JPH0522023A - Microstrip antenna - Google Patents

Abstract

PURPOSE:To narrow a gap between radial conductors and to miniaturize a microstrip antenna by shifting the positions of arranging the adjacent radial conductors in a longitudinal direction each other. CONSTITUTION:At a microstrip antenna 1 adjacently juxtaposing plural band- shaped radial conductors 13 on the surface of a dielectric substrate 11 whose bottom is covered with a ground conductor 12, the positions of arranging the adjacent radial conductors 13 are shifted in the longitudinal direction each other. Namely, for the adjacent strip antennas 13, the arranging positions are shifted in the longitudinal direction each other and the length of a conductor part facing both the conductors each other is shortened so that both strip antennas 13 can be coupled more coarsely. For example, one terminal Q of a radial conductor 13a and one terminal Q' of a radial conductor 13b shift the positions between the radial conductors 13a and 13b so as to make the length (r) of the overlapped conductor part shorter rather than that in the case of making both the terminals Q and Q' coincident (r=L). Similarly, even concerning the adjacent radial conductors among radial conductors 13b-13e, the length (r) of the overlapped conductor part is shortened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microstrip antenna in which a radiation conductor is provided on the surface of a dielectric substrate whose bottom surface is covered with a ground conductor, and more particularly to the structure of the radiation conductor.

[0002]

2. Description of the Related Art FIG. 5 is a perspective view showing an embodiment of a conventional microstrip antenna. In the conventional microstrip antenna 3, a plurality of strip-shaped radiation conductors 13 are provided on the surface of the dielectric substrate 11 whose entire bottom surface is covered with the ground conductor 12.
Has a structure in which gaps 14 are provided in parallel with each other,
The dielectric substrate 11 is connected to the feeding point P of the radiation conductor 13c by the feeding line 2.
Power is supplied from the bottom side of the.

Each of the radiating conductors 13a to 13e has an approximately same width w, and constitutes an antenna element composed of a half-wavelength open-ended stripline having mutually different resonance frequencies f1 to f4. ing.

The radiating conductors 13a to 13e are formed such that one ends Q thereof are aligned on the same line, and adjacent radiating conductors 13 have conductor portions facing each other (hereinafter referred to as overlapping conductor portions) in the gap 14. The capacitor is capacitively coupled by means of and is excited via this coupling capacitance. For example, between the radiating conductors 13a and 13b, the overlapping conductor portion having the length r is capacitively coupled by the gap 14 and excited via this coupling capacitance.

The bandwidth ΔF of this microstrip antenna is determined by the size of the radiation conductor 13 and the gap 14
By appropriately adjusting the spacing d of the strip antenna elements 13a to 13e, the bandwidths Δf1 to Δf4 of the strip antenna elements 13a to 13e are combined in a staggered manner to be adjusted to a desired bandwidth ΔF.

[0006]

The above-mentioned conventional microstrip antenna 3 can be miniaturized by narrowing the gap d between the gaps 14.
If the distance d is narrowed, the coupling capacitance of the adjacent radiation conductors 13 becomes large, and the bandwidth ΔF becomes rather narrow.

That is, each strip antenna 13a ...
When 13e is moderately loosely coupled, each strip antenna 13a to 13e has independent band characteristics, and these are combined in a staggered manner to obtain a relatively wide band width ΔF. When the distance d is narrowed to form a tight coupling, the strip antennas 13a to 13e are coupled together to form a microstrip antenna having one band characteristic, so that the bandwidth ΔF is narrowed. Therefore, in the method of simply narrowing the gap d of the gap 14,
There is a limit to miniaturization of the antenna.

The present invention has been made in view of the above problems, and provides a microstrip antenna that can be miniaturized by loosely coupling adjacent radiation conductors and narrowing the gap accordingly. The purpose is to do.

[0009]

In order to solve the above problems, the invention according to claim 1 provides a plurality of strip-shaped radiation conductors arranged in parallel on the surface of a dielectric substrate whose bottom surface is covered with a ground conductor. In the above microstrip antenna, the arranging positions of adjacent radiating conductors are displaced from each other in the longitudinal direction.

The invention according to claim 2 is a microstrip antenna in which a plurality of strip-shaped radiation conductors are arranged in close proximity to each other on the surface of a dielectric substrate whose bottom surface is covered with a ground conductor, and the radiation is adjacent to each other. The conductor widths of the conductors are different from each other.

According to a third aspect of the present invention, there is provided a microstrip antenna in which a plurality of strip-shaped radiation conductors are juxtaposed on a surface of a dielectric substrate having a bottom surface covered with a ground conductor. The substrate is composed of a high dielectric constant substrate having a relative dielectric constant of 10 or more.

[0012]

According to the first aspect of the present invention, the positions of the radiation conductors adjacent to each other in the longitudinal direction are displaced from each other, so that the coupling amount between the radiation conductors is reduced, and the gap between the radiation conductors is reduced accordingly. Can be narrowed. This allows the antenna to be downsized.

According to the second aspect of the present invention, by making the conductor widths of the adjacent radiation conductors different from each other, the coupling amount between both radiation conductors is reduced, and the gap between both radiation conductors is narrowed accordingly. It becomes possible. This allows the antenna to be downsized.

According to the third aspect of the invention, since a high dielectric constant substrate having a relative dielectric constant of 10 or more is used, the area is larger than that of a microstrip antenna using a dielectric constant substrate such as glass epoxy. Is about 1/2 or less.

[0015]

1 is a perspective view showing the structure of an embodiment of a microstrip antenna according to the present invention. The microstrip antenna 1 has a plurality of strip-shaped radiation conductors 1 on the surface of a dielectric substrate 11 whose entire bottom surface is covered with a ground conductor 12.
3 has a structure in which gaps 14 having a predetermined distance d are provided in parallel, and power is fed from the bottom surface side of the dielectric substrate 11 to the feeding point P of the radiation conductor 13c only by the feeding line 2. In addition, other radiation conductors 13a, 13b, 13d, 13
e is capacitively coupled to each other by the gap 14 between the conductors,
It is adapted to be excited through the coupling capacitance. The feeding point P is provided at an appropriate position near one end of the radiation conductor 13c due to various characteristics such as radiation characteristics and input impedance.

Each of the radiating conductors 13a to 13e is an antenna element consisting of a half-wavelength stripline having both resonance frequencies f1 to f4 which are different from each other, and has substantially the same width w. ing. Also,
The dimension L in the longitudinal direction of each of the radiation conductors 13a to 13e is determined by the wavelength λg (≈λo) of the resonance frequency f in the dielectric substrate 11.
/ √ε, λo; wavelength in air, ε; relative permittivity of dielectric substrate 11) is set to approximately 1/2.

The gap d of the gap 14 is set so that an appropriate coupling capacitance is formed between the adjacent radiation conductors 13 and the radiation characteristics of the radiation conductors 13a to 13e are superimposed in a staggered manner. . That is, each radiation conductor 13a-
Reference numeral 13d is a narrow band strip antenna, and the radiation characteristics of these strip antennas 13a to 13d are superposed like a double tuning circuit to form the bandwidth ΔF of the microstrip antenna 1.

Further, the strip antennas 13 adjacent to the strip antenna 13 are displaced from each other in the longitudinal direction so as to shorten the lengths of the conductor portions (hereinafter, referred to as overlapping conductor portions) of the two conductors facing each other. The strip antennas 13 are more loosely coupled. For example, between the radiation conductor 13a and the radiation conductor 13b, the radiation conductor 13a
The one end Q and the one end Q'of the radiating conductor 13b are displaced so that the length r of the overlapping conductor portion becomes shorter than that when both ends Q and Q'are matched (r = L). There is. Similarly, between adjacent radiating conductors 13 of the radiating conductors 13b to 13e, the positions of the one ends Q are shifted from each other to shorten the length r of the overlapping conductor portion.

The strip antennas 13 adjacent to each other in this manner
Since the gaps are more loosely coupled, when the microstrip antenna 1 having the same characteristics as the conventional microstrip antenna configured by matching both ends Q and Q ′ with each other is configured, the spacing of the gap 14 is equivalent to the amount of the loose coupling. Since d can be narrowed, the dimension of the radiation conductors 13 in the arrangement direction is shortened, and the microstrip antenna 1 can be miniaturized.

In the above embodiment, the radiation conductors 13a ...
Although the arrangement position of 13e was shifted in a zigzag manner in the longitudinal direction, as shown in FIG. 2, the radiation conductors 13a, 13b, 13d, 13e on both sides of the central radiation conductor 13c are sequentially moved upward (in a direction away from the feeding point P). ). Although not shown, the radiation conductor 13 may be sequentially displaced upward in the direction from the radiation conductor 13a to the radiation conductor 13e or in the opposite direction.

Although the above embodiment uses the half-wavelength strip antenna with both ends open, a quarter-wavelength strip antenna with one end short-circuited may be used instead.

FIG. 3 shows the structure of an embodiment of a microstrip antenna using a 1/4 wavelength strip antenna. The microstrip antenna 1'shown in the figure has a line length L'of each of the radiation conductors 13a to 13d.
Is set to approximately ¼ of the wavelength λg of the resonance frequency f in the dielectric substrate 11, and one end thereof is connected to the ground conductors 15a to 15b provided on the side surfaces 11a and 11b of the dielectric substrate 11.
It is short-circuited to the ground conductor 12 at e.

The radiation conductors 13a, 13c and 13e are short-circuited on the side face 11a side, the radiation conductors 13b and 13d are short-circuited on the side face 11b side, and the radiation conductors 13a to 13e are arranged so that their open ends are alternately opposed to each other. It is set up.

In this embodiment, since the overlapping conductor portions are formed at a part on both open end sides between the adjacent strip antennas 13, the adjacent strip antennas 13 are adjusted by adjusting the width D of the dielectric substrate 11. The length r of the overlapping conductor portion between is adjusted.

In this embodiment, the line length L'of each radiating conductor 13 is approximately 1/2 of that of the radiating conductor 13 of the microstrip 1 using the 1/2 wavelength strip antenna, and the distance between adjacent radiating conductors 13 is increased. Length r of overlapping conductor is 1
Since it is shorter than the radiation conductor 13 of the microstrip 1 using the / 2 wavelength strip antenna and the gap d of the gap 14 can be made narrower, the area of the microstrip antenna 1'can be made smaller.

In the above embodiment, the adjacent radiating conductors 13 are displaced from each other in the longitudinal direction to reduce the area of the overlapping conductor portion to reduce the coupling capacitance. However, as shown in FIG. The line widths w1 to w5 of 13e may be changed to each other to reduce the coupling capacitance between the radiation conductors 13.

In this case, one ends Q of the radiation conductors 13a to 13e may be aligned and only the line width w of each radiation conductor 13 may be changed. The positions of the one ends Q of the radiation conductors 13a to 13e described above may be changed. It may be combined with a method of shifting the length to shorten the length r of the overlapping conductor portion.

Further, in the present invention, when a high dielectric substrate having a relative dielectric constant of 10 or more is used, the required area is about 1/2 or less as compared with the case where a glass epoxy substrate or the like is used. Generally, the larger the relative permittivity, the narrower the frequency bandwidth becomes, and therefore the size is naturally limited. However, according to the present invention, since the frequency bandwidth is originally wide, further size reduction can be achieved.

[0029]

As described above, according to the present invention,
Since a plurality of strip-shaped radiation conductors are juxtaposed and juxtaposed on the surface of the dielectric substrate whose bottom surface is covered with the ground conductor, the positions of the adjacent radiation conductors are shifted in the longitudinal direction. The microstrip antenna can be miniaturized by narrowing the gap between the radiating conductors by the amount of loose coupling between the radiating conductors.

Further, since the conductor widths of the adjacent radiating conductors are made different from each other, the adjacent radiating conductors are more loosely coupled, and the same effect as described above can be obtained.

Further, since a high dielectric substrate having a relative dielectric constant of 10 or more is used, it is possible to further reduce the size.

[Brief description of drawings]

FIG. 1 is a perspective view showing a structure of an embodiment of a microstrip antenna according to the present invention.

FIG. 2 is a perspective view showing the structure of a second embodiment of the microstrip antenna according to the present invention.

FIG. 3 is a perspective view showing a structure of a third embodiment of the microstrip antenna according to the present invention.

FIG. 4 is a perspective view showing the structure of a fourth embodiment of the microstrip antenna according to the present invention.

FIG. 5 is a diagram showing a structure of an example of a conventional microstrip antenna.

[Explanation of symbols]

1,1 ', 1 "Microstrip antenna 2 power lines 11 Dielectric substrate 12 Ground conductor 13, 13a to 13e Radiating conductor 14 Gap 15a to 15e Ground conductor P feeding point

Claims (3)

[Claims] 1. A microstrip antenna in which a plurality of strip-shaped radiation conductors are arranged in close proximity to each other on a surface of a dielectric substrate whose bottom surface is covered with a ground conductor, wherein the positions where adjacent radiation conductors are arranged are set in the longitudinal direction. A microstrip antenna characterized by being mutually offset. 2. A microstrip antenna in which a plurality of strip-shaped radiation conductors are arranged in close proximity to each other on the surface of a dielectric substrate whose bottom surface is covered with a ground conductor, wherein adjacent conductors have different conductor widths. A microstrip antenna characterized by that. 3. A microstrip antenna in which a plurality of strip-shaped radiation conductors are closely arranged in parallel on the surface of a dielectric substrate having a bottom surface covered with a ground conductor, wherein the dielectric substrate has a relative dielectric constant of 10 or more. A microstrip antenna characterized by being a high dielectric constant substrate.