CN114421165A - A Resistive Loaded Ultra-Broadband Dual-Polarized Quad-ridged Horn Antenna - Google Patents

Abstract

The invention discloses a resistance-loaded ultra-wideband dual-polarized four-ridge horn antenna, which comprises a ridge sheet (1), a circular waveguide (3), and two coaxial probes (5, 6). Four, and are circumferentially installed along the inner side of the circular waveguide at equal intervals to form a bell mouth surface; the circular waveguide is installed on the base (4), and two coaxial probes are respectively inserted from the first ridge piece and the second ridge piece, and pass through the circular waveguide. After passing through the center of the circular waveguide, the third ridge sheet and the fourth ridge sheet at opposite positions are respectively extended to form the orthogonal dislocation placement of the two coaxial probes; the upper edge of the circular waveguide is installed with a fixed flange (2). Connecting blocks (9) are respectively fixed on the blue at the positions of the corresponding ridges, each connecting block is connected with a resistor (8), and the other end of the resistor is connected with the top of the corresponding ridge through a connecting rod (7); the four The ridge lines of each ridge piece are composed of straight line segments and curved segments, and the entire ridge line is chamfered. The invention has small size and stable phase center, and can be used for near-field antenna measurement.

Description

A Resistive Loaded Ultra-Broadband Dual-Polarized Quad-ridged Horn Antenna

technical field

The invention belongs to the technical field of antennas, and particularly relates to an ultra-wideband dual-polarized four-ridge horn antenna loaded with resistance, which can be used for near-field antenna measurement.

Background technique

The near-field measurement method is an important means of antenna measurement. By using a probe antenna with known characteristics, the far-field performance parameters of the antenna can be obtained at a short distance. This method overcomes the limitation of the field size and improves the measurement accuracy. Therefore, received extensive attention.

The performance of the probe antenna directly affects the efficiency of near-field testing. At present, the open-ended waveguide antenna is the most commonly used probe antenna, but this type of antenna has a narrow bandwidth and works with single polarization. a great inconvenience. To solve this problem, a broadband dual-polarized quad-ridged horn antenna has appeared on the market. In "Research", a dual-polarized quad-ridged horn antenna is disclosed, as shown in Figure 1, including four ridges 1, a reflector 2, a circular waveguide 3, a base 4 and a coaxial probe 5, etc. The ridge curve adopts an exponential The ridge-curve four-ridge structure combining the curve and the Bessel curve achieves dual-polarization output by feeding two coaxial lines respectively, and the overall size reaches 115*110*110mm. Although the antenna can work from 2GHz to 20GHz, its size is large, and the phase center will change greatly with the change of frequency. Therefore, the phase center of this large-size antenna is less stable, which affects the near-field measurement accuracy. Accuracy and testing efficiency.

SUMMARY OF THE INVENTION

The purpose of the present invention is to propose a resistance-loaded ultra-wideband dual-polarized quad-ridged horn antenna in view of the above-mentioned deficiencies of the prior art, so as to reduce the size of the antenna and stabilize the phase center by loading the resistance, thereby improving the near field Measurement accuracy and test efficiency.

In order to achieve the above purpose, a resistance-loaded ultra-wideband dual-polarized four-ridge horn antenna proposed by the present invention includes a ridge sheet, a circular waveguide, a base and two coaxial probes, and the ridge sheets are set to four, and so on The intervals are installed circumferentially along the inner side of the circular waveguide to form a bell mouth surface; the circular waveguide is installed on the base, and two coaxial probes are inserted from the first ridge sheet and the second ridge sheet respectively, and extend into the center of the circular waveguide respectively. The third ridge sheet and the fourth ridge sheet in opposite positions form an orthogonal offset placement of two coaxial probes for fixing, and are characterized by:

A fixed flange is installed on the upper edge of the circular waveguide, and a connection block is fixed on the flange at the corresponding position with the four ridge pieces, each connection block is connected with a resistor, and the other end of the resistor is connected to the corresponding position through the connecting rod. The top of the ridge is connected to ensure better matching characteristics while reducing the size of the antenna;

The ridge lines of the ridge pieces are all composed of straight line segments and curved segments, and are chamfered at 40 degrees to 50 degrees to improve matching characteristics.

Further, a reflection cavity is opened at the bottom of the ridge sheet to filter out high-order modes excited in the waveguide, expand the working bandwidth of the antenna, and improve the matching characteristics.

Further, the distances between the two coaxial probes extending into the third ridge sheet and the fourth ridge sheet at opposite positions after passing through the center of the circular waveguide are 0.5 mm-1 mm.

Further, the curve segment of each ridge piece is in the form of a ridge curve combining an exponential curve and a Bessel curve.

Further, the value range of each resistor is 400-1000Ω.

Further, the height L of each ridge curve segment is 30mm-35mm; the ridge spacing d is 0.9mm-1.1mm; the value range of the diameter g of the bell mouth surface is 40mm-50mm; the value range of the distance from the base to the bell mouth surface 41mm-47mm.

Compared with the prior art, the present invention has the following advantages:

1. In the present invention, the resistance is loaded between the fixed flange and each ridge, which absorbs the low-frequency echo at the end of the antenna, so that the size of the antenna can be reduced, so that the antenna can be used in an ultra-wideband and dual-polarized environment. At the same time, it has a stable phase center, thereby improving the accuracy of near-field measurement;

2. In the present invention, since the reflection cavity is started at the bottom of the four ridges, the excited high-order modes in the waveguide are filtered, the working bandwidth of the antenna is expanded, and the matching characteristics of the small-sized antenna are improved;

3. The present invention further improves the matching characteristics of the small-sized antenna due to the use of the ridge curve form combining the exponential curve and the Bessel curve of the four ridge pieces forming the horn aperture, and the chamfer is opened at the ridge line part.

Simulation experiments show that, compared with the prior art, the present invention has ultra-wideband and dual-polarization characteristics, stable phase center and better matching characteristics, can be used for near-field measurement, and at the same time improves near-field measurement performance. Accuracy and testing efficiency.

Description of drawings

Fig. 1 is the overall structure schematic diagram of the prior art;

Fig. 2 is the overall structure schematic diagram of the present invention;

Fig. 3 is the sectional view of Fig. 2;

Fig. 4 is the top view of Fig. 2;

Fig. 5 is a partial enlarged view of Fig. 2;

Fig. 6 is the front view of the ridge piece in the present invention;

Fig. 7 is the side view of the ridge piece in the present invention;

Fig. 8 is the two-port voltage standing wave ratio VSWR simulation curve of the antenna of the present invention;

Fig. 9 is the two-port S21 simulation curve of the antenna of the present invention;

Fig. 10 is the gain simulation curve of the antenna of the present invention;

Fig. 11 is the phase center position curve of the antenna of the present invention.

Detailed ways

The specific embodiments and effects of the present invention will be described in further detail below with reference to the accompanying drawings.

2, 3, 4 and 5, this example includes a ridge 1, a fixed flange 2, a circular waveguide 3, a base 4, two coaxial probes 5 and 6, wherein:

The ridges 1 are set to four, namely the first 11 , the second 12 , the third 13 and the fourth 14 . These four ridges are equally spaced along the inner side of the circular waveguide 3 . Circumferential installation to form a flared surface. The bottom of the four ridges is provided with a reflection cavity 15 to filter out the high-order modes excited in the waveguide, expand the working bandwidth of the antenna, and improve the matching characteristics; the top of each ridge is fixed with a vertically downward connecting rod 7 .

The circular waveguide 3 is mounted on the base 4, the first coaxial probe 5 and the second coaxial probe 6 are inserted from the first ridge sheet 11 and the second ridge sheet 12 respectively, and extend through the center of the circular waveguide 3 respectively. At the position of 0.5mm-1mm of the third ridge sheet 13 and the fourth ridge sheet 14 in opposite positions, the two coaxial probes are orthogonally misaligned for fixing, so that the antenna has dual polarization characteristics.

The fixed flange 2 is installed on the upper edge of the circular waveguide 3, and the flange 2 is respectively fixed with a connection block 9 at the corresponding position with the four ridge pieces, and each connection block 9 is connected with a resistor 8, and the resistor 8 The other end of the antenna is connected to the top of the corresponding ridge sheet through the connecting rod 7, so as to absorb the low-frequency echo at the end of the antenna, so as to ensure that the size of the antenna is reduced and the matching characteristics are better.

Referring to Figure 6 and Figure 7, the ridge line of each ridge piece 1 is composed of straight line segments and curved segments, wherein the curved segments are in the form of ridge curves combined with exponential curves and Bessel curves to reduce the incident field and horn at the edge of the horn aperture. The diffraction of the aperture itself, and then the edge diffraction is eliminated, which is beneficial to the matching of impedance and the broadening of the frequency band, which significantly improves the pattern at high frequencies and reduces the deterioration. There is a 40-50 degree cut angle, which makes the ridges as close as possible without contacting, reducing the equivalent input impedance. The ridge curve equation at the end of this curve is expressed as follows:

Among them, Y(z) represents the lateral distance from the starting point of the ridge line in the width direction of the exponential curve, z represents the height of the exponential curve, d represents the ridge spacing, L represents the maximum height of the exponential curve, g represents the diameter of the bell mouth, Z( y ₁ ) represents the height of the Bessel curve, Y′(L) represents the slope of the end of the exponential curve, y ₁ represents the lateral distance from the starting point of the ridge line in the width direction of the Bessel curve, and _hr represents the distance between the end of the exponential curve and the inner wall of the bell mouth. The maximum lateral distance between them.

The value range of the height z of each ridge piece above is 0-L, the height L of the ridge piece curve segment is 30mm-35mm, the ridge spacing d is 0.9mm-1.1mm, the diameter g of the bell mouth surface is 40mm-50mm, the index The lateral distance h _r between the end of the curve and the inner wall of the bell mouth surface is 6mm-8mm, the value range of y ₁ is g/2-h _r ≤y ₁ ≤g/2, and the diameter D of the circular waveguide is 13mm-15mm , the height H of the base 4 is 1mm-2mm, the distance S from the base to the bell mouth surface is in the range of 41mm-47mm, and the resistance value of each resistor R is 400Ω-1000Ω.

In this example, but not limited to L=30mm, d=1.1mm, _g =40mm, hr=8mm, D=13mm, H=1mm, S=41mm, the chamfering angle is 45°, the chamfering width is 1.2mm, R= 510Ω

The effect of the present invention can be further illustrated by the following simulation experiments:

1. Simulation conditions:

The simulation frequency is 2GHz～18GHz

The simulation software uses the high-frequency structural simulator from ANSYS.

2. Simulation content and results:

Simulation 1. Under the above conditions, the two-port VSWR of the antenna in this example is simulated. The result is shown in Figure 8. It can be seen from Figure 8 that in the 2GHz to 18GHz frequency band, the two-port VSWR is all less than 3, indicating that the antenna Has better matching characteristics.

Simulation 2: Under the above conditions, the S21 curve of the two ports of the antenna in this example is simulated. The result is shown in Figure 9. It can be seen from Figure 9 that in the 2GHz-18GHz frequency band, the isolation between the two ports is greater than 34.9dB, which satisfies the dual polarization condition. .

Simulation 3: Under the above conditions, the gain of the antenna of this example is simulated. The result is shown in Figure 10. It can be seen from Figure 10 that in the frequency band of 2GHz to 18GHz, the gain is -0.46dB to 11.57dB, which can meet the actual needs.

Simulation 34. Under the above conditions, the phase center position of this example line is simulated and analyzed, and the result is shown in Figure 11. It can be seen from Figure 11 that in the frequency band of 2GHz to 18GHz, the phase center fluctuation is 14.4mm, when the phase center position is 16mm When the 2GHz～18GHz phase center fluctuation is less than 22.5°, it meets the near-field test conditions.

To sum up, the antenna of the present invention has ultra-wideband and dual-polarization characteristics and has a stable phase center, can be used for near-field measurement, and simultaneously improves the accuracy and test efficiency of near-field measurement.

The above description is only a specific example of the present invention, and does not constitute any limitation to the present invention. Obviously, for those skilled in the art, after understanding the content and principles of the present invention, they may not deviate from the principles and structures of the present invention. Under certain circumstances, various corrections and changes in form and details are made, but these corrections and changes based on the idea of the present invention are still within the protection scope of the claims of the present invention.

Claims (7)

1. A resistance-loaded ultra-wideband dual-polarization four-ridge horn antenna comprises a ridge sheet (1), a circular waveguide (3), a base (4) and two coaxial probes (5, 6), wherein the ridge sheet (1) is four (11, 12, 13, 14), and the ridge sheet is circumferentially arranged along the inner side of the circular waveguide (3) at equal intervals to form a horn mouth surface; circular waveguide (3) are installed on base (4), and two coaxial probes (5, 6) are inserted from first spine (11) and second spine (12) respectively, stretch into third spine (13) and fourth spine (14) of relative position respectively after passing circular waveguide (3) center, form the orthogonal dislocation of two coaxial probes and place to it is fixed, its characterized in that:

the upper edge of the circular waveguide (3) is provided with a fixed flange (2), connecting blocks (9) are respectively fixed on the flange (2) at positions corresponding to the four ridge pieces, each connecting block (9) is connected with a resistor (8), and the other end of each resistor (8) is connected with the top end of the corresponding ridge piece through a connecting rod (7), so that the antenna is ensured to have good matching characteristics while the size of the antenna is reduced;

the ridge line of the ridge piece (1) is composed of straight line sections and curved line sections, and chamfers of 40-50 degrees are formed on the straight line sections and the curved line sections, so that the matching characteristic is improved.

2. The antenna of claim 1, wherein: the bottom of the ridge sheet (1) is provided with a reflecting cavity (15) to filter the high-order mode excited in the waveguide, expand the working bandwidth of the antenna and improve the matching characteristic.

3. The antenna of claim 1, wherein: the distance between the two coaxial probes (5, 6) penetrating through the center of the circular waveguide (3) and respectively extending into the third ridge sheet (13) and the fourth ridge sheet (14) at opposite positions is 0.5mm-1 mm.

4. The antenna of claim 1, wherein: the curve section of each ridge sheet (1) is in the form of a ridge curve formed by combining an exponential curve and a Bessel curve, and the ridge curve equation is expressed as follows:

wherein Y (Z) represents a lateral distance from a start point of the ridge line in a width direction of the exponential curve, Z represents a height of the exponential curve, d represents a ridge pitch, L represents a maximum value of the height of the exponential curve, g represents a flare face diameter, and Z (y)₁) Representing the height of the Bessel curve, Y' (L) representing the slope of the end of the exponential curve, Y₁Represents the lateral distance, h, from the start of the ridge line in the width direction of the Bessel curve_rRepresenting the maximum value of the lateral distance between the end of the exponential curve and the inner wall at the flare face.

5. The antenna according to claim 1, characterized in that the value of each resistor (8) ranges from 400 Ω to 1000 Ω.

6. The antenna of claim 1, wherein: the height L of the curve section of each ridge sheet (1) is 30mm-35 mm; the ridge spacing d is 0.9mm-1.1 mm.

7. The antenna of claim 1, wherein: the value range of the diameter g of the bell mouth surface is 40mm-50 mm; the distance between the base (4) and the bell mouth surface ranges from 41mm to 47 mm.

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