CN202695719U - Time reversal subwavelength array antenna used for wireless communication - Google Patents

Abstract

A time-reversal sub-wavelength array antenna for wireless communication belongs to the technical field of antennas. It is formed by stacking multiple identical antenna units, and the distance between two adjacent unit antennas is less than 1/2 of the working wavelength λ. The metal patch on the front of the dielectric substrate includes a peach-shaped radiation unit. The peach-shaped radiation unit is composed of an isosceles triangle metal patch and a semi-elliptical metal patch. There are 26 peach-shaped small holes evenly etched on the radiation unit patch. . The radiating unit is fed by a microstrip line with a characteristic impedance of 50 ohms, and the semi-elliptical metal patch part is connected to the microstrip feeder line through a trapezoidal transition microstrip line. The metal patch on the back of the dielectric substrate is a metal floor, and 14 semi-elliptical small holes are symmetrically etched on the metal floor. The utility model is applied to a time domain communication mobile terminal for time inversion, and the channels of each antenna unit are relatively independent, the adjacent channel interference is extremely low, and the utility model can support higher data transmission rate and higher frequency spectrum utilization rate.

Description

A time-reversal subwavelength array antenna for wireless communication

technical field

The utility model belongs to the technical field of antennas, and relates to an array antenna whose spacing between antenna elements works on a sub-wavelength, in particular to a time-reversal sub-wavelength array antenna for wireless communication terminals.

Background technique

Improving the communication capacity and communication rate of the mobile communication system is the goal pursued by mobile communication. With the continuous growth of personal service requirements, mobile terminals are faced with a huge demand for urgent improvement in communication capacity and communication rate. Designing multiple antenna units on the mobile terminal and increasing the number of independent wireless channels is one of the main means for future mobile communication to improve the communication performance of the mobile terminal.

According to the traditional theory, in order to make the multi-antenna system (array antenna) obtain good space diversity gain and space multiplexing gain, it is required that the distance between antenna elements should not be less than half the working wavelength. If the distance between the antenna units is much smaller than half the working wavelength in a limited space, the coupling between the units will increase, and the correlation of the wireless channels corresponding to each antenna will be greatly improved, resulting in a significant reduction in the communication capacity and communication rate of the mobile terminal system. , seriously impairing the communication quality, thus losing the meaning of introducing a multi-antenna system. Although people have done a lot of research on the miniaturization of the antenna unit, due to the limited size of the mobile terminal platform, it still takes a lot of space to integrate multiple antennas for different channels on the mobile terminal.

With the increasing maturity of time-reversal technology, many problems that cannot be solved by traditional methods can be solved by using the space-time and synchronous focusing characteristics of time-reversal electromagnetic wave self-adaptation. Time reversal (Time Reversal) needs to arrange scatterers near the source to form a multipath channel. After the transmitted signal is scattered by the scatterer, it is received by the time reversal mirror (TRM) placed in the far field, and the received signal is retransmitted after time inversion. The retransmitted signal can then be spatially and temporally focused near the source. In 1991, D.R.Jackson and D.R.Dowling published an article entitled "Phase conjugation in underwateracoustics" (J.Acoust.Soc.Amer., vol.89, pp.171-181). "The focusing characteristic of the transmission case has given the theoretical proof. In 2004, G.lerosey et al. published an article entitled "TimeReversal of electromagnetic waves" (Phys.Rev.Lett., vol.92, pp.1939041), in which the first experiment verified that "time-reversed electromagnetic waves" also have space-time time-focusing feature. In 2007, R. Carminati et al published an article entitled "Theory of the time reversal cavity for electromagnetic fields" (Optics Lett., vol.32, Nov. 2007), in which the dyadic Green's function was used to reverse the "vector electromagnetic wave The focus of " was proved. Also in 2007, G.Lerosey et al published an article entitled "Focusing beyond the diffraction limit with far-field timereversal" in "Science" (Science, vol.315, pp.1119-1122, Feb.2007.), A sub-wavelength array antenna is presented in this paper, which consists of randomly distributed metal wires surrounded by coaxial probes. This array antenna combines time-reversal electromagnetic waves in a closed metal cavity, works at 2.45 GHz, and can exhibit super-resolution focusing characteristics of 1/30 wavelength. These achievements are currently limited to the experimental stage, and the bandwidth of the time-reversal array antenna needs to be improved, but it has initially demonstrated the feasibility of the sub-wavelength super-resolution antenna array.

In 2011, Wang Bingzhong and others proposed "A Time Reversal Subwavelength Array Antenna for Wireless Mobile Terminals" (patent application number: 201110066620.1; application publication date: 2011.06.29; inventors: Wang Bingzhong, Ge Guangding, Zang Rui) , can also exhibit far-field subwavelength super-resolution focusing properties. Compared with the antenna array proposed in the 2007 "Science" article, the array uses a planar monopole as a unit, which has a relatively compact structure and is easy to design and integrate. The unit size (width × height) is 50mm × 55mm, and the operating frequency range is 2.7~6.7GHz, the impedance bandwidth (the value of S11 is less than -10dB or the voltage standing wave ratio VSWR is less than 2) is about 4GHz. However, it can be seen from Figure 4 of the patent specification that the impedance bandwidth of the sub-wavelength array antenna unit invented by it is not large, and not all frequencies corresponding to VSWR are less than 2 in the frequency range of 2.7~6.7GHz, so to a certain extent This limits the applicable range of the working frequency of the array antenna.

The utility model aims at researching the sub-wavelength microstructure antenna array whose channels are independent of each other and whose spacing is far smaller than the wavelength based on the far-field super-resolution focusing characteristics of time-reversal electromagnetic waves, and is a sub-wavelength microstructure antenna array for high-performance mobile terminals The design provides the best array structure, efficient and high-precision design method.

Contents of the invention

In order to effectively reduce the spacing between time-reversal array antenna units and reduce the space volume occupied by the array antenna, the utility model provides a time-reversal sub-wavelength array antenna for wireless communication. The voltage standing wave ratio of the input port of each antenna unit in the working frequency band of the array antenna is less than 2, and the distance between two adjacent array units is less than 1/2 of the working wavelength (the wavelength is calculated based on the center frequency), which has the advantages of small size, low production cost and high performance. Good, easy to integrate advantages.

The technical scheme of the utility model is:

A time-reversal sub-wavelength array antenna for wireless communication, as shown in Figure 1, is formed by stacking multiple identical antenna units, and the distance between two adjacent antenna units is less than 1/2 of the working wavelength λ. Each antenna unit, as shown in Figures 2 and 3, includes a rectangular dielectric substrate and metal patches located on the front and back of the rectangular dielectric substrate.

The front metal patch is shown in Figure 2, including a peach-shaped radiation unit, which is formed by connecting an isosceles triangular metal patch and a semi-elliptical metal patch, wherein the semi-elliptical metal patch The long axis of the isosceles triangle metal patch is equal in length and overlaps with each other; on the peach-shaped radiation unit, 26 peach-shaped small holes are evenly etched from top to bottom, and the shape of the peach-shaped small holes is consistent with the overall The shape of the peach-shaped radiation unit is similar, but the direction is opposite; the lower end of the short axis of the semi-elliptical metal patch in the peach-shaped radiation unit is connected to a section of microstrip feeder line with a characteristic impedance of 50 ohms through a trapezoidal transition microstrip line whose width gradually becomes wider , the end of the microstrip feeder with a characteristic impedance of 50 ohms is located at the center of the short side of the rectangular dielectric substrate.

The metal patch on the back is a metal floor, as shown in Figure 3, which is semi-elliptical in shape; the position of the semi-elliptical metal floor on the back of the rectangular dielectric substrate is the same as the position of the microstrip feeder with a characteristic impedance of 50 ohms on the front of the rectangular dielectric substrate. Corresponding; the long axis of the semi-elliptical metal floor is equal to the width of the rectangular dielectric substrate and coincides with one of the broad sides of the rectangular dielectric substrate, and the height of the semi-elliptical metal floor is less than the microstrip feeder with a characteristic impedance of 50 ohms plus the trapezoidal transition micro The total length of the belt line; 14 semi-elliptical small holes are symmetrically etched in the area near the edge of the elliptical arc on the semi-elliptical metal floor, and the shape of the semi-elliptical small holes is similar to that of the overall semi-elliptical metal floor. But in the opposite direction.

The utility model realizes a high-density integrated sub-wavelength array antenna with high spatial resolution based on the coupling of time-reversed electromagnetic waves between high-density array antenna units and the resonance characteristics near the units, and proposes a mobile terminal with limited space. To achieve an effective solution to the problem of high-density multi-antenna system integration, to explore the design method of a multi-antenna integrated system with spatial super-resolution characteristics in a new generation of high-performance mobile communication networks, in order to improve the spatial multiplexing gain and space diversity of multi-antenna systems Gain and other performance. Compared with the existing mobile terminal antenna system, the sub-wavelength array antenna can support higher data transmission rate, higher spectrum utilization, higher information security and greater flexibility, greatly improving The communication capacity and communication rate of the mobile terminal are determined.

Although the spacing between subwavelength array antenna elements is less than or even much less than half a wavelength, combined with the spatial super-resolution characteristics of time-reversed electromagnetic waves, the mutual coupling between extremely close-distance antennas can be greatly suppressed. In the limited space of the multi-antenna wireless mobile terminal communication system platform, the number of units in the array antenna expands rapidly compared with the number of traditional antenna units, which leads to a rapid increase in communication rate and communication capacity. When the utility model is applied in actual communication, it does not need to perform complex processing on the signal, and only simple inversion processing can display super-resolution characteristics. The whole process is convenient to realize and easy to realize in engineering.

In particular, it should be pointed out that due to the adaptive space and time focusing characteristics of time-reversed electromagnetic waves, the focusing effect is better when the multipath is more abundant and the environment is more complex. The sub-wavelength multi-antenna array designed by the utility model has strong flexibility, can be used in various complex environments (including mountainous areas, rivers, forests, cities and suburbs), and can make full use of the multipath signals in complex environments. , using the coupling and local resonance characteristics between antenna elements is more conducive to high-speed, large-capacity, high-reliability, and high-security communications in complex environments.

To sum up, the utility model is applied in the mobile terminal of the time domain communication system, and uses the time inversion technology to directly invert the time domain signal, so that each channel in the multi-antenna system remains relatively independent and the mutual coupling is small. The adjacent channel interference is extremely low, which can support higher data transmission rate, higher spectrum utilization, higher information security and greater flexibility, which greatly improves the communication capacity and communication rate of mobile terminals. This ensures communication quality during multi-antenna, high-capacity communication.

Description of drawings

Fig. 1 is a schematic diagram of the structure of the array antenna provided by the present invention.

Fig. 2 is a schematic front view and dimensions of the antenna unit structure of the array antenna provided by the present invention.

Fig. 3 is a schematic view of the back of the structure of the antenna unit of the array antenna provided by the present invention and the dimensions are marked.

Fig. 4 is the simulation result of the voltage standing wave ratio of the input port of the array antenna unit structure provided by the utility model.

Fig. 5 is the simulation result of the far-field radiation pattern of the antenna unit of the array antenna provided by the present invention at a frequency of 4 GHz.

Fig. 6 is the simulation result of the far-field radiation pattern of the antenna unit of the array antenna provided by the present invention at a frequency of 5.5 GHz.

Fig. 7 is the simulation result of the far-field radiation pattern of the antenna unit of the array antenna provided by the present invention at a frequency of 6 GHz.

Fig. 8 is the super-resolution test result of the array antenna array provided by the present invention.

Detailed ways

A time-reversal sub-wavelength array antenna for wireless communication, as shown in Figure 1, is formed by stacking multiple identical antenna units, and the distance between two adjacent antenna units is less than 1/2 of the working wavelength λ. Each antenna unit, as shown in Figures 2 and 3, includes a rectangular dielectric substrate and metal patches located on the front and back of the rectangular dielectric substrate.

The front metal patch is shown in Figure 2, including a peach-shaped radiation unit, which is formed by connecting an isosceles triangular metal patch and a semi-elliptical metal patch, wherein the semi-elliptical metal patch The long axis of the isosceles triangle metal patch is equal in length and overlaps with each other; on the peach-shaped radiation unit, 26 peach-shaped small holes are evenly etched from top to bottom, and the shape of the peach-shaped small holes is consistent with the overall The shape of the peach-shaped radiation unit is similar, but the direction is opposite; the lower end of the short axis of the semi-elliptical metal patch in the peach-shaped radiation unit is connected to a section of microstrip feeder line with a characteristic impedance of 50 ohms through a trapezoidal transition microstrip line whose width gradually becomes wider , the end of the microstrip feeder with a characteristic impedance of 50 ohms is located at the center of the short side of the rectangular dielectric substrate.

The metal patch on the back is a metal floor, as shown in Figure 3, which is semi-elliptical in shape; the position of the semi-elliptical metal floor on the back of the rectangular dielectric substrate is the same as the position of the microstrip feeder with a characteristic impedance of 50 ohms on the front of the rectangular dielectric substrate. Corresponding; the long axis of the semi-elliptical metal floor is equal to the width of the rectangular dielectric substrate and coincides with one of the broad sides of the rectangular dielectric substrate, and the height of the semi-elliptical metal floor is less than the microstrip feeder with a characteristic impedance of 50 ohms plus the trapezoidal transition micro The total length of the belt line; 14 semi-elliptical small holes are symmetrically etched in the area near the edge of the elliptical arc on the semi-elliptical metal floor, and the shape of the semi-elliptical small holes is similar to that of the overall semi-elliptical metal floor. But in the opposite direction.

The value range of the thickness of the dielectric substrate is between 1/20~1/2 of the working wavelength, the relative dielectric constant is 2.2, and the loss tangent is 0.001.

It should be noted that Fig. 2 and Fig. 3 only show a specific embodiment, which is a proof of the technical effect of the utility model, rather than a further limitation of the utility model. According to the description of the technical solutions of the present utility model, those skilled in the art should determine that the present utility model has more similar implementation solutions.

The peach-shaped small hole is spliced by a semi-ellipse with a major axis of 1.6 mm and a minor axis of 1.2 mm and an isosceles triangle with a height of 0.8 mm. The base of the isosceles triangle coincides with the major axis of the semi-ellipse; The major axis of the semi-elliptical hole is 2.0 mm, and the minor axis is 1.6 mm.

As shown in Figure 2: the rectangular dielectric substrate is 35mm long, 33mm wide, and 0.5mm thick, the relative dielectric constant of the dielectric substrate is 2.2, and the loss tangent is 0.001; the microstrip feeder with a characteristic impedance of 50 ohms is 10mm long and 1.6mm wide , the length of the trapezoidal transition microstrip line is 2.75mm, and the width gradually increases from 0.97mm to 1.6mm; The axes are coincident and the height is 12mm; 26 peach-shaped holes are evenly etched on the patch of the peach-shaped radiation unit, and the direction is opposite to that of the peach-shaped radiation unit. The semi-ellipse and the isosceles triangle with a height of 0.8mm are spliced together. The base of the isosceles triangle coincides with the long axis of the semi-ellipse. The 26 peach-shaped holes are divided into 7 rows. The number of holes is 1, 2, 3, 4, 5, 6, 5 in sequence.

The semi-elliptical metal floor has a long axis of 33mm and a short axis of 25mm. There are 14 semi-elliptical small holes symmetrically etched on the patch along the edge of the elliptical arc. The direction is opposite to that of the semi-elliptical metal floor. The semi-elliptical small holes The long axis is 2.0mm, the short axis is 1.6mm, five rows are arranged parallel to the long axis of the semi-elliptical floor, the vertical spacing is 1.5mm, 2mm, 2mm, 2mm, and the horizontal spacing of adjacent small holes on the side of the short axis The order is 4mm, 4mm, 3mm.

See Figure 4, Figure 5, Figure 6 and Figure 7 for the voltage standing wave ratio and far-field radiation direction characteristics of the above-mentioned antenna array unit in the 2GHz-10GHz frequency band.

Figure 4 shows the voltage standing wave ratio of the feed port, and the voltage standing wave ratio must be below 2 within the bandwidth of 3.19-10GHz.

Figure 5 shows the electric field pattern of the E plane of the antenna unit at a frequency of 4GHz.

Figure 6 shows the electric field pattern of the E plane of the antenna unit at a frequency of 5.5 GHz.

Figure 7 shows the electric field pattern of the E plane of the antenna unit at a frequency of 6 GHz.

As shown in Figure 1, four antenna elements form an array, and the antennas are placed face to face, with a spacing of less than half a wavelength, and super-resolution focusing characteristics can be displayed up to 1/40 wavelength. Figure 8 shows the super-resolution characteristics of the antenna array combined with the time-reversal technique. Define the antenna units as antenna units 1, 2, 3, and 4 from top to bottom. Taking antenna No. 2 as an example, when antenna No. 2 sends a signal, TRM extracts its channel characteristics and sends it again. Only antenna No. 2 receives the largest signal amplitude, and the signal amplitude received by other antennas is less than half of that of antenna No. 2. . This means that during communication, the No. 2 antenna is an independent channel, and the No. 2 antenna has little interference to other antennas. The other antennas also have the same status as the No. 2 antenna when communicating. Each antenna represents a mutually independent channel, and there will be little interference to other antennas. It is very convenient to use time-reversal technology for high-speed , High-quality multi-antenna communication.

Compared with the applied invention patent (patent application number: 201110066620.1) described in the background technology, the size of the antenna unit in this utility model patent is only 33mm×35mm, which is smaller in size, and the impedance bandwidth is 6.81GHz, which is wider. It is 1.7 times the impedance bandwidth of the above-mentioned patents, and the application range of the antenna working frequency basically covers the ultra-wideband (UWB) frequency range, which has strong engineering application value. Table 1 lists the comparison of antenna unit parameters between the utility model patent and the above-mentioned invention patents, where λ _L is the working wavelength corresponding to the low-end working frequency of the antenna unit.

Table 1 Comparison of antenna unit parameters between the utility model patent and the applied invention patent

λ _L (mm) Dimensions (width x height) Operating frequency range/impedance bandwidth (GHz) Applied for invention patents 111 0.45λ _L × 0.50λ _L 2.7~6.7/4 This utility model patent 94 0.35λ _L × 0.37λ _L 3.19~10/6.81

Claims (3)

1. A time-reversal sub-wavelength array antenna for wireless communication, which is formed by stacking a plurality of identical antenna units, and the distance between two adjacent antenna units is less than 1/2 of the working wavelength λ; each antenna unit includes a rectangular A dielectric substrate and metal patches located on the front and back of the rectangular dielectric substrate; it is characterized in that: The front metal patch includes a peach-shaped radiation unit, which is formed by connecting an isosceles triangular metal patch and a semi-elliptical metal patch, wherein the long axis of the semi-elliptical metal patch is the same as the isosceles The bases of the triangular metal patches are equal in length and coincide with each other; on the peach-shaped radiation unit, 26 peach-shaped small holes are uniformly etched from top to bottom, and the shape of the peach-shaped small holes is similar to the shape of the overall peach-shaped radiation unit , but in the opposite direction; the lower end of the short axis of the semi-elliptical metal patch in the peach-shaped radiation unit is connected to a microstrip feeder line with a characteristic impedance of 50 ohms through a trapezoidal transition microstrip line whose width gradually becomes wider. The end of the microstrip feeder is located at the center of the short side of the rectangular dielectric substrate; The metal patch on the back is a metal floor with a semi-elliptical shape; the position of the semi-elliptical metal floor on the back of the rectangular dielectric substrate corresponds to the position of the microstrip feeder with a characteristic impedance of 50 ohms on the front of the rectangular dielectric substrate; the semi-elliptical metal The long axis of the floor is equal to the width of the rectangular dielectric substrate and coincides with one broad side of the rectangular dielectric substrate, and the height of the semi-elliptical metal floor is less than the total length of the microstrip feedline with a characteristic impedance of 50 ohms plus the trapezoidal transition microstrip line; There are 14 semi-elliptical small holes symmetrically etched in the area near the edge of the elliptical arc on the semi-elliptical metal floor. The shape of the semi-elliptical small holes is similar to that of the overall semi-elliptical metal floor, but the direction is opposite. 2. The time-reversal sub-wavelength array antenna for wireless communication according to claim 1, wherein the value range of the thickness of the dielectric substrate is between 1/20~1/2 of the working wavelength, and the relative permittivity is 2.2, and the loss tangent is 0.001. 3. The time-reversal sub-wavelength array antenna for wireless communication according to claim 1, characterized in that the rectangular dielectric substrate is 35mm long, 33mm wide, and 0.5mm thick, the relative dielectric constant of the dielectric substrate is 2.2, and the loss tangent is 0.001; the microstrip feedline with a characteristic impedance of 50 ohms is 10mm long and 1.6mm wide, the trapezoidal transition microstrip line is 2.75mm long, and the width gradually increases from 0.97mm to 1.6mm; the long axis of the semi-elliptical patch of the peach-shaped radiation unit is 21mm, the short axis is 12mm, the bottom edge of the isosceles triangle patch coincides with the long axis of the semi-ellipse, and the height is 12mm; 26 peach-shaped small holes are evenly etched on the peach-shaped radiation unit patch, and the direction is opposite to the peach-shaped radiation unit , the peach-shaped hole is spliced by a semi-ellipse with a major axis of 1.6mm and a minor axis of 1.2mm and an isosceles triangle with a height of 0.8mm. The base of the isosceles triangle coincides with the major axis of the semi-ellipse. 26 peaches The peach-shaped holes are divided into 7 rows, and the number of peach-shaped holes in the first row to the seventh row is 1, 2, 3, 4, 5, 6, 5; The semi-elliptical metal floor has a long axis of 33mm and a short axis of 25mm. There are 14 semi-elliptical small holes symmetrically etched on the patch along the edge of the elliptical arc. The direction is opposite to that of the semi-elliptical metal floor. The semi-elliptical small holes The long axis is 2.0mm, the short axis is 1.6mm, five rows are arranged parallel to the long axis of the semi-elliptical floor, the vertical spacing is 1.5mm, 2mm, 2mm, 2mm, and the horizontal spacing of adjacent small holes on the side of the short axis The order is 4mm, 4mm, 3mm.

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