CN203747043U - A Circularly Polarized High Gain Low Profile Resonant Antenna - Google Patents

Abstract

The utility model discloses a circularly-polarized high-gain low-profile resonant antenna comprising a resonant cavity and a linearly-polarized feed source located in the resonant cavity. The resonant cavity comprises a metal plate and a dielectric substrate which are arranged in a parallel manner. The metal plate is periodically provided with a plurality of cross slits to form a partially-reflective surface in two orthogonal directions. The upper surface of the dielectric substrate which is opposite to the metal plate is periodically provided with a plurality of rectangular metal patches to form an artificial magnetic conductor in two orthogonal directions. The lower surface of the dielectric substrate is provided with an earth plate. The metal plate, the dielectric substrate and the earth plate are connected and fixed through fasteners. The circularly-polarized high-gain low-profile resonant antenna provided in the utility model can be used to solve the problem of complex feed and the problem that the antenna performance is influenced by unit mutual coupling because the feed network and unit array mode is adopted with existing high-gain circularly-polarized antennas.

Description

A Circularly Polarized High Gain Low Profile Resonant Antenna

technical field

The utility model relates to a high-gain antenna, in particular to a circularly polarized high-gain low-profile resonant antenna.

Background technique

Modern radar, satellite communication and other fields usually require the use of circularly polarized antennas with higher gain. A feed network is usually required to achieve the amplitude and phase conditions of circular polarization. On the other hand, in order to achieve higher gain, an array of elements is usually used, so the problem is that the feeding is complex and the mutual coupling between elements affects the performance of the antenna.

Contents of the invention

Purpose of the invention: In order to overcome the deficiencies in the prior art, the utility model provides a circularly polarized high-gain low-profile resonant antenna, which solves the problem that the existing high-gain circularly polarized antenna uses a feeding network and a unit array , which brings complex feeding and mutual coupling between elements affects the performance of the antenna.

In order to solve the problems of the technologies described above, the technical solution adopted in the utility model is:

A circularly polarized high-gain low-profile resonant antenna includes a resonant cavity and a linearly polarized feed source located in the resonant cavity. The resonant cavity includes a metal plate and a dielectric substrate arranged in parallel to each other. A number of cross-shaped gaps are periodically arranged in the orthogonal direction to form a part of the reflective surface, and a number of rectangular metal patches are periodically arranged in two orthogonal directions on the upper surface of the dielectric substrate opposite to the metal plate to form an artificial magnetic conductor. The grounding plate, the metal plate, the dielectric substrate and the grounding plate are connected and fixed by fasteners.

The period lengths of the cross-shaped slits forming part of the reflective surface are equal in two orthogonal directions; the lengths of the two orthogonal slits forming the cross-shaped slits are unequal and the widths are equal.

The rectangular metal patch constituting the artificial magnetic conductor has different period lengths in two orthogonal directions, and the period length in the short side direction of the rectangular metal patch is smaller than the period length in the long side direction.

The polarization direction of the linearly polarized feed source forms an included angle of 45° with the long side or short side direction of the rectangular metal patch.

The distance between the ground plate and the partially reflecting surface satisfies the condition of d=(1/4+n/2) _λ0 , where _λ0 is the free-space wavelength of the center frequency electromagnetic wave, n=0,1,2.. ..

The beneficial effects of the utility model: 1. Compared with the existing circularly polarized antenna, the utility model eliminates the feeding network of the traditional circularly polarized antenna, and the longitudinal size is small, and the structure is simpler; 2. The utility model adopts partial reflection The surface and the artificial magnetic conductor parallel to the part of the reflective surface form a resonant cavity, and the gain can be significantly improved without using an array structure by utilizing the resonance characteristics; The direction of the long side or short side of the metal patch is at an angle of 45 degrees, that is, the electromagnetic wave radiated by the linearly polarized feed can always be decomposed into two polarized orthogonal electromagnetic waves, whose directions are respectively parallel to the long side of the rectangular metal patch Together with the short side, the partially reflective surface composed of cross-shaped gaps and the artificial magnetic conductor composed of rectangular metal patches form a resonant cavity, which respectively provide a suitable reflection phase difference between two polarized orthogonal electromagnetic waves, which can be adjusted by The length of the cross-shaped metal gap along the two-dimensional direction is used to adjust the reflection phase frequency response of part of the reflective surface, and the reflection phase frequency response of the artificial magnetic conductor is adjusted by adjusting the length of the long side and short side of the rectangular metal patch, so as to realize the linear polarity The polarized wave is transformed into a circularly polarized wave, achieving low profile and high gain at the same time.

Description of drawings

Fig. 1 is the overall structure schematic diagram of the present utility model.

Fig. 2 is a side view of the utility model.

FIG. 3 is a structural schematic diagram of a partially reflective surface of the present invention.

FIG. 4 is a schematic structural view of a partially reflective surface periodic unit of the present invention.

Fig. 5 is a schematic structural view of the artificial magnetic conductor of the present invention.

Fig. 6 is a schematic structural view of the artificial magnetic conductor periodic unit of the present invention.

Fig. 7 is a schematic diagram of the position of the linearly polarized feed.

Fig. 8 is a curve diagram of reflection coefficient of the present utility model.

Fig. 9 is a curve diagram of axial ratio frequency response of the present invention.

Fig. 10 is a gain frequency response curve diagram of the utility model.

Fig. 11 is a horizontal direction diagram of the utility model.

Fig. 12 is a vertical direction diagram of the utility model.

Detailed ways

Below in conjunction with accompanying drawing, the utility model is described further.

As shown in Figures 1, 2, 3 and 5, a circularly polarized high-gain low-profile resonant antenna includes a resonant cavity 2 and a linearly polarized feed 1 located in the resonant cavity 2, and the resonant cavity 2 includes mutual The metal plate 22 and the dielectric substrate 21 are arranged in parallel, and several cross-shaped slits 23 are periodically arranged on the two orthogonal directions of the metal plate 22 to form a partial reflection surface. A plurality of rectangular metal patches 24 are periodically arranged in the orthogonal direction to form an artificial magnetic conductor, and a ground plate 25 is arranged on the lower surface of the dielectric substrate 21, and the distance between the ground plate 25 and a part of the reflective surface satisfies d=(1/4+n/2 ) condition of λ ₀ , wherein λ ₀ is the free-space wavelength of the central frequency electromagnetic wave, n=0,1,2..., the metal plate 22, the dielectric substrate 21 and the ground plate 25 are connected and fixed by the fastener 26.

As shown in Figure 4, the period lengths of the cross-shaped slits 23 forming part of the reflective surface are equal in two orthogonal directions, both being P, and the lengths of the two orthogonal slits forming the cross-shaped slits 23 are respectively S _x and S _y , the widths are both S _w , and the gap lengths are not equal.

As shown in Figure 6, the period lengths of the rectangular metal patch 24 forming the artificial magnetic conductor are not equal in two orthogonal directions, and the period length P _y of the short side direction of the rectangular metal patch 24 is less than the period of the long side direction Length P _x , where P _x is 0.2-0.3 times the free space wavelength of the central frequency electromagnetic wave, and the lengths of the long and short sides of the rectangular metal patch 24 are l _x and _ly , respectively.

The polarization direction of the linearly polarized feed source 1 of the above-mentioned resonant antenna forms an included angle of 45° with the long side or short side direction of the rectangular metal patch 24, that is, the electromagnetic wave radiated by the linearly polarized feed source can always be decomposed into two Two polarized orthogonal electromagnetic waves, whose directions are respectively parallel to the long side and short side of the rectangular metal patch 24, the partial reflection surface formed by the cross-shaped slit 23 and the artificial magnetic conductor formed by the rectangular metal patch 24 together form a resonant cavity 2. The two respectively provide a suitable reflection phase difference between two polarized orthogonal electromagnetic waves. The reflection phase frequency response of a part of the reflection surface can be adjusted by adjusting the length of the cross-shaped slit 23 along the two-dimensional direction. By adjusting the rectangular metal The lengths of the long side and the short side of the patch 24 are used to adjust the reflection phase frequency response of the artificial magnetic conductor, so as to convert linearly polarized waves into circularly polarized waves, while achieving low profile and high gain.

In order to facilitate the description of the design process of each structural parameter, the given structural parameters: l _x = 4mm, _ly = 2.5mm of the rectangular metal patch 24, the period length P _x = 5mm along the long side direction, and the period along the short side direction Length P _y =3.6mm, period length P=11mm of cross-shaped slot 23, S _x =10.5mm, S _y =7.2mm, slot width S _w =2mm, center frequency f=14GHz, ground plate 25 and partially reflective surface The distance between them is 5.5mm, satisfying: Where λ ₀ is the free space wavelength of the center frequency electromagnetic wave. Select simulation software such as HFSS from Ansoft Company, Microwave Studio CST from CST Company and other high-frequency simulation software, and simulate on the computer to obtain: the reflection coefficient curve shown in Figure 8, and the axial ratio frequency response curve shown in Figure 9 , the gain frequency response curve shown in FIG. 10 , the horizontal plane direction diagram shown in FIG. 11 , and the vertical plane direction diagram shown in FIG. 12 . The curves obtained above are obtained under given conditions, and similar curves can also be obtained by changing the structural parameters.

In order to facilitate circular polarization, the linearly polarized feed source 1 of the present utility model can be composed of a microstrip patch or its modified structure. The linearly polarized feed source 1 of this structure is attached to the dielectric substrate 21 opposite to the metal plate 22. On the upper surface, the rest of the upper surface of the dielectric substrate 21 is periodically arranged with several rectangular metal patches 24 along the long and short sides of the rectangle, as shown in FIG. 7 .

The above is only a preferred embodiment of the utility model, it should be pointed out that for those of ordinary skill in the art, without departing from the principle of the utility model, some improvements and modifications can also be made. Retouching should also be regarded as the scope of protection of the present utility model.

Claims (6)

1. the low section resonant antenna of the high-gain of a circular polarization, it is characterized in that: the linear polarization feed (1) that comprises resonant cavity (2) and be arranged in resonant cavity (2), described resonant cavity (2) comprises metallic plate (22) and the medium substrate (21) being arranged in parallel, on two orthogonal directions of metallic plate (22), the cycle arranges some crosss gap (23) component part reflecting surface, on two orthogonal directions of medium substrate (21) upper surface relative with metallic plate (22), the cycle arranges some rectangular metal pasters (24) formation artificial magnetic conductor, lower surface at medium substrate (21) arranges ground plate (25), described metallic plate (22), medium substrate (21) and ground plate (25) are connected and fixed by securing member (26).

2. the low section resonant antenna of the high-gain of a kind of circular polarization according to claim 1, is characterized in that: the Cycle Length of the cross gap (23) of described component part reflecting surface on two orthogonal directions equates.

3. the low section resonant antenna of the high-gain of a kind of circular polarization according to claim 2, is characterized in that: the length in two quadrature gaps in described formation cross gap (23) is unequal, and width equates.

4. the low section resonant antenna of the high-gain of a kind of circular polarization according to claim 1, it is characterized in that: not etc., the Cycle Length of rectangular metal paster (24) short side direction is not less than the Cycle Length of long side direction to the Cycle Length of the rectangular metal paster (24) of described formation artificial magnetic conductor on two orthogonal directions.

5. according to the low section resonant antenna of the high-gain of a kind of circular polarization described in claim 1 or 4, it is characterized in that: the long limit of the polarised direction of described linear polarization feed (1) and rectangular metal paster (24) or short side direction angle at 45 °.

6. the low section resonant antenna of the high-gain of a kind of circular polarization according to claim 1, is characterized in that: the distance between described ground plate (25) and part reflecting surface meets d=(1/4+n/2) λ ₀condition, λ wherein ₀centered by the electromagnetic free space wavelength of frequency, n=0,1,2....