JP2003046312A - Planar antenna device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an enhanced planer antenna which is mounted on the front side of a planar. SOLUTION: The planar antenna includes a rectangular conductive element formed from two square elements. The square elements are defined within the rectangle by a centrally located and bifurcated return conductor having two legs. Each square element is connected at one end to a connector element and at the other end to the return conductor. The dimensions of the square elements are chosen so as to maximize gain for selected radio frequencies. The antenna further includes one or more additional but partial square elements, each additional partial square element terminating adjacent the respective square element at one end and being defined by one leg of the return conductor on one side.

Description

Detailed Description of the Invention

This application is a co-pending US application Ser. No. 09/0.
It is a partial continuation application of No. 98,771.

[0002]

TECHNICAL FIELD The present invention relates to a mobile phone, a GPS
It relates to an antenna intended for use with radio frequency devices, such as position determination systems and other RF applications, to be affixed to a surface. Furthermore, the present invention relates to a method of manufacturing a conductor pattern on a substrate.

[0003]

BACKGROUND ART Currently, there are many applications in which RF antennas are used for communication. For example, a mobile phone,
Examples include GPS systems and wireless data networks. An antenna may be provided on the device, such as a stub unit in a cell phone, but in some cases it may be necessary to provide an external antenna. Further, in applications such as in-car cell phones, it is desirable to provide an auxiliary antenna that enhances signal strength. Traditional antennas traditionally used for such purposes have typically been mounted on top of cars. This increases wind noise, tends to destroy public objects, and ruins the appearance of the car.

For any antenna of this type, various issues need to be considered. Even away from the above problems, it is desirable that the antenna ideally be visually unobtrusive and provide maximum capture area. In addition, it is required to be easy to install and have electrical and structural reliability.

It has been proposed to provide the antenna by mounting the array inside the vehicle window. Shoemaker US Pat. No. 5,363,114 describes a planar serpentine antenna mounted on a carrier layer and mounted on the surface of a suitable vehicle. The antenna is disclosed as awaiting a curved pattern placement.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an improved antenna mounted on a planar surface.

[0007]

[Means for Solving the Problem] According to one viewpoint,
The present invention is a planar antenna including a rectangular conductive element formed from two square elements,
A square element is formed in the rectangle by a bifurcated return conductor centrally located and having two legs, each square element being connected at one end to the connector element and at the other end to the return conductor, the dimensions of the square element Is a planar antenna chosen to maximize the gain of the selected radio frequency,
The planar antenna further includes one or more additional but partial square elements, each additional incomplete square element being adjacent at one end to the corresponding square element. A planar antenna, characterized in that it is terminated and is formed by one leg on one side of the return conductor at the other end.

It will be appreciated that the term planar means both flat surfaces and surfaces that are smoothly curved, such as automobile windshields.

The antenna arrangement of the present invention has many advantages over existing designs. In intended applications, where the antenna is glued to an existing surface such as a window, it is not required that the conductive element itself is constitutively rigid, which allows the use of slight geometries. become. This also allows the antenna to have a relatively large capture area, even if the antenna is mounted on a surface and does not seem to be self-supporting.
In addition, the antenna is better able to receive vertically or horizontally polarized signals because there are elements that are arranged both horizontally and vertically. This is advantageous for applications where scattering is generated by buildings and other buildings.

The present invention is also a method of providing a conductive element on a substrate, comprising the steps of printing a conductive pattern on the substrate using conductive ink, and forming a pattern of the conductive ink on an electrode in an electroplating process. For use as a method, the method further comprises the step of electrodepositing a conductive material on the printed conductor pattern.

Traditionally, the conductive material will be copper. The parameters of the electroplating process will depend on the process chosen, but should be set to provide the proper copper thickness, but too much copper deposit will cause the pattern to suffer mechanical failure. It shouldn't be so much that it gets easier. The inventor has found that a thickness of about 25 microns is suitable for mobile phone applications.

The pattern is properly printed using screen printing. In fact, large sheets of flexible material can be printed and cut with the proper tools to provide many antenna arrays.

After deposition, it is preferred to use a film that is tacky on both sides and is preferably transparent to provide a mechanism of adhesion to the desired surface and to prevent copper corrosion.

The inventor has investigated various practical manufacturing methods for antennas. The invention was born in this, but the method of the invention is equally applicable to the production of conductors in other substrate devices. The use of conductive ink alone did not provide adequate resistance to the antenna, and after enormous trials and failures reached the addition of electrodeposition to the printing approach.

[0015]

DETAILED DESCRIPTION OF THE INVENTION The present invention, in terms of a device designed to be adhered to a surface as an add-on device,
It is mainly explained. However, it will be appreciated that the antenna design of the invention can be formed as part of an article or within a portion of a vehicle or electronic device casing.

FIG. 1 shows an embodiment of the present invention which is suitable for use as a multi-band antenna for bands such as mobile phone frequencies, global positioning system (GPS) frequencies, and personal communication service (PCS) frequencies. Shows.

The antenna 10 has a substantially rectangular shape and is formed with four elements 12, 13, 17, and 18. The two elements 12 and 13 are square elements connected to the connector elements 32 and 33, respectively. Adjacent sides of elements 12 and 13 are formed from common return element legs 41, 42 which are connected to connector element 31. The two elements 17, 18 are incomplete square elements,
They are provided inside the elements 12 and 13, respectively.
However, instead of being connected to the connector elements 32 and 33 (like the square elements 12 and 13), the imperfect square elements 17, 18 stop before the legs 41, 42 respectively. The bifurcated element with legs 41, 42 comprises elements 12, 13, 17,
It forms the same side of the square (or imperfect square) formed by each of the 18 and is connected to the central connector 31.

This design is useful for many applications in the reception of multiple bands, and the multiple harmonics of the 900 MHz band are close to other bands, 1575 MHz for the GPS band and 1800-2000 for the PCS band.
It is based on the perception that it will occur, like MHz.
Elements 12 and 13 are 900MHz +/- 50MHz
Have suitable dimensions for. Central element 17, 1
8 allows for proper resonance in the GPS and PCS bands.

The dimensions of the antenna are shown on the figure. The tracks are preferably 1 mm in diameter, 30 microns thick and contain conductive ink and copper. The corners are shown at right angles, but may be rounded if desired. The antenna elements are mounted on a sheet 11, shown in dotted lines, made of a material of suitable flexibility. This is a suitable substrate such as clear polyester or materials used in flexible PCBs. This material is preferably transparent, and should be used to minimize obstruction of vision, especially when used in vehicles. For this discussed application, the film is 75 to 3
A thickness between 00 microns is suitable.

The appropriate length of the antenna element is determined by the following formula.

L = K / F where L is the length, F is the frequency, and K is a constant that varies with the dielectric properties of the material surrounding the conductor. In the case of the above mode, it is necessary to consider the dielectric characteristics of the substrate. It can be seen that in use, for example, the dielectric properties of the surface adhered to the windshield are also related to the constant K and consequently the length L.

In an antenna having a size as shown in FIG. 1, the resonant frequencies of the glass substrate are 99 MHz and 18
00MHz, antenna is 1.08: 1 in 900MHz band
With a VSWR of 2.8: 1 V in the 1575 MHz band
Has SWR.

The clear film used in the preferred embodiment cannot withstand high temperatures such as soldering. FIG. 3 shows in exploded view the arrangement developed by the inventor, which enables the connection of the antenna to the transmission circuit.

In the embodiment of FIGS. 2 and 3, the element 2
0 is a copper track connection. It is placed between the substrate film 11 and a film (not shown) with adhesive on both sides, so that it can be seen that the contacts are not exposed as in the case of a simple connection. Shim 21 is element 20
Underneath, the socket 22 is placed on top of the element 20. A conductive rivet, such as brass, has a shim hole 2
4, 25, 26, 27, element 20 and socket 2
It is inserted through two corresponding holes. This provides an electrical connection between the body of the socket 22 and the outer part 16 of the element 20. Further, another rivet passes through the central part of the element 20 and into the central part of the socket 22. The plug 23 is then easily connectable, in particular by means of a force-fitting mechanical connection, which allows the device to be provided with a cable link and to form a connection with the antenna.

FIG. 2 represents the connection arrangement of the device according to the invention. Multiple bands are received, causing them to connect to individual devices. Specifically, the individual devices are mobile phones and GPS receivers. Antenna 30 is socket 22
Is connected to the plug 23 of the cable 24 via.
The cable 24 connects the antenna to the antenna output division unit 2
Connect to 5. This enables connection 26 and G to the mobile phone.
A connection 27 to the PS receiver is formed.

Devices suitable for use as the antenna power divider 25 are commercially available. The function of this device is to isolate the output ports 26, 27 from each other so that they do not interfere with each other. In this particular situation, what is important is to protect the transmitted energy of the mobile phone from getting into the GPS receiver. It is desirable for the antenna power divider to wait at least -25 dB isolation in this application. The required isolation is the antenna 30
It can be seen that it depends on the device to be connected to.

Although the present invention has been described primarily in the context of an in-car antenna glued to the inside of a window, it will be appreciated that many other applications exist. The antenna of the present invention could be used to mount inside or outside a building wall, or to build a wireless LAN or other data network. It can easily be used to record and transfer mobile and fixed data, with modifications to suit changing bands.

The method of the present invention can be applied wherever highly conductive patterns are required, especially where transparent substrates are used.

[Brief description of drawings]

FIG. 1 is a plan view of an embodiment of the device of the present invention.

FIG. 2 is a schematic view of a connection according to another embodiment of the present invention that enables connection of a plurality of devices.

FIG. 3 is an exploded view of the connector arrangement of FIG.

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] July 1, 2002 (2002.7.1)

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

[Figure 3]

[Figure 1]

[Fig. 2]

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5J046 AA02 AA04 AA09 AA12 AB11                       MA09                 5J047 AA02 AA04 AA09 AA12 AB11                       EA01 EA06

Claims (9)

[Claims] 1. A planar antenna including a rectangular conductive element formed from two square elements, the square element being formed within said rectangle by a bifurcated return conductor centrally located and having two legs. , Each square element being connected to a connector element at one end and to the return conductor at the other end, the dimensions of the square element being chosen to maximize the gain of the selected radio frequency, the planar antenna further comprising: Contains one or more additional but imperfect square elements,
A planar antenna, characterized in that each additional, imperfect square element terminates at one end in the vicinity of the corresponding square element and is formed at one end by one leg on one side of the return conductor. 2. The antenna according to claim 1, wherein the conductive element is formed on a substrate. 3. The antenna according to claim 2, wherein the substrate is a flexible film. 4. The antenna according to claim 2, wherein the substrate is transparent. 5. The antenna according to claim 1, wherein all square elements are electrically connected to the same connector element and the return conductors are connected to electrically isolated connector elements. 6. The conductive element comprises a step of printing a conductive pattern on a substrate using a conductive ink, and a pattern formed from the conductive ink is used as an electrode in an electroplating process to print the conductive pattern on the printed conductive pattern. The antenna of claim 2 provided by a method further comprising the step of electrodepositing a conductive material on the substrate. 7. The antenna according to claim 6, wherein the conductor pattern is screen-printed on the substrate. 8. The antenna according to claim 6, wherein a plurality of conductor patterns are printed on the substrate, and a protective film is provided on the conductor patterns after electrodeposition. 9. The membrane is adhesive on both sides.
The antenna described.