Ultra-wideband composite polarization antenna

Abstract

The present invention discloses an ultra-wideband composite polarization antenna, comprising a feed balun, a reflective mounting panel, a reflective back cavity, a composite polarization radiator, and a matching network. The feed balun is fixed to the bottom surface of the reflective mounting panel via a standard SMA flange; the feed balun probe is fixedly connected to the bottom of the reflective back cavity located in front of the reflective mounting panel; the composite polarization radiator is fixed to the top of the reflective back cavity; and the matching network is electrically connected to the composite polarization radiator and then fixed to the reflective mounting panel. The present invention meets the requirements of a direction-finding system that simultaneously covers UHF, S, C, X-band, and Ku-band, facilitates the integrated development and design of direction-finding systems, and improves the efficiency of direction-finding systems used on various platforms.

Description

Technical Field

[0001] The invention belongs to a direction finding system, and in particular relates to an ultra-wideband composite polarization antenna. Background Art

[0002] Ultra-wideband direction-finding systems can accurately acquire target characteristic parameters and determine their attributes and categories. They typically operate over a wide frequency band, typically 0.5 GHz to 40 GHz. With technological advancements, higher bandwidth requirements are being imposed. Direction-finding systems often employ digital interferometers, with the number of channels determined by the frequency bands within the direction-finding array antenna. Typical antenna operating bands are 0.5 GHz to 0.8 GHz, 0.8 GHz to 2.0 GHz, 2.0 GHz to 6.0 GHz, 6.0 GHz to 18.0 GHz, and 18.0 GHz to 40.0 GHz. Consequently, the antenna arrays in direction-finding systems require a significant number of components, hindering integrated system design. Therefore, key technologies are urgently needed to broaden the antenna operating frequency bands and significantly reduce the number of components required for the direction-finding array.

[0003] The typical operating frequency band covers a wide range, namely 0.5GHz-40GHz. With the demands of technological advancement, higher system operating bandwidth requirements are being placed on the system. Direction-finding systems often employ digital interferometers, with the number of channels depending on the number of divisions within the direction-finding array antenna's operating frequency band. Typical antenna operating bands are 0.5GHz-0.8GHz, 0.8GHz-2.0GHz, 2.0GHz-6.0GHz, 6.0GHz-18.0GHz, and 18.0GHz-40.0GHz, making this a widely used and effective method. Consequently, the number of antenna arrays required for direction-finding systems is extremely large, hindering system performance. Therefore, there is an urgent need to address the key technologies and difficulties associated with broadening the antenna operating frequency bands and significantly reducing the number of direction-finding antenna arrays required. This is a topic of ongoing research in this field worldwide.

[0004] A search of domestic and international literature has yet to uncover any literature related to direction-finding system antennas. Analysis of direction-finding system antennas for other application platforms reveals that most antennas operate in the UHF, S-, C-, X-, or Ku-band bands. These antennas have narrow operating bandwidths relative to their operating frequency bands and are relatively large in size, such as commonly used dipole, monopole, planar spiral, log-periodic, and ridged horn antennas. Existing direction-finding antennas struggle to meet the requirements of ultra-wideband (simultaneous coverage of UHF, S-, C-, X-, and Ku-bands), typically employing multiple antennas and frequency bands. This results in a significant increase in the number of devices required for direction-finding systems, severely hindering the development of integrated equipment. Therefore, expanding the antenna's operating bandwidth becomes a key technical challenge. Different platforms also impose strict requirements on antenna size, making antenna miniaturization a necessity. These factors hinder the development of effective direction-finding systems. Literature research indicates that no effective solution has yet emerged.

[0005] Therefore, developing an ultra-wideband direction-finding antenna unit is a key technology and challenge in direction-finding systems. At the same time, direction-finding systems also have clear requirements for the antenna's adaptability to target polarization, meaning it must be able to adapt to unknown incoming wave polarization. Analysis of domestic and international literature indicates that currently, ultra-wideband antennas struggle to simultaneously meet the requirements of ultra-wideband (covering UHF, X, and Ku bands), miniaturization, wide beam, high gain, and complex polarization. This severely restricts the development of ultra-wideband direction-finding systems. Summary of the Invention

[0006] The present invention aims to provide an ultra-wideband composite polarization antenna that is miniaturized, ultra-wideband, and composite polarized. The antenna meets the requirements of a direction-finding system that simultaneously covers UHF, S, C, X-band, and Ku-band, facilitates the integrated development and design of direction-finding systems, and improves the efficiency of direction-finding systems used on various platforms.

[0007] The technical solution for implementing the present invention is: an ultra-wideband composite polarization antenna, including a feed balun, a reflective mounting panel, a reflective back cavity, a composite polarization radiator, and a matching network; the feed balun is fixed to the bottom surface of the reflective mounting panel through a standard SMA flange; the probe of the feed balun is fixed to the bottom of the reflective back cavity located on the front of the reflective mounting panel; the composite polarization radiator is fixed to the top of the reflective back cavity; the matching network is electrically connected to the composite polarization radiator and then fixed to the reflective mounting panel.

[0008] The optimization function of the composite polarization radiator is as follows:

[0009]

[0010]

[0011] x=±L,-πr-l0≤L≤πr+l0 (3)

[0012] y=±W (4)

[0013] z=±H (5)

[0014] l=2πr1 (6)

[0015] in, is the initial azimuth, r0 is the initial radial distance of the spiral, and a is a constant that determines the speed of spiral growth. is the azimuth angle, x is the length function of the composite polarization radiator, r1 is the radius of the composite polarization radiator, l0 is the constant of the length function of the composite polarization radiator, and L is the top length of the composite polarization radiator; y is the width function of the composite polarization radiator, l is the circumference of the spiral, W is the width of the composite polarization radiator, z is the radiator height function, H is the height of the composite polarization radiator, and r is the spiral radial distance.

[0016] Compared with the prior art, the present invention has the following significant advantages:

[0017] (1) One antenna covers UHF, S, C, X, and Ku bands, with ultra-wideband characteristics, solving the shortcomings of frequency band division and multiple antennas in existing technologies.

[0018] (2) Due to the use of composite polarization radiator technology, the working bandwidth is expanded, the antenna gain is improved, and the antenna size is further reduced, which can meet the corresponding technical requirements and solve the technical difficulties of existing antenna miniaturization.

[0019] (3) Due to the ultra-wideband and miniaturization characteristics of the present invention, the present invention can be easily transplanted to relevant weapon platforms for use. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a block diagram of the composition and working principle of the ultra-wideband composite polarization antenna.

[0021] Figure 2 Schematic diagram of the ultra-wideband composite polarization antenna structure.

[0022] Figure 3 These are typical gain patterns of the antenna, where (a) is the gain pattern at Freq = 0.35 GHz, (b) is the gain pattern at Freq = 10 GHz, and (c) is the gain pattern at Freq = 18 GHz. DETAILED DESCRIPTION

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0025] In the present invention, unless otherwise specified or limited, the terms "connection" and "fixation" should be understood in a broad sense. For example, "fixation" can refer to fixed connection, detachable connection, or integration; "connection" can refer to mechanical connection or electrical connection. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0026] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in this field can implement it. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0027] The following will further introduce the specific implementation methods, as well as the technical difficulties and inventive points of this invention in combination with this design example.

[0028] Combine Figure 1 The working principle of the ultra-wideband composite polarized antenna of the present invention is as follows: its working process is reciprocal. Taking electromagnetic wave emission as an example, the electromagnetic wave enters the feed balun 1 through the external RF interface, and is connected to the composite polarized radiator 4 through the internal conductor of the feed balun 1. The electromagnetic wave forms a surface current on the surface of the composite polarized radiator 4, that is, a field mode distribution. Since the feed balun 1 adopts the fundamental mode excitation mode, the excitation state is in the TEM fundamental mode state at this time, and the far-field radiation pattern of the corresponding polarization is superimposed on the surface of the composite polarized radiator 4. At this time, the antenna completes the electromagnetic radiation pattern, and the antenna completes the electromagnetic radiation. The opposite process is the working process of the antenna receiving electromagnetic waves.

[0029] Combine Figure 2The ultra-wideband composite polarization antenna of the present invention comprises a feed balun 1, a reflective mounting panel 2, a reflective back cavity 3, a composite polarization radiator 4, and a matching network 5. The feed balun 1 is composed of a coaxial cable and is used to connect to an external RF interface. The reflective mounting panel 2 is used to securely mount the reflective back cavity 3, the composite polarization radiator 4, and the matching network 5, and also controls the beam shape. The reflective back cavity 3 is constructed of a non-metallic material with a specific shape, which constrains the antenna pattern. The composite polarization radiator 4 is formed by an optimized function and is used to form the antenna's electromagnetic wave radiation field pattern, converting the field pattern to free space and determining the antenna radiation pattern and operating bandwidth. The positional connection relationship of the various components is as follows: the feed balun 1 is fixed to the bottom surface of the reflective mounting panel 2 via a standard SMA flange; the probe of the feed balun 1 is fixed to the bottom of the reflective back cavity 3 located on the front of the reflective mounting panel 2 via a threaded connection; the composite polarization radiator 4 is fixed to the top of the reflective back cavity 3; and the matching network 5 is electrically connected to the composite polarization radiator 4 and then fixed to the reflective mounting panel 2.

[0030] Combine Figure 2 , the realization of the composite polarized radiator 4 of the present invention. The design of the composite polarized radiator 4, in order to ensure the characteristics of ultra-wideband, needs to give its geometric structure according to the following optimization function. The optimization function reduces the diameter of the traditional antenna of this type to about one tenth of the wavelength of the lowest operating frequency. Because the optimization function adopts a structure combining a composite straight line and a curve segment, replacing the traditional single function straight line segment. Specifically, the commercial electromagnetic field simulation software Ansoft HFSS can be applied. In the software simulation environment, according to the given optimization function, a 3D antenna structure model is established. Combined with the finite element calculation electromagnetic algorithm of the commercial electromagnetic field simulation software Ansoft HFSS, the electromagnetic field boundary conditions are set in the software to meet the electromagnetic environment conditions of the actual antenna. In this way, the optimal parameters of the antenna radiator can be calculated. Combined with the actual requirements of the project, the deviation of the electromagnetic simulation software can be corrected. The general expression of its optimization function is composed of formulas (1), (2), (3), (4), (5) and (6):

[0031]

[0032]

[0033] x=±L,(-πr-l0≤L≤πr+l0) (3)

[0034] y=±W (4)

[0035] z=±H (5)

[0036] l=2πr1 (6)

[0037] in, is the initial azimuth angle, r0 is the initial radial distance of the spiral, a is a constant that determines the growth rate of the spiral, and a is a constant that determines the growth rate of the spiral. The criterion usually selected is: if a is small, the spiral curvature is small. Under the condition that the outer diameter of the antenna is the same, the corresponding electrical length of the spiral increases. The advantage is that the terminal effect of the antenna is better suppressed. The final specific value can be determined by the simulation optimization results of the electromagnetic simulation software Ansoft HFSS. is the azimuth angle, x is the radiator length function, L is the radiator length function value, π is pi, r1 is the radiator radius, l0 is the constant of the radiator length function, L is the top length of the compound polarization radiator 4, y is the radiator width function, l is the circumference of the spiral line, W is the width of the compound polarization radiator 4, r is the spiral radial distance, z is the radiator height function, H is the height of the compound polarization radiator 4. The specific value can be determined by the simulation optimization results of the electromagnetic simulation software Ansoft HFSS.

[0038] Combine Figure 2 The matching network of the present invention is implemented using a printed circuit board (PCB) circuit with resistors of a certain value connected in series to form the matching network. The specific resistance values ​​of the resistors are optimized and designed using the electromagnetic field simulation software Ansoft HFSS. The design principle for the resistance R is based on the antenna's voltage standing wave ratio (VSWR) design requirements. The resistance R is determined based on comprehensive engineering experience and is typically 95 to 105 ohms when achieving a balance between the antenna's VSWR and gain.

[0039] Combine Figure 3 , which are the typical gain radiation patterns of the antenna, Figure (a) Freq = 0.38GHz gain radiation pattern, Figure (b) Freq = 10GHz gain radiation pattern, Figure (c) Freq = 18GHz gain radiation pattern, realizing the antenna's high gain characteristic under ultra-wideband conditions.

Claims

1. An ultra-wideband composite polarized antenna, characterized by: The invention comprises a feeding balun (1), a reflection mounting panel (2), a reflection back cavity (3), a composite polarization radiator (4), and a matching network (5); the feeding balun (1) is fixed to the bottom surface of the reflection mounting panel (2) through a standard SMA flange; the probe of the feeding balun (1) is fixedly connected to the bottom of the reflection back cavity (3) located on the front of the reflection mounting panel (2); the composite polarization radiator (4) is fixed to the top of the reflection back cavity (3), and the composite polarization radiator (4) comprises a helical antenna and a radiating structure located on the left and right sides of the helical antenna and connected to the helical antenna; the matching network (5) is electrically connected to the radiating structures on the left and right sides of the composite polarization radiator (4) and then fixed to the reflection mounting panel (2); The optimization function of the composite polarimetric radiator (4) is as follows: （1）， （2）， ， （3）， （4）， （5）， （6）， in, is the initial azimuth, is the initial radial distance of the spiral, is the constant that determines the speed of spiral growth, is the azimuth, is the length function of the composite polarimetric radiator (4), is the radius of the compound polarimetric radiator (4), is a constant as a function of the length of the composite polarimetric radiator (4), is the top length of the composite polarization radiator (4); is the width function of the composite polarization radiator (4), is the circumference of the spiral, is the width of the composite polarization radiator (4), is the radiator height function, H is the height of the compound polarization radiator (4), is the spiral radial distance; Matching network (5) uses a printed circuit board and connects resistors of a certain resistance value in series to form a matching network; The resistance value of resistor R is 95 to 105 ohms.

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