JPS63171004A - Dual frequency printed dipole antenna - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention aims to make a printed dipole antenna for a base station antenna for land mobile communication resonate at two frequencies.
Printed Guiball antenna configuration that widens the band of the second resonant frequency by controlling the directivity at the second resonant frequency higher than the resonant frequency of tJS,i and by changing the lengths of the two parasitic elements. It is related to.

[Conventional technology]

Conventionally, there is a method of achieving two-frequency resonance using a printed dipole antenna, as disclosed in Japanese Utility Model Application No. 1983-78229. This is achieved by placing . An example of the structure of such an antenna is shown in FIG.

In FIG. 1, 51 is a radiating element of a printed dipole antenna, 52 is a parasitic element, 53 is a feed terminal, 54 is a dielectric substrate, and 55 is a grounding plate. In addition, the length of the radiating element of the printed dipole antenna is the length of the parasitic element! ,
Let the width of the parasitic element be ω, and the distance between the radiating element and the ground plate be t.

FIG. 2 shows an example of measuring the directivity in the horizontal plane, where A shows the directivity in the horizontal plane at the first resonant frequency, and B shows the directivity in the horizontal plane at the resonant frequency of NS2. Such directivity in the horizontal plane is uniquely determined by the distance t between the radiating element and the ground plate, and there are cases where the directivity in the horizontal plane at the first resonance frequency and the directivity in the horizontal plane at the second resonance frequency do not match. do.

Furthermore, since there is one parasitic element, the fractional band of the second resonant frequency is 4% to 5%.

[Problem that the invention seeks to solve]

In the conventional dual-frequency printed gouball antenna, as mentioned above, the directivity in the horizontal plane is determined by the mounting position of the parasitic element, so the disadvantage is that the directivity of the second resonant frequency cannot be changed. However, it also had the disadvantage of not being able to achieve a wide band.

In view of the above-mentioned conventional problem, g, the present invention arranges two parasitic elements facing each other on a radiating element with one printed dipole antenna in between, and changes the installation position on the radiating element. By changing the directivity by changing the directivity in the horizontal plane of the first resonant frequency and the resonant frequency of f52, and by slightly changing the length of the parasitic element that resonates the second frequency, a wide band can be achieved. The purpose of the present invention is to provide a printed dipole antenna that can be used as a printed dipole antenna.

c. Means for Solving Problems] According to the present invention, the above objects are achieved by the means described in the claims.

That is, the present invention makes it possible to change the directivity in the horizontal plane at a second resonant frequency higher than the resonant frequency of NS1 in a printed dipole antenna that resonates at two frequencies using one printed dipole antenna. The main feature is that it can be made broadband at the resonant frequency of 2, and a pair of parasitic elements is attached near the electromotive point of the radiating element of the printed dipole antenna. , different from the conventional one.

〔Example〕

FIG. 3 is a diagram showing the configuration of a dual-frequency printed dipole antenna according to an embodiment of the present invention, in which 1.1' is a radiating element, 2.2' is a parasitic element, 3 is a feeding terminal, and 4 ．．
4' and 4'' represent dielectric substrates, and 1 and 2.1'
The distance between and 2' is d, the width of the parasitic element is ω, the length of the parasitic element is 11, the length of the radiating element 9 is Ll, and the width is W.

For the resonant frequency of the radiating element, L is approximately 1/1 of the resonant wavelength.
2, and the second frequency resonates due to the parasitic element 2.2'.

It is a requirement of the present invention that L>1. 1 is related to the second resonant frequency, ω is related to the fractional band with respect to that frequency, and there is an optimal spacing at which the parasitic elements are coupled.

Also, the second resonant frequency is! It can be set arbitrarily.

Figure 4 shows when the parasitic element is moved parallel to the radiating element.
This figure shows the change in the maximum return loss due to the difference in the position of the parasitic element (the direction of movement is indicated by χ in FIG. 3). The length of A-A' is ω. When the parasitic element is near the center of the radiating element, it is the value indicated by the 0 point,
When it is shifted toward the front in the NS3 diagram in parallel with the radiating element, the value is in the direction of A, and when it is shifted toward the back, it is the value in the direction of A'. If the parasitic element is not on the radiating element, the coupling will be weaker,
The maximum return loss becomes smaller.

From this, it can be seen that if the parasitic element is located on the radiating element, the effect of the parasitic element becomes stronger and two-frequency resonance occurs.

Note that point A is the end of the radiating element farthest from the feeding point, point 0 is the center of the radiating element, and point A' is the end of the radiating element closest to the feeding point.

C in Figure 5 is the directivity in the horizontal plane at the second resonant frequency when the parasitic element is located at point A in Figure 4, and D is the horizontal plane when the parasitic element is located between point A and point 0. inward direction,
E indicates the directivity in the horizontal plane when the parasitic element is located at the zero point.

It can be seen that by changing the mounting position of the parasitic element on the radiating element, the directivity at the second resonant frequency can be changed. Note that the directivity in the horizontal plane at the frequency of fPJl is hardly affected by the parasitic element.

Furthermore, by changing the lengths of the parasitic elements 6 and 6' as shown in Fig. 6, it is possible to widen the specific band by more than 10% without almost affecting the directivity in the horizontal plane. .

In other words, the length of the two parasitic elements! , β' are different, each has a resonant frequency corresponding to its length, and in this case, together with the first resonant frequency, there are three resonant points.

Therefore, by setting the second and third resonant frequencies to relatively close values, the band can be effectively expanded.

〔Effect of the invention〕

As explained above, according to the printed dipole antenna of the present invention, the mounting of the parasitic element can be performed by changing the position and length of the parasitic element, so that the second resonant frequency can be adjusted with one printed dipole antenna. Since it is possible to change the directivity in the horizontal plane, there is an advantage that an antenna having broadband characteristics can be easily realized.

[Brief explanation of the drawing]

f: IS1 diagram is a diagram showing an example of the structure of a dual-frequency antenna in a conventional printed dipole antenna, FIG. 2 is a diagram showing the directivity in the horizontal plane of a conventional printed dipole antenna, and FIG. 3 is an example of an implementation of the present invention. A diagram showing the configuration of an example dual-frequency printed dipole antenna. Figure 4 is a diagram showing the relationship between the position of the parasitic element and the maximum reflection loss when the parasitic element is moved parallel to the radiating element. Figure 5 shows the difference in directivity in the horizontal plane due to the difference in the mounting position of the parasitic element on the radiating element of the present invention, and Figure 6 shows another embodiment of the present invention when widening the band FIG. 2 is a diagram showing the configuration of a dual-frequency printed dipole antenna. 1.1'...radiating element of printed dipole antenna, 2,2', 6,6'...parasitic element, 3...feeding terminal, 4
. 4', 4"...Dielectric substrate, 5...
...Printed dipole antenna earth plate agent Patent attorney Takashi Honma 6/
s2 Fig. 7 Fig. 0゜ Fig. 2 Fig. 3 Fig. 4 Fig. 5

Claims (2)

[Claims] (1) Near the electromotive point of the radiating element of a printed dipole antenna configured on a dielectric substrate, a pair of metal conductors is placed parallel to the electric field axis with the printed dipole antenna in between.
A dual-frequency printed dipole antenna characterized by two parasitic elements facing each other and attached to each other. (2) A dual-frequency printed dipole antenna according to claim (1), in which the two parasitic elements made of metal conductors have different lengths.