JPH03186002A - Slotted array antenna - Google Patents

Abstract

PURPOSE:To form slots almost uniformly over an antenna aperture surface and to obtain high antenna efficiency by grouping 1st-4th slots which are arranged as specified in one group and forming many groups on one surface of a waveguide almost at intervals lambdag. CONSTITUTION:On one magnetic field surface of the rectangular waveguide 10, a slot group is formed. In this case, 1st and 2nd slots 1a and 1a' which are at almost 45 deg. to the travel direction of a radio wave and perpendicular to each other are formed along a 1st straight line (a) perpendicular to the travel direction of the radio wave, 3rd slots 1b which is at about 45 deg. to the travel direction is formed along a 2nd straight line (b) advancing from the 1st straight line (a) by about lambdag/4 in the travel direction, and 4th slots 1c which are at about 45 deg. to the travel direction and perpendicular to the 3rd slots 1b are formed along a 3rd straight line lagging the 1st straight light (a) by lambdag/4 in the travel direction as one group. Consequently, the antenna can be designed so that the effective area of all the slots is >=75% of the antenna aperture surface, so the slot array antenna having high efficiency is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a slot array antenna suitable for use as a broadcasting, communication antenna, etc.

[Conventional technology]

Conventionally, in a traveling wave type waveguide slot array antenna, the slot for generating circularly polarized waves is located at a certain point in the traveling direction at an angle of 45° with respect to the traveling direction, as shown in FIG.
On the other hand, a slot X is formed at a point that lags or advances in phase by 90'' from this point, that is, at a point λg/4 apart in the direction of propagation, where λg is the internal wavelength of the waveguide. forms a thrower 1-y that is perpendicular and forms an angle of 45° with the direction of travel, and the composite waves radiated from slots X and y rotate over time to generate circularly polarized waves. It is known that slot pairs consisting of slots X and slots y are arranged at intervals of λg in the traveling direction, and also arranged in a direction perpendicular to the traveling direction.

[Problem to be solved by the invention]

In this way, in the conventional slot array antenna as described above, the effective area of the slot is (λ/4)・(λ/2).
-λ2/8 and assuming a shortening rate of 80%, the effective area of the entire slot excluding the part where these effective areas overlap is:
This is approximately 70% of the antenna aperture area. This means that there is a useless area S in terms of radiation efficiency in which slots are not formed in the traveling direction, and there is a problem that the antenna efficiency can only be expected to be 70% at maximum.

The present invention attempts to solve this problem, and aims to provide a slot array antenna in which slots are formed substantially uniformly over the antenna aperture surface and high antenna efficiency can be obtained.

[Means to solve the problem]

For this reason, in the slot array array C of the present invention, in the additional wave type waveguide type slot array antenna, when the wavelength in the waveguide is λg, a substantially straight line that is perpendicular to the direction of propagation of the radio wave is obtained. first and second slots formed along a first straight line, forming an angle of approximately 45° with the traveling direction and perpendicular to each other; and a substantially straight line extending approximately λg/4 from the first straight line in the traveling direction. a third slot formed along a second straight line of the shape and forming an angle of about 45° with the traveling direction;
A third straight line is formed along a substantially linear third line delayed by about λg/4 in the traveling direction from the first straight line, and is perpendicular to the third slot and at an angle of about 45° with the traveling direction. The waveguide is characterized in that a large number of sets of four slots are formed on one surface of the waveguide at intervals of about λg. Note that in this specification, "roughly linear" means that the slots are excited so that the phases are the same, since the same phase planes with the same phase are generally straight lines.

[For production]

In the slot array antenna of the present invention described above, in the traveling wave type waveguide slot array antenna, when the wavelength in the waveguide is λg, the antenna is arranged on a substantially linear first straight line that is perpendicular to the traveling direction. first and second slots formed along the line and forming an angle of approximately 45° with the traveling direction and perpendicular to each other; and approximately λg/4 in the traveling direction from the first straight line.
a third slot formed along a second substantially linear straight line that is approximately 45° with respect to the traveling direction; A large number of slot groups each including a fourth slot formed along a third straight line, at a right angle to the third slot, and at an angle of about 45° to the traveling direction, are arranged at intervals of about λg. Therefore, when electric power travels through the waveguide, circularly polarized waves are radiated from these slots, and it is possible to obtain a slot array antenna in which the slots are arranged almost uniformly over the antenna aperture.

〔Example〕

Hereinafter, embodiments of the present invention will be explained with reference to the drawings.
Figures 1 to 4 show a slot array antenna as an embodiment of the present invention. Figure 1 is a perspective view thereof, Figure 2 is a plan view of the slot portion, and Figures 3m, 3b, and 3c are slot array antennas. FIG. 4 is a plan view of a slot portion showing a modified example of the slot and pattern.

In FIGS. 1 and 2, a radio wave is placed on one of the magnetic surfaces of a flat rectangular waveguide 10 whose magnetic surface width is at least four times the tube wavelength λg and whose electric surface width is approximately λg/4. first and second slots 1a and la' formed along a substantially linear first straight line a perpendicular to the direction of travel of the slot machine and forming an angle of about 45 degrees with the direction of travel of the slot machine, and perpendicular to each other; straight line a
A third slot 1b formed along a second substantially straight line extending approximately λg/4 in the traveling direction from the first straight line a and forming an approximately 45° angle with the traveling direction; A fourth thrower) 1c is formed along a substantially straight third straight line C delayed by λg/4 in the direction, and is perpendicular to the third slot 1b and at approximately 45° with the traveling direction.
A slot group is formed with a set of . and,
The multiple sets are formed at intervals of approximately λg (the interval between straight line a and straight line n is approximately λg).

In this case, the lengths of the slots la, la', lb, and lc are each selected to be 0.45λ.

Note that the slot length is generally around 0.5λ, but the optimum value is around this due to the slow wave factor, the presence of dielectric materials, etc.

Further, a horn-shaped waveguide 3 in which a radio wave lens 2 is disposed as a power feeding section is connected to one opening of the rectangular waveguide 10,
A termination resistor 4, which can be used depending on the presence or absence of surplus power, is disposed in the other opening. This terminating resistor can be set at the terminal end so that it has an integral α with a slot of 1, so that the resistor can be omitted.

With the above configuration, when the bone waveguide 3 is excited in the TE mode in which the electric field component is perpendicular to the magnetic interface of the rectangular waveguide 1, the radio wave G spread by the bone waveguide 3 and the radio wave lens 2
TE, whose wavefront is flat and approximately parallel to the aperture of the rectangular waveguide l. A mode is generated and the rectangular waveguide 1
Propagate within 0. T.E. The power supplied in the mode is transmitted to each slot l arranged in a row on the magnetic surface of the rectangular waveguide 10.
A, la', lb, and lc gradually radiate to the outside space, and the remaining power field α is consumed by the terminating resistor 4.

To explain in detail the radiation of power from each slot using Figures 3a, 3b, and 3c, arrow 5 in the figure indicates the direction of the surface current, and the center of the arrow is the sine of the largest value. distribution.

The pattern of the surface current at a certain time and the electric field component of the power radiated from the slot in that case are as shown in Figure 3a. 1, the slot 1b produces an electric field 6' of magnitude 1 in the direction of 135°, and the slot 1c produces an electric field 6' of magnitude 1 in the direction of 45°. At this time, no current flows at the points of slots 1a and la', and no electric field is generated. Therefore, slots 1m and 1a
', lb, and 1c, the electric field 6 becomes an electric field of magnitude I2 in the traveling direction and 90'' direction.If the power propagates from the bottom to the top of the diagram, one period is T. As shown in Fig. 3b, the pattern of the surface current at time t+T/8 and the electric field component of the power radiated from the thrower) ~ in that case are 1/J2 in the direction of 45° from the slot 1a. , 11 to (thrower) or 135 from (thrower) -1b in the direction of 315°
An electric field 6' of magnitude l/v'2 in the direction of 135 degrees is generated, and electric fields 6' of magnitude 1/I2 in the direction of 45 degrees are generated, and these combined electric fields 6 have a magnitude of l/v'2 in the direction of 135 degrees. I2
Then, the pattern of the surface Th flow at time L+T/4 and the electric field component radiated from the slot in that case are 45 degrees from the slot 1m, as shown in Figure 3c.
size 1/-/'2 in the direction of , 31 from slot 11
Each electric field 6' having a magnitude of 1/f2 is generated in the direction of 5°, and no electric field is generated from the throwers 1 to lb and lc, so that the combined electric field 6 has a magnitude of I2 in the direction of Oo.

In this way, the combined electric field rotates once in time T, generating a circular wave.

Although the explanation has been made here in terms of time, the same thing can be said if the explanation is made in terms of the phase in which the traveling wave excites the slot.

As mentioned above, in this embodiment, the rectangular waveguide 10 has a square root shape and the radio waves are TE. In the direction perpendicular to the traveling direction, the surface current flows in the same direction and period, although the magnitude is different, so the slots la, la',
By arranging lb and lc, in-phase circularly polarized waves can be emitted. Regarding the direction of travel, slots 1 m, la', 1 b
, 1 c as one set, and the multiple sets are spaced apart.

Furthermore, although the delay or advance of the phase due to the slot actance component varies depending on the angle, length, etc., in this case, the interval between each slot in the advancing direction may be adjusted.

Furthermore, although a horn-shaped waveguide is used as the power supply section to the rectangular waveguide 10 in the above embodiment, any other power supply section capable of exciting a substantially plane wave may be used. Although this study was conducted on a typical waveguide, similar effects can be obtained using a general waveguide.

As described above, according to the slot array antenna as an embodiment of the present invention, a highly efficient slot array antenna can be obtained because it can be designed so that the effective area of the entire slot with respect to the antenna aperture is 75% or more.

Further, even in an antenna in which rectangular waveguides of a conventional size are arranged in a row, the same effect can be obtained by forming slots in the same pattern.

Although a slot pattern that generates a wave is shown, it is obvious that a counterclockwise wave can be generated by forming the slot pattern as shown in FIG.

〔Effect of the invention〕

As described above, according to the slot array antenna of the present invention, the slots can be set so that the effective area of the entire slot with respect to the antenna aperture surface is 75% or more, and a highly efficient slot array antenna can be obtained.

[Brief explanation of drawings]

1 to 11 show a slot array antenna as a first embodiment of the present invention, FIG. 1 is a perspective view thereof, FIG. 2 is a plan view of the slot portion, and FIG. 3A. 311.30 is an explanatory diagram of the generation of circularly polarized waves in the slot, FIG. 4 is a plan view of the slot section showing a modified example of the slot pattern, and FIG. 5 is a diagram of the slot section of the conventional slot array. FIG. la, la', lb, lc...Slot, 2...Radio wave lens, 3...Horn type waveguide, 4...Terminal resistor, 5...Surface current, 6...Synthesis Electric field, 10...
square waveguide. Figure Figure Figure 30 Figure 3b Figure 3C Figure 5 Procedural Amendment February 8, 1990 1999 Patent Application No. 325361 Postal Code 53 Address 2-2-16 Matsunami, Chigasaki City, Kanagawa Prefecture Name: Alimura Giken Co., Ltd. Agent Postal code: 60 Address: Room 706, Odakyu Shinanomachi Apartment, 5-3 Minamimotomachi, Shinjuku-ku, Tokyo Date of amendment order (voluntary amendment) 6 Column for detailed explanation of the invention in the specification subject to amendment . 7 Contents of amendment (1) Change “1/” written on page 9, line 4 of the specification to “1,”
” he corrected. (2) "1/" written on page 9, line 5 of the specification is replaced with "1/
” he corrected. (Otsu B

Claims (1)

[Claims] In a traveling wave type waveguide slot array antenna, when the internal wavelength of the waveguide is λ_g, the antenna is formed along a first straight line that is substantially straight at right angles to the traveling direction of the radio wave. and the first one at right angles to each other and approximately 45 degrees apart.
and a second slot, and a third slot formed along a second substantially straight line extending approximately λ_g/4 in the traveling direction from the first straight line and forming an angle of approximately 45° with the traveling direction. and about λ_g in the traveling direction from the first straight line.
/4 A plurality of sets of fourth slots formed along a substantially linear third straight line, perpendicular to the third slot, and at an angle of approximately 45° to the traveling direction. are formed on one surface of a waveguide at intervals of about λ_g.