JPH066588Y2 - Waveguide slot antenna - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] This invention is suitable for use in ships and mobile vehicles.
The present invention relates to an antenna for transmitting and receiving radio electromagnetic waves in the F (ultra high frequency) band.

[Conventional technology]

The waveguide slot antenna is a type of antenna that is rarely known because it is generally used as a ship radar antenna and is not generally visible. A brief description will be given below.

"Antenna Engineering Handbook" (edited by The Institute of Electronics and Communication Engineers, published by Ohmsha, first edition October 30, 1955), excerpted from page 223. "Figure 8.2 (omitted) is an example of the simplest structure of the series power supply circuit. A waveguide slot antenna in which the power coupling part from the waveguide, which is the main line, forms the element antenna as it is, and the coupling degree is determined by the inclination angle of the slot. 1 / wavelength in the wave tube
2, and the condition of co-phase excitation is satisfied by reversing the tilt direction for each element. Excerpt from page 249 Reprinted "7.6.3-3 Radar antenna for navigation [1] Radar antenna for ship installation (b) Slot-type radar antenna (Omitted) Currently, slot antennas with a small aperture can be used for navigation radar. As shown in Figure 6-19 (omitted), the slot antenna cuts a groove in the waveguide wall and uses the radio waves radiated from the slot as an array. And the current distribution on the antenna is easy to select arbitrarily.The current distribution to be used may be the Chebyshev distribution that minimizes both the beam width and the side rope level for a given antenna length, or the beam distribution. The width is slightly wider, but the Taylor distribution is used to obtain a high gain pattern with a low side rope.Slot length is slightly shorter than λg / 2. It has a wide band property as a long or non-resonant slot. Therefore, the direction of the beam is slightly deviated from the broadside direction. (Omitted) "The shape of the waveguide slot antenna of the drawing omitted in the above quote is shown in FIG. The slots a to n are provided on one side of the rectangular waveguide whose end face is closed, and when the power is supplied from the open end, electromagnetic waves of the same phase are radiated from each slot. Is an array antenna that is a radiating element. However, in order to rotate the antenna for radar, this shape is inconvenient. Therefore, as shown in FIG. 7, a feeding probe 3 which is parallel to the slot surface and penetrates the waveguide at a right angle is provided.
A structure that rotates around is being put to practical use. The installation position of the feeding probe 3 does not need to be limited to the center of the waveguide slot antenna, but it is convenient to install it in the center of the rotating antenna from the viewpoint of the rotation mechanism.

[Problems to be solved by the device]

As is clear from the above, the waveguide slot antenna is structurally robust because it has an outer shape in which a slot is provided on one side surface of a rectangular waveguide, and is a parapolar antenna or horn antenna that is often used in the SHF band. It has the advantage that it does not require a special curved surface or large volume, but it is thought that it is rarely used for anything other than marine radar antennas for the following reason.

That is, since each slot of the waveguide slot antenna corresponds to a radiating element, the directivity in the plane direction including the central axis of the waveguide and perpendicular to the slot surface is good, but orthogonal to the central axis of the waveguide. Since directivity in the plane cannot be expected so much, it is useful for radars that rotate horizontally with the center axis of the waveguide as the horizontal direction and observe the direction and intensity of the reflected wave, but for general transmission and reception applications Has a weakness in that it is inferior in gain and noise rejection performance to an omnidirectional antenna.

Therefore, in order to use a waveguide slot antenna, which has an excellent mechanical aspect, as a general-purpose antenna, it has been desired to improve the omnidirectional directivity.

[Means for Solving the Problems]

In the present invention, as shown in FIG. 1, the waveguide slot antenna 1 and the waveguide slot antenna 2 having the same shape are used, and the slot surfaces are oriented in the same plane and in the same direction in order to match the directivity and the phase. And fix them integrally with each other, and approximately 1/4 between the center lines of the respective slots of the waveguide slot antennas 1 and
A structure in which a stack having a wavelength length is set, and a waveguide slot antenna 1 and a waveguide slot antenna 2 are inserted in a skewered shape and a feeding probe 3 having a length of about a half wavelength is inserted from the lower side. Is.

[Action]

FIG. 3 is a conceptual diagram of directional characteristics when the waveguide slot antennas 1 and 2 are stacked. The directional characteristics of the waveguide slot antenna 1 and the waveguide slot antenna 2 are shown by dotted lines, respectively, and the directional characteristics obtained by combining the two become the combined directional characteristics indicated by the solid line, and the beam becomes sharp. The gain increase corresponding to the solid line is the effect of the stack.

〔Example〕

In order to improve the omnidirectional directivity of the waveguide slot antenna, it is most effective to improve the directivity in a plane orthogonal to the central axis of the waveguide having a weak directivity. As a method of improving the directivity of the antenna, the technology of stacking the radiating element at right angles to the radiation direction is well known, and it is also applicable to the waveguide slot antenna, but for that reason it has the advantage of the waveguide slot antenna. One must avoid losing the strength of certain mechanisms and the advantage of being suitable for rotary antennas for radar.

The structure of the waveguide slot antenna of the present invention is shown in FIGS.
This will be described in detail with reference to the drawings. 1 and 2 are waveguide slot antennas of the same shape. 1 for the waveguide slot antenna 1
A plurality of slots 1a to 11n are provided. The waveguide slot antenna 2 is provided with a plurality of slots 21a to 21n.

Feeding to the waveguide slot antenna 1 and the waveguide slot antenna 2 is carried out for about two minutes from the waveguide slot antenna 2 side to the waveguide slot antenna 1 side as shown in the partial sectional view of FIG. Is provided with a 1-wavelength feeding probe 3, and a through hole for that is provided in the waveguide slot antenna 1,
It is provided in 2. The current distribution on the feeding probe 3 is shown by the dotted line in FIG. Further, the current phase is the same in both the waveguide slot antenna 1 and the waveguide slot antenna 2 as shown by the arrows in the figure, so that both waveguide slot antennas 1 and 2 are stack antennas excited in the same phase. The condition of is satisfied.

However, in a stack antenna operating at an extremely short wavelength, it is usual that the calculated value synthesized from the individual radiation characteristics does not match the actually measured value due to the interference between the waveguide slot antennas 1 and 2. Therefore, in practical design, the stack spacing between the waveguide slot antennas 1 and 2 is 2
The center spacing of the stack is determined by measuring the radiation characteristics while finely adjusting the centerlines of the slots of the set.

FIG. 4 shows a waveguide slot antenna 1 to which the present invention is applied.
2 is an example of the outer shape of a radar antenna for a ship according to 2.

The waveguide slot antennas 1 and 2 have conventionally been structured to rotate about a central portion in the longitudinal direction.
As is apparent from the figure, the two waveguide slot antennas 1 and 2 are vertically stacked and fixed at both ends in the longitudinal direction using metal fittings. Even when the antenna is stacked in this state, the thickness and weight of the antenna portion are approximately doubled, but since the original thickness and weight are not so large, it is not necessary to reinforce the rotation support portion.

On the other hand, since the feed probe 3 has a shape that vertically penetrates the central portions of the waveguide slot antennas 1 and 2, the waveguide slot antennas 1 and 2 can rotate horizontally with the feed probe 3 as an axis. It is convenient that the rotary connection mechanism can be configured most easily.

[Other Examples]

FIG. 5 shows a structure in which the electromagnetic wave horn 4 is added to the slot surface of the waveguide slot antenna of the present invention in which the waveguide slot antenna 1 and the waveguide slot antenna 2 having the same shape are stacked.

This sharpens the radiation beam of the antenna to improve the center gain. Moreover, since unnecessary side lobes can be reduced, it is suitable to be applied according to the purpose of use.

[Effect of device]

The waveguide slot antenna of the present invention is a stack of waveguide slot antennas used in ship radars, where mechanical strength has been emphasized in the past. Due to the increased omnidirectional directivity and improved gain, it is particularly suitable for installation on the roof or side of a moving vehicle. Furthermore, it is expected to be used in the future for satellite broadcasting reception operating in the 12 GHz band or higher. In the above description, the operation as an antenna and the radiation characteristic are mainly described in the transmission state, but since the transmission characteristic and the reception characteristic are reversible in the antenna,
The antenna of the present invention can be applied to both transmission and reception for general communication.

[Brief description of drawings]

FIG. 1 is a sketch drawing of the waveguide slot antenna of the present invention. FIG. 2 is a partial sectional structural view. FIG. 3 is a conceptual diagram showing an improvement in directional characteristics of the waveguide slot antenna of the present invention. FIG. 4 is an outline view of a radar antenna for a ship according to an embodiment of the present invention. FIG. 5 is an external view of an electromagnetic horn combined with a stacked waveguide slot antenna according to another embodiment of the present invention. FIG. 6 is a basic external view of a waveguide slot antenna.
FIG. 7 is an outline view of a waveguide slot antenna with different feeding types. 1-2 waveguide slot antenna, 3 feeding probe,
11a to 11n, 21a to 21n ... Slots.

Claims (1)

[Scope of utility model registration request] 1. A waveguide slot antenna for a wireless device, wherein two sets of waveguide slot antennas of the same shape are arranged with their slot surfaces aligned vertically, and both of the waveguide slot antennas are arranged. The waveguide slot antenna part in which the center distance of the slot is stacked to approximately 1/4 wavelength and the both waveguide slot antennas are inserted and mounted from one side to supply currents of the same phase to both waveguide slot antennas. A waveguide slot antenna, characterized in that the waveguide slot antenna is configured with a feeding probe of approximately 1/2 wavelength.