JP2690159B2 - Wideband antenna - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a wideband antenna that can be used for an antenna such as a float storage type floating floating buoy.

[Prior Art] FIG. 2 is a structural diagram of an antenna of a conventional float storage type floating floating buoy. In the figure, 21 is a feed line made of a coaxial cable, 22 is a ground wire, 23 is an antenna wire, 24 is a rubber material, and 25 is a rubber material.
Is a float and 26 is a flange.

 FIG. 3 is an electrical connection diagram of the antenna of FIG.

2 and 3 will be described. One end of the feed line 21 of the coaxial cable is connected to the output of the transmitter, the inner conductor (hereinafter referred to as a core wire) at the other end is the antenna wire 23, and the outer conductor at the other end (hereinafter referred to as a shield wire) is a ground wire 22. , Respectively. The ground wire 22 is formed by three braided wires, and is connected to the shield wire of the power supply wire 21 and the flange 26.
The flange 26 is a conductor, and a part thereof comes into contact with seawater to form a ground plane. The antenna wire 23 is formed by two parallel vinyl wires, and the core wires are short-circuited at both ends thereof.
Further, one end of this tenana wire 23 is connected to the core wire of the power supply line 21, and the other end is fixed to the float 25, and the antenna height expands as the float expands due to gas or the like. The rubber material 24 is for absorbing dimensional variations during float expansion.

With the above configuration, it operates as a transmitting antenna that covers the bandwidth of 162 to 174 MHz in the VHF band.

FIG. 4 is a Smith chart showing an example of measurement of the impedance of the antenna of FIG. In the figure, the circle near the center is the circle when the VSWR (voltage standing wave ratio) value is 2.

As shown in the measurement example of FIG. 4, the conventional antenna having the structure of FIG. 2 has a VSWR value within a circle of 2 within the transmission frequency range of 162 to 177 MHz, but the frequency is 162 MHz.
When it becomes below, the VSWR value becomes 2 or more, and the radiation characteristic deteriorates. Therefore, the bandwidth that can practically adapt the antenna impedance is about 15 MHz.

[Problems to be Solved by the Invention] In the above-mentioned conventional floating buoy antenna, practically, the antenna impedance can be adapted only to the bandwidth of about 15 MHz in the VHF band, and the frequency exceeding this bandwidth is used. Then, there was a problem that the antenna radiation characteristic deteriorates.

The present invention has been made to solve such a problem, and an object of the present invention is to obtain a wideband antenna capable of widening a bandwidth matching the antenna impedance to about 40 MHz in the VHF band.

[Means for Solving the Problem] A broadband antenna according to the present invention is formed by a single conductive wire in a plane shape symmetrical with respect to the vertical axis, and is fed from one corner of the conductive wire. An antenna element that radiates power to be fed and a single conducting wire are formed in a plane shape with left and right symmetrical with respect to the vertical axis, and one side of the planar conducting wire is coupled to a ground conductor material connected to a ground plane. The height of the planar conductor from the ground conductor is set within a range not exceeding the height of the antenna element, and the surface formed by the planar conductor is arranged so as to intersect the surface formed by the antenna element at a right angle. And a sleeve that is cut.

[Operation] In the wideband antenna according to the present invention, the antenna element is formed by a single conductive wire in a plane shape symmetrical to the left and right with respect to the vertical axis, and is fed from one corner of the shaped conductive wire. Radiates. The conducting wire having the shape has the same effect as expanding the area of the antenna element equivalently, and obtains a wide band frequency characteristic. Further, the sleeve is formed in a plane shape by one conductor wire, and one side of the plane conductor wire is connected to a ground conductor material connected to a ground plane,
The height of the planar conductor from the ground conductor is set within a range not exceeding the height of the antenna element, and the surface formed by the planar conductor intersects at right angles with the surface formed by the antenna element. Will be placed. The sleeve provides wide band characteristics based on the same principle as the open sleeve antenna. With the antenna system with the above configuration,
By combining the two means for widening the band, it is possible to obtain a wide band frequency characteristic, for example, a bandwidth in which the antenna impedance is suitable up to 40 MHz in the VHF band.

[Embodiment] FIG. 1 is a structural view of a wideband antenna according to the present invention, in which 1 is a feed line, 2 is a ground line, 3 is an antenna line, 7 is a sleeve, 8 is a copper plate, and 9 is a plastic plate.

FIG. 5 is an electrical connection diagram of the broadband antenna of FIG.

6 (a), (b) and (c) are detailed structural views of the broadband antenna of FIG. 1, (a) is a plan view and (b) is a plan view.
6A is a YY side view in FIG. 7A, and FIG. 7C is a XX side view in FIG.

The description of FIGS. 1, 5, and 6 will be given. The feed line 1 is formed by a coaxial cable, one end of which is connected to the output of the transmitter, the other end of which is connected to the antenna line 3, and the other end of which is connected to the circular copper plate 8. The ground wire 2 formed of a braided wire is connected to three positions of the copper plate 8, and one end of each ground wire is in contact with seawater forming a ground plane. Also, a sleeve 7 made of one soft conductor is vertically extended from two positions of the copper plate 8 into a rectangular shape as shown in FIGS. 1 and 6 (b), and one of the short sides of the rectangular conductor is It is connected to the copper plate 8 and electrically connected.

The antenna wire 3 is composed of one soft conductor wire, and as shown in FIGS. 1 and 6 (c), the antenna wire 3 is symmetrical with respect to the vertical axis of the antenna wire 3, but is horizontal with respect to the horizontal axis. It develops into an asymmetrical deformed rhombus at the top and bottom. To describe the shape of the antenna wire 3 in the present embodiment accurately, it is a deformed rhombus formed by synthesizing two isosceles triangles whose bases are commonly connected and whose lower height is larger than their upper height. Yes, it is simply referred to as a modified diamond. Also a rectangular sleeve 7
As shown in FIG. 6 (a), and the modified rhombus-shaped antenna wire 3 are arranged such that the surfaces formed by them intersect at a right angle. The height of the rectangle formed by the sleeve 7 in the longitudinal direction is as shown in FIGS. 6 (b) and 6 (c).
To the shorter diagonal of the deformed rhombus formed by the antenna wire 3. The plastic plate 9 fixes the relative positional relationship between the antenna wire 3 and the sleeve 7.

An open-sleeve antenna is an example of a conventional antenna having wideband frequency characteristics. Further, as an open document about this open-sleeve antenna, for example, "Antenna Engineering Handbook" (pages 120 to 121, 3/4/3 sleeve antenna, edited by The Institute of Electronics, Communication and Communication, October 1980, Ohmsha) Is published). According to the above-mentioned document, it is possible to have a frequency band of about one octave, and a frequency of 50Ω over a frequency range of 310 to 510MHz.
It has been reported that VSWR can be kept within 1.8 with coaxial system.

However, since the antenna of the present invention is intended to be applied to a floating buoy on the sea, the structure of the antenna is limited, and the shape of the open sleeve antenna cannot be adopted as it is. Therefore, the antenna wire 3 and the sleeve 7 are composed of two soft conductors, which are folded and housed in the float when not in operation, and the antenna system can be deployed by utilizing the expansion of the float when in operation. The antenna system of the present invention configured as described above can have wideband frequency characteristics similarly to the open sleeve antenna.

FIG. 7 is a Smith chart showing an example of measurement of the impedance of the antenna of FIG. 1, and circles in the figure are measured values.

As shown in FIG. 7, the VSWR value is 2 or less in a wide band over a frequency range of 135 to 175 MHz. Therefore, with the antenna of the present invention, the impedance can be practically adapted to a bandwidth of about 40 MHz in the VHF band, and the antenna can be easily folded and unfolded. Therefore, the antenna of the present invention can be easily applied to a floating buoy.

In the above embodiment, an example in which the antenna of the present invention is applied to a floating buoy is shown, but since the present invention has a characteristic as a wide band VHF band antenna with good storage, for example, a land mobile station antenna, etc. It can also be applied to, and its application range is considered to be wide.

[Effects of the Invention] As described above, according to the present invention, a wide-band antenna with good storability can be realized by the configuration of the substantially diamond-shaped antenna element and the rectangular sleeve arranged at a right angle to the antenna element. Therefore, it is possible to obtain the effect of improving the performance by expanding the frequency band and the effect of reducing the antenna storage space as compared with the conventional case.

[Brief description of the drawings]

FIG. 1 is a structural diagram of a wideband antenna according to the present invention, FIG. 2 is a structural diagram of a conventional float storage type floating floating buoy, FIG. 3 is an electrical connection diagram of the antenna of FIG. 2, and FIG. Is a Smith chart showing an example of measuring the impedance of the antenna of FIG. 2, FIG. 5 is an electrical connection diagram of the broadband antenna of FIG. 1, and FIGS. 6 (a), (b) and (c) are the first. FIG. 7 is a Smith chart showing a measurement example of impedance of the antenna of FIG. In the figure, 1,21 are feeder lines, 2,22 are ground lines, 3,23 are antenna lines, 7 is a sleeve, 8 is a copper plate, 9 is a plastic plate,
24 is a rubber material, 25 is a float, and 26 is a flange.

Claims (1)

(57) [Claims] 1. An antenna element, which is formed by a single conducting wire in a plane shape in which the left and right sides are symmetrical with respect to a vertical axis, is fed from one corner of the conducting wire, and radiates the fed power, The conductor wire is formed in a plane shape in which the left and right sides are symmetrical with respect to the vertical axis, and one side of the plane conductor wire is coupled to a ground conductor material connected to a ground plane, and the height of the plane conductor wire from the ground conductor material is It has a wide band frequency characteristic, which is set in a range not exceeding the height of the antenna element, and has a sleeve arranged so that the surface formed by the planar conductor intersects the surface formed by the antenna element at a right angle. A wideband antenna characterized in that.