JPH1155032A - Antenna structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna structure of opposite side communication equipment with which satisfactory transmission/ reception sensitivity can be secured independent of mobile body direction. SOLUTION: An antenna 30 is provided with an antenna 10 for horizontal polarization composed of plural waveguides 1, a radiator 2 and a reflector 3, and with an antenna 20 for vertical polarization composed of plural waveguides 4, a radiator 5 and a reflector 3. The plural waveguides 1, the radiator 2 and the reflector 3 consisting of the antenna 10 for horizontal polarization are arranged on the same plane parallel to the ground. Besides, the plural waveguides 4 and the radiator 5 consisting of the antenna 20 for vertical polarization are arranged on the same plane vertical to the ground. Radio waves are exchanged while arranging the respective antennas 10 and 20 so that their polarizing planes can be mutually orthogonal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna structure of a communication device for transmitting and receiving radio waves to and from a non-contact type IC card or the like.

[0002]

2. Description of the Related Art Conventionally, IC cards have been used as shopping cards, hospital outpatient cards, and the like. The IC card has a built-in IC chip, and can store data, input / output data to / from the outside of the card, and the like.

[0003] IC cards are roughly classified into a contact type and a non-contact type according to a method of inputting and outputting data. Contact type
This is a method in which an external electric contact is brought into contact with an electric contact formed on the card surface to input / output operating power and data. The non-contact type is a method in which there is no physical contact portion on the card surface and data with the outside of the card is input / output by wireless or magnetic coupling.

In particular, when data is wirelessly input / output by a non-contact type IC card, a transmission / reception antenna is required for each of the inside of the IC card and a communication device on the other side for transmitting / receiving radio waves to / from the IC card. Becomes This transmission / reception method includes a case where data is input / output after placing the IC card in a predetermined place, and a case where data is input / output without placing the IC card within a range where radio waves can be transmitted / received (for example, when a person Input / output of data while moving while holding the IC card).

[0005]

When data is transmitted and received without a non-contact type IC card as a mobile body being fixed by radio, the direction of an antenna built in the IC card, the direction of the IC card, Since the relative orientation with respect to the antenna of the communication device on the other end that transmits and receives radio waves is not determined, the reception sensitivity of radio waves is not stable.

For example, if a dipole antenna having directivity is considered as an antenna in an IC card and an antenna in a communication device on the other end, respectively, the direction of a pole constituting the antenna in the IC card and the antenna in the communication device on the other side are considered. When the direction of the poles constituting the antenna is parallel, the receiving sensitivity is highest, but when the direction is vertical, the receiving sensitivity is lowest. When the receiving sensitivity is in the lowest state, data cannot be transmitted and received between the IC card and the communication device on the other end, and desired processing cannot be performed.

[0007] The present invention has been made in view of the above points, and an object of the present invention is to provide an antenna structure of a communication device of a communication partner which can ensure good transmission / reception sensitivity regardless of the direction of a moving body. Is to provide.

[0008]

In order to solve the above-mentioned problems, an antenna structure according to the present invention is arranged such that the polarization planes of a plurality of antennas having directivity are arranged so as to intersect with each other, thereby providing an arbitrary polarization plane. Transmission / reception can be performed with respect to a radio wave having the following characteristics, so that good transmission / reception sensitivity can be obtained even when transmission / reception is performed with a device whose antenna direction is not determined.

In particular, by arranging a plurality of antennas so that the planes of polarization are orthogonal to each other, it is possible to secure good reception sensitivity to horizontally polarized waves or vertically polarized waves, and to improve horizontal and vertical polarization. Even for a radio wave having a polarization plane deviated from the wave, the horizontal and vertical components therein are transmitted / received to or from any of the antennas, so that transmission / reception sensitivity can be ensured for radio waves of all polarizations.

[0010] Further, by configuring the plurality of antennas with Yagi antennas, the transmission / reception sensitivity in one direction can be increased, and good transmission / reception sensitivity can be ensured for moving objects within a predetermined range.

Further, since the reflector used in the Yagi antenna is formed in a curved shape, the reflector can be shared among a plurality of antennas, and the radio wave can be reflected over a wide range. Transmission / reception sensitivity can be improved.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an antenna structure according to an embodiment of the present invention will be specifically described with reference to the drawings.

FIG. 1 is a perspective view showing an antenna structure according to one embodiment. The antenna 30 includes a horizontal polarization antenna 10 including a plurality of directors 1, a radiator 2, and a reflector 3;
The antenna includes a vertically polarized antenna 20 including a plurality of directors 4, a radiator 5, and a reflector 3, and a rod-shaped fixing member 6 for fixing the antenna. The horizontal polarization antenna 10 and the vertical polarization antenna 20 are generally called Yagi antennas.

The above-mentioned antenna 30 is for transmitting and receiving radio waves to and from an antenna built in, for example, an IC card (not shown) as a moving body.
It is connected to a data processing device (described later) that performs a predetermined process based on data sent from the card.

Each of the directors 1 is a rod-shaped conductive member having a predetermined length, and the length is set, for example, to a value obtained by multiplying a half wavelength of a transmission / reception radio wave by a predetermined value.
The radiator 2 is a folded half-wave dipole antenna, and a transmission / reception signal line is connected to an end thereof. Reflector 3
Is formed as a reflector having a curved surface shape in which an incident radio wave converges at the position of the radiator 2.

Each of the plurality of directors 1, radiators 2, and reflectors 3 constituting the antenna 10 for horizontal polarization is a fixed member 6
The plurality of directors 1 and the radiators 2 are arranged on the same plane at predetermined intervals. A plane including the plurality of directors 1 and the radiator 2 is horizontal to the ground, and can receive a horizontally polarized radio wave with the highest sensitivity. Similarly, each of the plurality of directors 4, radiators 5, and reflectors 3 (common to the reflectors 3 configuring the horizontal polarization antenna 10) configuring the antenna 20 for vertical polarization is fixed on the fixing member 6. The plurality of directors 4 and the radiator 5 are arranged at a predetermined interval, and are arranged on the same plane (different from the plane including the above-described director 3 and the like). The plane including the plurality of directors 4 and radiators 5 is perpendicular to the ground, and can receive a vertically polarized radio wave with the highest sensitivity. In addition, the antenna 3 of the present embodiment is the antenna 1 for horizontal polarization.
Although the antenna 0 and the antenna 20 for vertical polarization are combined, the present invention is not limited to the case where two antennas for horizontal polarization and vertical antenna are combined, and two antennas whose polarization planes are orthogonal to each other may be combined. .

Next, a method of transmitting and receiving radio waves using the above-described antenna 30 will be described. FIG.
FIG. 2 is a diagram illustrating a configuration of a data processing device connected to the data processing device. For example, assuming that an IC card (not shown) as a moving object is considered as a communication device for transmitting and receiving data to and from the data processing device 40 shown in FIG. A radio wave including a request for transmitting storage data is transmitted to the IC card, and the storage data is returned from the IC card as a response to the transmission request. The data processing device 40 receives a radio wave including the stored data returned from the IC card via the antenna 30, and performs a predetermined process based on the stored data.

A data processing device 40 shown in FIG. 2 includes a processing unit 41 for processing transmission / reception data, a memory 43 for storing transmission / reception data, etc., a transmission unit 45 for modulating transmission data and outputting a transmission signal. A receiving unit 47 for demodulating a received signal and outputting received data, a switch 49 for switching a transmitting antenna under the control of the processing unit 41, a switch 51 for switching a receiving antenna, and an amplifier for amplifying and outputting the transmitted signal 53 and 55, amplifiers 57 and 59 for amplifying and outputting the received signal, and transformers 61 and 63 for impedance matching.

FIG. 3 is a diagram showing an operation procedure of a radio wave transmission / reception process performed via the antenna 30, and shows a control operation by the data processing device 40. Hereinafter, description will be given along the operation procedure shown in FIG.

The processing section 41 outputs a control signal to the two switches 49 and 51 so that data can be transmitted and received via the horizontal polarization antenna 10. Switches 49, 5
1 switches the connection state to the horizontal polarization antenna 10 side according to the control signal output from the processing unit 41. Next, the processing unit 41 sends a data transmission request to one of the transmission / reception partner devices (for example, an IC card) via one horizontal polarization antenna 10 (step 101).

Specifically, predetermined data corresponding to the data transmission request is input from the processing unit 41 to the transmission unit 45,
This data is modulated by the transmission unit 45. The modulated signal is further input to the amplifier 53 via the switch 49 and power-amplified, and then transmitted from the horizontal polarization antenna 10 via the transformer 61.

Next, the processing section 41 executes the above-described step 1
In order to check whether there is a response corresponding to the transmission request output from the horizontal polarization antenna 10 in the process of 01, the radio wave arriving at the horizontal polarization antenna 10 is received (step 10).
2) The receiving data obtained by demodulating the received radio wave by the receiving unit 47 is temporarily stored in the memory 43 (step 103).

Thereafter, the processing section 41 determines whether or not the received data contains a predetermined synchronization pattern (step 104). In response to the data transmission request transmitted in step 101, an IC which is
When an expected response is transmitted from the card and this response signal is received by the antenna 10 for horizontal polarization, a predetermined synchronization pattern is included in the data stored in the memory 43 in step 103. There should be. If the synchronization pattern is included, the processing unit 41 reads necessary data from the data stored in the memory 43 and executes a predetermined process (step 109).

On the other hand, when the data stored in the memory 43 does not include a predetermined synchronization pattern,
The processing unit 41 determines that the radio wave is not normally transmitted and received between the horizontal polarization antenna 10 and the antenna in the partner device (for example, the antenna in the IC card), and sets the vertical polarization antenna 20 to A control signal is sent to the two switches 49 and 51 so that data can be transmitted and received through the switch, and the connection state is switched to the vertical polarization antenna 20 side. Next, the processing unit 41 sends a
A data transmission request is sent via the vertical polarization antenna 20 (step 105).

Specifically, predetermined data corresponding to the data transmission request is input from the processing unit 41 to the transmission unit 45,
This data is modulated by the transmission unit 45. The modulated signal is further input to the amplifier 55 via the switch 49 and power-amplified, and then transmitted from the vertically polarized antenna 20 via the transformer 63.

Next, the processing section 41 executes the above-described step 1
In order to check whether there is a response corresponding to the transmission request output from the vertical polarization antenna 20 in the process of step 05, the radio wave arriving at the vertical polarization antenna 20 is received (step 10).
6) The receiving data obtained by demodulating the received radio wave by the receiving section 47 is temporarily stored in the memory 43 (step 107). After that, the processing unit 41 determines whether a predetermined synchronization pattern is included in the received data (Step 108).

When a valid response is sent from the IC card, which is the partner device, in response to the data transmission request transmitted in step 105, and this response signal is received by the vertical polarization antenna 20 Step 107
In, the data stored in the memory 43 should include a predetermined synchronization pattern. If the synchronization pattern is included, the processing unit 41 reads necessary data from the data stored in the memory 43 and executes a predetermined process (step 109).

As described above, the horizontally polarized antenna 10
And the vertical polarization antenna 20 are arranged so as to intersect with each other, and these antennas are switched according to transmission / reception sensitivity to be used to transmit / receive radio waves having an arbitrary polarization plane. Therefore, good transmission / reception sensitivity can be obtained even when the direction of the antenna of an IC card or the like on the other side of transmission / reception cannot be determined.

In particular, by arranging the horizontal polarization antenna 10 and the vertical polarization antenna 20 so that their respective polarization planes are orthogonal to each other, it is possible to obtain good reception of horizontally polarized or vertically polarized radio waves. Sensitivity can be ensured, and even for radio waves with a polarization plane deviated from horizontal and vertical polarizations, the horizontal and vertical components in them are transmitted to and received from either antenna, so radio waves of all polarizations , A good transmission / reception sensitivity can be secured.

In addition, since the horizontal polarization antenna 10 and the vertical polarization antenna 20 are Yagi antennas, the transmission / reception sensitivity in one direction can be increased, which is good for an IC card or the like within a predetermined range. Transmission and reception sensitivity can be secured.

The reflector 3 used for the Yagi antenna
Is formed in a curved shape, so that the horizontally polarized antenna 10
The reflector 3 can be shared by the antenna and the vertical polarization antenna 20, and the radio wave can be reflected over a wide range, so that the transmission / reception sensitivity can be further improved.

The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the present invention. For example, in the above-described embodiment, the horizontal polarization antenna 10 and the vertical polarization antenna 20 are configured by Yagi antennas, but may be configured by other antennas. For example, another antenna having directivity such as a dipole antenna may be used. Further, the shapes, arrangements, and the like of the horizontal polarization antenna 10 and the vertical polarization antenna 20 of the above-described embodiment are as shown in FIG. 1, but they may be changed as appropriate. For example, the number and length of the directors 1 and 4 may be changed as appropriate.

In the above-described embodiment, the horizontal polarization antenna 10 and the vertical polarization antenna 20 are fixed to the fixing member 6.
Are arranged so as to be orthogonal to each other, but these arrangements may be changed as appropriate. For example, a horizontally polarized antenna 1
Instead of making the plane of polarization 0 and the plane of polarization of the antenna 20 for perpendicular polarization intersect at a predetermined angle other than orthogonal, the antenna 10 for horizontal polarization and the antenna 20 for vertical polarization You may arrange | position separately.

In the above-described embodiment, the reflector 3 is a parabolic antenna having a curved surface. However, the shape may be changed as appropriate. For example, it may be formed of a rod-like member like the director 1 and the like.

[0035]

As described above, according to the present invention, by arranging the polarization planes of a plurality of antennas having directivity so as to intersect with each other, good transmission / reception sensitivity is ensured regardless of the direction of the moving object. can do.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an antenna structure according to an embodiment.

FIG. 2 is a diagram illustrating a configuration of a data processing device connected to an antenna.

FIG. 3 is a diagram illustrating an operation procedure of a radio wave transmission / reception process performed by the data processing device.

[Explanation of symbols]

 1, 4 director 3 reflector 2, 5 radiator 10 antenna for horizontal polarization 20 antenna for vertical polarization 30 antenna 40 data processing device

Claims (4)

[Claims] A plurality of antennas having directivity;
An antenna structure, wherein the polarization planes of the plurality of antennas cross each other. 2. The antenna structure according to claim 1, wherein the polarization planes of the plurality of antennas are arranged to be orthogonal to each other. 3. The antenna structure according to claim 1, wherein the plurality of antennas are Yagi antennas. 4. The antenna structure according to claim 3, wherein the Yagi antenna includes a reflector having a curved surface, and the reflector is shared by the plurality of antennas.