JPH11312909A - Waveguide and microstrip line converter and microstrip array antenna provided with the converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide also a function to distribute power from an antenna probe and to reduce removal of antenna elements on a substrate as much as possible by attaching the antenna probe to the substrate with microstrip lines connected to its both ends. SOLUTION: On a waveguide 2 whose axis is perpendicular to a base plate, etched microstrip lines 5a and 5b are arranged on a printed board, and an antenna probe 4 is placed in their front ends. The printed board 3 where the antenna probe 4 is arranged so as to be directed to the aperture part of the waveguide 2 is held between a cap 6 facing the aperture part of the waveguide and a base member 1. Further, A cavity 7 of the cap 6 is made face the aperture of the perpendicular waveguide 2, and its depth is made longer than the waveguide 2 by λ/4. Microstrip lines 5a and 5b are connected to both ends of the antenna probe 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waveguide / microstrip line converter and a microstrip array antenna having the same, and more particularly to a microstrip array antenna having a waveguide interface for use in a planar antenna feed portion. , A waveguide / microstrip line converter.

[0002]

2. Description of the Related Art In a microstrip array antenna, a loss due to a microstrip line (feeding line) is not negligible due to its characteristics, and greatly affects the efficiency of the antenna. Usually, the microstrip line converter is arranged outside the substrate of the microstrip array antenna. In this case, however, there is a feed loss from the conversion portion to the center of the substrate of the microstrip array antenna, and the gain is reduced. To reduce this loss, it is desirable to supply power at the center of the array.

Therefore, minimizing the length of the microstrip line by providing an antenna feed portion at the center of the substrate has been proposed in various Japanese Patent Application Laid-Open No. 9-172323. , Has been advocated.

[0004]

However, in this method, if the microstrip line converter is large, the antenna element at the center of the substrate must be removed accordingly.

The present invention has been made based on the above circumstances, and an object of the present invention is to provide a function of distributing power supply from an antenna probe in order to minimize the removal of antenna elements on a substrate. It is an object to provide a microstrip line converter and a microstrip array antenna having the same.

[0006]

Therefore, in the present invention,
A waveguide having a microstrip line provided so that an antenna probe is positioned so as to face an opening of a waveguide between a cap and a base member corresponding to the opening of the waveguide. In the microstrip line converter, the antenna probe is attached to the substrate in a configuration in which the microstrip lines are connected to both ends thereof.

In a microstrip array antenna using this converter, the waveguide / microstrip array converter is disposed at the center of the substrate, and each antenna on the substrate passes through each microstrip line. The elements are fed in opposite phases to each other. Further, the output of the converter, which is fed to each antenna element on the substrate via each microstrip line, is supplied to the micro-strip line. The strip lines are characterized in that the phases are opposite to each other, and that the feed directions to the antenna elements are opposite to each other.

Accordingly, a distribution function of supplying power to each antenna element from one antenna probe via a plurality of relatively short microstrip lines can be exhibited.
Therefore, high antenna efficiency is maintained, and the integration of the antenna elements is not hindered.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
This will be specifically described. In this example, a waveguide is arranged in such a manner that a microstrip line 5 etched on a printed circuit board 3 and an antenna probe 4 at the tip thereof are positioned above a waveguide 2 whose tube axis is perpendicular to the base plate 1. Tube 2
The printed circuit board 3 with the antenna probe 4 facing the opening of the waveguide 2 is placed on the cap 6 corresponding to the opening of the waveguide 2.
And the base member 1. Further, in this embodiment, the cavity 7 of the cap 6 corresponds to the opening of the vertical waveguide 2 opposed thereto, and the depth thereof is extended by λ / 4 wavelength of the waveguide 2. Is equivalent to

In such a waveguide / microstrip line converter, according to the present invention, the microstrip lines 5 are, as indicated by reference numerals 5a and 5b, respectively:
The antenna probe 4 is connected to both ends. Therefore, these microstrip lines 5a,
The outputs fed to the microelements 9a and 9b (each represented by a group of a plurality of elements) of the microstrip array antenna via 5b have opposite phases to each other for each microelement. Note that, in the embodiment of the present invention, reference numerals 8a and 8b indicate port portions parallel to the printed circuit board 3.

The signals input from the waveguide 2 to the microstrip lines 5a and 5b via the antenna probe 4 are output as signals having the same amplitude and opposite phases through the feed line on the substrate B. Each antenna element 9
a and 9b.

FIG. 2 is a plan view showing a state in which the waveguide / microstrip line converter A having such a configuration is mounted at the center of the substrate B of the microstrip array antenna.

Therefore, by integrating the waveguide / microstrip line converter and the distributor, the space consumed for the converter and the distribution structure can be reduced. Usually, the converter is placed outside the array, in which case there is a feed loss from the conversion part to the center of the array, which reduces the gain. In order to reduce this loss, it is necessary to supply power at the center of the array as shown in FIG. 2, but at this time, if the space allocated to the converter is small, the number of elements in the array does not need to be reduced much. Thereby, deterioration of the antenna radiation pattern can be reduced.

In the array antenna of FIG. 2, the direction of the antenna is reversed left and right with respect to the converter. This is because the phase of the two output ports of the converter is inverted. , Ie, by physically inverting the phase to cancel each other. As a result, a completely symmetrical circuit with respect to the converter can be realized, a good radiation pattern can be obtained, and the labor of CAD design can be reduced. When the inverted phase is electrically shifted by λg / 2, the radiation pattern is affected by the frequency.

(Second Embodiment) Next, a second embodiment of the present invention will be described.
An embodiment will be described. In the above description, the converter of the present invention is provided at the center of the array antenna. However, the following cases may be applied to other applications. The phases of the two microstrip lines distributed from the waveguide are opposite to each other, and by combining this with reversing the feeding direction to the antenna element as shown in FIG. Can be reversed.

When a normal converter having no distribution structure as shown in the present invention (indicated by A ') is used, the feed direction to the antenna is the same for all the elements (route a and route a) as shown in FIG. b), or as shown in FIG.
And the phase is inverted by the line length (the line length of route a and route b is longer by λg / 2 than the latter by λg / 2). It is conceivable, however, that anyway, there is a drawback that the layout is difficult or that it has a frequency characteristic.

[0017]

According to the present invention, as described in detail above, a substrate provided with a microstrip line so that an antenna probe is located opposite to an opening of a waveguide is provided. In the waveguide / microstrip line converter sandwiched between the cap and the base member corresponding to the above, the antenna probe is attached to the substrate with the microstrip line connected to both ends. .

In a microstrip array antenna using this converter, the waveguide / microstrip array converter is disposed at the center of the substrate, and each antenna on the substrate passes through each microstrip line. By feeding the elements out of phase with each other, and further via each microstrip line, the output of the converter, which is fed to each antenna element on the substrate, By integrating the converter and the distributor, which are in opposite phases and the feeding directions to the antenna elements for each are opposite, to the mounting space of the converter and the antenna element on the substrate of the microstrip array antenna. Space for the distribution structure of the antenna can be reduced, and the deterioration of the antenna radiation pattern can be reduced. . Therefore, high antenna efficiency is maintained, and the integration of the antenna elements is not hindered.

[Brief description of the drawings]

FIGS. 1A to 1C are a bottom view of a cap, a vertical side view of the entire converter, and a vertical end view, respectively, showing an embodiment of the present invention.

FIG. 2 is a schematic plan view showing an example in which a converter according to the present invention is applied to a microstrip array antenna.

FIG. 3 is a schematic plan view of a modified example.

FIG. 4 is a schematic plan view showing a conventional example for comparison with the present invention.

FIG. 5 is a schematic plan view showing a conventional example.

[Explanation of symbols]

 Reference Signs List 1 base member 2 waveguide 3 printed board 4 antenna probe 5 (5a, 5b) microstrip line 6 cap 7 cavity 8a, 8b port 9a, 9b antenna element A waveguide / microstrip line converter B microstrip array antenna Substrates a, b Feeding line

Claims (3)

[Claims] 1. A substrate provided with a microstrip line so that an antenna probe is positioned so as to face an opening of a waveguide between a cap and a base member corresponding to the opening of the waveguide. A waveguide / microstrip line converter, wherein the antenna probe is attached to the substrate in a configuration in which the microstrip lines are connected to both ends of the antenna probe. converter. 2. The microstrip array antenna according to claim 1, wherein the waveguide / microstrip line converter is provided in a planar antenna feed unit, wherein the converter is disposed at a center of a substrate. A microstrip array antenna, wherein power is supplied to each antenna element on a substrate in opposite phases via each microstrip line. 3. The output of the converter fed to each antenna element on the substrate via each microstrip line is in opposite phase to each other with respect to the microstrip line, and the antenna element for each is output. 3. The power supply direction to the power supply is opposite.
7. The microstrip array antenna according to 1.