JP3308895B2 - Microstrip array antenna with waveguide / microstrip line converter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microstrip array antenna having a waveguide / microstrip line converter, and more particularly, to a microstrip array antenna having a waveguide interface, which is used for a planar antenna feeding portion. A microstrip array antenna with 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 in view of the above circumstances, and has as its object the purpose of distributing power supply from an antenna probe in order to minimize the removal of antenna elements on a substrate . Moreover, Po
Microstrip line that cancels phase inversion due to
The present invention provides a microstrip array antenna having a transducer .

[0006]

According to the present invention, there is provided a microstrip array antenna comprising: a substrate provided with a microstrip line in which an antenna probe is positioned so as to face an opening of a waveguide; In a microstrip array antenna having a waveguide / microstrip line converter sandwiched between a cap corresponding to a portion and a base member, the antenna probe has a configuration in which the microstrip lines are connected to both ends. And attached to the substrate, the waveguide /
The microstrip line converter is mounted on the planar antenna feeder while being arranged at the center of the substrate,
Via each microstrip line, power is supplied to each antenna element on the substrate in the opposite phase to each other, and the power supply output thereof is in opposite phase to each other with respect to the microstrip line. The feeding direction to the antenna element is opposite ,
The cross-trip antenna is a waveguide / micro strip
It is characterized in that the circuit is symmetrical with respect to the pline converter .

[0007]

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. Besides, it depends on the port
Phase inversion can be offset.

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
This will be specifically described with reference to FIGS. 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. A printed circuit board 3 having an antenna probe 4 facing the opening of the tube 2 is sandwiched between a base 6 and a cap 6 corresponding to the opening of the waveguide 2. 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. In the embodiment of the present invention, reference numerals 8 a and 8 b 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 portion 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. 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 labor saving in CAD design can be achieved. If the inverted phase is electrically shifted by λg / 2, the radiation pattern is affected by the frequency.

In the above description, the converter is an array
Although it is provided at the center of the tena, it is particularly important to
State, the two microstrips distributed from the waveguide
By reversing the phase of the pipeline and further reversing the power supply direction to the antenna element as shown in FIG. 3, the inversion of the phase by the port can be canceled.

When a normal converter having no distribution structure as shown in the present invention (indicated by reference numeral A ') is used, the feeding direction to the antenna is the same for all elements (route a and route 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 there is a drawback that the layout is difficult or that it has frequency characteristics.

[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 showing a characteristic portion of the present invention .

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

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-57303 (JP, A) JP-A-2-171006 (JP, A) JP-A-7-183724 (JP, A) JP-A-4- 46403 (JP, A) JP-A-2-17001 (JP, A)

Claims (1)

(57) [Claims] 1. A substrate provided with a microstrip line so that an antenna probe is positioned facing an opening of a waveguide, and a substrate provided between a cap corresponding to the opening of the waveguide and a base member. In a microstrip array antenna having a waveguide / microstrip line converter sandwiched therebetween, the antenna probe has a configuration in which the microstrip lines are connected to both ends thereof, and is attached to the substrate. The waveguide / microstrip line converter is mounted on the planar antenna feed section while being arranged at the center of the substrate, and is provided via each microstrip line.
The antenna elements on the substrate are fed in opposite phases to each other. The feed outputs of the microstrip lines are in opposite phases to each other, and the feed directions to the respective antenna elements are opposite . And the microstrip antenna is a waveguide / micro
A microstrip array antenna having a circuit symmetrical with respect to a stripline converter .