JPH04133504A - Microstrip antenna - Google Patents

Abstract

PURPOSE:To feed power from an arbitrary position except the central part without using a connecting pin by using an annular slot which is smaller as compared with the wavelength instead of the conventional power feeding slot and connecting the leading end of a strip line to a conductor in the annular slot. CONSTITUTION:When the leading end of a microstrip line is connected to a discoid conductor 9 for constituting an annular slot, a similar electric field distribution to that obtained when power feeding is made through a coaxial line 11 is obtained. In this case, the end section of this microstrip antenna is more strongly coupled than the central part and has the larger degree of freedom in the power feeding position than the central part has, since the antenna is coupled with the slot through an electric field. In addition, the input impedance can be adjusted by changing the size, namely, width of the annular slot or power feeding position. Therefore, the electromagnetic waves propagated through the microstrip line 7 excite the annular slot 8.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a microstrip antenna integrated with a power feeding circuit using a microstrip line.

[Prior art] Fig. 4 shows, for example, 1985, Institute of Electronics and Communication Engineers, IEICE Technical Report on Antennas and Propagation, A-P87-130. FIG. 2 is a diagram showing an example of the configuration of a microstrip antenna integrated with a conventional power feeding circuit shown in Basic characteristics of a slot-coupled wideband microstrip antenna.

In the figure, (1) is a radiation conductor plate, (2) is a first ground conductor plate, and (3) is a first dielectric substrate, and these three constitute a microstrip antenna (4). .

Furthermore, (5) is a second dielectric substrate, and (6) is a strip conductor.

This strip conductor (6) constitutes a microstrip line (7) having the first ground conductor plate (2) as a ground conductor.

(10) is a slot provided in the first ground conductor plate (2).

The microstrip antenna, which is integrated with a power supply circuit using a conventional microstrip line, is configured as described above, so the microstrip antenna (7)
The magnetic field of the radio waves that have propagated becomes maximum at the position where the slot (10) is located approximately 1/4 tL from the open end of the microstrip line (7), and easily excites the slot (10).

The radio waves passing through the second strip line (7) and the slot (10) excite a microstrip antenna (4) consisting of a radiation conductor plate (1), which is a type of resonator, and a first ground conductor plate (2). , this causes radio waves to be emitted.

[Problems to be Solved by the Invention] The conventional microstrip antenna as described above has an excellent structure because it does not use a connecting pin that requires soldering to connect the feed line and the microstrip antenna, but it has an excellent structure. There are problems such as.

That is, the slot is generally rectangular in shape and placed approximately in the center of the microstrip antenna.

In the second case, the microstrip antenna is coupled to the microstrip line by a magnetic field.

Coupling is best when placed near the center of the antenna, but coupling becomes weaker at the ends.

Therefore, the feeding position is limited to approximately the center of the antenna.

In addition, the slot length is relatively large, and if two slots are placed, the number of close and miss times will be nine, so the coupling between the slots cannot be ignored.

Therefore, it is extremely difficult to excite circularly polarized waves with two-point feeding.

This invention was made to solve the above-mentioned problems, and aims to supply power from any position other than the center without using a connection bin.

[Means for Solving the Problems] A microstrip antenna according to the present invention uses an annular slot that is smaller than the wavelength in place of the conventional slot for power feeding, and connects the tip of the strip line to the conductor inside the annular slot. The configuration was such that they were connected.

! Effect] Since the microstrip antenna of the present invention is coupled to the annular slot by an electric field, the coupling is stronger at the ends, and therefore the degree of freedom in the feeding position is greater than when feeding at the center.

This is exactly the same principle of coupling operation as when power is fed from the back via a coaxial line.

Furthermore, by using an annular slot that is smaller than the wavelength, two-point power feeding is possible, and nine-circularly polarized wave excitation is also possible.

[Example] An embodiment of the present invention will be described below with reference to nine drawings.

FIG. 1 is a diagram showing the configuration of a microstrip antenna according to an embodiment of the present invention, in which FIG. 1(a) is a front view and FIG. 1(b) is a sectional view taken along line AA' in FIG. It is. In the figure, (1) to (7) are the same as in Figure 4, (8) is an annular slot provided in the first ground conductor plate (2), and (9) is an annular slot provided in the first ground conductor plate (2). It is a disc-shaped conductor for configuring.

FIG. 2 shows the operating principle of this invention. Figure (a) shows a cross-sectional view when power is supplied from the back using a coaxial line (11). FIG. 5B shows a cross-sectional view when power is supplied using the annular slot according to the present invention. By connecting the tip of the microstrip line to a disc-shaped conductor (9) forming an annular slot, an electric field distribution similar to that obtained when power is supplied using a coaxial line (11) can be obtained. In this case, the microstrip antenna is coupled to the slot by an electric field, so the coupling is stronger at the ends.

The degree of freedom in the power feeding position is greater than in the center. Furthermore, by changing the size and width of the annular slot, the input impedance can be adjusted by changing the power feeding position. Since the microstrip antenna integrated with the feeding circuit using the microstrip line is configured as described above, the radio waves propagating through the microstrip line (7) can be easily transmitted through the annular slot (
8) Excite. This microstrip line (7),
The radio waves passing through the annular slot (8) excite a microstrip antenna (4) consisting of a radiation conductor plate (1), which is a type of resonator, and a first ground conductor plate (2), thereby radiating radio waves. Ru.

FIG. 3 is a diagram showing another embodiment according to the present invention,
Figure (a) is a front view, Figure (b) is A-A in Figure (a).
In this way, in the case of TM1 (mode), nine circularly polarized waves can be generated by feeding power with a phase difference of 90 degrees at two points separated by 90 degrees.

In the figure, (0 to (9) are the same as in FIG. 1.

In addition, in the embodiments 9 and above, the microstrip antenna 1
Although only one microstrip antenna has been illustrated and described, the present invention is not limited to this, and can also be applied to an array antenna in which a plurality of microstrip antennas are arranged.

[Effects of the Invention] As described above, according to the present invention, power can be supplied from any position except the center without using connection pins, and power can be supplied from multiple points.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing one embodiment of the present invention, and FIG.
The figure shows the operating principle of the invention, and FIG. 3 is a configuration diagram showing another embodiment of the invention. FIG. 4 is a diagram of an antenna for explaining a conventional power feeding method of a microstrip antenna. In the figure, (1) is a radiation conductor plate, (2) is a first ground conductor plate, (3) is a first dielectric substrate, (4) is a microstrip antenna, and (5) is a second dielectric substrate. Substrate, (6)
is a strip conductor, (7) is a microstrip line,
(8) is an annular slot, and (9) is a disc-shaped conductor piece for forming the annular slot. (10) is a slot, (11) is a coaxial line, 02)
is the inner conductor of the coaxial line. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] A radiation conductor plate formed on one surface of a first dielectric substrate, a ground conductor plate formed on the other surface, a slot formed in the ground conductor plate, and a microstrip line for feeding power to the slot. In the microstrip antenna constructed by using an annular slot as the slot,
A microstrip line consisting of the ground conductor plate and a second dielectric plate is used as the strip line, and the terminal end of the microstrip line is connected to a disc-shaped conductor located inside the annular slot. Microstrip antenna.