CN104300203A - Circularly polarized microstrip patch antenna with slot radiation fed by L-waveband microstrip - Google Patents

Abstract

The invention designs a circularly polarized microstrip patch antenna for L-band microstrip feeding slot radiation, belongs to the field of antenna engineering, and is characterized in that it includes a metal reflector (1), and a microstrip line (2) is used to connect a grounded metal plate. The slot (3) on the feed, the parasitic patch (4), and the dielectric plates (5) and (6). The invention is an L-band microstrip patch antenna that realizes circular polarization by rotating the patch angle and using a slot coupling method. The antenna is novel and ingenious in design, light and small in overall size, easy to move, high in gain to meet the requirements of communication with satellites after forming an array, compact in structure, and easy to process, so that the present invention has high market potential.

Description

A circularly polarized microstrip patch antenna for L-band microstrip fed slot radiation

technical field

The invention belongs to the technical field of antenna engineering, in particular to a satellite ground station antenna.

Background technique

The classification of ground station antennas is generally divided into two categories: one is omnidirectional antenna; the other is directional antenna, which is the mainstream antenna of mobile satellite communication ground station antenna.

The omnidirectional antenna of the communication ground station can be divided into the following forms: the first is the microstrip antenna. A circular microstrip antenna excited by signals with a 90° difference in space and phase can realize a circularly polarized radiation pattern with good rotational symmetry, which is realized by a double-layer microstrip antenna formed by two circular patches Broadband and Dual Band. The second is the cross-slot antenna, which can achieve a circularly polarized wide beam pattern. This antenna radiates through the crossed slots at the top of the cavity. The third antenna form is the cross-droop dipole antenna, which achieves circular polarization by exciting signals with equal amplitude and a phase difference of 90° on mutually orthogonal symmetrical dipoles. This antenna can be improved by changing the shape of the dipole arm. Its beam and axial ratio. The fourth type of antenna is a resonant quadrifilar helical antenna whose radiation principle is similar to that of the third type. This type of antenna improves electrical performance by winding its dipole arms identically into a helical shape and adjusting its physical size. Because the working frequency band of this antenna is narrow and it is not easy to broaden, an eight-arm helical antenna was designed by improving its structure and feeding method. It not only has the advantages of the quadrifilar helical antenna but also can realize wide-band and dual-band characteristics.

For directional antennas, it can also be divided into four categories: the first type of mechanical scanning antenna, which aligns the main lobe beam of the antenna with the communication satellite by changing the position of the antenna array, and it controls the stepping motor To achieve beam tracking, this type of antenna has a simple structure and low cost, but its tracking speed is slow, its reliability is low and its antenna profile is high. Later, in order to solve the problem of slow tracking speed, a second type of directional antenna, which uses electrical scanning instead of mechanical scanning, appeared—beam switching antenna. However, the gain of this type of antenna is relatively low, and there are beam coverage blind spots to a certain extent. The third category is the software antenna, which converts the microwave signal into a digital baseband signal through some methods, and then processes it to form the required beam. But this kind of antenna design technology is not mature enough, and the equipment is complicated. The fourth category is the phased array antenna. This type of antenna was first used in military radar. It has the advantages of good electrical performance, fast tracking speed, high reliability and easy carrier conformal installation.

The present invention uses a slot-coupled microstrip antenna structure, which adopts a new feeding method: coupled feeding. The mechanism is to feed power through the electromagnetic coupling between the microstrip line and the slot on the metal ground plate. This antenna has two outstanding advantages. First, for the traditional coaxial probe feed, welding must be carried out between the patch and the feed line, while the gap coupling method avoids the antenna performance caused by welding. It is more favorable for the feed form of large microstrip antenna array. Second, the gap-coupled microstrip structure avoids punching holes on the substrate and facilitates processing.

Contents of the invention

The present invention designs an L-band microstrip patch antenna that realizes circular polarization by rotating the patch angle and using a slot coupling method. The antenna is novel and ingenious in design, light and small in overall size, easy to move, high in gain to meet the requirements of communication with satellites after forming an array, compact in structure, and easy to process, so that the present invention has high market potential.

Description of drawings:

Fig. 1 is the front view three-dimensional figure of the circularly polarized patch antenna of the present invention-L band slot coupling feed

Fig. 2 is the three views of the circularly polarized patch antenna of the present invention-L band slot coupling feed

Fig. 3 is the circularly polarized patch antenna standing wave coefficient VSWR of the present invention-L band slot coupling feed

Fig. 4 is the azimuth plane (H plane) and the elevation plane (E plane) direction diagram of the circularly polarized patch antenna of the present invention-L band slot coupling feed under the Cartesian coordinate system

Fig. 5 is the axial ratio direction diagram of the circularly polarized patch antenna of the present invention-L band slot coupling feed

Fig. 6 is the front view of the antenna array composed of circularly polarized patch antennas fed by the L-band slot coupling feed of the present invention

Fig. 7 is each port standing wave coefficient VSWR of the antenna array formed by the circularly polarized patch antenna of the present invention-L band slot coupling feeding

Fig. 8 is the central frequency point pattern characteristic of the antenna array formed by the circularly polarized patch antenna of the present invention-L band slot coupling feed

Fig. 9 is the central frequency point axial ratio characteristic of the antenna array formed by the circularly polarized patch antenna of the present invention-L band slot coupling feed

specific implementation plan

Figures 1 and 2 depict specific embodiments of the invention. As shown in Figures 1 and 2, the unit antenna of this antenna array includes a metal reflector (1), a microstrip line (2) feeding the gap (3) on the grounded metal plate (7), and a parasitic patch (4) , and dielectric plates (5) and (6).

The dimensions of the two dielectric plate substrates of the microstrip patch antenna are 120mm×90mm×1mm, the dielectric constant of the dielectric substrate is 2.55, and the dimensions of the grounded metal plate and the metal reflector are 120mm×90mm. The size of the parasitic patch is 65.3mm×47.4mm, the rotation angle along the horizontal counterclockwise is 27°, the distance between the two dielectric boards is 20mm, and the size of the microstrip line for feeding is 158.98mm×4.1mm. The size of the slot is 52.8mm×2.45mm, and the distance between the end of the feeding microstrip line and the center of the slot is 7.8mm. The present invention adopts the microstrip line feeding method to feed the microstrip patch antenna. Since it is slit radiation and the antenna is only required to radiate in one direction, a reflective metal plate is added behind the grounded metal plate to ensure the antenna is unidirectional. The characteristics of radiation, in order to widen the bandwidth, we use the method of adding parasitic patches.

We have adopted the HFSS three-dimensional electromagnetic simulation software of Ansoft Company to simulate the present invention.

FIG. 3 is a graph of the standing wave coefficient (VSWR) of the antenna. It can be seen from the figure that within the required frequency band, the input port of the antenna is well matched, and its input standing wave coefficient VSWR<1.06.

Fig. 4 is the direction diagram of the azimuth plane (H plane) and the elevation plane (E plane) of the antenna drawn in the Cartesian coordinate system, wherein the elevation plane is Azimuth is We selected the frequency point of the center frequency for investigation. It can be found that the gain of the present invention reaches above 9dB.

Figure 5 shows the axial ratio characteristics of the antenna. It can be seen from the figure that the axial ratio characteristics of the two planes are less than 4dB within the range of the main lobe width, which conforms to the circular polarization characteristics.

Figure 6 is a planar array of 7*16 elements composed of the antenna.

Figure 7 is the standing wave coefficient curve of each port in the array antenna. It can be seen from the figure that the standing wave coefficient of the antenna is less than 1.26 within the required frequency band.

Figure 8 and Figure 9 show that the gain of the center frequency antenna is 28.42dB, the side lobe is -18.9dB, the main lobe width of the azimuth plane is about 6.12° and the main lobe width of the elevation plane is 7.37°, and its axial ratio characteristic is within the range of the main lobe width within less than 2.65dB.

The array antenna formed by the invention has good antenna indexes, compact structure, easy processing and high designability, so it has strong practicability and competitiveness.

The foregoing descriptions of the present invention and its embodiments are provided to those skilled in the art of the invention and are to be considered illustrative rather than restrictive. Engineers and technicians can implement specific operations based on the ideas in the invention claims, and naturally can also make a series of changes to the implementation plan according to the above. Moreover, the present invention is not limited to the L frequency band, and the structure of the present invention can naturally be transplanted to microstrip patch antennas of other different frequency bands. All of the above should be considered as the scope of the present invention.

The content that is not described in detail in the specification of the present invention belongs to the well-known technology of those skilled in the art.

Claims (5)

1. a kind of circularly polarized microstrip patch antenna of L band microstrip feeding slot radiation, it is characterized in that: comprise metal reflector (1), microstrip line (2) gives the slit on the grounding metal plate (7) (3) Feed, parasitic patch (4), and dielectric plates (5) and (6), the entire microstrip patch antenna has a compact and simple structure and is easy to process. 2. the circularly polarized microstrip patch antenna of a kind of L band microstrip feeding slot radiation according to claim 1, the effect of metal reflector is to allow microstrip patch antenna unidirectional radiation. 3. the circularly polarized microstrip patch antenna of a kind of L band microstrip feeding slot radiation according to claim 1, the broadening of bandwidth can be realized by adding parasitic patch (4), parasitic patch (4) Located 20mm forward of the gap (3). 4. the circularly polarized microstrip patch antenna of a kind of L band microstrip feeding slot radiation according to claim 1, by adjusting the size of the slot (3) and the size of the patch (4) and its relative position, Good working bandwidth can be obtained. 5. The circularly polarized microstrip patch antenna of a kind of L-band microstrip feeding slot radiation according to claim 1, feeds the microstrip patch antenna by microstrip line (2).