so that it can move between an open deployed position and a folded position, the second part of the housing projecting outward from the first part of the housing in the open position. An antenna assembly is

  positioned in the second part of the housing.

  The antenna assembly includes an antenna conductor and an earth element, the earth element being positioned between the antenna conductor and the high frequency circuits when the first and

  second parts of the housing are in the folded position.

  The antenna system according to the invention is shown in a radiotelephone 100 comprising a cover 103 (FIG. 1), in which this invention is particularly advantageous. However, the invention can also be advantageously used in other devices, such as one-way or two-way radios, or any other communication device employing an antenna. Therefore, the term "device" as used in this document refers to all equipment of this type and their equivalents. A radiotelephone 100 is shown in FIG. 1. The radiotelephone comprises a housing 102 comprising a first part of the housing 101 and a second part of the housing 103. In the embodiment shown, the first part of the housing 101 is a radiotelephone body and the second part of the housing 103 is a cover pivotally connected to the body. the cover portion 103 of the housing moves between a deployed or open position, shown in FIG. 1 during an active communication mode, and a folded or closed position, shown in the

Figure 2 in standby mode.

  The radiotelephone body 101 comprises a rear body casing section 104 and a front body casing section 105 which are interconnected so as to define an interior volume containing electronic circuits among which there is in particular a printed circuit board HF 315 (FIG. 3 ) and a logic printed circuit board 314. A key block 106 includes keys 109 (only some of which are indicated by marks) associated with the key block. The keys 109 are accessible for manual actuation by the user in order to selectively close the switches 322 (only some of which are indicated by marks). The cover portion 103 of the housing shown at least partially covers the key block 106 when it is closed. The cover part of the housing can be longer in order to cover all the keys. The cover portion of the housing prevents actuation of the keys 109 when the cover is closed. In addition, the cover part of the case can put the phone in standby mode

when closed.

  The cover portion 103 of the housing has a

  antenna 107 referred to as the hood antenna in this document.

  The hood antenna is positioned between a front hood housing 111 (FIGS. 7 and 8) and a rear hood casing section 112 and it is therefore shown in transparency in FIG. 1. The sections of front hood housing and rear hood housing 111 and 112 are generally planar elements. The rear cover housing section 112 comprises a recess 439 intended to receive the antenna 107 and the front housing part 111. The cover housing sections are made of a suitable dielectric material, such as an organic polymer. The hood antenna 107 is sandwiched between these elements. The hood antenna 107 is in a deployed position shown in FIG. 1 when the hood 103 is open. The hood antenna is in a folded or retracted position, when the

cover 103 is closed (Figure 2).

  The transceiver circuit 415 is shown

  schematically in Figure 4. The transmitter circuit-

  receiver is mounted on the H.F. 315 circuit board (Figure 3). The transceiver circuit can be put

  implemented using any transmitter-

  traditional receiver adapted. The transmitter circuit

  receiver 415 is positioned in the first part of the housing 101 by traditional means, such as by assembling the printed circuit board 315 on the

  front housing section 105. The transmitter circuit

  receiver is connected to an elastomer connector 319 or to another means, which is connected to a flexible conductor 320. The flexible conductor 320 extends in a hinge assembly 418. The hinge assembly

418 includes a toggle 419.

  As shown in Figure 5, the hinge assembly 418 also includes a toggle 420 on the cover portion 103 of the housing intended to engage with the toggle 419. The flexible conductor, or transmission line, 320 is connected to the hood antenna 107 through the hinge assembly 318 when the hood 103 is connected to the body 102. The transmission line and the hinge assembly 418 ensuring the connection

  between the hood antenna 107 and the transmitter circuit

  receiver 415 can have any suitable structure, such as the hinge described in the US patent application, serial number 08/148718, filed on November 8, 1993 in the name of Tanya Rush et al. , whose

  description is incorporated into this document in

reference to it.

  Hood antenna 107 is a ribbon antenna

  which will be described with reference to Figures 6, 9 and 10.

  The antenna includes a ribbon conductor 542, a dielectric layer 544, and an earth layer 446. The ribbon conductor 542 is a microstrip ribbon. The conductor 542 (FIG. 9) is represented in the form of a half-wave conductor, generally rectangular, applied in a thin film on the dielectric layer 544. Alternatively, the ribbon conductor 542 can be a quarter-wave conductor with the remote edge of the supply line 440 connected to the earth layer 546 by conductive connectors 550. Those skilled in the art will understand that the configuration of the ribbon conductor can be circular, oval, square, or any other suitable configuration . The conductor can be made of any suitable electroconductive material, such as copper, a copper alloy, an aluminum alloy, or any other suitable material which can be applied in a thin layer on the dielectric by spraying the material into a liquid state or by fixing the material in a solid state using an adhesive. The

  ribbon conductor is connected to the transmitter circuit

  415 receiver through the line conductor

  440, strip 320, and conductor 319.

  The conductor 440 is connected to the ribbon conductor 542 by any suitable means, such as by welding, by the direct connection of the two conductors in

  using a ribbon, or by any other suitable means.

  The dielectric layer 544 is preferably a material with a high dielectric constant. Those skilled in the art will understand that the higher the dielectric constant of the material used for the dielectric layer, the smaller may be the structure of the conductor 542. Alternatively, the dielectric may be a charged dielectric. The dielectric is preferably a more solid material which can resist the forces exerted on the device if it is dropped or if it is subjected to any other ill-treatment. Therefore, Duroid 6010, having a dielectric value of 10, is a preferred dielectric material because it will not break if the radiotelephone 100 is dropped. Ceramics with more dielectric values

  can be used instead of Duroid 6010.

  The earth layer 446 is formed by any suitable electrical conductor. For example, the earth layer is a rectangular copper alloy plate. The earth layer, or element, 446 is connected to the earth through the conductor 441, the flexible strip 420, and a conductor 338. The earth conductor 338 is connected to an earth circuit, which comprises a metallized layer applied to inside the radiotelephone case 105. The conductor 441 is connected to the ground element 446 by any suitable means, such as by welding a direct contact between the two conductors with a tape over the point contact, or by any other

adapted means.

  To assemble the cover, the cover antenna 107 is inserted into the recess 439 (FIG. 7) with the layer of earth 446 facing upwards. In this orientation, the ribbon conductor 542 is oriented downward and abuts against the interior surface 760 of the rear cover housing section 112. The cover casing

  before 111 is then placed in the hollow 439 par-

  above the ribbon antenna 107. The front and rear boxes can be fixed with suitable adhesives,

  by fasteners, or by similar means.

  Flexible strips 440 and 441 extend outward from the cover portion of the housing. These conductors are fused into a flexible strip 320. The flexible strip 320 is inserted so as to extend through the hinge 418 and penetrate into the body casing section 105. The conductors in the strip are separated in order to be connected to the earth conductor

  338 and to the transceiver circuit 415.

  During commissioning, in the open position shown in Figure 11 the figure of the user (not shown) is positioned so that the user's ear rests against the earpiece 160 (Figure 1) and the cheek of

  the user is adjacent to the keypad 106.

  The ribbon antenna 107 is positioned in the cover so that the earth element abuts against the

  front housing section 111 facing the user.

  Consequently, the ribbon conductor 542 (FIGS. 11 and 12) is oriented in the opposite direction relative to the user, and towards the free space. Thus, the ground element 446 is positioned between the ribbon conductor and the user and it acts as a screen between the user and the ribbon. The user's body will not disturb the tuning of the ribbon conductor

542 in the active position.

  In the closed position shown in Figure 2, a rear housing section 112 is oriented in the opposite direction relative to the internal printed circuit boards 314 and 315 inside the radiotelephone body 102. The layer of soil 446 is positioned against the front cover section 111 (FIG. 12), which abuts the key block 106. Consequently, the ground layer 446 is positioned between the ribbon conductor and the electronic circuits in the housing 102. The ground layer provides a screen between the high frequency circuits inside the part of the radiotelephone body casing 102 and the layer of conductive tape 542. This grounded screen limits the effect of the transceiver circuit on the tuning of the ribbon antenna in the closed position. The ribbon antenna thus has substantially the same tuning characteristics in the folded storage position as well as in the active deployed position. Consequently, the constancy of the operation of the antenna in the folded storage position is

considerably improved.

  In practice, it is contemplated that a flexible dielectric layer, such as commercially available Duroid 6010 from Rogers Corporation (Chandler, Arizona), will be used. With such a dielectric, a

  half wave for a transmitter operating frequency

  800 MHz receiver requires approximately 5.92 cm and the quarter wave requires approximately 3 cm. For 1500 MHz, the half-wave implementation requires approximately 3.2 cm and the quarter-wave embodiment requires approximately 1.6 cm. The dielectric and earth elements preferably have external dimensions greater than those of the ribbon conductor, as shown in

Figures 9 and 10.

Claims (5)

  1. A portable radio communication device (100), comprising: a first part of the housing (101) high frequency circuits (415) positioned in the first part of the housing; a second part of the housing (103) movably supported on the first part of the housing so as to be able to move between an open deployed position and a folded position, the second part of the housing projecting outwards from the first part of the housing in the open position; an antenna assembly (107) positioned in the second part of the housing, characterized in that the antenna assembly comprises an antenna conductor (542) a flexible dielectric layer (544), the antenna conductor being mounted on the flexible dielectric layer, an earth conductor (446) fixed on the flexible dielectric layer, the earth conductor being positioned between the antenna conductor and the high frequency circuits when the first and second housing parts are in the folded position; and a power line strip (440) coupled between the antenna conductor and the high circuits frequency.   2. Portable radio communication device according to claim 1, further characterized in that the earth conductor (446) is a planar element having peripheral dimensions substantially greater than the peripheral dimensions the antenna conductor (542).   The portable radio device according to claim 2, further characterized in that the flexible dielectric layer (542) is a material   with high dielectric constant.   4. Portable radio communication device according to claim 3, further characterized in that the second part of the bolt case is a cover comprising dielectric sections (111, 112) and in that the antenna assembly 107 is arranged in   sandwich between the dielectric sections.   5. Portable radio communication device according to claim 4, further characterized in that the first and second housing parts are connected by a hinge assembly (418) and in that the supply line strip comprises a flexible conductor extending through the hinge assembly. Multi-position ribbon antenna and method of realization thereof.