JPH01284105A - Stacked microstrip antenna - Google Patents

Abstract

PURPOSE:To make an earthing pin difficult to fuse without causing the deterioration of a VSWR characteristic even when a driven element and a parasitic element are misaligned by making the diameter of the earthing pin thick, and making it column-shaped or pipe-shaped. CONSTITUTION:A driven element plate 1 is provided with a circular driven element 7 formed on the top surface of an insulating substrate 6 and a grounding surface 8 formed on the bottom surface of the insulating substrate, and a grounding line 5 is connected to the grounding surface 8. Feeding lines 4a, 4b are connected to the driven element 7 through through-holes 9a, 9b, and when the high frequency signals S1, S2 of a required phase difference, e.g., of 90 deg. are supplied, an electromagnetic wave whose plane of polarization rotates is emitted in the air. Both the center of the parasitic element 11 and the center of the driven element 7 are connected to the grounding surface 8 by the earthing pin 3. In this case, by making the diameter of the earthing pin thick, the deterioration of the VSWR characteristic can be prevented even when the centers of the driven element and the parasitic element are misaligned to some extent, and the fusing of the earthing pin can be prevented even in the case of a thunderbolt, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a stacked microstrip antenna.

(Prior Art) In recent years, microstrip antennas have been actively developed as antennas mounted on airplanes and the like.

FIG. 10 is a perspective view showing an example of such a microstrip antenna, and FIG. 11 is a partially cutaway perspective view of this microstrip antenna.

The microstrip antenna shown in these figures consists of an insulating substrate 1oo that serves as the base of the antenna, and this insulating substrate 1oo.
A ground plane 101 formed on the lower surface side of 00 and an excitation element (metal plate) formed on the upper surface side of the insulating substrate 100.
102, two feeder lines 103a that penetrate the insulating substrate 100 and are connected to the excitation element 102 from the lower surface side,
103b, and one ground wire 104 connected to the ground plane 101.

In this microstrip antenna, the angle (offset angle) from the center of the excitation element 102 is "9" in order to generate radio waves (circularly polarized waves) whose plane of polarization rotates.
At the points (feeding points) Pl and P2 where the temperature is 0 degrees, each feeder line 10
3a, 103b, etc., are connected to the excitation element 102.

Then, with the grounding wire 104 grounded, a high frequency signal with a "0 degree" phase is supplied to the power supply line 103a, and a high frequency signal with a "90 degree" phase is supplied to the power supply line 103b. At this time, circularly polarized waves are generated by this microstrip antenna and radiated into the air (in this figure, on the top side).

As described above, this microstrip antenna can be made extremely thin as a whole and can generate circularly polarized waves, so it is considered to be extremely promising as an antenna for airplanes.

However, although such conventional microstrip antennas have a simple structure and can be made thin, there is a problem that the usable frequency band for VSWR is narrow when put into practical use, and this becomes a bottleneck for practical use. was.

Therefore, in order to solve this problem, Fig. 12,
As shown in FIG. 3, an insulating substrate 107 is placed a predetermined distance away from the excitation element 102, and the center point of the parasitic element (metal plate) 108 formed on the insulating substrate 107 and the ground point 101 are and earth pin 109
A microstrip antenna connected with (hereinafter, such an antenna is referred to as a stacked microstrip antenna) ■! 2 is proposed as tM.

The purpose of the ground pin 109 of this antenna is to
．． The improvement of electrical performance was limited to maintaining the symmetry of the current distribution excited on the 102. Therefore, the thickness of the ground pin 109 was not considered at all.

In this case, the theoretical operation of the stacked microphone [l strip antenna is not certain, but this parasitic element 10B
It has been experimentally confirmed that the following characteristics can be obtained by providing the following.

First, as the insulating substrate 100.107, the thickness is "1.6n".
+a+" stack type microstrip antenna 112 using Teflon glass substrate, 2°6Ct!z"
When the radius a of the excitation element 102 is determined so as to coexist in the band, the ratio of the radius a of the excitation element 102 to the radius of the parasitic element 108 is used as a parameter to
By changing the distance of 07rW1, it is possible to obtain a bandwidth/element spacing characteristic in which the VSWR is "1.5" or less as shown in 141ffl.

As is clear from this figure, the ratio of the radius a of the excitation element 102 to the radius of the parasitic element 10 is set to "1.05", and the distance ah between each insulating substrate 100 and 107 is set to "IO+
+us'' is the most convenient characteristic. Under this condition, the VSWR characteristic is as shown in the characteristic curve 110 of FIG. 15.

As is clear from this characteristic curve 110, in this example,
“±+cuz” range centered on “2.6G H2”,
That is, the frequency “2.5 GHz ~ 2-TG Hz”
Te, VSWR (direction becomes less than "1.5".

As is clear from comparing the characteristic curve 110 at this time with the characteristic curve 111 when there is no parasitic element 108,
With the establishment of unpaid 7fi Z child 10B, “
2.5GH,! In the range of ~2.7CI+□', the VSWR characteristic can be improved to a practically acceptable level.

However, in such a conventional stacked microstrip antenna 112, as shown in FIG. 16, if the center of the excitation element 102 and the center of the parasitic element 108 are misaligned, the VSWR characteristic deteriorates rapidly. it is conceivable that.

For this reason, stacked microstrip antenna 1.
12, processing accuracy and assembly accuracy must be high to prevent these from shifting, but this requires a large number of manufacturing steps and increases costs.

Furthermore, when this stacked microstrip antenna 112 is mounted on Flight 0113 as shown in FIG.
There was a risk that the ground pin 109 would melt due to a lightning strike.

(Object of the Invention) In view of the above circumstances, the present invention provides an excitation element and 7! ! The stacked microstrip prevents the V S WR characteristics from deteriorating even if the power supply element becomes misaligned, and also prevents the ground pin from fusing in the event of an accident such as a lightning strike. The purpose is to provide an antenna.

(Summary of the Invention) In order to solve the above problems, in the stacked microstrip antenna according to the present invention, the diameter of the ground pin connecting the parasitic element and the exciting Wi element is increased to form a columnar or pipe-like structure. It is characterized by what it did.

(Embodiment) FIG. 1 is a perspective view showing an embodiment of a stacked microstrip antenna according to the present invention, and FIG. 2 is a partially cutaway perspective view of the same embodiment.

The stacked microstrip antenna 20 shown in these figures includes an excitation element plate 1, a parasitic element plate 2, a ground pin 3, two feed lines 4a and 4b, and a ground line 5. With the line 5 grounded, each feeder line 4a
, 4b, when high frequency signals S1 and S2 with a phase difference of 90 degrees are supplied, a radio wave (circularly polarized wave) whose polarization plane rotates over time is generated and radiated into the air.

The excitation element plate l includes an insulating substrate 6 made of Teflon glass or the like, an eye-shaped excitation element 7 formed on one prong (the upper surface in this figure) of the insulating substrate 6, and the insulating substrate 6. The ground plane 8 formed on the lower surface of the ground plane 8 is connected to the ground line 5, and the excitation element 7 has a through hole 9a formed in the insulating substrate 6. Power supply lines 4a and 4b are connected via 9b.

In this case, the connection point between the excitation element 7 and each feeder line 4a, 4b (feeding point P7, P2) has an angle θ of 105 degrees from the center point T as shown in the third UiJ, and an impedance of “50Ω”. It is located at the point where

Furthermore, the parasitic element plate 2 includes an insulating substrate lo made of Teflon glass or the like, and a circular parasitic nitrogen 11 formed on the upper surface of the insulating substrate IO. The center of the excitation element 7 is located between the through hole 12 formed in the insulating substrate 10 and the excitation element 7.
, and is connected to the ground plane 8 by an earth pin (diameter, 4 mm) 3 inserted through a through hole 13 formed in the insulating substrate 6.

In this case, as shown in FIG. 4, the thicknesses do and d2 of the insulating substrates 6 and 10 are set to "4 mm" and "1.6 mo+", respectively, and the spacing between the insulating substrates 6 and 10 is " It is set to 4mm.

Next, the characteristics of this embodiment will be explained with reference to the characteristic diagrams shown in FIGS. 5 to 9.

First, in a conventional stacked microstrip antenna, if the distance between the insulating substrates is narrower than a "10m mesh", the isolation between each feeding point will be reduced, but in this embodiment, each insulating substrate 6. 10 intervals 1
1 is set to "41", each power feeding point P1. When the offset angle θ of P2 is set to 105 degrees, the design frequency F is set as shown in FIG. is "1595.25MHz", the transmission frequency F is "1660.5MHz", and the reception frequency F2 is "1530MH7," and the isolation of each feed point P1 and P2 is "-".
We were able to reduce the noise level to 14 dB'' or less.

This allows the transmitted and received radio waves to be made into almost completely circularly polarized waves.

Furthermore, in this embodiment, since the diameter of the ground pin 3 is made thick, even if the center of the excitation element 7 and the center of the parasitic element 11 are slightly shifted, the VSWR characteristic of the stacked microstrip antenna 2° can be prevented from decreasing. In addition, by increasing the diameter of the ground pin 3 in this way, as shown in FIG. 6, the design frequency F0 is set to "1595.25M1+□', the transmission frequency is set to "1660-5MHz", and the receiving frequency is set to "1660-5MHz". 1530M112'', the isolation value of each feed point PI and P2 can be lowered.

Also, since the ground pin 3 is made thicker, the parasitic element 1
It is possible to prevent the earth pin 3 from melting even when the pin 1 is struck by lightning.

Further, in this embodiment, the radius a of the excitation element 7 is set to "6".
4.82 mm", and the radius a of this excitation element,
Since the tq diameter ratio of the parasitic element 11 is set to "1.14", the transmission frequency is set to "lG60.5" as shown in FIG.
MH□” and further set the receiving frequency to “1530MH2”
It is possible to improve the VSWR characteristics when

Further, in the embodiment described above, there is a space between each insulating substrate 6.10, but as shown in FIG.
By inserting a dielectric plate 21 having a dielectric constant ε of approximately "1O" between
The VSWR characteristic may be improved.

As is clear from comparing the characteristic curves 24.25 at this time with the characteristic curves 22.23 when the dielectric plate 21 is not inserted, the VSWR characteristics are improved by inserting the J electric plate 21. be able to.

Furthermore, in each of the embodiments described above, the offset angle θ of the feeding points P and P2 is set to 105 degrees, but if the isolation between the feeding points P1 and 22 is less than a predetermined value, then this offset The angle θ may be set to another value.

(Effects of the Invention) As explained above, according to the present invention, the diameter of the ground pin is made thick, so that even if the excitation element and the parasitic element are misaligned, the VSWR characteristic is prevented from deteriorating. In addition, it is possible to prevent the ground pin from melting even in the event of an accident such as a lightning strike.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of a stacked microstrip antenna according to the present invention, FIG. 2 is a partially cutaway perspective view of the same embodiment, and FIG. 3 is a plan view of the excitation element plate shown in FIG. 1. , Fig. 4 is a front view of the same embodiment, Fig. 5 is an isolation/offset angle characteristic diagram of the same embodiment, Fig. 6 is an isolation/earth bin diameter characteristic diagram of the same embodiment, and Fig. 7 is a diagram of the same implementation. VSWR/element diameter ratio characteristic diagram of the example, FIG. 8 is a front view showing another embodiment of the stacked microstrip antenna according to the present invention, and FIG. 9 is the VSWR of the embodiment shown in FIG. 8.
WR/element diameter ratio characteristic diagram, Fig. 10 is a perspective view showing an example of a conventional microstrip antenna, Fig. 11 [J
is a partially cutaway perspective view of the microstrip antenna shown in No. 101m, FIG. 12 is a perspective view showing an example of a conventionally proposed stacked microstrip antenna, and FIG. 13 is the stacked microstrip antenna shown in FIG. 12. A partially cutaway perspective view of the antenna, FIG. 14 is a bandwidth/element rr: 1 interval characteristic diagram of the stacked microstrip antenna shown in FIGS. 12 and 13, and FIG. 15 is a diagram of the stacked microstrip antenna shown in FIGS. 16 is a front view for explaining the problems of the stacked microstrip antenna shown in FIGS. 12 and 13, and FIG. 17 is a diagram of the stacked microstrip antenna shown in FIGS. This is the #coal content for explaining other problems in the stacked microstrip antenna shown in FIG. 3... Conductor pillar or conductor pipe (earth pin), 7...
... Excitation element, 11... Parasitic element, 20... Stacked microstrip antenna, Po, P2...
Feeding point. Figure 1 Figure 2 Figure 3 Figure 4 Figure 7 ＼ Q Book 9 Toku N
t-1 Figure 8 Figure 9 ■-1""° 1°S 1. i4 Figure 10 Figure 12 Figure 13 Figure 15 Figure 1a

Claims (2)

[Claims] (1) In a stacked microstrip antenna in which a circular parasitic element, a circular excitation element, and a ground plane are sequentially stacked at a predetermined interval, the centers of each of the parasitic element and the excitation element are connected to a conductor. A stacked microstrip antenna characterized by being connected by a pillar or a conductor pipe. (2) The stacked microstrip antenna according to item (1), wherein the conductor column or conductor pipe is electrically grounded.