JPH05191126A - Foil-shaped antenna - Google Patents

Abstract

PURPOSE: To obtain an antenna with as less loss as possible, with excellent radiating characteristics, which is easily manufactured and whose size is extremely shorter than a quarter of wavelength to be a problem. CONSTITUTION: An inductance 2 is arranged as a serial circuit between radiating factors 1 and constituted as an approximately linear lead wire chip. The lead wire chip is arranged so that a radiating area radiated from the lead wire chip is compensated in a remote area. Only one side of a foil is coated. A matching circuit is constituted as an electrically conductive coating part of a carrying material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a non-conductive carrier material,
A foil-like antenna having a radiating element configured as a conductive coating coating a carrier material and an inductance configured as a conductive coating, the matching circuit being provided on the foil. It is about.

[0002]

2. Description of the Related Art A rod-shaped antenna is usually used as an antenna for a radio telephone. The length of the rod antenna is a quarter of the wavelength to be transmitted or received. But,
This may not always be possible for mechanical reasons, so a matching circuit is needed in some cases. This matching circuit is usually composed of discontinuous components. An antenna signal is supplied to these components or is supplied from these components to the antenna.

A rod-shaped antenna usually mounted on the outside of a radio telephone and discontinuous components (capacitor, coil,
The configuration of the resistor) can be regarded as a time-consuming process in manufacturing technology.

From EP 0 274 592 a foil-shaped antenna is known in which the radiating element and the inductance are constructed as a conductive coating of the carrier material. The radiating element and the inductance are arranged as a series circuit. Since the size of the foil antenna used as the indoor antenna is relatively large, both the radiating element and the inductance can be configured as a conductor track having a constant width. The inductance extends as a linear conductor track piece and the radiating element extends in a meandering line. Separate electrical components are used to construct the matching circuit. The capacitors and inductances required for this are brazed to the associated conductor tracks.

[0006] EP-A-0 066 094 discloses a foil-shaped antenna provided with switching elements in order to predetermine the mode of operation of the individual elements of the antenna which are electromagnetically coupled to each other.

DE-A 3306054 proposes a foil antenna in which the spatial position and shape of the antenna system is determined by a flat structure (foil). Further, it has been proposed that the line transformer, the coil, and the capacitor are formed on the foil in a flat and flexible structure by arranging the conductors in parallel, in addition to the original antenna. As with matching circuits with discontinuous components, such a structure causes losses that weaken the antenna signal.

The antenna proposed in this publication must have a substantially square surface and must be laid, for example, under a carpet. On the other hand, in the case of a wireless telephone, it is important to make the antenna compact.

[0008]

The object of the present invention is to reduce loss as much as possible, to have excellent radiation characteristics, to be easy to manufacture,
It is to provide an antenna whose size is significantly shorter than a quarter of the wavelength in question.

[0009]

According to the present invention, in order to solve the above-mentioned problems, the inductance is arranged between the radiating elements as a series circuit and is configured as a substantially linear conductor wire piece. The conductor pieces are arranged so that the emitted radiation area is compensated (kompensieren) in the far range,
The foil is coated on only one side and the matching circuit is designed as a conductive coating of the carrier material.

The foil antenna according to the invention is designed as a linear antenna. In order to keep the size of the antenna as small as possible, the antenna is divided into several radiating elements with an inductance arranged between them. The radiating elements are then arranged for optimum matching at the desired frequency. Both the radiating elements and the inductance arranged between them are formed on the carrier (foil) as electrically conductive surfaces. Similarly, despite the antenna being optimally matched to the desired frequency,
Furthermore, the necessary matching circuits are provided on the carrier. In order to reduce the structural length, in particular, the radiating elements are arranged in the direction of polarization (at the mounting position of the foil), while they are also arranged in the plane of the foil in a direction perpendicular thereto. The desired polarization direction is maintained despite the very space-saving construction in which the radiating elements are arranged on a substantially square surface.

According to the invention, the inductance arranged between the individual radiating elements is designed as a substantially straight conductor piece. In this configuration, the vertically long S
A letter-shaped configuration or a stepped configuration is also conceivable.

In this case, it should be noted that the inductance partially compensates the anti-phase conductors. The foil antenna according to the invention should also be designed in such a way that the linear conductor strips act as an inductance, while in the far field the radiation areas of these inductances are compensated. The in-phase radiation field of the radiating element is maintained.

The foil antenna according to the invention can be manufactured by coating both sides of a carrier material. However, it is also possible to coat only one side. This is particularly advantageous in terms of manufacturing technology.

Advantageously, the individual radiating elements are juxtaposed in one direction. This results in a first, substantially linear arrangement, which substantially corresponds to the desired polarization direction in the mounted state of the antenna. It is advantageous to provide a second, likewise substantially linear arrangement of radiating elements laterally offset with respect to this first substantially linear arrangement of radiating elements.

In a particularly advantageous embodiment, the individual faces of the radiating element intersect in the direction of projection perpendicular to the two parallel arrangements which are linear. The radiating elements in this arrangement, together with the inductance placed between them,
Almost forms a lightning structure. In this case, the radiating element is located almost at the bend of the lightning stroke. This increases the radiation resistance. Therefore, the influence of loss on the carrier and its surroundings is significantly reduced. Of particular importance is that the radiating elements are electrically accurately coupled. This means that the radiating elements are wired in phase exactly.

[0016]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a configuration (A) for mechanically shortening a half-wave dipole. High-frequency energy is supplied to the radiating element 1 of the half-wave dipole via the connecting member 4. This supply can be done symmetrically via suitable means or asymmetrically via coaxial cables.

When the radiating element 1 is unwound and the more inductive element 2 is inserted as a radiating element, this shortens the mechanical length and, more precisely, the higher the inductive inductance 2 inserted. Become. B and C in FIG. 1 show specific examples thereof. Of course, the effect diminishes in the direction of the end of the radiating element 1, so that the inductivity must be even higher. If the inductivity is too high, the loss may increase.

Any conductor is inductive. It can be almost assumed that the smaller the diameter of the conductor, the greater the inductivity of the conductor. Therefore, it is also possible to form various inductive properties in the decimeter or microwave range by stretching the conductor.

FIG. 1D shows the so-called "split inductive (verte
ilte Induktivitaeten) "is a concrete example of further shortening the antenna. This can reduce the loss. It has to be removed by a simple wiring part 3.

FIG. 2 shows an embodiment of the invention for a quarter wave antenna. In this case, the casing 5 is a "counterpoise". From F to I in FIG. 2, the configuration for shortening the quarter-wave antenna is shown. The radiating elements do not necessarily have to be stacked. According to the invention, the radiating elements can be arranged laterally offset. Of course, you can only shift a small amount. If this is not the case, the antenna directivity diagram of the quarter-wave antenna I will shift considerably due to phase disappearance. It should be noted that the inductance of the reverse wire as illustrated in I of FIG. 2 is partially compensated. The quarter-wave antenna should also be designed in such a way that the straight wire piece 2 acts as an inductance, while the radiation field of this inductance is compensated in the far field. According to the invention, the in-phase radiation range of the radiating element 1 remains.

FIG. 3 shows an embodiment of a shortened antenna having a size of about 25 × 25 mm. The antenna has a copper layer coated on a suitable carrier material (eg, polyamide, or epoxy glass fiber foil). The four radiating elements 1 are connected by three inductances 2. A transmitter consisting of a conductor inductance 3 adapts the antenna to a 50 ohm antenna connector 4. This embodiment is considerably more compact than the 300 mm wavelength to be received.

Other antennas are also conceivable, for example an antenna such as a dipole which has been strongly shortened as described above.

Next, advantageous structures of the present invention will be listed.

(1) A foil-shaped antenna characterized in that the radiating elements are arranged in series on a substantially straight line.

(2) A foil antenna, wherein the radiating elements are arranged in series on at least two straight lines which are parallel to each other.

(3) The foil-like antenna according to the above-mentioned item 2, wherein the radiating elements form projection planes which vertically intersect with each other on a straight line parallel to each other in the projection direction.

[0028]

Since the antenna according to the present invention has a compact structure, it can be completely housed in the casing of a radio telephone. The casing then forms the counterpoise of the antenna. The antenna according to the invention is also simple to manufacture, especially for SMD technology. Furthermore, it is possible to save external parts, and the directional characteristics are excellent and the efficiency is high. The main emission direction is about 30 ° downward with the device standing vertically and excellent omnidirectional characteristics. Further, the antenna according to the present invention is less likely to be detuned by operating the wireless telephone.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration for shortening a conventional half-wavelength dipole.

FIG. 2 shows a configuration for shortening a quarter wave radiator according to the present invention.

FIG. 3 shows a special configuration of a shortened quarter wave radiator.

[Explanation of symbols]

 1 radiating element 2 inductance 3 coating part 4 antenna connector

Claims (1)

[Claims] 1. A non-conductive carrier material, a radiating element configured as a conductive coating portion coating the carrier material, and an inductance also configured as a conductive coating portion, In a foil antenna in which a matching circuit is provided on the foil, the inductance is arranged as a series circuit between the radiating elements and is configured as a substantially straight wire piece,
The conductor piece is arranged so that the radiation area radiated from the conductor piece is compensated in a long-distance region, the foil is coated on only one side, and the matching circuit is configured as a conductive coating part of the carrier material. A foil-shaped antenna characterized by being present.