JPH05259728A - Dipole antenna system - Google Patents

Abstract

PURPOSE:To easily and accurately control a change in an antenna element length of a dipole antenna for EMI measurement. CONSTITUTION:Each of antenna elements 2, 3 consists of plural rods 4 and the rods 4 are fitted at each end freely slidably. A forward/reverse torque of a motor being a drive section 7 is delivered to a tip rod of the antenna elements 2, 3 by cords 5, 6 and blocks 9-11, and the antenna elements 2, 3 are driven while being shrinked/elongated by an equal quantity in the horizontal direction. As a result, the manual elongation/contraction of the antenna elements is not required but the automatic elongation/contraction of the antenna elements is attained, the total length of the antenna elements is smoothly and accurately set and the antenna in matching with an objective measured wavelength is obtained.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a dipole antenna device,
In particular, the present invention relates to a dipole antenna device for EMI (Electromagnetic Interference) measurement.

[0002]

2. Description of the Related Art The structure of a conventional dipole antenna of this type is shown in FIG. FIG. 3 is a schematic cross-sectional view thereof, which has a vertical fixing portion 1 in the shape of a long rod, and a pair of antenna elements 2 and 3 which are horizontally extended symmetrically with respect to each other on both upper sides of the fixing portion 1.

The pair of antenna elements 2 and 3 have the same structure, and each is composed of a plurality of rods 4.
The diameters of the rods are gradually reduced as the distance from the fixed portion 1 is increased, and the rods 2 and 3 are horizontally expandable and contractable so that adjacent rods are slidably fitted at their ends. There is.

At the time of EMI measurement, the respective lengths of the elements 2 and 3 are set symmetrically with respect to the fixed portion 1 as the center,
Moreover, the lengths of the elements 2 and 3 are manually set using a scale or the like so that the total length of the dipole antenna matches the measurement wavelength.

Here, when it is necessary to change the measurement wavelength, the elements 2 and 3 are manually expanded and contracted, and the total length is adjusted again to match the changed measurement wavelength in the same manner as above, and the element length is set. To do.

As described above, in the conventional dipole antenna for EMI measurement, it is necessary to adjust the length of the element so as to be bilaterally symmetric while manually expanding and contracting each time the measurement wavelength is changed, which is complicated. At the same time, there is a drawback that an error in setting the total length of the antenna cannot be avoided.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an EMI measuring dipole antenna device which eliminates the complexity of manual operation.

Another object of the present invention is to provide an EMI measuring dipole antenna device capable of setting an element length that optimally and automatically matches the EMI measuring wavelength.

[0009]

The dipole antenna device according to the present invention comprises a fixed portion, a pair of antenna elements which extend horizontally symmetrically with respect to each other on both sides of the fixed portion, and which are extendable and contractible in the horizontal direction, and a pair of these antenna elements. And a control means for controlling the expansion and contraction of the element with the same size at the same time.

In another dipole antenna device according to the present invention, as the control means in the dipole antenna device, a means for controlling the expansion / contraction amount of the rod corresponding to an EMI measurement wavelength within a predetermined range, and an expansion / contraction amount control for this rod. And a means for detecting the maximum level of measurement noise at the time.

[0011]

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram including a cross section of an embodiment of the present invention, and the same portions as those in FIG. 3 are designated by the same reference numerals. A pair of antenna elements 2, which are symmetrically extended and attached to both sides of the upper portion of the vertical fixing portion 1,
3, the antenna elements 2 and 3 both have an expandable structure by combining a plurality of rods 4, which is the same as that of FIG.

A drive portion 7 such as a motor is provided in the fixed portion 1, and the expansion and contraction of each element 2 and 3 is controlled by the forward and reverse rotation of the motor. Therefore, in order to transmit the unidirectional rotational power of the motor to the tip of the antenna element, the transmission string 5 connected from the motor to the tip of the antenna element through the inside of the cylindrical rod 4 and the directional power of the motor in the other direction are transmitted to the antenna element. In order to transmit to the tip of the antenna, there is provided a transmission cord 6 which is connected from the motor to the tip of the antenna element through the outside of the cylindrical rod 4.

These transmission strings 4 and 5 are provided via pulleys 9 to 11 for facilitating the conversion of the rotational force in the transmission direction. The rotation control of the motor 7 is performed by the control unit 8.

In this configuration, in order to obtain the antenna length corresponding to the EMI measurement wavelength, the motor 7 is controlled to rotate in the predetermined direction by the predetermined angle by the drive control signal from the control unit 8. In response to this, the rod 4 of each antenna element 2 and 3 expands and contracts, so that the total length of the dipole antenna can be easily adjusted.

A pair of left and right antenna elements 2 and 3 are provided.
The lengths of the two must be symmetrical and equal, but of course, depending on the settings of the drive transmission strings 5, 6 and the pulleys 9-11,
Of course, the same rotation amount of the motor 7 should be designed so that the same expansion and contraction amount is generated.

FIG. 2 is a block diagram including a cross section of another embodiment of the present invention, and the same portions as those in FIG. 1 are designated by the same reference numerals. In this embodiment, a receiving unit 13 and a maximum level detecting unit 12 are added to the configuration of FIG. Needless to say, the receiver 13 is also provided in the example of FIG.

The range of the EMI measurement wavelength is generally defined, and the controller 8 controls the change in the total length of the dipole antenna so as to sweep the defined wavelength range. At this time, the noise level received from the receiving unit 13 is sequentially detected, and the maximum noise level in the wavelength range is detected by the detecting unit 12. This allows the EMI measurement to be automatically and accurately performed.

[0019]

As described above, according to the present invention, the expansion and contraction control of the antenna element in the horizontal direction is automatically performed by the control of the motor, etc., so that the E element can be accurately and smoothly operated.
There is an effect that MI measurement becomes possible.

There is also an effect that the maximum noise level can be automatically detected within the measurement range of the EMI measurement wavelength.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an exemplary embodiment of the present invention.

FIG. 2 is a diagram showing the configuration of another embodiment of the present invention.

FIG. 3 is a diagram showing a structure of a conventional EMI measuring dipole antenna.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fixed part 2,3 Antenna element 4 Rod 5,6 Transmission string 7 Driving part 8 Control part 9-11 Pulley 12 Maximum level detection part 13 Reception part

Claims (3)

[Claims] 1. A fixed part, a pair of antenna elements extending horizontally symmetrically with respect to each other on both sides of the fixed part and extendable and contractible in the horizontal direction, and a pair of these antenna elements are simultaneously expanded and contracted with the same size. A dipole antenna device comprising: 2. The pair of antenna elements are both cylindrical rods, and the control means transmits the driving force from the driving means and the driving means to the tip of the cylindrical rod through the inside of the rod. And a second transmitting means for transmitting a driving force from the driving means to the tip through the outside of the rod, and the driving means controls expansion and contraction of the pair of rods by a predetermined amount. The dipole antenna device according to claim 1, wherein 3. The dipole antenna is for EMI measurement, and the control means controls the expansion / contraction amount of the rod corresponding to the measurement wavelength in a predetermined range, and the measurement at the time of the expansion / contraction amount control of the rod. The dipole antenna device according to claim 2, further comprising means for detecting a maximum value of the noise level.