EP1575124A1

EP1575124A1 - Integrated antenna and solar cell assembly and apparatus incorporating same

Info

Publication number: EP1575124A1
Application number: EP04445025A
Authority: EP
Inventors: Zhinong Ying; Mats Wolf
Original assignee: Sony Ericsson Mobile Communications AB
Current assignee: Sony Mobile Communications AB
Priority date: 2004-03-11
Filing date: 2004-03-11
Publication date: 2005-09-14

Abstract

The invention relates to an integrated antenna and solar cell assembly (2) and an apparatus (1A) provided with such an integrated antenna and solar cell assembly, e.g. a laptop computer or a mobile phone having such an assembly arranged on the outside. The antenna and solar cell assembly comprises at least one antenna patch and at least one solar cell panel being integrated as one multilayer element.

Description

Field of the invention

The present invention relates to an integrated antenna and solar cell assembly and an apparatus provided with such an integrated antenna and solar cell assembly, e.g. a laptop computer or a mobile phone having such an assembly arranged on the outside.

State of the art

Antennas in the form of flat antenna patches and solar cells are known components within the field of e.g. mobile communications. Both components require areas as large as possible to be most efficient. The problem is that there is only limited area available, especially in case of smaller electronic devices such as mobile phones, but also in laptop computers and palm computers.

Summary of the invention

The object of the present invention is to use the area on the apparatus in an efficient way by using the same area for both the antenna and the solar cell unit. The invention suggests an integrated unit of the antenna and solar cell, typically implemented as a layered structure.
In a first aspect the invention provides an antenna and solar cell assembly comprising at least one antenna patch and at least one solar cell panel.
According to the invention the assembly is integrated as one multilayer element.
In a preferred embodiment, the assembly comprises a solar cell panel layer, a conducting circuit layer, and an antenna patch layer.
Suitably, the conducting circuit layer comprises trace lines for connection to the solar cell panel layer.
Preferably, the trace lines are located at the sides of the conducting circuit layer, and symmetrically relative to a feeding position to the antenna patch layer.
Suitably, LC circuits are arranged to isolate the antenna patch layer from the solar cell panel layer.
A feeding pad may be arranged at a point on a central line of the antenna patch layer.
In one embodiment, the assembly comprises several antenna patches connected together as an antenna array.
The assembly may comprise several solar cell panels connected together.
Suitably, the solar cell panels are connected by means of a circuit strip arranged in the conducting circuit layer.
Suitably, the assembly is etched as one element.
In a second aspect the invention provides an apparatus comprising electronic components including a radio part connected to an antenna and powered by a battery, the battery being connected to a solar cell unit for providing charge power to the battery.
According to the invention, the apparatus comprises an antenna and solar cell assembly as set forth above.
The apparatus may comprise a base part and a lid, the lid being attached with a hinge to the base part so that the apparatus is foldable, wherein the antenna and solar cell assembly is arranged in the lid on the outside of the apparatus when the apparatus is folded.
In a preferred embodiment, the antenna and solar cell assembly is arranged above a ground plane.
Suitably, the ground plane is connected to the antenna patch by means of a pin.
In one embodiment, the ground plane is a circuit board carrying electronic components.
Said electronic components may comprise the radio part having a radio port connected to the antenna patch.
The apparatus may be a mobile radio terminal, e.g. a mobile telephone, a pager, a communicator, an electric organiser, a smartphone or a computer.

Brief description of the drawings

The invention will be described in detail below with reference to the accompanying drawings, in which:
Fig. 1A is a schematic perspective view of a laptop computer with an integrated antenna and solar cell assembly according to the present invention,
Fig. 1B is a schematic perspective view of a handheld size terminal with an integrated antenna and solar cell assembly according to the present invention,
Fig. 2 is an exploded view of the various layers of an assembly according to the invention, and
Fig. 3 is a schematic top view of the electric connections of the antenna patch.

Detailed description of preferred embodiments

As is mentioned in the introduction, the present invention relates to a combined antenna and solar cell assembly for portable devices, such as mobile telephones, pagers, communicators, electronic organisers, smartphones and computers. The common features are that they have a radio part using an antenna and rely on a battery as power source, which is supplied with auxiliary power from solar cells. Future mobile terminals will be multimedia wireless terminals. An advanced and thin system such as an adapted antenna will be required to enhance the data bit rate speed and system performance. This can be realised by using a smart antenna array. Built-in type miniantennas are attractive for portable mobile terminals.
Antennas consisting of flat antenna patches are known components. Generally, an antenna patch consists of a metal patch and a feeding pin
Another trend is that future mobile terminals will have a good energy backup and additional power collector by using solar cell panels. As is known, solar cell panels can be made from usually series-connected photovoltaic cells. There exists a multitude of different types of which several can be considered suitable for use in mobile terminals. Design parameters include efficiency in different lighting conditions, mechanical integrity, and cost.
Both the antenna and solar cells need an open surface to collect light and to transmit or receive RF signals.
A portable terminal has very limited room for the antenna installation, especially a patch antenna array which needs a lot of surface area. At the same time, solar cells also need a large surface area and usually they have a rectangular shape. According to the present invention, the antenna patch is integrated with a rectangular solar cell to form a patch antenna array. This kind of antenna can be used for cellular systems, diversity, satellite communication, Bluetooth and wideband LAN.
Fig. 1A shows a laptop size mobile computer 1A provided with an integrated antenna and a solar cell assembly 2 according to the invention. As is conventional, the computer comprises a base part 11A and a lid 12A connected by a hinge 13A. When the apparatus 1A is completely folded the assembly 2 is directed upwards for collecting light. When the apparatus is open the lid is more or less upright but can still collect some light. Usually a keypad is arranged on the base part 11A and a display is arranged on the lid 12A. When the apparatus is folded, the keypad and display are located on the inside. The keypad may consist of a touch screen. The keypad and the display are not shown as they do not form part of the present invention.
Fig. 1B shows a similar design in the case of a hand-held size mobile terminal 1B having an integrated antenna and solar cell assembly 2 in accordance with the present invention. The apparatus 1B comprises a base part 11 B, a lid 12B connected together by a hinge 13B as discussed above.
Fig. 2 shows an integrated antenna and solar cell assembly 2. The assembly is conveniently a rectangular patch element having a multilayer structure. The top layer is the semi-conductor solar cell panel layer 3, the second layer is a circuit layer 4 for guiding DC current from the solar cell panel layer 3, and the bottom layer is a conducting patch forming the patch antenna layer 5.
The solar cell panel is a photovoltaic cell and the patch antenna is a metal patch.
The size of the patch element is about half the wavelength of radio frequency. All three layers can be etched very closely as one multi-layer element. The assembly is located over a ground plane circuit board 6. The ground plane may be identical with the main printed circuit board (PCB) of the apparatus which also carry further components, especially the radio part of the apparatus. The main PCB forms a negative ground plane and a radio port constitutes the positive output of the radio part. In the alternative, the radio part of the apparatus is located on the main PCB in the base part 11A, 11B of the apparatus and the radio port is connected by leads through the hinge 13A, 13B to the antenna.
The solar cell panel is connected by metal trace lines 7 in the circuit layer 4. In order not to disturb the antenna by the DC circuits, the trace lines have to be located at the sides, symmetrically to the feeding position of the patch antenna 5.
Fig. 3 shows the arrangement of the RF feeding of the antenna 5 and the DC +/- port connected to the solar cell panel in the simplest case of one rectangular patch. LC circuits are used at each side to have RF isolation between the metal trace lines 7 and the patch antenna 5. The LC circuit thus acts as a high frequency filter letting DC current through and stopping RF current. Conveniently the RF feeding point 10 is on the dashed line which results in that the antenna radiates from the top and lower sides in fig. 3. In an alternative, two feeding points are used to obtain dual polarity. The feeding point is suitably a metal pad arranged on the patch antenna layer. The antenna may be fed by a metal pin (not shown) from the ground plane 6. A feeding network (not shown) for the antenna array is printed on the ground plane 6. The pin may by a pogo pin or spring etc.
As shown in figures 1A and 1B, the assembly 2 may be composed by a number of solar cell panels and patch antennas. In this case, the solar cells are connected by a DC thread 14A and 14B, respectively, and the circuit strip line 8 located in the circuit layer 4. The solar cell panels are connected in parallel/series depending on their output characteristics.
The antenna patches in figures 1A and 1B are further connected by an underlying network located in the ground plane (not shown). The feeding network may have various lengths to the different antenna patches in order to create the required phase difference for feeding the antenna patches as an array. Each assembly 2 is provided with an antenna feeding metal pin connected at feeding points and LC circuits arranged as shown in figure 3.
Thus the present invention provides an integrated antenna and solar cell assembly making efficient use of the available area on a portable apparatus. The solar cell may involve some RF loss because of its location on top of the antenna, but this is very small, especially with a bigger antenna array. With the present invention in fact a large area is made available for the antenna. As is appreciated by a person skilled in the art, the specific design of the solar cell panels and patch antennas may be varied within the frame of the present invention, the scope of which is only limited by the claims below.

Claims

An antenna and solar cell assembly (2), comprising at least one antenna patch (5) and at least one solar cell panel (3), characterised in that the assembly is integrated as one multilayer element.
An antenna and solar cell assembly according to claim 1, characterised in that the assembly comprises a solar cell panel layer (3), a conducting circuit layer (4), and an antenna patch layer (5).
An antenna and solar cell assembly according to claim 2, characterised in that the conducting circuit layer (4) comprises trace lines (7) for connection to the solar cell panel layer (3).
An antenna and solar cell assembly according to claim 3, characterised in that the trace lines (7) are located at the sides of the conducting circuit layer (4), and symmetrically relative to a feeding position (10) to the antenna patch layer (5).
An antenna and solar cell assembly according to any one of the preceding claims, characterised in that LC circuits (9) are arranged to isolate the antenna patch layer (5) from the solar cell panel layer (3).
An antenna and solar cell assembly according to any one of the preceding claims, characterised in that a feeding pad is arranged at a point (10) on a central line of the antenna patch layer (5).
An antenna and solar cell assembly according to any one of claims 1 to 5, characterised in that the assembly comprises several antenna patches connected together as an antenna array.
An antenna and solar cell assembly according to any one of the preceding claims, characterised in that the assembly comprises several solar cell panels connected together.
An antenna and solar cell assembly according to claim 8, characterised in that the solar cell panels are connected by means of a circuit strip (8) arranged in the conducting circuit layer (4).
An antenna and solar cell assembly according to any one of the preceding claims, characterised in that the assembly is etched as one element.
An apparatus comprising electronic components including a radio part connected to an antenna and powered by a battery, the battery being connected to a solar cell unit for providing charge power to the battery, characterised in that the apparatus (1A; 1B) comprises an antenna and solar cell assembly (2) as defined in any one of the preceding claims.
An apparatus according to claim 11, characterised in that the apparatus (1A; 1B) comprises a base part (11A; 11B) and a lid (12A; 12B), the lid (12A; 12B) being attached with a hinge (13A; 13B) to the base part (11A; 11B) so that the apparatus (1A; 1B) is foldable, wherein the antenna and solar cell assembly (2) is arranged in the lid (12A; 12B) on the outside of the apparatus when the apparatus is folded.
An apparatus according to claim 11 or 12, characterised in that the antenna and solar cell assembly (2) is arranged above a ground plane (6).
An apparatus according to claim 13, characterised in that the ground plane (6) is connected to the antenna patch (5) by means of a pin.
An apparatus according to claim 13 or 14, characterised in that the ground plane (6) is a circuit board carrying electronic components.
An apparatus according to claim 15, characterised in that said electronic components comprise the radio part having a radio port connected to the antenna patch (5).
An apparatus according to any one of claims 11 to 16, characterised in that it is a mobile radio terminal, e.g. a mobile telephone (1B), a pager, a communicator, an electric organiser, a smartphone or a computer (1A).