CN102544722A - Polarization reconfigurable high-gain panel antenna - Google Patents

Abstract

The invention provides a polarization reconfigurable high-gain panel antenna. 21dBi gain can be achieved and aperture efficiency can achieve 70% by only one feed antenna; and furthermore, by switching control, the polarization state of the antenna can be converted between left-hand circular polarization and right-hand circular polarization, a complex feed network and a control circuit are eliminated, and the polarization reconfigurable high-gain panel antenna has the advantages of simple feed, low loss, high efficiency, easiness in control and high polarization purity.

Description

Polarization Reconfigurable High Gain Panel Antenna

technical field

The invention relates to a polarization reconfigurable high-gain panel antenna, in particular to a polarization-reconfigurable high-gain panel antenna with simple structure, low cost, and easy realization and control.

Background technique

With the increasing requirements of modern radar and communication systems, antenna systems are becoming more and more complex, and it is of great significance to reduce the number, size and weight of antennas. In order to achieve this goal, people have proposed the concept of reconfigurable antennas in recent years. At present, PIN diode switches, optical control devices, RF microwave MEMS switches and other methods are mainly used to control and change the aperture and structure of the antenna to achieve frequency, pattern and polarity. The reconstruction of the way of transformation and so on. The polarization reconfigurable antenna is a kind of reconfigurable antenna, which can reconfigure the polarization state of the electromagnetic wave radiated by the antenna, and can meet the requirements of different wireless communication systems. Polarization reconfigurable antennas can also eliminate the adverse effects of signal fading caused by multipath effects on wireless communication systems. In addition, the use of polarization diversity technology can also improve spectrum utilization and increase the capacity of communication systems, which is of great significance in modern communication systems.

Most of the existing polarization reconfigurable antennas adopt a microstrip structure, but a single microstrip polarization reconfigurable antenna has a gain of only 6-9 dB due to the limitation of its radiation aperture. If the gain is increased by the traditional way of forming an array, the feed network and control circuit will be very complicated. On the one hand, a complex feed network will cause large antenna loss and reduce antenna efficiency, and on the other hand, it will increase the difficulty of layout. However, complex control circuits will cause low polarization purity due to the inevitable delay between array elements. Therefore, how to realize a polarization-reconfigurable high-gain antenna with simple structure, low cost, and easy control is an urgent problem to be solved.

Contents of the invention

The invention provides a polarization reconfigurable high-gain planar antenna with simple structure, low cost and easy control. Switching between left-handed circular polarization and right-handed circular polarization can be realized by controlling the switch state. The maximum gain of the antenna is 21dBi, the aperture efficiency is 70%, and the 3dB axial ratio bandwidth is 1.5%.

The technical solution adopted:

A polarization reconfigurable high-gain panel antenna includes a dielectric cover 1 , a frequency selective surface 2 , a polarization reconfigurable feed antenna 3 and a floor 4 . The dielectric cover 1 is on the top, the frequency selective surface 2 is located on the lower surface of the dielectric cover, and the polarization reconfigurable feed antenna 3 is located on the floor 4; the frequency selective surface 2 is arranged in the same period but the size is gradually changed; the feed antenna 3. It includes a dielectric board 3-1 and a radiation patch 3-2. There are two mutually orthogonal slots 3-3 on the radiation patch. There is a control switch 3-4 in the middle of each slot. The radiation patch is composed of Coaxial inner conductor 3-5 excitation.

this invention:

Using the polarization reconfigurable feed antenna 3, on the square microstrip patch antenna, open two slots 3-3 with the same size and orthogonal to each other at appropriate positions, and there is a switch 3-4 in the middle of each slot . By controlling the states of the switches 3-4, the flow directions of the currents of the two orthogonal components can be controlled, thereby realizing the conversion between left-handed and right-handed circular polarization. Only one feed antenna is needed to achieve a gain of 21dBi, eliminating the need for complex feed networks and control circuits.

Frequency selection surface 2 with a gradient. The frequency selective surface consists of square metal patches with the same period and gradually changing sizes. Compared with the arrangement with the same size, this type of arrangement can make the gain change more smoothly with frequency on the one hand and broaden the gain bandwidth, and on the other hand can make the impedance change more gentle and thus widen the standing wave bandwidth. The frequency selective variable surface is located at an appropriate position above the floor 4, and plays a role of partial reflection and partial transmission. The electromagnetic waves radiated by the feeding antenna 3 are reflected multiple times between the frequency selective surface 2 and the floor 4 and finally superimposed and radiated out in the same phase to form a high gain.

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

1. Simple feeding, low loss and high efficiency. The invention only needs one feeding antenna to achieve a gain of 21dBi, and simultaneously the aperture efficiency reaches 70%. Compared with the array antenna, the complex feed network is omitted, the loss is reduced, and the aperture efficiency is improved.

2. Easy to control, high polarization purity. The invention only needs a control circuit of one unit, and compared with the variable polarization array antenna, it saves complicated control circuits, avoids the problem of unavoidable delay between control circuits, and improves the polarization purity.

3. Simple structure, flat structure, low cost. The invention only needs ordinary microstrip antenna processing technology, simple structure, low cost, and flat plate structure, which is easy to transport and assume.

Description of drawings

Fig. 1 is a schematic perspective view of the present invention.

Fig. 2 is an exploded schematic view of the present invention.

Figure 3 is a side view of the present invention.

Figure 4 is a schematic diagram of a frequency selective surface.

Fig. 5 is a perspective schematic diagram of a polarization reconfigurable feed antenna structure.

Fig. 6 is a top view of a polarization reconfigurable feed antenna structure.

Fig. 7 is the reflection loss curves in the states of left-handed circular polarization and right-handed circular polarization.

Fig. 8 is a curve of gain changing with frequency in the state of left-handed circular polarization and right-handed circular polarization.

Fig. 9 is a curve of axial ratio changing with frequency in the state of left-handed circular polarization and right-handed circular polarization.

Fig. 10 is the direction diagram of the center frequency when the antenna works in the left-handed state.

Fig. 11 is the direction diagram of the center frequency when the antenna works in the right-handed state.

Detailed ways

A polarization reconfigurable high-gain panel antenna includes a dielectric cover 1 , a frequency selective surface 2 , a polarization reconfigurable feed antenna 3 and a floor 4 . The dielectric cover 1 is on the top, the frequency selective surface 2 is located on the lower surface of the dielectric cover, and the polarization reconfigurable feed antenna 3 is located on the floor 4; the frequency selective surface 2 is arranged in the same period but the size is gradually changed; the feed antenna 3. It includes a dielectric board 3-1 and a radiation patch 3-2. There are two mutually orthogonal slots 3-3 on the radiation patch. There is a control switch 3-4 in the middle of each slot. The radiation patch is composed of Coaxial inner conductor 3-5 excitation.

The dielectric substrate and the feed antenna dielectric substrate have a dielectric constant of 2.65 and a thickness of 1mm. The distance H between the dielectric substrate and the floor was 13.8 mm. Both the dielectric substrate and the floor are square in shape and the same size, W=96mm. The frequency selection surface is symmetrically distributed on the dielectric substrate as square metal patches with gradient sizes, and the period ZQ=8mm, W1=7.7mm, W2=7.3mm, W3=6.9mm, W4=6mm, W5=5mm, W6=4mm. The dimensions of the polarization reconfigurable feed antenna are: the feed medium is square, JW=10mm, the patch is square, PW=6.4mm, the slot length FL=4.9mm, the width FW=0.3mm, the slot position FP= 2.1mm, the position of coaxial inner conductor feeding OFF=2.1mm.

Figure 7 is a reflection loss curve, Figure 8 is a curve of gain versus frequency, and Figure 9 is a curve of axial ratio versus frequency. Figure 10 and Figure 11 are the direction diagrams of the center frequencies of the antenna working in the left-handed and right-handed states respectively. It can be seen from Fig. 10 and Fig. 11 that whether it is left-handed circular polarization or right-handed circular polarization, the pattern has high gain and excellent radiation characteristics with good cross-polarization. The maximum gain is 21.2dBi, the aperture efficiency is 70%, the minimum axial ratio is 0.5dB, and the 3dB axial ratio bandwidth is 1.5%.

Claims (5)

1. A polarization reconfigurable high-gain panel antenna, comprising: a dielectric cover plate (1), a metal frequency selective surface (2), a polarization reconfigurable feed antenna (3) and a floor (4), its characteristics in: The dielectric cover (1) is at the top, the frequency selective surface (2) is located on the lower surface of the dielectric cover (1), and the polarization reconfigurable feed antenna (3) is located on the floor (4); the frequency selective surface (2) , are arranged in the same period, but the size is gradually changed; the feed antenna (3) includes a dielectric plate (3-1), a radiation patch (3-2), and two mutually orthogonal There are slots (3-3), a control switch (3-4) in the middle of each slot, and the radiation patch is excited by the coaxial (3-5). 2. The polarization reconfigurable high-gain panel antenna according to claim 1, characterized in that the size of the dielectric cover (1) is the same as that of the floor (4). 3. The polarization reconfigurable high-gain panel antenna according to claim 1 is characterized in that the frequency selective surface (2) adopts the same cycle and a metal square patch structure with gradual changes in patch size, and the size of the innermost circle is the largest , the size of the outermost ring is the smallest, and the frequency selective surface can partially reflect electromagnetic waves in the frequency band. 4. The polarization reconfigurable high-gain panel antenna according to claim 1, characterized in that the distance between the dielectric cover (1) and the floor (4) is about half of the working wavelength. 5. The polarization reconfigurable high-gain panel antenna according to claim 1 is characterized in that the feed antenna (3) is a polarization reconfigurable microstrip patch antenna, and is located in the middle of two orthogonal slots by controlling The state of the switch (3-4) can realize that the antenna works in the state of left-handed circular polarization or right-handed circular polarization.

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