JPS6243602B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a horn antenna, and more specifically, to an improvement of a conical horn antenna with a chiyoke groove that can be used in multiple frequency bands.

A so-called chiyoke grooved conical horn antenna, which has a groove with a depth of 1/4 to 1/2 wavelength on the outer periphery of the aperture of the conical horn, is axially symmetrical and has low sidelobe radiation characteristics, so it was compared. It is used as a small, low-gain antenna, and is often used as the primary radiator of a reflector antenna. However, like multi-frequency band antennas,
When used in a frequency range of more than an octave, the depth of the groove exceeds the range of 1/4 wavelength to 1/2 wavelength, so it has the disadvantage that axially symmetrical and low sidelobe radiation characteristics cannot be obtained. .

In order to eliminate this drawback, this invention reduces the depth of the groove on the outer periphery of the horn aperture to 1/4 at the lowest frequency.
wavelength, the lowest frequency of each used frequency band,
The depth from the aperture surface gives the best radiation characteristics 1/
This device has series resonant elements inserted at four wavelength positions, and will be described in detail below with reference to the drawings.

1 and 2 show an embodiment of the present invention, in which numeral 1 is a conical horn, 2 is an annular chiyoke groove, 3 is a short-circuit surface of the annular chiyoke groove, and 4 and 5 are series resonant elements.

In Figures 1 and 2, the depth L _L of the chiyoke groove 2 to the shorting surface 3 is selected to be approximately 1/4 wavelength in the lowest frequency band, so that it is axially symmetrical in this frequency band. A low sidelobe radiation characteristic can be obtained. Regarding the second frequency band, the series resonant element 4 for this frequency band is inserted at the position L _M where the depth of the chiyoke groove is about 1/4 wavelength at the lowest frequency, so it is axially symmetrical and has a low side. The radiation characteristics of the lobe are obtained. Similarly, regarding the third frequency band, the series resonant element 5 for this frequency band is inserted at the position L _H where the depth of the chiyork groove is about 1/4 wavelength at the lowest frequency, so it is axially symmetrical. Low sidelobe radiation characteristics can be obtained. Note that even if the frequency used is higher than this, the same axially symmetrical radiation characteristics with low side lobes can be obtained.

When the polarized waves used are single polarized waves, the series resonant elements 4 and 5 may be provided only on two sides on both sides in the E-plane direction.
In the case of dual linear polarization and circular polarization,
As shown in FIGS. 1 and 2, they must be provided in four directions on the circumference.

Therefore, according to the present invention, even if the antenna is used for multiple frequency bands over a frequency range of one octave or more, it has the same axial symmetry as a horn antenna with a chiyok groove whose depth is approximately 1/4 wavelength in each frequency band. This has the advantage of providing low sidelobe radiation characteristics.

Note that although the above explanation has been made regarding a conical horn antenna, it goes without saying that the same can be applied to a square horn antenna as well.

[Brief explanation of the drawing]

1 and 2 are schematic configuration diagrams showing one embodiment of the present invention, with FIG. 1 being a front view and FIG. 2 being a central sectional view. In the figure, reference numeral 1 is a conical horn, 2 is a ring-shaped groove, 3 is a short-circuit surface, and 4 and 5 are series resonant elements. It should be noted that the same or corresponding parts in the drawings are designated by the same reference numerals.

Claims (1)

[Claims] 1 An annular groove is provided on the outer periphery of the aperture, and the depth of the groove is approximately 1/4 wavelength of the lowest frequency used, and the depth of the groove is set at approximately 1/4 wavelength of the lowest frequency used, and the minimum frequency of each of multiple frequency bands other than the frequency band including the lowest frequency used is Approximately 1/4 of the groove above
A multi-frequency band common horn antenna, characterized in that a series resonant element for the frequency band is provided at a position at the depth of the wavelength.