JPH10260251A - Wireless data collection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make an apparatus small and low-cost by forming an antenna patch on a case box of an inquiry device, and connecting the antenna patch with a power feed point by a microstrip line. SOLUTION: A case box of an inquiry device is formed of resin by injection molding. An antenna patch 20 and microstrip lines 21, 22 are formed on a front face of the case box by plating. A ground pattern 23 is formed on a rear face of the case box. One end of the microstrip line 21 is connected to a right edge of the antenna patch 20 and one end of the microstrip line 22 is connected to a lower edge of the antenna patch 20. The other ends of the microstrip lines 21, 22 are connected to a power feed point 24. A transmission signal from a modulation circuit is applied to the power feed point 24, which propagates in the microstrip lines 21, 22. The propagating transmission signals are synthesized again at the antenna patch 20 and transmitted as an inquiry wave to a response device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless data collecting apparatus for collecting data of a device using wireless, and more particularly to a wireless data collecting apparatus using an antenna which can be easily miniaturized and has a low cost.

[0002]

2. Description of the Related Art A conventional wireless data collection device collects an output signal of a sensor circuit attached to a device or the like by an interrogator via a transponder, and uploads measurement data collected by the interrogator to a host computer or the like. And required processing.

FIG. 4 is a block diagram showing an example of such a conventional wireless data collecting apparatus. In FIG.
Is an oscillator, 2 is a divider, 3 and 11 are modulation circuits, 4, 5
And 8 are antennas, 6 is a demodulation circuit, 7 is a display, 9 is a detector, 10 is a control circuit, and 12 is a sensor circuit. 1 to 7 constitute an interrogator 50, and 8 to 11 constitute a responder 51.

In the interrogator 50, the output of the oscillator 1 is connected to the divider 2, and the two outputs of the divider 2 are
And the demodulation circuit 6. The output of modulator 3 is connected to antenna 4 and the output of antenna 5 is connected to demodulation circuit 6. The output of the demodulation circuit 6 is connected to a display 7.

On the other hand, in the transponder 51, the input / output of the antenna 8 is connected to the input terminal of the detector 9 and the output terminal of the modulation circuit 11, and the output of the detector 9 is connected to the control circuit 10.

The output of the control circuit 10 is connected to the modulation circuit 11, and the output from the sensor circuit 12 is connected to the control circuit 10.

Here, the operation of the conventional example shown in FIG. 4 will be described. First, the interrogator 50 uses the output of the oscillator 1 as a carrier for a command or the like in the modulation circuit 3 to perform ASK (Amplitude shift k).
The signal is modulated by the modulation or the like and transmitted to the transponder 51 via the antenna 4 as a query wave.

[0008] The transponder 51 receives the modulated signal by the antenna 8, demodulates the signal by the detector 9, and outputs the demodulated signal to the control circuit 10.
The control circuit 10 extracts a command from the signal input from the detector 9, interprets the content of the command, and performs necessary processing.

For example, consider the case where the command is to read data from the sensor circuit 12.

The control circuit 10 takes in measurement data and the like from the sensor circuit 12 and outputs it to the modulation circuit 11. The modulation circuit 11 converts the unmodulated interrogation wave from the interrogator 50 based on the output of the control circuit 10 into BPSK (Binary phase shift keying).
The light is modulated by modulation or the like and reflected by the interrogator 50.

As a result, it is possible to collect data from the sensor circuit 12 using wireless communication.

As an antenna used in such a wireless data collection device, an antenna patch is formed by a conductor pattern on a substrate in consideration of antenna gain, directivity, and the like, and a transmission signal is applied from the back surface of the antenna patch. Preferably, a microstrip antenna is used.

FIG. 5 is a plan view showing an example of such a conventional microstrip antenna. 5A shows a front surface, FIG. 5B shows a side surface, and FIG. 5C shows a rear surface.

In FIG. 5, 13 is an antenna patch, 14 is a ground pattern, 15 is a substrate, 16 is a through hole, and 17 is a feeding point to which a transmission signal is applied.

[0015]

However, in a microstrip antenna as shown in FIG. 5, since a substrate having a small dielectric loss tangent and a stable dielectric constant is used to improve antenna characteristics, it becomes very expensive. There was the problem I mentioned. In addition, there is a problem that it is difficult to reduce the size because a space for the antenna substrate is required in the housing.
Therefore, an object of the present invention is to realize a low-cost wireless data collection device that can be easily reduced in size.

[0016]

In order to achieve the above object, according to a first aspect of the present invention, an interrogator and a response which modulates an interrogation wave from the interrogator based on data and reflects it as a response wave. A wireless data collection device comprising: an antenna patch formed on a housing of the interrogator; a feeding point to which a transmission signal is applied; and the antenna patch formed on a housing of the interrogator. And an antenna comprising a microstrip line connecting between the feeding point and the feeding point.

According to a second aspect of the present invention, there is provided an interrogator and a transponder which modulates an interrogation wave from the interrogator based on data and reflects it as a response wave. In the wireless data collection device, an antenna patch formed on a housing of the transponder, a feeding point to which a transmission signal is applied, and the antenna patch and the feeding point formed on the housing of the transponder. And an antenna composed of a microstrip line connecting between them.

In order to achieve the above object, according to a third aspect of the present invention, in the first and second aspects of the present invention, a matching means is formed on a housing of the transponder to form a detector constituting the transponder. It is characterized in that matching between the antenna and the antenna is achieved.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the antenna formed on the housing of the interrogator is a circular, elliptical or linearly polarized antenna. It has a function.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is a perspective view showing an example of the appearance of an interrogator of the wireless data collection device according to the present invention. Since the basic configuration of the wireless data collection device is the same as that of FIG.

In FIG. 1, reference numerals 4, 5, 7 and 50 denote the same reference numerals as in FIG. 4, reference numeral 18 denotes input means such as a keyboard, and reference numeral 19 denotes a housing.

The housing 19 is formed by injection molding a resin.
The antennas 4 and 5 are formed by plating a conductor pattern on the surface of the housing 19. Further, the display 7, the input unit 18, and the like are appropriately attached to the housing 19.

Here, the details of the antennas 4 and 5 will be described with reference to FIG. FIG. 2 is a plan view showing details of the antennas 4 and 5. 2A shows a front surface, FIG. 2B shows a cross section, and FIG. 2C shows a rear surface.

In FIG. 2, reference numeral 20 denotes an antenna patch;
And 22 are microstrip lines, 23 is a ground pattern, and 24 is a feeding point. Further, 20 to 22 and 24 constitute the antenna 4.

On the surface of the housing 19, an antenna patch 20,
Microstrip lines 21 and 22 are respectively formed by plating or the like, and a ground pattern 23 is similarly formed on the back surface of the housing 19.

One end of a microstrip line 21 is connected to the right edge of the antenna patch 20, and one end of a microstrip line 22 is connected to the lower edge of the antenna patch 20.

The other ends of the microstrip lines 21 and 22 are connected to a feeding point 24, respectively. However,
The feeding point 24 is not connected to the ground pattern 23 on the back surface.

Here, the operation of the antenna shown in FIG. 2 will be described. The transmission signal from the modulation circuit 3 is applied to the feeding point 24, and the transmission signal is applied to the microstrip lines 21 and 22.
Propagate.

The transmission signals transmitted through the microstrip lines 21 and 22 are multiplexed again at the antenna patch 50, radiated to the space at the antenna patch 50, and transmitted to the transponder 51 as an interrogation wave. That is, it functions as the transmitting antenna 4.

The length of the microstrip lines 21 and 22 is such that the transmission signal applied from the feeding point 24 is
Adjustments are made so that a propagation delay difference of "90 degrees" occurs when reaching the right and lower edges of the antenna patch 20 shown in "a" and "b", respectively.

Thus, the antenna patch 20 functions as a circularly polarized antenna. Incidentally, the circularly polarized wave is more suitable for use because there is no angle dependency between the interrogator 50 and the transponder 51.

As a result, by forming the antennas 4 and 5 directly on the housing 19, the space for the antenna substrate in the housing 19 is not required, so that miniaturization is facilitated.

Further, since the precision of forming the housing 19 is determined by the mold, the finishing precision such as plate thickness is good, and since the mixing ratio of the resin is easy to control, the electric characteristics such as the dielectric constant are stable, so that an expensive substrate is used. There is no necessity, and the cost can be reduced.

In FIGS. 1 and 2, the interrogator 50 is used.
Although the description has been made on the miniaturization of the transponder, it is of course possible to use an antenna as shown in FIG.
In addition, although the transmitting antenna 4 has been described, the same goes for the receiving antenna 5.

By providing matching means such as an open stub or a short stub on the housing of the transponder 51, it is possible to match the diode serving as the detector 9 with the antenna 8.

FIG. 3 is a partial block diagram showing a configuration example for matching the detector 9 and the antenna 8. 3, 8, 9 and 11 are denoted by the same reference numerals as in FIG.
Is a matching means such as an open stub or a short stub.

The alignment means 25 is constructed as shown in FIG.
The antenna 8 can be matched with the detector 9 by adjusting the impedance of the antenna 8.

Although the resin is exemplified as the housing 19, a dielectric material other than the resin may be used.

In addition, as a method of forming the casing 19, injection molding is exemplified, but injection compression molding, compression molding, vacuum pressure molding, or the like may be used.

Further, in the embodiment, the microstrip antenna is illustrated, but a spiral antenna, a horn antenna, a helical antenna, or the like may be used.

In the case of an antenna configuration as shown in FIG. 2, mismatch between the impedance of the microstrip line 21 or 22 and the input impedance of the antenna patch 20 generally occurs.

In this case, by using an impedance conversion method using a 波長 wavelength line, it is possible to match the two.

That is, when the input impedance of the antenna patch 20 is "Zin" and the impedance of the microstrip line 21 or 22 is "Z0", the characteristic impedance Z = (Zin × Z0) ^1/2 (1) Thus, by inserting a microstrip line having a line length of 1/4 wavelength between the antenna patch 20 and the microstrip line 21 or 22, matching can be achieved.

In the embodiment, the antenna is configured to function as a circularly polarized antenna, but the function of an arbitrary polarized antenna such as a circle, a straight line, and an ellipse can be realized.

That is, if the propagation delay difference between the microstrip lines 21 and 22 is "90 degrees", the function of a circularly polarized antenna is produced. Function as

If only the microstrip line 21 or 22 is used, it functions as a linearly polarized antenna,
If only the microstrip line 21 is used, it functions as a horizontally polarized antenna, and if only the microstrip line 22 is used, it functions as a vertically polarized antenna.

In the above description, a wireless data collection device is described, but it is of course easy to apply to a mobile object identification device.

In the interrogator 50, the two antennas 4 and 5 are used for transmission and reception, respectively.
It may be shared as a transmitting and receiving antenna.

[0049]

As is apparent from the above description,
According to the present invention, the following effects can be obtained. By forming the antenna directly on the interrogator or transponder housing,
It is possible to realize a low-cost wireless data collection device that can be easily reduced in size.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of the appearance of an interrogator of a wireless data collection device according to the present invention.

FIG. 2 is a plan view showing details of antennas 4 and 5;

FIG. 3 is a partial block diagram showing an example of a configuration for matching a detector with an antenna 8;

FIG. 4 is a configuration block diagram illustrating an example of a conventional wireless data collection device.

FIG. 5 is a plan view showing an example of a conventional microstrip antenna.

[Explanation of symbols]

 Reference Signs List 1 oscillator 2 distributor 3, 11 modulation circuit 4, 5, 8 antenna 6 demodulation circuit 7 display 9 detector 10 control circuit 12 sensor circuit 13, 20 antenna patch 14, 23 ground pattern 15 substrate 16 through hole 17, 24 Point 18 Input means 19 Housing 21, 22 Microstrip line 25 Matching means 50 Interrogator 51 Transponder

Claims (4)

[Claims] 1. A wireless data collection device comprising: an interrogator; and a transponder which modulates an interrogation wave from the interrogator based on data and reflects it as a response wave, wherein the radio data collection device is formed on a housing of the interrogator. Antenna patch, a feed point to which a transmission signal is applied, and a microstrip line formed on the interrogator housing and connecting the antenna patch and the feed point. A wireless data collection device, characterized in that: 2. A wireless data collection device comprising: an interrogator; and a transponder which modulates an interrogation wave from the interrogator based on data and reflects it as a response wave, wherein the radio data collection device is formed on a housing of the transponder. Antenna patch, a feed point to which a transmission signal is applied, and a microstrip line formed on the housing of the transponder and connecting between the antenna patch and the feed point. A wireless data collection device, characterized in that: 3. The apparatus according to claim 1, wherein matching means is formed on a housing of said transponder, and a detector and an antenna constituting said transponder are matched with each other. Wireless data collection device. 4. The wireless data collection device according to claim 1, wherein the antenna formed on the housing of the interrogator has a function of a circular, elliptical, or linearly polarized antenna.