JP3064395B2 - Microstrip antenna - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microstrip antenna having a structure integrated with a feeder circuit using a triple strip type strip line, and more particularly to an input impedance of the micro strip antenna. This is related to broadening the dance band.

[Prior Art] A conventional example is a microstrip antenna disclosed in Japanese Patent Application No. 2-243227.

FIG. 6 shows an example of the configuration of a microstrip antenna integrated with this conventional feeding circuit. In the figure, (1) is a first radiation conductor plate, (2) is a first ground conductor plate, (3) is a first dielectric substrate, and (4) is a second dielectric substrate. A microstrip antenna (5) is formed from the four antennas. Further, (6) is a second ground conductor plate, (7) is a strip conductor (also referred to as a feed conductor), and the strip conductor (7) is a first ground conductor plate (2) and a second ground conductor. A strip-type strip line (hereinafter referred to as "strip line") (8) using the conductor plate (6) as a ground conductor. (9) is the first and second dielectrics (2),
A connection conductor for connecting (6), which is formed on the first and second dielectric substrates (3) and (4) by using a technique such as sulfor plating. This connecting conductor (9) is arranged around the microstrip antenna.

Since the microstrip antenna integrated with the conventional feeder circuit using the stripline is configured as described above, the radio wave propagating through the stripline (8) passes through the resonator through the stripline (8). A microstrip antenna (5) composed of a radiating conductor plate (1) and a first ground conductor plate (2), which is one of the above, is excited to emit radio waves. Here, by connecting the two ground conductors with the conductor using the connection conductor (9), the current flowing through the two ground conductors can be merged in front of the microstrip antenna. The current is coupled with the microstrip antenna, and the mode conversion from the strip line mode to the microstrip antenna can be easily performed.
No parallel plate mode is generated.

[Problem to be Solved by the Invention] The conventional microstrip antenna as described above is
A strip line is used as a feed line for exciting the antenna. Since the stripline and the microstrip antenna use the same dielectric, a microstrip antenna integrated with the feed circuit can be configured with two dielectric layers. Although excellent in this respect, there are the following two problems.

First, the first problem will be described. Generally, in order to broaden the input impedance characteristics of a microstrip antenna, it is necessary to reduce the Q as an antenna resonator. To this end, it is necessary to increase the thickness of a dielectric layer, Needs to be reduced. In this case, since the microstrip antenna and the empty electrode line are formed in the same layer, the dielectric layer (FIG. 6B)
In order to make the characteristic impedance of the feeder line the same when the upper and lower widths in the drawing are increased, the strip line (8)
(The vertical width in the drawing of FIG. 6 (a)) needs to be increased in proportion to the thickness of the dielectric layer. Also, if the relative permittivity of the dielectric material is reduced, it is necessary to increase the line width as well. If an array antenna in which a plurality of microstrip antennas are arranged in an array is configured, if the line width becomes large, There is a problem that the feed line cannot be arranged within a limited area.

Next, as a second problem, in the conventional structure, there is a problem that two ground conductors are connected by a conductor and the connection conductor has a frequency characteristic even at the same potential. As described above, when the thickness of the dielectric layer is increased for broadening the band, the length of the connection conductor becomes longer, and the frequency characteristics of the connection conductor have a further adverse effect.

SUMMARY OF THE INVENTION The present invention has been made to solve the above two problems, and uses a strip line having a thin dielectric layer as a power supply line to suppress the frequency characteristics of a connection conductor and to provide a wide-band input impedance. The object is to obtain a microstrip antenna having dance characteristics.

[Means for Solving the Problems] The microstrip antenna according to the present invention is a first embodiment.
The third dielectric layer is provided on the upper part of the radiating conductor, and the second radiating conductor plate is arranged.

[Operation] In the microstrip antenna according to the present invention, both the first and second radiation conductor plates resonate due to the structure in which the second radiation conductor plate is disposed above the first radiation conductor. Therefore, even if the first and second dielectric layers are made of a thin dielectric, the third dielectric layer is made thick and the relative dielectric constant is made small, so that it has a wide-band input impedance characteristic. A microstrip antenna is obtained.

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, (1) is a first radiation conductor plate, and the other (2) to (9) are the same as those shown in FIG. (10) is a second radiation conductor plate, and (11) is a third dielectric layer. Since the microstrip antenna according to the present invention is configured as described above, the radio wave propagating through the strip line (8) passes through the strip line (8) to form the first radiation conductor plate (a type of resonator). A microstrip antenna (5) consisting of 1) and a first ground conductor plate (2) is excited, and then a second radiating conductor plate (10) is excited, and both emit radio waves. .

Thus, by providing the third dielectric layer and increasing the thickness or decreasing the relative permittivity, the Q
Can be reduced, and the input impedance can be broadened. This third dielectric layer is the first dielectric layer.
And between the second radiation conductor plate (1) and (10).
It does not need to be in another area. Therefore, the strip line can be made at least as thick as before or thinner than before. Conventionally, the first and second dielectric layers (3) and (4) are commonly used over both the antenna portion and the feed line portion. Has not been accepted as a contradiction, whereas the present invention provides a method of increasing the thickness of the antenna part by the third part which only needs to be present in the antenna part.
This is achieved by providing the dielectric layer of

Here, the third dielectric layer (11) may be an air layer. For example, foamed styrene may be used, or the space between the first radiating conductor (1) and the second radiating conductor (10) may be used. A structure in which a plurality of columnar objects are sandwiched between them may be used.

By providing the second radiation conductor (10) in this manner, the input impedance characteristic can be broadened with the same configuration as in the related art. However, by adopting such a configuration, the dielectric layer (10) can be formed. Even if 3) and (4) are made thin, the conventional input impedance characteristics can be maintained. Since the frequency characteristics of the connection conductor (9) are limited as the connection conductor length is shortened, if the dielectric layers (3) and (4) can be made thinner in this manner, the connection conductor length is reduced. Therefore, the frequency characteristics caused by the connection conductor (9) can be suppressed.

In the above embodiment, an example in which a circular microstrip antenna is used is shown. However, a square or arbitrary shaped microstrip antenna, and a degenerate separation element for exciting circularly polarized waves are provided. The present invention is effective even if a microstrip antenna having a structure is used.

In the above embodiment, the case where the number of feed lines is one is shown. However, as shown in FIG. 2, two input / output ports are used to excite circularly polarized waves or to obtain an orthogonal dual-polarized antenna. It goes without saying that the present invention is effective even when there are terminals.

In the above embodiment, two connecting conductors (9) are used. However, as shown in FIG. 3, several connecting conductors (9) are used, or as shown in FIG. Needless to say, similar characteristics can be obtained.

As described above, in FIGS. 1 to 4, each of the first and second dielectric layers has a ground conductor plate on one surface of the first dielectric layer. A ground conductor plate and a first radiation conductor plate are arranged on one surface of the layer, and the first and second radiation conductor plates are arranged.
Forming a strip-type strip line having a strip conductor disposed approximately at the center of the ground conductor, feeding the strip conductor and the first radiating conductor plate close to each other, and feeding the first and second ground conductors. In a microstrip antenna having a configuration in which the plates are electrically connected, a second strip is provided above the first radiation conductor plate.
The microstrip antenna characterized in that the radiation conductor plate is arranged as described above.

Further, while the above description has been given of an example in which the strip line and the microstrip antenna are coupled close to each other, the present invention can be applied to a case where the strip line is directly coupled to the microstrip antenna as shown in FIG. It is valid.

FIG. 5 is composed of first and second dielectric layers, having a ground conductor plate on one surface of the first dielectric layer, and a ground conductor plate and a ground conductor plate on one surface of the second dielectric layer. An opening is arranged, a strip conductor is arranged at a substantially center of the first and second ground conductors to form a strip-type strip line, and a radiation conductor plate is arranged at a tip end of the strip conductor. A microstrip antenna having a configuration in which first and second ground conductor plates are conducted, wherein a second radiation conductor plate is arranged above the opening. It is a thing.

The dielectric substrates (3) and (4) of the above embodiment may be an air layer or a foam material. However, in order to obtain an integrated high-performance antenna having a wide band, it is necessary to use a foam material. It is also desirable to use a dielectric having a large relative dielectric constant.

[Effects of the Invention] As described above, in the microstrip antenna according to the present invention, the second radiating conductor plate resonates by disposing the second radiating conductor plate above the first radiating conductor plate. Therefore, a wide band characteristic can be obtained, and the effect of suppressing the Q as the resonator of the antenna cancels out the influence on the Q by the dielectric layer having a large relative permittivity, thereby selecting the dielectric layer having a large relative permittivity. to enable. by this,
The power supply line can be miniaturized, and high integration can be achieved. In addition, the effect of suppressing Q cancels out the influence of the thin dielectric layer on Q, making it possible to reduce the thickness of the dielectric layer. This makes it possible to miniaturize the power supply line, shorten the connection conductor, and suppress the influence of frequency characteristics.

In other words, it is possible to solve the problems of wideband and high integration, which were not compatible with each other, and to obtain an integrated high-performance antenna having a wideband.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a microstrip antenna according to one embodiment of the present invention, and FIGS. 2, 3, 4, and 5 are diagrams showing another embodiment of the present invention. FIG. 6 is a diagram showing a configuration of a conventional microstrip antenna. In the figure, (1) is a first radiation conductor plate, (2) is a first ground conductor plate, (3) is a first dielectric substrate, (4) is a second dielectric substrate, and (5) is Microstrip antenna, (6) is a second ground conductor plate, (7) is a strip conductor, (8) is a triple strip strip line, (9) is a connection conductor, and (10) is a second radiation. Conductor plate, (11) third dielectric substrate, (12) cavity. In the drawings, the same reference numerals indicate the same or corresponding parts.

Continuation of the front page (56) References JP-A-63-135003 (JP, A) JP-A-2-7703 (JP, A) JP-A-4-82405 (JP, A) JP-A-2-236803 (JP) JP-A-4-122106 (JP, A) JP-A-1-147905 (JP, A) JP-A-2-7703 (JP, A) JP-A-63-50532 (JP, A) 63-3612 (JP, U) U.S. Pat. No. 4,835,538 (US, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01Q 13/08

Claims (1)

(57) [Claims] 1. A microstrip antenna having the following elements: (a) first and second dielectric layers; (b) a first ground conductor plate disposed on one surface of the first dielectric layer; (C) a second ground conductor plate having an opening disposed on one surface of the second dielectric layer, (d) a feed conductor disposed between the first and second dielectric layers, (E) a first radiating conductor plate connected to an end of the power supply conductor and arranged at a position corresponding to the opening; (f) a connection conductor that conducts the first and second ground conductor plates (G) a second radiating conductor plate disposed at a position corresponding to the opening at an interval from one surface of the second dielectric layer, (h) first and second dielectric layers Smaller relative permittivity,
A third dielectric layer disposed between the first and second radiating conductor plates;