JPH03167905A - Circular polarized wave primary radiator - Google Patents

Abstract

PURPOSE:To prevent the deterioration in the voltage standing wave ratio(VSWR) characteristic and in the circularly polarized wave ratio characteristic and to reduce the cost by forming a tilt part inclined toward the adjacent part to the end to either or both the front end part and the rear end part of a circularly polarized wave generating section in a circularly polarized wave primary radiator. CONSTITUTION:A couple of flat faces 12, 13 and a couple of concentric circular-arc faces 14 and 15 opposite to each other in parallel are formed for the inner circumferential faces of a circularly polarized wave generating section 11. When inner outer both circumferential faces of the circularly polarized wave generating section 11 have a taper, the tapered angle of the circularly polarized wave generating section 11 with respect to the axial line is selected to be 1-several degrees. The tilt part, even one tilt part in existence, avoids the production of rapid discontinuous point in the relative relation between the horn part 1 and the circularly polarized wave generating section 11 or between the circularly polarized wave generating section 11 and a circular- rectangular conversion section 21 by the production of the tilt part. Thus, the VSWR characteristic and the circularly polarized wave rate characteristic are not deteriorated, the manufacture is simplified to reduce the cost and to attain mass-production.

Description

[Detailed description of the invention] r Industrial application field” The present invention relates to improvements in circularly polarized primary radiators.

``Prior art'' When receiving radio waves from a broadcasting satellite (BS satellite), the power transmitted from the broadcasting satellite to the ground is generally excited by circularly polarized waves, and such circularly polarized waves are received with high sensitivity. requires an antenna system to excite circularly polarized waves.

The primary radiator of a satellite broadcasting antenna, that is, the circularly polarized primary radiator, is roughly divided into a horn section, a circularly polarized wave generating section, and a circular-to-rectangular converting section. In a circular waveguide for transmitting the mouth mode, circularly polarized waves are generated by shifting the phases of two mutually orthogonal linearly polarized waves by 90''.More specifically, circularly polarized waves There are dielectric plates, metal pieces,
By fixing a suitable insertion member such as a screw post, the phase difference between the electric fields transmitted along two orthogonal axes in the cross section of the circularly polarized wave generating section is set to 90°.

However, these techniques have circular polarization coefficient-frequency (f) characteristics,
Adjustment of standing wave ratio (VSWR) and frequency (f) characteristics,
Work is required to fix the insertion member inside the circular waveguide, and as a result, it takes too much time to assemble and adjust the circularly polarized wave generator, which increases costs. Moreover, since the above-mentioned characteristics must be adjusted for each individual circularly polarized wave generating section, it is not suitable for mass production.

To deal with this, a circularly polarized wave generator shown in FIGS. 5 and 6 has been proposed.

below. The technical content shown in Figures 5 and 6 will be described below. The circularly polarized wave generating section l1 shown in FIGS. 5 and 6 has a waveguide structure. The inner peripheral surface of the circularly polarized wave generating section 11 includes a pair of flat surfaces 12 facing each other and parallel to each other. 3 and these flat surfaces l2,
A pair of concentric circular arc surfaces extending between 13 and 14. It is formed by 15. In FIG. 6, if two axes that pass through the center of the cross-section of the circularly polarized wave generator 1l and are orthogonal to each other are Ex and E, respectively, then the pair of flat surfaces 12 and l3 are relative to the three orthogonal axes Ex and Ey. It has a slope of 45°. moreover,! In Figure s5 and Figure 6, the circularly polarized wave generating section l1
If the dimension of the long axis in the cross section is d, the dimension of the short axis is W, and the length of the circularly polarized wave generating section 11 is d, then the phase difference between the electric field transmitted along the long axis and the electric field transmitted along the short axis is The long axis dimension d. 'fi axis dimension W and length statement are set respectively. Generally, the above-mentioned phase difference δ is determined by the following equation (1). δ(rad) = 2vr((1/λgS) −(1/
Enter gL))? ...(1) Input gS: Inner wavelength of the electric field transmitted along the short axis (m) Input gL: Inner wavelength of the electric field transmitted along the long axis (ms) View: Length of the circularly polarized wave generating section Input gS, Input gL are as shown in equations (2) to (5) below.
8gS(am)=λ/r 1-(in/in cs)2 ・-
−− ・− (2) Input as (am) = 2π/Kc
S ・・・・・・・・・・・・◆(3) Entering gL (Hoho) = λ/r 1-(Entering/Entering cL) 2......(4
) input cL (mpeng) = 2π/KcL ・・・・・・
...... (5) Input: Free space wavelength KcS: Eigenvalue in the short axis direction KcL: Eigenvalue in the long axis direction Therefore, from the above equation (1), the circularly polarized wave generating part l1
The major axis dimension d, minor axis dimension W, and length statement are obtained, respectively.
As a specific example, d*19a+s (curvature radius 8++u
s), w=18+sm. It will look like Jls41wm. As described above, this circularly polarized wave generating section 11 is interposed between the horn section and the circular-to-rectangular-circular converting section in the primary radiator, and these parts of the primary radiator are integrated by, for example, the die cast + 4 type method. It is dignified. At this time, by controlling each dimension of the circularly polarized wave generating section l1, it is possible to ensure a predetermined circular polarization factor-frequency characteristic and standing wave ratio-frequency characteristic. Moreover, the circularly polarized wave generating section 11 is not only easy to manufacture, but also can maintain predetermined characteristics without the need for troublesome adjustment or fixing of components, thereby reducing the cost of the primary radiator and increasing mass productivity. be able to. Problems to be Solved by the Invention As mentioned above, the circularly polarized wave generating section 11 shown in FIGS. 5 and 6 is desirable in that it solves the problems of the prior art. However, this circularly polarized wave generating part 1l is located between the horn part and the circular-to-rectangular converting part, and both ends of the flat surfaces l2 and 13 in the axial direction form a sharp discontinuity point (step). A large change in impedance increases reflected waves, causing VS
Deteriorates WR characteristics, circular polarization characteristics, etc. In view of such technical issues, the present invention has been developed to improve the VSWR characteristics,
The objective is to provide a circularly polarized primary radiator that does not cause deterioration of the circular polarization characteristics and is easy to manufacture. Means for Solving Problems 1 In order to achieve the intended purpose, the present invention comprises a waveguide structure in which a circularly polarized wave generating section is provided between a horn section and a circular-to-rectangular converting section, The inner circumferential surface of the circularly polarized wave generating section is formed by a pair of flat surfaces facing each other and a pair of circular arc surfaces extending between these flat surfaces, and two orthogonal axes passing through the center of the cross section of the circularly polarized wave generating section are formed. Each E. , E, the pair of flat surfaces are aligned with the orthogonal two axes Ex. It has a slope of 45° with respect to Ey, and the phase difference between the electric field that propagates along the long axis of the cross section of the circularly polarized wave generator and the electric field that travels along the short axis of the cross section of the circularly polarized wave generator is 90° at the radiation output end. The circularly polarized primary radiator is characterized in that an axial end of the flat surface of the circularly polarized wave generating section is formed with an inclined part that slopes toward a part adjacent to the end. Suppose that In the case of the circularly polarized wave generating section according to the present invention, the pair of flat surfaces and the pair of concentric arcuate surfaces that form the inner peripheral surface of the circularly polarized wave generating section satisfy the predetermined conditions, so that the circularly polarized wave generating section It can generate waves. Moreover, the axial end of the flat surface of the circularly polarized wave generating section,
In other words, since an inclined part is formed at one or both of the front end and the rear end of the circularly polarized wave generating section and is inclined toward the part adjacent to the end, such an inclined part is formed. As a result, no sharp discontinuities (steps) occur in the relative relationship between the circularly polarized wave generating part, the horn part, and the circular-to-rectangular converting part. As a result, there is almost no large change in impedance or an increase in reflected waves caused by this, and the VSWR characteristics and circular polarization characteristics do not deteriorate.

Moreover, each part of the horn part, the circularly polarized wave generating part, and the circular-to-rectangular converting part can be easily manufactured by, for example, the die-casting method, which makes it possible to reduce the cost of the next radiator and mass-produce it. is also possible.

Embodiment 1 A circularly polarized primary radiator according to the present invention will be described based on the illustrated embodiment.

1 to 4, the circularly polarized primary radiator has a waveguide structure including a horn section 1, a circularly polarized wave generating section 11, and a circular-to-rectangular converting section 21. A circularly polarized wave generator 1l is interposed between the rectangular converter 21 and the rectangular converter 21. The horn portion 1 may have a publicly known or well-known shape depending on its intended use; for example, in addition to the conical type shown, a corrugated type with a flare may also be used. The horn portion 1 of the type illustrated has, for example, a maximum inner diameter of 30 mm, a minimum inner diameter of 19 mm, and a length of 16.5 mm.

The circularly polarized wave generating section l1 is basically the same as that shown in FIGS. 5 and 6, and the inner peripheral surface of the circularly polarized wave generating section 11 includes a pair of parallel flat surfaces 12 facing each other, 13, a pair of concentric arcuate surfaces l4 spanning between these flat surfaces 12 and 13,
It is formed by 15. the inner circumferential surface of the circularly polarized wave generating section 11;
The outer circumferential surface is exemplified as having a diameter that gradually decreases from left to right in FIG. 1, that is, having a taper. Only the outer circumferential surface may have the above-mentioned taper, or both the inner and outer circumferential surfaces may have no taper. When both the inner and outer circumferential surfaces of the circularly polarized wave generating section 11 have tapered surfaces,
These taper angles (gradients) with respect to the axis of the circularly polarized wave generator 11 range from 1 degree to several degrees, and as a specific example, the Taber angle of the inner peripheral surface is 2.1 degrees, and the Taber angle of the outer peripheral surface is 2.1 degrees. 1.
Each is set in 3 degrees. A pair of flat surfaces 12 and 13 of the circularly polarized wave generator 11 are arranged along two orthogonal axes Ex and E shown in FIG.
In addition to having a slope of 45° with respect to y, as described in FIGS. 5 and 6 above, the phase difference δ between the electric field transmitted along the long axis and the electric field transmitted along the short axis of the cross section of the circularly polarized wave generating section is d, w, 1, etc. are set so that the angle is 80° at the output end of the primary radiator. More specifically, the front end side d *19mm (curvature radius 9
．． 5+o+), w-16ms+ on the front end side. d on the rear end side
-17mm (curvature radius 8.5mm), rear end side w-14
．． 51I1. Sentence = 41n. The circular-to-rectangular conversion section 21 has a cylindrical shape.

In the circular-to-rectangular converting section 21, a coupling window 22 for coupling the BS converter is opened in the lower peripheral wall in the E and axial direction at the middle part in the longitudinal force direction, and an absorber is provided in the rear end part. 23 and a short plate 24 are combined and attached in a cross shape. The circular-to-rectangular conversion section 21 has two types: a cylindrical shape with a constant inner diameter, and a tapered cylindrical shape with a diameter gradually increasing from left to right in FIG.

In the illustrated example, a tapered cylindrical shape is adopted as the circular-to-rectangular conversion section 21. In this case, the minimum inner diameter (left end) of the circular-to-rectangular conversion section 21
14.5mmφ, maximum inner diameter (right end) 20.5mmφ,
The length is 45sm. In the above, both flat surfaces 12 and 13 of the circularly polarized wave generating section 1l
, i.e., both flat surfaces 12 and 13
As shown in FIGS. 2 and 3, the front and rear ends of the
Adjacent parts to each end (horn part l, circular to rectangular conversion part 2
1) a plurality of inclined parts 31. 32, 33
, 34 are formed. Even if there is only one sloped portion, the horn portion 1 and the circularly polarized wave generating portion 11 . Alternatively, the occurrence of abrupt discontinuities (steps) in the relative relationship between the circularly polarized wave generator 11 and the circular rectangular converter 21 is eliminated. Therefore, the sloped portion is re-flattened to the surface 12. One or more flat surfaces are provided at the front end and rear end of the 12. The front and rear ends of 13 are all provided with sloped parts. In the case of the uninvented circularly polarized primary radiator, the horn section l, the circularly polarized wave generating section IL, and the circular-to-rectangular converting section 21 can be easily shaped by, for example, a die-casting method. Thus, the shaped circularly polarized primary radiator can be put to practical use as a primary radiator for satellite broadcasting antennas. Next, regarding specific examples of the present invention and comparative examples thereof, VSWR
Figures 7 and 8 show the results of measuring the characteristics and circular polarization coefficient. The specifications of the specific example are based on the numerical values already mentioned, and the comparative example has the same specifications as the specific example, but does not have an inclined part. As is clear with reference to FIGS. 7 and 8, the specific example of the present invention has better VSWR characteristics and circular polarization than the comparative example, and these results indicate that the slope portion is effective. I was able to confirm the gender. r Effects of the Invention J As explained above, the present invention has a VSWR characteristic because in a predetermined circularly polarized primary radiator, an inclined part is formed at the axial end of the flat part of the solar polarized wave generating part. , the circular polarization characteristics do not deteriorate, and the manufacturing process is simple, allowing cost reduction and mass production.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing an embodiment of a circularly polarized primary radiator according to the present invention, Fig. 2 is a sectional view taken along the line ■--■ in Fig. 1, and Fig. 3 is a cross-sectional view taken along the line m--■ in Fig. 1. A sectional view of FIG. 4 is a cross-sectional view of FIG. 1 ff-IV
5 and 6 are perspective views and sectional views showing a circularly polarized wave generating section according to the prior art of the present invention, and FIG. 7 shows VSIIR characteristics of a specific example of the present invention and a comparative example. The figure shown in FIG. 8 is a diagram showing the circular polarization coefficient of a specific example of the present invention and a comparative example. l...Horn 11...Circularly polarized wave generating section 12...Flat surface 13...Flat surface 14...Circular surface l5. . . . Arc surface 21 . . . Circular-to-rectangular conversion section 22 . . . Combination window 23 . . . Absorber 24 . . . Short plate 3] ... Slanted part 32 ... Slanted part 33 ... Slanted part 34 ... Slanted part

Claims (1)

[Claims] It consists of a waveguide structure in which a circularly polarized wave generating section is provided between a horn section and a circular-rectangular converting section, and the inner circumferential surface of the circularly polarized wave generating section is formed by a pair of flat surfaces facing each other and a pair of flat surfaces facing each other. If the orthogonal two axes passing through the cross-sectional center of the circularly polarized wave generating section are E_x and E_y, respectively, then the pair of flat surfaces are formed by the orthogonal two axes E_x and E.
It has a slope of 45° with respect to _y, and the phase difference between the electric field transmitted along the long axis of the cross section of the circularly polarized wave generator and the electric field transmitted along the short axis of the cross section of the circularly polarized wave generator is 90° at the radiation output end. The circularly polarized primary radiator is characterized in that an axial end of the flat part of the circularly polarized wave generating section is formed with an inclined part that slopes toward a part adjacent to the end. A circularly polarized primary radiator.