JPH027701A - Microstrip circuit - Google Patents

Abstract

PURPOSE:To minimize a space among a circuit pattern, a conductor pattern and a case and to make the device small in size by forming the circuit pattern to only one side with respect to the ground conductor face of a 1st dielectric substrate. CONSTITUTION:A ground conductor face 12 is formed to the lower face of the 1st dielectric substrate 11, a conductor pattern 14 is formed to the upper face of a 2nd dielectric substrate 13, and the lower face is overlapped to the upper face of the 1st substrate 11 so that the dielectric surfaces of them are brought into contact with each other. One end of a connection line pattern 15 formed to the upper face of the 1st substrate 11 is connected to the conductor pattern 14 via a conductor 16 such as a throughhole formed to the 2nd substrate 13, and the other end is connected to a modulation circuit pattern 17 comprising a microstrip circuit formed to the upper face of the 1st substrate 11. Thus, since only a space between the conductor pattern 14 and the case 19 is taken into consideration as to the space between a patch antenna part and the case 19 comprising the 1st, 2nd substrates 11, 13, the conductor pattern 14 and the ground conductor face 12, the device is made small in size.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the structure of a microstrip circuit used in a transponder of a mobile object identification device consisting of an interrogator and a transponder using microwaves, for example. It is.

Traditional leather dish In recent years, entry and exit management for one person in production management within a factory.

Mobile object identification devices that use radio waves from interrogators to recognize the contents of transponders have come into the spotlight for gate control in parking lots, logistics management, etc.

In the case of production management in the above factory, a transponder is attached to the product on the production line, and various data such as part code, processing procedure, destination, etc. for the product are input in advance into the internal memory of this transponder. Meanwhile, interrogators are installed at each point on the production line. The interrogator transmits an interrogation radio wave to the transponder attached to the products flowing on the production line, reads the unique information inside the transponder based on the signal returned from the transponder, and uses that information to control the production. It is for management.

A microwave strip circuit is usually used in the microwave processing section of a transponder of a mobile object identification device using microwaves due to its size, cost, ease of handling, etc.

FIG. 2 shows the configuration of a conventional device using a conventional microwave strip circuit as a transponder of a mobile object identification device, (a)
is a side view, 0)) is a top view, and (C) is a bottom view.

A first dielectric substrate made of a material such as, on one side of the substrate, a modulation circuit pattern 22 is formed in a part thereof, and on the other side, a ground conductor surface 23 is formed over the entire surface. do. A second dielectric substrate 24 is made of a material such as Teflon or glass epoxy, and a conductor pattern 25 is formed on one side of the substrate, and nothing is formed on the other side, and the second dielectric substrate 24 is made of a material such as Teflon or glass epoxy.
The ground conductor surface 23 of the dielectric substrate 21 is overlapped with the ground conductor surface 23 of the dielectric substrate 21 . Therefore,
A part of the ground conductor surface 23 of the first dielectric substrate 21 becomes the ground conductor surface of the second dielectric substrate 24, and the ground conductor surface, the dielectric substrate 24, and the conductor pattern 25 constitute a patch antenna. The conductor pattern 25 of the patch antenna and the connection line pattern 26 connected to the modulation circuit pattern 22 are connected by a conductor rod 27.

A signal processing section 2B including a CPU section, a battery, etc. is installed on the surface opposite to the modulation circuit pattern 22 with respect to the ground conductor surface 23 of the first dielectric substrate 21, and the signal processing section 2B includes a CPU section, a battery, etc.
The entire case 29, including the antenna and modulation circuit, is made of a material that transmits microwaves well.
It is stored inside.

The interrogator transmits an unmodulated carrier as an interrogation signal to the transponder, and the transponder transmits the conductive pattern 25. Second dielectric substrate 24. The unmodulated carrier is received by a patch antenna consisting of a ground conductor plane 23 and inputted to the modulation circuit pattern 22 . On the other hand, the signal processing unit 28 outputs the unique data stored in the internal memory to the modulation circuit pattern 22, modulates the received unmodulated carrier, and then transmits the radio wave to the interrogator via the patch antenna. re-radiate. In the interrogator, the information inside the transponder can be known by demodulating the modulated signal in the receiving section.

■In a circuit with a microstrip configuration that is relatively stable, an electromagnetic field also exists on the conductor pattern, so there is a gap between the conductor pattern surface and the casing (case) that houses the microstrip circuit. It is necessary to provide a space that is almost unaffected by the electromagnetic field.

This space should be used especially when devices such as transponders are attached to the surface of metal objects or are carried by people (personnel management), where the metal objects or the human body may adversely affect the microwave characteristics. It is also very important to avoid this.

In the case of the conventional example shown in FIG. 2, the conductor pattern 25. It was necessary to provide two spaces between each of the modulation circuit patterns 22 and the case 29. Therefore, there was a drawback that the size of the equipment such as the transponder became large. In order to make devices such as transponders thinner, it is possible to reduce the space between cases by half by forming the antenna pattern and modulation circuit pattern on one side of a single board. However, in this case, if you try to configure a microstrip circuit with a substrate as thin as possible, the thinner the dielectric substrate is, the lower the gain of the patch antenna will be, resulting in a decrease in the gain of the patch antenna. The disadvantage is that the communication distance of the device is shortened.

On the other hand, if a thick dielectric substrate is used, the gain of the patch antenna will not be reduced, but the width of the modulation circuit pattern will become wider, resulting in a disadvantage that the area of the modulation circuit section will become larger.

That is, for example, if the dielectric substrate is glass epoxy (relative dielectric constant 4.5), the impedance is 50.
The line pattern width that is Ω is the board thickness (mm)
Line pattern width (mm) 0.8 1
．． 45 1.6 2.9 As the substrate thickness increases, the line pattern width becomes wider and the area occupied by the circuit section becomes larger.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides a method in which a second dielectric substrate having a smaller area than the first dielectric substrate is placed on top of the first dielectric substrate so that their dielectric surfaces are in contact with each other. A ground conductor surface is formed on the surface of the first dielectric substrate opposite to the contact surface with the second dielectric substrate, and a conductor pattern is formed on the same surface as the contact surface but other than the contact surface. , a conductive pattern is formed on the surface of the second dielectric substrate opposite to the surface in contact with the first dielectric substrate;
and the second conductor pattern are connected by a conductor.

With the above-described configuration, the circuit pattern is formed on only one side of the first dielectric substrate relative to the ground conductor surface, so even when the entire circuit is housed in a case, the space between the circuit pattern, conductor pattern, and case is saved. can be minimized. Also number 1. The characteristics of the microstrip circuit element formed by the second dielectric substrate, the conductor pattern formed on the second dielectric substrate, and the ground conductor surface can be appropriately selected by adjusting the thickness of the second dielectric substrate. , the thickness of the first dielectric substrate can be reduced, and the size of the device can be reduced.

Husband - Shi Yiyan An embodiment of the present invention will be described below with reference to FIG.

In FIG. 1, reference numeral 11 denotes a first dielectric substrate made of Teflon, glass epoxy, etc. and having a thickness of 11. On the lower surface of the first dielectric substrate 11, a ground conductor surface 12 is provided over the entire surface.
is formed. 13 is a second dielectric substrate made of Teflon, glass epoxy, etc. and having a thickness of 12;
A conductor pattern 4 is formed on the upper surface, and the dielectric material is exposed on the lower surface so that the dielectric surfaces of the first dielectric substrate 11 come into contact with the exposed upper surface of the first dielectric substrate 11. Overlap. Reference numeral 15 denotes a connection line pattern formed on the upper surface of the first dielectric substrate 11, and one end of the pattern is connected to a conductor through a conductor 16 such as a through hole formed in the second dielectric substrate 13. It is connected to the pattern 14, and the other end is connected to a modulation circuit pattern 17 formed of a microstrip circuit formed on the upper surface of the first dielectric substrate 11. The through hole and the connection line pattern 15 are arranged such that a conductor land is provided on the surface of the through hole in contact with the first dielectric substrate 11, and V P S (V
The connection can be made very easily by using a method such as aper phase soldering, but the connection may be made using a metal rod or the like instead of a through hole. 18 is a signal processing section connected to the modulation circuit pattern 17, and 19 is a case that houses and protects the entire device composed of the above-mentioned microstrip circuit device, etc., and is made of a material that transmits microwaves well. . Furthermore, this case 19 is designed to form a certain space between the conductor pattern 14 and the modulation circuit pattern 17, so that even if the case 19 touches a human body or comes into contact with metal, the electromagnetic field generated in the conductor pattern of the microstrip circuit will be adversely affected. I try not to give it.

With the above configuration, when the microstrip circuit of the present invention is used in a transponder of a mobile object identification device, the first. Second dielectric substrate 11, 13. The gain of the patch antenna section formed by the conductor pattern 14 and the ground conductor surface 12 can be easily adjusted without changing the modulation circuit pattern 17 by changing the thickness it of the second dielectric substrate. In this case, the materials used for both the substrates 11 and 13 may be changed. Furthermore, with regard to the space between the patch antenna section and the case 19, only the space between the conductor pattern 14 and the case 19 needs to be considered, so that the device can be made smaller.

Effects of the Invention Therefore, according to the present invention, first. The characteristics of the microstrip circuit element formed by the second dielectric substrate, the conductor pattern, and the ground conductor surface can be easily adjusted, and an apparatus that can be applied to various uses can be provided.

Further, when a device using the circuit of the present invention is housed in a case, it can be made smaller and lighter, and it has a remarkable effect when used as a transponder of a mobile object identification device.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment in which the present invention is applied to a transponder of a mobile object identification device. FIG. 1A is a side view, FIG. 2 is a top view, and FIG. 2 shows a conventional example of a transponder, in which (a) is a side view, (b) is a top view, and (b) is a top view.
C) is a bottom view. 11-First dielectric substrate. 12 - Ground conductor plane. 13-Second dielectric substrate. 14-Conductor pattern. 15-Connection line pattern. 16--Conductor. Figure Figure

Claims (1)

[Claims] (1) A second dielectric substrate having a smaller area than the dielectric substrate is arranged on the first dielectric substrate with the dielectric surfaces thereof in contact with each other, and the second dielectric substrate of the first dielectric substrate A ground conductor surface is formed on the opposite side of the contact surface with the substrate, a conductor pattern is formed on the same surface as the contact surface and other than the contact surface, and the second dielectric substrate is connected to the first dielectric substrate. A microstrip circuit characterized in that a conductor pattern is formed on the side opposite to the contact surface of the microstrip circuit, and the two conductor patterns are connected by a conductor.