JPH04317204A - Antenna - Google Patents

Abstract

PURPOSE:To provide an antenna having intense field intensity in an arbitrary direction in a simple construction. CONSTITUTION:Two or more microstrip antennas consisting of a dielectric panel 3, a radiation conductor panel 1 formed on one face of the dielectric panel 3, and a grounding conductor panel 2 formed on the other face of the dielectric panel 2, is electrically connected in series with a feeder line 14, the maximum radiation direction of the respective microstrip antennas are directed in the directions different from each other, and one of the plural microstrip antennas is connected to either a transmitter or a receiver.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna that combines a plurality of microstrip antennas to obtain desired directivity.

0002

[Prior Art] Microstrip antennas are thin, have a planar structure, and are relatively easy to manufacture.
It is ideal as a built-in antenna for communication equipment (particularly mobile phones, etc.) in the Hz band. FIG. 7(a) shows the configuration of the microstrip antenna, and FIG. 7(b) shows the directivity. In FIG. 7, 1 is a radiation conductor plate, 2 is a ground conductor plate, 3 is a dielectric plate, 4 is a power supply pin, and 5 is a power supply connector. The outer conductor of the feed connector 5 is connected to the ground conductor plate 2 , the center conductor is connected to the feed pin 4 , and the feed pin 4 is connected to the radiation conductor plate 1 . Here, the electric field strength of the microstrip antenna has a maximum radiation direction at θ = 0° as shown in Fig. 7(b), and is weak in the direction of θ = 180°, with a difference of 20
It becomes more than dB. Furthermore, when feeding power to a microstrip antenna using a 50Ω power supply connector, the position of the power supply pin 4 in the x direction is important. That is, it is necessary to find a position in the x direction where the distance between the radiation conductor plate 1 and the ground conductor 2 is 50Ω, and to attach the power supply pin 4 and the power supply connector 5 thereto, which causes many manufacturing problems.

FIG. 8 shows a case where power is supplied by a microstrip line, and since the end of the radiation conductor 1 is normally several hundred ohms,
A λ/4 microstrip line 6 is inserted between the microstrip line 7 having a characteristic impedance of 50Ω for impedance conversion. At this time, if the impedance of the end of the radiation conductor plate 1 is R1 and the characteristic impedance of the λ/4 microstrip line 6 is R6, then R1×50=R6 2 is satisfied.

A method shown in FIG. 9 is disclosed as a method for combining a plurality of microstrip antennas. (Japanese Unexamined Patent Publication No. 60-236303) According to this method, two or more microstrip antennas are configured so that their directivity characteristics are in different directions, and two or more microstrip antennas are electrically connected in parallel to obtain the desired directivity. It is something that gives you sex. However, in this case, the characteristic impedance R of the power feeding coaxial line 8
8 and the characteristic impedance R9 of the coaxial line 9 to the multiple antennas, 2R8 = R
9, and there was a problem in that it took time to achieve consistency. This tendency is especially noticeable when the number of antennas increases.

FIG. 10 shows a method of combining a plurality of microstrip antennas and feeding power in series on the same substrate. At this time, L=λ/2 (λ is the wavelength in the dielectric material). In this case, the waves fed to the two radiation conductor plates are in phase, resulting in an antenna with the maximum radiation direction in the Z-axis direction. 10 is a microstrip line connecting two radiation conductor plates 1, and the resistance at the end of the radiation conductor plates 1 is used as a characteristic impedance. Even with such an array antenna, it is possible to manipulate the directivity to some extent by changing the value of L, but the range where the electric field strength is strongly radiated is still
In the coordinate system of FIG. 4, the space is limited to -90°≦θ≦90°.

[0006]

Problems to be Solved by the Invention As mentioned above, in a normal single microstrip antenna,
), strong electric field strength was obtained only in the range of -90°<θ<90°, and an antenna with strong electric field strength in any direction could not be obtained. This is exactly the same even if multiple microstrip antennas are combined and fed in series on the same board.

[0007]Also, by electrically connecting two or more microstrip antennas with directivity in different directions in parallel, it is possible to provide a strong electric field strength in any direction, but the configuration is complicated due to the parallel connection. In addition, impedance matching must be performed using coaxial lines with different characteristic impedances, and in this case, there is a problem that matching is time-consuming. An object of the present invention is to provide an antenna having a strong electric field strength in any direction with a simpler configuration.

[0008]

[Means for Solving the Problems] The antenna according to the present invention includes a dielectric plate, a radiation conductor plate formed on one side of the dielectric plate, and a ground conductor plate formed on the other side of the dielectric plate. two or more microstrip antennas are electrically connected in series by a feeder line, and each microstrip antenna has a maximum radiation direction in a different direction, and the plurality of microstrip antennas One of the two is configured to be connected to a transmitter or a receiver.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained with reference to the drawings. FIG. 1 shows a first embodiment of an antenna according to the present invention. In FIG. 1, 1 is a first radiation conductor plate, 2 is a first ground conductor plate, and 3 is a first dielectric, which constitute a first microstrip antenna. Further, 6 indicates a microstrip line, and 15 indicates a transmitting/receiving circuit (not shown in the drawing). In this embodiment, the antenna and the transmitting/receiving circuit are configured on the same substrate, so that they can be manufactured efficiently. 11 is a second radiation conductor plate, 12 is a second ground conductor plate, 13 is a second dielectric material and constitutes a second microstrip antenna;
4 is a coaxial line for connection with a characteristic impedance of 50Ω. In this way, by feeding the first microstrip antenna with the microstrip line 6, and feeding the second microstrip antenna with the connecting coaxial line 14 so as to be electrically connected in series with the first microstrip antenna, a simple and neat configuration can be achieved. The configuration achieves the objectives of the present invention. In this embodiment, since the second microstrip antenna is fed from the first microstrip antenna by the connecting coaxial line 14, the direction of the strong electric field strength of the second microstrip antenna is connected to the first microstrip antenna. It can be directed in any direction different from the direction of strong electric field strength, and desired directivity can be obtained.

FIG. 6 shows the directivity in the yz plane of the antenna of this embodiment. With the configuration shown in Figure 1, it is possible to provide a strong electric field strength not only in the direction of θ = 0° but also in the direction of θ = 180°, and according to experiments, the gain at this time is 1 compared to the configuration of Figure 7. It is ~3 dB lower, but this is small and the effect is large. In this case, the position where the connecting coaxial line 14 is connected to the first microstrip antenna and the second microstrip antenna is such that the impedance of the radiation conductor plate and the ground conductor plate of each antenna is the same as that of the connecting coaxial line 14. It is equal to the characteristic impedance. Moreover, although power is fed to the first microstrip antenna by a microstrip line here, it is also possible to feed power by electromagnetic coupling using a coaxial line or a microstrip line.

FIG. 2 shows another embodiment. 16,1 in Figure 2
8 is a radiation conductor plate, and 17 and 19 are short circuit plates that short-circuit this radiation conductor plate and the ground conductor plates 2 and 12, respectively. A microstrip antenna having such a short circuit plate (hereinafter referred to as a short circuit type microstrip antenna) resonates at half the size of a normal size microstrip antenna. The present invention is also applicable to short-circuited microstrip antennas. In this embodiment, the first microstrip antenna is fed with a microstrip line, and the second microstrip antenna is fed with a microstrip line.
A coaxial line is used to feed the microstrip antenna.

In the case of a short-circuit type microstrip antenna, the input impedance between the radiation conductor plate and the ground conductor plate is from 0Ω to several hundreds of Ω from the short-circuit plate side. Therefore, as in this embodiment, a microstrip line with a characteristic impedance of several hundred Ω is used to feed the first microstrip antenna, and a characteristic impedance is used to feed the power from the first microstrip antenna to the second microstrip antenna. Using a coaxial line with an impedance of 50Ω or 75Ω makes the configuration simple and neat. However, in the case of a short-circuited microstrip antenna, the configuration becomes quite complicated if power is supplied to both the first and second antennas using a coaxial line having the same characteristic impedance.

FIG. 3 shows a third embodiment of the present invention. In this example, the connection pin 20 is used instead of a transmission line when feeding power from the first microstrip antenna to the second microstrip antenna. The connection pin 20 is
The two radiation conductor plates 1 and 11 are short-circuited so that they do not come into contact with the ground conductor plate 2. Further, at this time, the first microstrip antenna and the second microstrip antenna share one ground conductor plate. In this embodiment, the directions in which the electric field strengths of the first and second microstrip antennas are strong are fixed at θ=0° and θ=180°, respectively in FIG. 3, but there is an advantage that the configuration is simpler. , its utility value is high. Further, in this embodiment, since the pin 20 is connected over a short distance, there is no need to consider the characteristic impedance of the pin, and the pin 20 can be placed at any position in the x direction, so there is a large degree of freedom in manufacturing.

FIG. 4 shows a fourth embodiment of the present invention. Here, the third embodiment is modified so that the maximum radiation directions of the electric field strengths of the four microstrip antennas are set in different directions. The four microstrip antennas are fed in series through the connection pin 20 and the coaxial line 8.

FIG. 5 shows a fifth embodiment of the present invention. In this case, power is fed to the four microstrip antennas in series, with the maximum radiation directions of the electric field strengths of the four microstrip antennas facing different directions. In this embodiment, it is only necessary to perform impedance matching between each microstrip antenna and the coaxial line, so it can be manufactured very easily.

In the above embodiments, all dielectrics have a dielectric constant εr>1, but the same effect can be obtained even in the case of air (εr=1).

[0017]

As explained above, the antenna according to the present invention uses a plurality of microstrip antennas connected in series to obtain directional characteristics that cannot be achieved with a single microstrip antenna. is simpler and more effective than the conventional method using multiple microstrip antennas.

[Brief explanation of drawings]

FIG. 1 shows an antenna of the present invention using a normal microstrip antenna.

FIG. 2 is an antenna of the present invention using a short-circuited microstrip antenna.

FIG. 3 is an antenna of the present invention in which a pin is used to connect two microstrip antennas.

FIG. 4 is an antenna of the present invention configured by feeding four microstrip antennas in parallel.

FIG. 5 is an antenna of the present invention in which coaxial cables are used to connect four microstrip antennas.

FIG. 6 shows the directional characteristics of the antenna of the present invention.

FIG. 7 is a schematic structure of a microstrip antenna using conventional coaxial line feeding and its directivity.

FIG. 8 is a schematic structure of a microstrip antenna using conventional microstrip line feeding.

FIG. 9 is an antenna configured by feeding a plurality of conventional microstrip antennas in parallel.

FIG. 10 is an antenna in which a plurality of conventional series-fed microstrip antennas are configured on the same substrate.

[Explanation of symbols]

1, 11, 16, 18, 21, 22 radiation conductor plate 2,
12 Grounding conductor plate 3, 13, 23, 24 Dielectric plate 4 Power supply pin 5 Power supply connector 6, 7, 10 Microstrip line 8 Power supply coaxial line 9, 21 Coaxial line to multiple antennas 14 Connection coaxial line 15 Transmission/reception circuit (omitted in the drawing) 17, 19 Shorting plate 20 Connection pin

Claims (1)

[Claims] 1. A microstrip antenna comprising a dielectric plate, a radiation conductor plate formed on one side of the dielectric plate, and a ground conductor plate formed on the other side of the dielectric plate. The plurality of microstrip antennas are electrically connected in series by electric wires, each of the microstrip antennas is configured to have a maximum radiation direction of electric field strength in a different direction, and one of the plurality of microstrip antennas is provided with a feeding terminal. antenna.