CN102509845B - Multimode occulting antenna with stable phase center - Google Patents

Abstract

A multi-mode phase center stable occultation antenna, including a reflection cavity, a radiating lower patch, a radiating upper patch, four feeding probe sleeves, four feeding probe inner cores and two supporting columns; The electric probe sleeve includes a metal base and a filling. One end of the metal base is a metal column, and the other end is a metal cylinder cavity. The filler fills up the cylinder cavity of the metal base. The invention uses sleeve-shaped probes for four-point coupling and feeding, and the probes are evenly distributed on a circle; the antenna radiation sheet is composed of upper and lower layers, the lower layer is coupled and fed by sleeve-shaped probes, and the upper layer is coupled through the lower radiation sheet The feed is supported by metal pillars in the middle; the reflection cavity is a circular bowl-shaped structure, and its height is lower than that of the upper radiation sheet. The invention has superior performance, simple and reliable structure and process, and wide frequency band, which can be used by GPS, BD-2, GALILEO, and GLONASS. It has wider beam coverage and higher gain, stable phase center, excellent axial ratio performance, and is suitable for precision Occultation and other high-precision detection systems.

Description

A Multi-mode Phase Center Stabilized Occultation Antenna

technical field

The invention relates to an occultation antenna with a stable multi-mode phase center, which is suitable for occultation detection of precision satellites, drones, airships and other aircraft and other high-precision detection systems, and belongs to the technical field of high-precision detection antennas.

Background technique

In the late 1980s, foreign countries began to study a new method of detecting the earth's atmospheric environment based on GPS satellite radio signals: GPS radio signals are affected by atmospheric refraction when passing through the earth's atmosphere, and the propagation path is bent, resulting in The signal phase produces a delay, and by measuring these delays to obtain information such as temperature, pressure, humidity, and electron density in the atmosphere, this method is called radio occultation measurement technology. In order to improve the accuracy of occultation detection and inversion, a global Navigation satellite system (GNSS, Global Navigation Satellite System) detection system. As a key component in the occultation detection system, high-precision occultation antenna technology has become an urgent problem to be solved.

The occultation antenna is a wide-beam antenna, which requires the antenna to have a high gain and a stable phase center in a wide-angle range. At present, most occultation antennas adopt the form of beam-forming antenna array, and the beam-forming of the antenna is performed by changing the phase of the input signal of each unit of the antenna array to achieve the purpose of widening the beam. The advantage of this kind of antenna is that it can realize the coverage of various special shape patterns through the phase change of each array element of the antenna, but the beamforming antenna array needs to realize the signal excitation of different phases for each array element of the antenna, which leads to the complexity of the antenna feeding network and the The phase of the array changes greatly in the wide-angle range, and the stability of the phase center is poor. Accurate calibration of the phase center is required. Moreover, due to the narrow bandwidth of the phase-shifting network, the overall bandwidth of the antenna is greatly limited, and it cannot fully cover GPS, BD- 2. Frequency range of GALILEO and GLONASS.

Contents of the invention

The problem solved by the technology of the present invention is: to overcome the deficiencies of the prior art, to provide a multi-mode occultation antenna with stable phase center, stable phase center, simple structure and processing technology, suitable for satellites, unmanned aerial vehicles, airships and other aircraft .

Technical solution of the present invention is:

A multi-mode phase-center-stabilized occultation antenna, including a reflection cavity, a radiating lower patch, a radiating upper patch, four feeding probe sleeves, four feeding probe inner cores, a first support column and a second Two support columns; the feeding probe sleeve includes a metal base and a filler, one end of the metal base is a metal column, and the other end is a metal cylinder cavity, and the filler fills the cylinder cavity of the metal base;

The reflective cavity is a metal hollow cylindrical cavity with a closed bottom surface, the second support column is a metal cylinder, and the second support column is installed at the center of the bottom surface of the internal cavity of the reflective cavity, the second support column The center of the bottom surface of the column is aligned with the center of the bottom surface of the inner cavity of the reflection cavity, the radiation patch is a circular metal sheet and installed on the top of the second support column, the radiation patch is concentric with the second support column, and the radiation patch is concentric with the second support column. The height of the lower patch is lower than the cavity height of the reflection cavity; the first support column is a metal cylinder and is installed on the radiation lower patch, concentric with the radiation lower patch; the radiation The upper patch is a circular metal sheet and is installed on the top of the first support column, concentric with the first support column and the radiation upper patch is higher than the cavity height of the reflection cavity;

The metal pillars at one end of the four metal seats are fixed on the bottom surface of the inner cavity of the reflective cavity and are evenly distributed on the same circumference with the center of the inner cavity bottom surface of the reflective cavity as the center, and the filler in the cylindrical cavity of the metal seat and the Patch contact under radiation;

The inner cores of the four feeding probes vertically pass through the sub-radiation patch and are inserted into the filler, and the inner cores of the feeding probes are electrically isolated from the metal seat; The patches are fixedly installed, and the inner core of the feeding probe is concentric with the metal base.

The diameter of the radiation patch is between 68mm and 72mm, and the thickness is between 1mm and 3mm.

The diameter of the patch under radiation is between 99mm and 101mm, and the thickness is between 1mm and 3mm.

The height of the first support column is between 14mm and 16mm.

The height of the second support column is between 15mm and 17mm.

The diameter of the evenly distributed circumference of the feeding probe sleeve is between 44mm and 48mm, the height of the metal column at one end of the metal seat of the feeding probe sleeve is between 7mm and 9mm, and the cylindrical cavity of the metal seat The body part height is between 5mm and 7mm.

The diameter of the inner core of the feeding probe is between 1.5mm and 3mm, and the length is between 8mm and 10mm.

The filler is polyimide.

The beneficial effect of the present invention compared with prior art is:

1. The present invention adopts the metal feeding probe of the sleeve structure to couple and feed the patch under radiation. Compared with the direct connection feeding of the traditional probe, the input is improved due to the capacitive coupling effect of the metal feeding probe of the sleeve. The impedance characteristics of the port have been verified by experiments. This method can expand the working bandwidth of the antenna by 30% to 35%, increase the frequency coverage of the antenna, and fully cover the frequency range of GPS, BD-2, GALILEO and GLONASS;

2. The primary requirement of on-board devices is high reliability. The coupling feeding method designed in the past is not stable enough in structural design. In this invention, the feeding probe is passed through and fixed on the patch under radiation, and the lower end is inserted into the filler Within polyimide, the insulation of polyimide makes the feed probe and the metal feed probe sleeve electrically isolated, so that the feed probe can play the role of feed coupling. At the same time, the use of polyimide The amine also plays a role in fixing the feeding probe, preventing the feeding probe from being damaged due to excessive swing range, and allowing the feeding probe to have elastic deformation space when the carrier vibrates, which greatly enhances the reliability of the antenna .

3. Circular polarization is formed through four-point feeding. Compared with the existing one-point self-circular polarization and two-point feeding to form circular polarization, the structure of four-point feeding is symmetrical, which can effectively suppress the asymmetrical feeding structure The unnecessary high-order mode brought by the antenna unit improves the purity of the main mode transmitted by the antenna unit. While expanding the matching characteristics of the antenna unit, it effectively improves the radiation characteristics of the antenna unit in the wide-angle range and improves the antenna unit in the wide-angle domain. The axial ratio characteristics and phase center characteristics within the range lay a good foundation for the overall gain and phase center stability of the antenna unit array.

4. In the present invention, in order to ensure that the operating frequency range of the antenna is sufficient to cover the frequency range of GPS, BD-2, GALILEO and GLONASS, the radiation patch adopts the form of a circular metal sheet, and the diameter of the patch on the radiation depends on the operating frequency of the antenna. Between 68mm and 72mm, the diameter of the patch under radiation is between 99mm and 101mm. Considering the reliability of the antenna structure, the thickness of the radiation patch is designed to be between 1mm and 3mm. The radiation patches are connected by metal cylinders and fixed at the center of the reflection cavity. The height of the second support column is between 15mm and 17mm. Between, the height of the first support column is between 14mm and 16mm, and the radius is increased at the connection part between the metal support column and the patch to ensure the reliability of the structure.

Four feeding probe sleeves are evenly distributed on the circumference with a diameter between 44mm and 46mm to realize four-point feeding. The height of the supporting part is between 7mm and 9mm, and the length of the sleeve part is between 5mm and 7mm. The diameter of the inner core of the four metal feeding probes is between 1.5mm and 3mm, and the length is between 8mm and 10mm. The above design can enhance the capacitive coupling characteristics of the feeding probe in the form of a sleeve, so that the operating frequency of the antenna can be further improved. expand. In order to further improve the wide-angle characteristics of the antenna, the coupling between the feeding probes is reduced by appropriately increasing the height of the reflection cavity and the patch on the radiation, and the height of the first support column 6 is between 14mm and 16mm to improve the working condition. Antenna port reflection coefficient.

Description of drawings

Fig. 1 is a schematic diagram of an array layout of an occultation antenna with a stable multimode phase center of the present invention;

Fig. 2 is a schematic cross-sectional view of an occultation antenna unit with a stable multimode phase center of the present invention;

Fig. 3 is a schematic diagram of the layout of the sleeve-shaped feeding probe of the multimode phase center stable occultation antenna of the present invention;

Fig. 4 is a schematic cross-sectional view of a sleeve-shaped feeding probe for an occultation antenna with stable multi-mode phase center according to the present invention.

Detailed ways

In the late 1980s, foreign countries began to study a new method of detecting the earth's atmospheric environment based on GPS satellite radio signals: radio occultation measurement technology. In order to improve the accuracy of occultation detection and inversion, a Global Navigation Satellite System (GNSS, Global Navigation Satellite System) is proposed, which includes GPS (Global Positioning System, American Navigation Satellite System), BD-2 (Beidou, Chinese Navigation Satellite System) , GALILEO (European Navigation Satellite System) and GLONASS (Russian Navigation Satellite System)) detection systems. As a key component in the occultation detection system, high-precision occultation antenna technology has become an urgent problem to be solved.

The invention provides an occultation antenna with a stable multi-mode phase center, which improves the impedance characteristics of the input port, expands the working bandwidth of the antenna by 30% to 35%, increases the frequency coverage of the antenna, and can fully cover GPS, BD- 2. The frequency range of GALILEO and GLONASS, its specific structure is shown in Figure 2, the multi-mode phase center stable occultation antenna of the present invention mainly includes a reflection cavity 1, a radiation lower patch 2, a radiation upper patch 3, and four metal The feeding probe sleeve 4 and its inner core 5, the first support column 6 and the second support column 7, the feeding probe sleeve 4 includes a metal seat 42 and a filler 41, as shown in Figure 4, the metal seat One end of 42 is a metal column, and the other end is a metal cylinder cavity, and the filler 41 fills up the cylinder cavity of the metal seat 42 .

The antenna radiation sheet is composed of upper and lower layers (radiation lower patch 2 and radiation upper patch 3), the lower layer is coupled and fed through the sleeve-shaped probe, the upper layer is coupled and fed through the lower radiation sheet, and the middle is supported by metal pillars; the reflection cavity It is a circular bowl-shaped structure (a metal hollow cylindrical cavity with a closed bottom surface), and its height is lower than that of the upper radiation sheet.

The reflective cavity 1 is a metal hollow cylindrical cavity with a closed bottom surface, with a diameter of about 150mm to 160mm and a height of 35 to 40mm. By properly increasing the height of the reflective cavity 1, the coupling degree between the feeding probes can be reduced and the working condition can be improved. The reflection coefficient of the antenna port improves the gain in the low elevation angle direction of the antenna.

The second support column 7 is a metal cylinder with a diameter between 8mm and 10mm. The size selection needs to be combined with the reliability of the overall structure of the antenna. The second support column 7 is connected to the center of the bottom surface of the inner cavity of the reflection cavity 1 through threads or conductive glue. position, and the center of its bottom surface is aligned with the center of the bottom surface of the reflection cavity 1, and its height is between 15mm and 17mm. The selection of this size not only ensures the operating frequency of the antenna, but also ensures the four sleeve-shaped metal feed probes capacitively coupled feed.

Four metal feeding probe sleeves 4 are installed vertically on the bottom surface of the inner cavity of the reflective cavity 1 and are evenly distributed on the same circumference with the center of the inner cavity bottom surface of the reflective cavity 1 as the center. Compared with the traditional probe directly connected to the feed, due to the capacitive coupling effect of the sleeve-shaped metal feed probe, the impedance characteristics of the input port are improved. After experimental verification, this method can expand the antenna working bandwidth to 30%~ 35%, increase the frequency coverage of the antenna.

The layout of the four sleeve-shaped feeding probes is shown in Figure 3. The four feeding probes are evenly distributed along the circumference with a diameter between 44mm and 46mm. The profile of the four sleeve-shaped metal feeding probes is shown in Figure 4. The metal pillars at one end of the four metal seats 42 are fixed on the bottom surface of the inner cavity of the reflection cavity 1 and are evenly distributed on the same circumference with the center of the bottom surface of the inner cavity of the reflection cavity 1 as the center. The cylindrical cavity of the metal seat 42 The filler 41 in the body is in contact with the patch 2 under radiation;

The four feeding probe inner cores 5 vertically pass through the patch 2 under the radiation and are inserted into the filler 41, and the inner cores 5 of the feeding probes are electrically isolated from the metal seat 42; the feeding probes The inner core 5 is fixedly installed between the patch 2 under the radiation, and the inner core 5 of the feeding probe is concentric with the metal seat 42, and the height of the supporting part (the metal column at one end of the metal seat 42) is between 7mm and 9mm. The height of the sleeve (cylindrical cavity at one end of the metal seat 42) is between 5mm and 7mm, the diameter of the inner core 5 of the four feeding probes is between 1.5mm and 3mm, and the length is between 8mm and 10mm. The probe sleeve 4 and its inner core 5 are fixed and electrically isolated by polyimide. The present invention adopts a four-point feeding method, and the feeding signal amplitudes are equal, and the phases are sequentially different by 90 degrees to realize right-handed circular polarization. Compared with the existing one-point self-circular polarization and two-point feeding to form circular polarization, Due to the symmetry of the feeding structure, it can effectively suppress the transmission of unnecessary high-order modes, improve the purity of the main mode of the antenna transmission, reduce the cross-polarization of the antenna, and effectively improve the antenna's wide-angle range while expanding the matching characteristics of the antenna. Radiation characteristics within a wide range, improve the axial ratio and phase center characteristics of the antenna in a wide angle range, and lay a good foundation for the overall gain and phase center stability of the antenna unit array. The feed-in signal can be realized through a one-point four-power-splitting feed network, and its output end is directly welded to four feed probe sleeves 4 through a metal core needle, and is fixed in the back cavity of the reflection cavity 1 by screws to form a closed Antenna system, reducing the impact of space radiation and other environments on dielectric materials.

The patch 2 under radiation is a circular metal sheet with a diameter between 99mm and 101mm and a thickness of about 1mm to 3mm, and it is connected to the top of the second support column 7 through threads or conductive glue, concentric with the second support column 7, and radiated under the patch. The sheet 2 is higher than the height of the sleeve metal feed probe sleeve 4 and lower than the cavity height of the reflective cavity 1 . The radiation upper patch 3 is a circular metal sheet with a diameter between 68 mm and 72 mm and a thickness of about 1 mm to 3 mm, and is connected to the top of the first support column 6 through threads or conductive glue. The radiation upper patch 3 is concentric with the first support column 6 And the radiation upper patch 3 is higher than the cavity height of the reflective cavity 1 .

The first support column 6 is a metal cylinder with the same diameter as the second support column 7 and is connected to the sub-radiation patch 2 by threads or conductive glue. The first support column 6 is concentric with the sub-radiation patch 2. The first support The height of the column 6 is between 14mm and 16mm. The connecting part of the support column and the radiation patch adopts chamfer transition to increase the contact area and increase the reliability of the structure.

The radiation patch adopts a circular metal sheet. The application of the patch on the radiation can broaden the working frequency band, improve the directivity, and improve the isolation between ports. The bottom patch mainly realizes power feeding.

In order to achieve antenna gain coverage, the antenna of the present invention can be formed into a 1×4 linear array of antennas, as shown in FIG. 1 , the distance between adjacent antennas is the same and is 0.5 to 0.8 times the working wavelength of the antenna. Compared with the beamforming array, the structure of the array is simple, and the four units are fed with equal amplitude and phase, which reduces the complexity of the feed network and can better ensure the broadband characteristics of the antenna. Due to the stable wide-angle domain phase center characteristics of the antenna unit, the phase center characteristics of the array within a certain angle range are guaranteed.

Example:

1. The cavity height of the reflection cavity 1 is 35mm, and the cavity diameter is 160mm;

2. The diameter of patch 3 on the radiating surface is 68 mm, and the thickness is 2 mm. There are four circular holes evenly distributed along the same circle on the radiating surface patch. The diameter of the circular holes is 6 mm. ;

3. The height of the first support column 6 is 15mm, and the diameter is 10mm. The height of the second support column 7 is 16mm, and the diameter is 10mm; The lower patch 2 is threaded and crimped through the first support column 6 and the second support column 7;

4. Four feeding probe sleeves 4 are uniformly distributed on the circumference, with a diameter of 46mm. The four supporting columns of the feeding probe sleeves (the metal column at one end of the metal seat 42) are metal cylinders with a height of 8mm and a diameter of 3mm. The barrel (cylindrical cavity at one end of the metal seat 42) is a metal cylindrical cavity with a height of 6 mm, an inner diameter of 6 mm, and an outer diameter of 8 mm. The inner cores 5 of the four feeding probes have a diameter of 2 mm and a height of 8.5 mm;

5. The array is a 1×4 linear array, and the spacing between each unit is equal, and the spacing is 170mm.

After a large number of simulations and processing tests, the antenna of this embodiment can fully cover the frequency range of GPS, BD-2, GALILEO and GLONASS, and within the range of -35 degrees to +35 degrees in the line array direction, the vertical line array direction is -8 degrees The stability of the phase center to +8 degrees is ≤2mm, the gain is higher than 10dB, and the axial ratio is smaller than 3dB, which is better than the existing occultation antenna.

Claims (6)

1. a stable occultation antenna with a multimode phase center, is characterized in that: comprise reflection chamber (1), patch (2) under radiation, patch (3) on radiation, four feeding probe sleeves ( 4), four feed probe inner cores (5), the first support column (6) and the second support column (7); the feed probe sleeve (4) also includes a metal seat (42) and Filler (41), one end of metal seat (42) is a metal column, and the other end is a metal cylinder cavity, and filler (41) fills up the cylinder cavity of metal seat (42) and the top of filler (41) The surface is higher than the top of the cylindrical cavity; The reflection cavity (1) is a metal hollow cylindrical cavity with a closed bottom surface, the second support column (7) is a metal cylinder, and the second support column (7) is installed in the reflection cavity (1) The position of the center of the bottom surface of the inner cavity, the center of the bottom surface of the second support column (7) is aligned with the center of the bottom surface of the inner cavity of the reflection cavity (1), and the radiation patch (2) is a circular metal sheet and installed On the top of the second support column (7), the radiation lower patch (2) is concentric with the second support column (7), and the height of the radiation lower patch (2) is lower than the cavity of the reflection cavity (1) Height; the first support column (6) is a metal cylinder and is installed on the radiation lower patch (2), concentric with the radiation lower patch (2); the radiation upper patch (3 ) is a circular metal sheet and is installed on the top of the first support column (6), concentric with the first support column (6) and the radiation upper patch (3) is higher than the cavity of the reflection cavity (1) body height; The metal pillars at one end of the four metal seats (42) are fixed on the bottom surface of the inner cavity of the reflection cavity (1) and are evenly distributed on the same circumference with the center of the bottom surface of the inner cavity of the reflection cavity (1) as the center. The filling (41) in the cylindrical cavity of the seat (42) is in contact with the patch (2) under radiation; The four feeding probe inner cores (5) vertically pass through the sub-radiation patch (2) and are inserted into the filler (41), and the feeding probe inner cores (5) and the metal seat (42 ) are electrically isolated; the feeding probe inner core (5) is fixedly installed between the radiation patch (2), and the feeding probe inner core (5) is concentric with the metal seat (42); The uniformly distributed circumference of the feeding probe sleeve (4) has a diameter between 44mm and 48mm, and the height of the metal post at one end of the metal seat (42) of the feeding probe sleeve (4) is between 7mm and 48mm. 9mm, the height of the cylindrical cavity part of the metal seat (42) is between 5mm and 7mm; The inner core (5) of the feeding probe has a diameter between 1.5mm and 3mm and a length between 8mm and 10mm. 2. A multi-mode phase center stable occultation antenna according to claim 1, characterized in that: the diameter of the radiation patch (3) is between 68mm and 72mm, and the thickness is between 1mm and 3mm. 3. The occultation antenna with multi-mode phase center stabilization according to claim 1, characterized in that: the diameter of the radiation patch (2) is between 99mm and 101mm, and the thickness is between 1mm and 3mm. 4. The occultation antenna with multi-mode phase center stabilization according to claim 1, characterized in that: the height of the first support column (6) is between 14mm and 16mm. 5. The multi-mode phase center stable occultation antenna according to claim 1, characterized in that: the height of the second support column (7) is between 15 mm and 17 mm. 6. The occultation antenna with multi-mode phase center stabilization according to claim 1, characterized in that: the filler (41) is made of polyimide.

Images