JPS6223209A - Circularly polarized wave plane array antenna - Google Patents

Abstract

PURPOSE:To attain thin profile and to simplify the mechanical constitution by forming a couple of exciting probes orthogonal to each other corresponding to many holes on a common plane and synthesizing the phase of a feeding signal to a couple o the exciting probes in a suspended line. CONSTITUTION:The 1st metallic plate 1 has a recessed hole 4, the 2nd metallic plate 2 has a hole 5 whose diameter is the same as that of the hole 4, which is penetrated vertically and whose upper side is formed as a circular cone shape. In clipping the base 3 by the 1st and 2nd metallic plates 1, 2, they are positioned so that the holes 4, 5 are made coincident. In using the 1st and 2nd metallic plates 1,2 to clip the base 3, a cavity 6 connected to the holes 4, 5 is formed. A conductor foil 7 coated to the base 3 is connected via the cavity 6 to constitute the suspended line. Since the circularly polarized wave is synthesized by deviating the phase of linearly polarized waves orthogonal to each other by pi/2, the exciting probe corresponding to each linearly polarized wave component is arranged.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a circularly polarized plane array antenna suitable for use, for example, in receiving satellite broadcasting.

[1 Summary of the Invention] The present invention provides a suspended line-fed planar antenna in which a pair of excitation probes orthogonal to each other are formed on a common plane, each corresponding to a plurality of holes forming a part of a radiating element. By phase-synthesizing the feed signals to a pair of excitation probes within a suspended line, a planar antenna with a simple configuration and high gain can be obtained.

[Conventional technology]

Various high-frequency planar antennas have been studied in the past.
In particular, when looking at direct satellite broadcast reception in the 12 GHz band or for similar purposes, the configurations are: ■ Microstrip line feed array antenna (travelling wave, punch, slot), ■ Radial line slot array antenna, ■ Conductive antenna. Wave tube slot array antennas, suspended line fed aperture array antennas, etc. have been proposed.

The microstrip line feed structure (2) has the advantage of being able to be created only by etching the substrate, but even if a low-loss substrate such as Teflon is used, there is dielectric loss and radiation loss in the middle of the feed line, making it difficult to create a high-efficiency antenna. It is quite difficult to realize, and low-loss substrates are also expensive. The power supply methods of ■ and ■ almost eliminate loss in the power supply part and solve the drawbacks of ■, but the structure is complicated and there are manufacturing problems, and Since the slot is a resonant structure, it has a wide band (e.g. 300-500
It is difficult to obtain gain and other good characteristics in the MIIz band). In addition, the coupling between slots complicates the design and makes it difficult to achieve the design performance.

The suspended line power feeding method (2) has a structure that can overcome these drawbacks to some extent, and also provides broadband characteristics with an inexpensive substrate. Regarding the structure of (1), it has already been announced, for example, Japanese Patent Application Laid-open No. 59-103406,
JP-A-59-207706 and MSN (Microw
ave System News) March 1
There are 984 PP110-126.

[Problems to be solved by the invention] However, the method described in JP-A No. 59-103406 forms two excitation probes by forming perpendicular copper foils on both sides of a dielectric sheet (substrate). Since the structure spans both sides of the board, there are drawbacks such as complicated wiring and a large structure.

Furthermore, the method described in JP-A-59-207706 constructs an excitation probe by forming copper foil on two dielectric sheets (substrates), which makes positioning difficult and the configuration complicated. There are drawbacks such as: Furthermore, the method described in MSN attempts to receive linearly polarized waves by forming one excitation probe in each of multiple holes, and if it receives circularly polarized waves manually, the gain is poor. Furthermore, there are drawbacks such as the need for two substrates when attempting to generate circularly polarized waves.

This invention has been made in view of the above, and has a simple configuration that is inexpensive, has excellent characteristics, and can transmit and receive circularly polarized waves by forming a pair of excitation probes on a common plane of a single substrate. This provides an excellent circularly polarized planar array antenna.

[Means for solving problems]

The circularly polarized planar array antenna according to the invention is made of a metal or metallized plastic (11, (21) with a number of holes (41, (5)) forming part of the radiating element (21).
3), in which a pair of excitation probes (81, 191) are formed on a common plane and are orthogonal to each other, corresponding to the plurality of holes, respectively, and a feeding signal to the pair of excitation probes is formed. are configured to perform phase synthesis within the suspended line.

[Effect]

A pair of mutually orthogonal excitation probes (8), +9 corresponding to a large number of holes (4), (51) are formed on a common plane. Then, the phases of the power supply signals to the pair of excitation probes are combined within the suspended line. This makes it possible to create a circuit configuration that can receive circularly polarized waves on a single board, making it thinner than before and simplifying the mechanical configuration. Even when used for commercial purposes, an antenna gain equivalent to or higher than that using an expensive microstrip line substrate can be obtained.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail based on FIGS. 1 to 8.

Fig. 1 shows the configuration of a circularly polarized wave radiating element according to the present invention, Fig. 1A is a top view thereof, and Fig. 1B is a cross-sectional view taken along line 1-1 in Fig. 1A. be. In Fig. 1, (1) is the first metal plate (or metallized plastic plate), (21 is the second metal plate (or metallized plastic plate), +31 is the first and second metal plate (
11, (2+) is a thin film substrate (film-like flexible substrate).

The first metal plate (1) had a recess-shaped hole (4), and the second metal plate (2) had the same diameter as the hole (4), passing through it vertically, and had a conical upper side. It has a hole (5). 1st and 2nd
metal plate +11. (The holes (4) and (5) are positioned so that they match when the board (3) is held between the two parts 21.

In addition, the first and second metal plates fil, (2) and the substrate (
A cavity (6) communicating with the holes (41, (51) is formed when the holes (41, (51) are held together).

(7) is a conductor foil attached to the substrate (3), and the conductor foil (7) is connected through the cavity (6) to form a suspended line. Further, this conductor foil (7) is placed on the common plane of the substrate (3) through hole +41. The excitation probe (8) is protruded by a predetermined length perpendicularly to the center direction of +51, and constitutes a pair of excitation probes (8) and +91. With such a configuration,
Since the circularly polarized wave is a combination of mutually orthogonal linearly polarized waves with their phases shifted by π/2, excitation probes corresponding to each linearly polarized wave component are arranged.

FIG. 2 shows the configuration of a suspended line that supplies power to a planar array, and shows a state cut along line 1--2 in FIG. 1B. In this case, for example, 25 to 100 μn
A conductive foil (7) formed by etching a printed circuit board (3) of approximately
It is surrounded by a hollow coaxial line. In this case, since the substrate (3) is thin and serves only as a support member, it becomes a feed line with low transmission loss even if it is not a low-loss substrate. For example, the transmission loss of an open strip line using a Teflon glass substrate is 4 to 6 dB/m at 12G)Iz, but in the case of a suspended line, it is about 2.5 to 3 dB/m with a 25 μm film substrate. Film-like flexible substrates are cheaper than Teflon glass substrates, so they have advantages in terms of structure (characteristics) as well.

Figure 3 shows a specific circuit for synthesizing circularly polarized waves, in which a pair of excitation probes (81, 91 are connected by a conductive foil (7), which is a suspended line on the same plane of the substrate (3). However, at that time, λg/4 (
A line (10) with λg: line wavelength at the center frequency is inserted into one side where the phase is advanced so that they are in phase at the combining section (11). In this way, the line of λg/4 (10
) can be applied to right-handed or left-handed circularly polarized waves by changing the direction of insertion. Incidentally, Fig. 3 shows the case of receiving right-handed circularly polarized waves, and assuming that the radio waves are directed toward the back rather than the front in the drawing, the electric field advances while rotating clockwise, so the excitation probe (9) first received, π/2(9
It can be seen that the excitation probe (8) receives the signal after a delay of 0''), and as a result, the synthesizer (11) becomes in phase.

FIG. 4 shows a circuit configuration in which a plurality of circularly polarized wave radiating elements as shown in FIG. 1 are mutually fed by a suspended line, thereby forming an array. At this time, the first and second metal plates (1).

(2) has a plurality of holes +41. corresponding to the radiating elements. (
5) are provided respectively, and an excitation probe +81 of each radiating element is provided.
．． +91 is the conductor foil that constitutes the suspended line (
7), they are interconnected so as to be equidistant from the feed point (12). In such a configuration, various directivity characteristics can be obtained by changing the feeding phase and power distribution ratio on the line. In other words, excitation probe +81,
The phase can be changed by changing the distance from the feed point (12) to +91, and the amplitude can be changed by changing the impedance ratio by making the line thinner or thicker where the suspended line branches. changes, thereby allowing the directional characteristics to be changed arbitrarily.

Figures 5 and 6 show the characteristics of the circularly polarized wave radiating element according to the present invention.
It can be seen that the above-mentioned isolation between the probes is achieved, and the reflection loss is good at -30 dB, so that it can be used as a circularly polarized wave radiating element. Figure 6 shows an example of measuring the axial ratio of circularly polarized waves. For example, at a frequency of 12 CIIz, the axial ratio is approximately 1
dB is the permissible range, and it can be seen that the circularly polarized wave radiating element according to the present invention fully satisfies this range.

FIG. 7 shows a plurality of array groups (13a
) to (13p). In this case, it is composed of 256 circularly polarized wave radiating elements, and each element is equally spaced with respect to the feeding point (14). placed at a distance.

Figure 88 shows the directional characteristics when the configuration is as shown in Figure 7. In this case, the element spacing is 0.95λ (f: 12G
llz) and the same phase and amplitude. Because there is little mutual coupling between elements, it exhibits well-defined directivity characteristics.

In addition, although the above-mentioned embodiment mainly explained the radiating element,
It goes without saying that the reversible principle of the antenna allows a radiating element (or an antenna constituted by an array of radiating elements) to act as a receiving element (receiving antenna) without equivalently changing its properties.

〔Effect of the invention〕

As described above, according to the present invention, a pair of excitation probes that are orthogonal to each other are formed on a common plane, corresponding to each of a large number of holes, and the phases of power feeding signals to the pair of excitation probes are combined within a suspended line. This makes it possible to reduce the thickness and simplify the mechanical configuration. Further, even if a substrate that is generally available at low cost is used for high frequency, an antenna gain equivalent to or higher than that obtained using an expensive microstrip line substrate can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a top view and a sectional view showing an embodiment of the present invention;
FIG. 2 is a sectional view of the main part of this invention, FIG. 3 is a configuration diagram of the main part of this invention, FIG. 4 is a diagram for explaining the power supply circuit according to the invention, and FIGS. 5 and 6. 7 is a configuration diagram of a circularly polarized wave radiating element according to the present invention, FIG. 7 is a layout diagram of the entire array according to the present invention, and FIG. 8 is a directional characteristic diagram according to the configuration of FIG. 7. (1) is the first metal plate (or metallized plastic plate), (2) is the second metal plate (or metallized plastic plate), (31 is the substrate, (41, (5) is the hole, (
6) is a cavity, (7) is a conductor foil, and +8+ and +91 are excitation probes. Fig. 1 Fig. 2 Fig. 3 Power supply circuit diagram Fig. 4 Special fiber diagram of circular IJi wave radiating element

Claims (1)

[Claims] In a suspended line-fed planar antenna in which a substrate is sandwiched between metal or metallized plastic having a large number of holes that form part of a radiating element, a pair of excitation elements orthogonal to each other correspond to the large number of holes, respectively. A circularly polarized planar array antenna characterized in that probes are formed on a common plane, and the phases of feed signals to the pair of excitation probes are combined within a suspended line.