WO2018119929A1 - Electromagnetic multi-input multi-output antenna system and mobile terminal - Google Patents

Abstract

The application relates to the field of radio communication, and specifically, to an electromagnetic multi-input multi-output (MIMO) antenna system and a mobile terminal. The electromagnetic MIMO antenna system comprises a circuit substrate, a first radiation unit and a second radiation unit. The first radiation unit and the second radiation unit are coupled to two opposite sites of the circuit substrate, respectively. One of the first radiation unit and the second radiation unit comprises an electrical antenna, and the other one comprises a magnetic antenna. Since the electrical antenna and the magnetic antenna are orthogonal to each other, isolation between the first radiation unit and the second radiation unit is high, resulting in high performance of the electromagnetic MIMO antenna system.

Description

Electromagnetic multi-input multi-output antenna system and mobile terminal Technical field

The present application relates to the field of wireless communications technologies, and in particular, to an electromagnetic multiple input multiple output antenna system and a mobile terminal.

Background technique

According to the standard requirements of wireless communication (for example, 802.11n, LTE, LTE-A, etc.), terminal devices for wireless communication need to provide multiple antennas to increase the transmission rate of the system and reduce the bit error rate. A multi-electromagnetic multiple-input multiple-output antenna system needs to include at least two antennas operating in the same frequency band, and the performance of a multi-electromagnetic multiple-input multiple-output antenna system largely depends on the degree of coupling between the antennas and the correlation of the signals. . Therefore, for volume-limited wireless communication terminal devices, especially mobile phone devices, multi-electromagnetic multiple-input multiple-output antenna systems often require a balance between performance and volume. Especially for frequency bands with lower operating frequencies, such as GSM850, GSM900 and LTE700, the isolation between multiple antennas is often less than 6dB, and the correlation is often greater than 0.5, which greatly reduces the performance of multi-electromagnetic multiple-input multiple-output antenna systems.

Most of the traditional antennas are electric antennas, that is, the near-field energy storage of the antenna is dominated by the electric field energy storage, and it is easier to couple with the electric field. For mobile phones, the electrical length of the mobile phone substrate is about 1/3 of the wavelength around 1 GHz. Therefore, the electric antenna loaded on the mobile phone substrate is very easy to stimulate the resonance mode of the mobile phone itself. When multiple electrical antennas are used, each antenna simultaneously excites the handset substrate mode, thus causing great coupling and high correlation. Therefore, the conventional technology tends to cause the performance of the electromagnetic multiple input multiple output antenna system to be low.

Summary of the invention

The application provides an electromagnetic multiple input multiple output antenna system and a mobile terminal to improve the performance of an electromagnetic multiple input multiple output antenna system.

A first aspect of the present application provides an electromagnetic multiple input multiple output antenna system including a circuit substrate, a first radiating unit, and a second radiating unit, the first radiating unit and the second spoke The firing units are respectively coupled to opposite sides of the circuit substrate, and one of the two includes an electric antenna, and the other includes a magnetic antenna.

Preferably, the electric antenna includes a first radiator and a feeding microstrip line, the first radiator is coupled to the circuit substrate through the feeding microstrip line, and the first radiator and the The feed microstrip line forms a bent structure.

Preferably, the electric antenna is a monopole electric antenna, and the electric antenna is a dual frequency antenna or a multi-frequency antenna.

Preferably, the first radiator includes a split ring segment having an opening, a T-shaped segment connected to one end of the split ring segment, the T-shaped segment being located inside the split ring segment, the feeding microstrip line Connected to the other end of the split ring segment.

Preferably, the magnetic antenna comprises a feed ring and a second radiator, the feed ring includes a first portion and a second portion, the first portion and the second portion are connected and form a bent structure, the first A second radiator is coupled to the circuit substrate through the feed ring.

Preferably, the magnetic antenna further includes a resonant capacitor, and the resonant capacitor is disposed on the feed ring.

Preferably, the second radiator includes a first straight segment, a second straight segment and a third straight segment disposed in parallel, and is connected to the same side of the first straight segment, the second straight segment and the third straight segment The fourth straight line segment.

Preferably, the second radiator further includes a fifth straight line segment and a switching diode, the fifth straight line segment is located between the first straight line segment and the second straight line segment, and the switching diode is connected to the Between the fifth straight line segment and the fourth straight line segment.

Preferably, a support portion is further included, and the magnetic antenna is supported on the support portion.

Preferably, the circuit substrate has a length direction and a width direction, and the first radiating unit and the second radiating unit are spaced apart along a length direction of the circuit substrate.

A second aspect of the present application provides a mobile terminal comprising an electromagnetic multiple input multiple output antenna system, the electromagnetic multiple input multiple output antenna system being the electromagnetic multiple input multiple output antenna system of any of the above.

The technical solution provided by the present application can achieve the following beneficial effects:

The electromagnetic multiple input multiple output antenna system provided by the present application includes a first radiating unit and a second radiating unit, one of which includes an electric antenna, and the other includes a magnetic antenna, and the electric antenna The magnetic antennas are orthogonal, so the isolation between the first radiating element and the second radiating element is high, so the performance of the electromagnetic multiple input multiple output antenna system is high.

The above general description and the following detailed description are merely exemplary and are not intended to limit the application.

DRAWINGS

1 is a schematic structural diagram of an electromagnetic multiple input multiple output antenna system according to an embodiment of the present application;

2 is a dimension diagram of the electromagnetic multiple input multiple output antenna system shown in FIG. 1;

3 is a schematic structural diagram of a feed ring in an electromagnetic multiple input multiple output antenna system according to an embodiment of the present application;

Figure 4 is a dimension drawing of the feed ring shown in Figure 3;

5 is a schematic diagram of frequency reconfigurability of a resonant capacitor;

6 is a schematic diagram of corresponding structures when simulating an electromagnetic multiple input multiple output antenna system provided by an embodiment of the present application;

7 is a transmission parameter diagram obtained when simulating an electromagnetic multiple input multiple output antenna system provided by an embodiment of the present application;

8 is a schematic structural diagram of an equivalent radiation resistance involved in an electromagnetic multiple input multiple output antenna system according to an embodiment of the present application;

9 is an equivalent circuit diagram of an equivalent radiation resistance involved in an electromagnetic multiple input multiple output antenna system according to an embodiment of the present application;

10 is a schematic diagram of isolation comparison obtained when simulating an electromagnetic multiple input multiple output antenna system provided by an embodiment of the present application;

FIG. 11 is a schematic diagram showing a comparison of directions obtained when simulating an electromagnetic multiple input multiple output antenna system provided by an embodiment of the present application; FIG.

FIG. 12 is a channel capacity parameter diagram obtained when simulating an electromagnetic multiple input multiple output antenna system provided by an embodiment of the present application.

Reference mark:

1-circuit substrate;

2-first radiation unit;

20-first radiator;

200-T segment, 201-opening ring segment;

21-feed microstrip line;

3-second radiation unit;

30-feed ring;

300-Part I;

301-Part II;

301a-metal strip;

302-resonant capacitor;

31-second radiator;

310-first straight line segment, 311-second straight line segment, 312-third straight straight line segment,

313 - fourth straight line segment, 314 - fifth straight line segment, 315 - switching diode.

The drawings herein are incorporated in and constitute a part of the specification,

detailed description

The present application will be further described in detail below through specific embodiments and with reference to the accompanying drawings.

As shown in FIG. 1 to FIG. 1 , an embodiment of the present application provides an electromagnetic multiple input multiple output antenna system, which may be a multiple input multiple output antenna, which may include a circuit substrate 1 and a first radiation. Unit 2 and second radiating element 3. The dielectric layer of the circuit substrate 1 may have a thickness of 0.8 mm, a rectangular shape, and a length to width of 135 mm × 50 mm. The circuit substrate 1 is a metallized substrate, and the dielectric layer can be an FR4 plate having a dielectric constant of 4.2 and a loss tangent of 0.02. The metal layer can be made of a copper material having an electrical conductivity of 5.8e+007s/m. The first radiating unit 2 and the second radiating unit 3 are respectively coupled to opposite sides of the circuit substrate 1, and one of them includes an electric antenna, and the other includes a magnetic antenna.

The magnetic antenna is a loop antenna coupled and fed, and a magnetic dipole can be formed after the loop antenna is constructed, so that the energy storage of the loop antenna in the near field is mainly magnetic field energy, and the coupling with the circuit substrate 1 is reduced. It can be specifically a planar structure.

After the setting, since the electric antenna is orthogonal to the magnetic antenna, the orthogonality between the antennas of the first radiating unit 2 and the second radiating unit 3 can be realized by polarization diversity, and thus the first radiating unit 2 The isolation between the second radiating element 3 and the second radiating element 3 is high, so that the correlation coefficient between the antennas of the entire electromagnetic multiple-input multiple-output antenna system is lowered, and the radiation efficiency is improved, thereby increasing the channel capacity. Therefore, the performance of the electromagnetic multiple input multiple output antenna system is high. In addition, the electromagnetic multi-input multi-output antenna system can achieve a lower absorption rate of the human body in the multi-antenna multiplexing mode, and provides a more healthy and environmentally friendly radiation mode.

In one embodiment, the electrical antenna may include a first radiator 20 and a feeding microstrip line 21, the first radiator 20 is coupled to the circuit substrate 1 through the feeding microstrip line 21, and the first radiator 20 is The feed microstrip line 21 forms a bent structure, for example, can be vertically disposed therebetween. The feed microstrip line 21 can be printed on the circuit substrate 1, which can be used to connect a 50 ohm coaxial feed line, or a port of an amplifier. The length of the feeding microstrip line 21 may be 4 mm, and the distance between the feeding microstrip line 21 and the edge of the mobile terminal may be 12 mm, and the widths of the first radiator 20 and the feeding microstrip line 21 may each be set to 1 mm. The form of the first radiator 20 can be flexibly selected, and may be, for example, an inverted F antenna, a planar inverted F antenna, an inverted L antenna, or the like.

Preferably, the electrical antenna may be a single-pole electrical antenna, and the electrical antenna may be a dual-frequency antenna or a multi-frequency antenna, so that the electromagnetic multiple-input multiple-output antenna system provided by the embodiment of the present application can be multi-frequency, multiple-input and multiple-output. Electromagnetic multiple input multi-output antenna system.

The specific structure of the first radiator 20 may have various options. In the embodiment of the present application, the first radiator 20 may include a split ring segment 201 having an opening, and a T-shaped segment 200 connected to one end of the split ring segment 201. The T-shaped section 200 is located inside the split ring segment 201, and the feed microstrip line 21 is connected to the other end of the split ring segment 201. Such a structure can make the electric antenna have a larger bandwidth.

In one embodiment, the magnetic antenna may include a feed ring 30 and a second radiator 31, and the second radiator 31 is coupled to the circuit substrate 1 through the feed ring 30. The feed ring 30 includes a first portion 300 and a second portion 301, and the first portion 300 and the second portion 301 are connected and form a bent structure such that the entire magnetic antenna assumes a three-dimensional structure, for example, the first portion 300 and the second portion 301 can be vertical Settings. The feed ring 30 can be a square half ring, an L-type feed structure or a T-type feed structure. The resonant frequency and matching of the feed ring 30 can be adjusted according to the size of the feed ring 30 and the magnitude of the capacitance value. The second portion 301 may include a metal strip 301a having a length L3 of 26 mm, which operates in a high frequency range, and a distance between the metal strip 301a and the inner edge of the magnetic antenna may be set to 5 mm.

In addition, the above magnetic antenna usually includes a metal wire that operates in a high frequency range.

Further, the foregoing second radiator 30 may include a first straight section 310, a second straight section 311 and a third straight section 312 which are disposed in parallel, and are connected to the first straight section 310, the second straight section 311 and the third straight line. A fourth straight line segment 313 on the same side of segment 312. The first straight line segment 310, the second straight line segment 311, the third straight line segment 312, and the fourth straight line segment 313 may each be a metal strip structure, and the feeder loop 30 formed by the four has higher performance.

In order to adjust the bandwidth of the magnetic antenna, the second radiator 31 may further include a fifth straight line segment 314 and a switching diode 315. The fifth straight line segment 314 is located between the first straight line segment 310 and the second straight line segment 311, and the switching diode 315 is connected. Between the fifth straight line segment 314 and the fourth straight line segment 313. When the switching diode 315 is turned on, the fifth straight line segment 314 is inserted into the antenna structure formed by the first straight line segment 310, the second straight line segment 311, the third straight line segment 312, and the fourth straight line segment 313, so that the entire magnetic antenna is at The first working frequency band; when the switching diode 315 is turned off, the antenna structure is formed only by the first straight line segment 310, the second straight line segment 311, the third straight line segment 312 and the fourth straight line segment 313, and the fifth straight line segment 314 is not working. The state is such that the entire magnetic antenna is in the first operating frequency band. Here, the first working frequency band and the second working frequency band are different from each other, thereby adjusting the working frequency band of the magnetic antenna, for example, the first working frequency band may be a low frequency, and the second working frequency band may be a high frequency. It can be seen that the switching of the switching diode 315 can generate a frequency jump, so that the electromagnetic multiple input multiple output antenna system can work in multiple frequency bands.

The distance between the fifth straight line segment 314 and the edge of the inner ring of the magnetic antenna (ie, the feed ring 30) (ie, the connection position of the feed ring 30 and the circuit substrate 1) may be 0.7 mm. The inner ring has a width of 2 mm. The feed ring 30 can be connected to the inner conductor of the 50 ohm RF connector, and the outer conductor of the RF connector is directly connected to the circuit substrate 1.

After the above switching diode 315 is used, when the switching diode 315 is turned off, the electromagnetic multi-input multi-output antenna system can operate in the 1.8 GHz and 2.6 GHz frequency bands, and the electromagnetic multi-input multi-output antenna system can operate at 0.9 GHz when the switching diode 315 is turned on. Frequency band.

In order to increase the bandwidth of the electromagnetic multiple input multiple output antenna system, the magnetic antenna may further include a resonant capacitor 302 that can adjust the resonant frequency and impedance matching of the magnetic antenna, which can be disposed on the feed ring 30. The resonant capacitor 302 can be a concentrated capacitive component or a printed interdigital capacitor. Optionally, the resonant capacitor 302 can be replaced by a variable capacitor. By adjusting the value of the variable capacitor, the magnetic antenna can achieve continuous frequency in the low frequency range. Structure. Specifically, the frequency reconfigurability of the resonant capacitor 302 can be referred to FIG. 5.

The resonant capacitor 302 is specifically disposed on the first portion 300 of the magnetic wire, and the first portion 300 may have a symmetrical structure with respect to the disposed position of the resonant capacitor 302. The first portion 300 can have a height of 4 mm and a capacitance value of 0.35 pF.

The magnetic antenna is a loop antenna. Therefore, in order to improve the structural strength of the magnetic antenna, a support portion may be provided, and the magnetic antenna may be supported on the support portion. Specifically, the support portion may employ a hollow plastic carrier having an average dielectric constant of approximately 1.2.

In the above embodiments, the circuit substrate 1 can generally have a length direction and a width direction, that is, the size of the circuit substrate 1 has directivity. At this time, the first radiating unit 2 and the second radiating unit 3 may be spaced apart along the width direction of the circuit board 1 or may be spaced apart along the longitudinal direction of the circuit board 1. In view of the spacing along the length direction here, the distance between the first radiating element 2 and the second radiating element 3 can be appropriately increased, thereby further improving the isolation between the first radiating element 2 and the second radiating element 3, In the embodiment of the present application, it is preferable that the first radiating unit 2 and the second radiating unit 3 are spaced apart along the length direction of the circuit substrate 1.

Of course, the first radiating unit 2 and the second radiating unit 3 are also provided except that the first radiating unit 2 and the second radiating unit 3 are disposed on opposite sides of the circuit substrate 1 along the length direction or the width direction of the circuit substrate 1. It may be disposed on the same side of the circuit substrate 1.

When the above electromagnetic multi-input multi-output antenna system provided by the embodiment of the present application is simulated and analyzed, the corresponding structure is shown in FIG. 6 , wherein A refers to a dipole antenna and B refers to a loop antenna, and after simulation analysis, FIG. 7 is obtained. The transmission parameter diagram shown. It can be concluded that the isolation between the two antennas is greater than 30 dB, the dipole antenna has a larger bandwidth, and the bandwidth of the loop antenna is small. The radiation resistance of the loop antenna is only 0.045 ohms. Because of the loss of metal and medium in practical applications, the value of the loss resistance is much larger than the value of the radiation resistance, which will result in very low radiation efficiency of the antenna (< 10%). Therefore, it is necessary to increase the radiation resistance of the antenna to improve the efficiency of the magnetic antenna. Based on the principle of a Split Ring Resonator (SRR), the electromagnetic multi-input multi-output antenna system provided by the embodiment of the present application implements an impedance conversion function by using a separate coupled feed ring, and increases the equivalent radiation resistance of the antenna. The structure and corresponding equivalent circuits are shown in Figures 8 and 9, respectively.

The function of the feed ring 30 is to couple energy to the second radiator 31 without changing its resonant frequency. The resonant frequency of the entire structure is determined by the size of the radiating half of the ring outside the feed ring 30. The degree of impedance matching is determined by the magnitude of the capacitance loaded in the middle of the feed ring 30. At this point, the input impedance of the antenna at the port is tens of ohms, making impedance matching easier. At the other end of the circuit substrate 1, a bent monopole antenna is used, which is a typical representative of an electric antenna. For example, most of the antennas in mobile phone antennas are electric antennas, which form a strong coupling with the mobile phone substrate, forming a pattern similar to a dipole, and achieving omnidirectional radiation on a plane perpendicular to the mobile phone.

For the parameters shown in FIG. 2 and FIG. 4, the preferred embodiments of the present application are as shown in Table 1 below:

Table I

parameter	Numerical value
L 1	15mm
W 1	50mm
L 2	20mm
W 2	5mm
W 3	2mm
W 4	21mm
h 1 , h 2	4mm
L 3	26mm
d 1	5mm
d 2	12mm
L m1	10mm
L m2	5mm
W m	1mm

The simulation results shown in Figure 10-12 are obtained after simulation analysis using the dimensions described in Table 1. The isolation between the antennas is greater than 20 dB at low frequencies and greater than 18 dB at high frequencies. The relatively narrow bandwidth of the magnetic antenna at low frequencies can be compensated by the resonant capacitor 302 frequency modulation. As shown in FIG. 11, the pattern between the two antennas has obvious orthogonality. By calculating the envelope correlation coefficient between the patterns, the correlation coefficient of the antenna has a low frequency of 0.008 and a high frequency of less than 0.1. The radiation efficiency is around 80% and 76%, respectively. Comparing the channel capacity of the antenna with the conventional antenna in the frequency band, as shown in FIG. 12, it can be seen that the average channel capacity is 2 bit/s/Hz higher than that of the conventional two-electromagnetic multiple-input multiple-output antenna system.

Based on the foregoing structure, the embodiment of the present application further provides a mobile terminal, where the mobile terminal may be a terminal device such as a mobile phone or a tablet computer, and the mobile terminal includes an electromagnetic multiple input multiple output antenna system, and the electromagnetic multiple input multiple output antenna system may be An electromagnetic multiple input multiple output antenna system provided by any of the above embodiments.

The above description is only the preferred embodiment of the present application, and is not intended to limit the present application, and various changes and modifications may be made to the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of this application are intended to be included within the scope of the present application.

Claims (11)

1. An electromagnetic multiple input multiple output antenna system, comprising: a circuit substrate, a first radiating unit and a second radiating unit, wherein the first radiating unit and the second radiating unit are respectively coupled to the circuit substrate Opposite two sides, and one of the two includes an electrical antenna and the other includes a magnetic antenna.
2. The electromagnetic multiple input multiple output antenna system according to claim 1, wherein the electrical antenna comprises a first radiator and a feeding microstrip line, and the first radiator passes through the feeding microstrip line The circuit substrate is coupled, and the first radiator and the feeding microstrip line form a bent structure.
3. The electromagnetic multiple input multiple output antenna system according to claim 2, wherein the electric antenna is a monopole electric antenna, and the electric antenna is a dual frequency antenna or a multi-frequency antenna.
4. The electromagnetic multiple input multiple output antenna system according to claim 2, wherein said first radiator comprises a split ring segment having an opening, a T-shaped segment connected to one end of the split ring segment, said T-shaped segment Located inside the split ring segment, the feed microstrip line is connected to the other end of the split ring segment.
5. The electromagnetic multiple input multiple output antenna system according to claim 1, wherein said magnetic antenna comprises a feed ring and a second radiator, said feed ring comprising a first portion and a second portion, said first portion And connecting to the second portion and forming a bent structure, wherein the second radiator is coupled to the circuit substrate through the feed ring.
6. The electromagnetic multiple input multiple output antenna system according to claim 5, wherein the magnetic antenna further comprises a resonant capacitor, and the resonant capacitor is disposed on the feed ring.
7. The electromagnetic multiple input multiple output antenna system according to claim 5, wherein said second radiator includes a first straight line segment, a second straight line segment, and a third straight line segment disposed in parallel, and is coupled to said first a fourth straight line segment on the same side of the straight line segment, the second straight line segment, and the third straight line segment.
8. The electromagnetic multiple input multiple output antenna system according to claim 7, wherein said second radiator further comprises a fifth straight line segment and a switching diode, said fifth straight line segment being located at said first straight line segment and said Between the second straight line segments, the switching diode is connected between the fifth straight line segment and the fourth straight line segment.
9. The electromagnetic multiple input multiple output antenna system according to any one of claims 1 to 8, further comprising a support portion, the magnetic antenna being supported on the support portion.
10. The electromagnetic multiple input multiple output antenna system according to any one of claims 1 to 8, wherein the circuit substrate has a length direction and a width direction, and the first radiating unit and the second radiating unit are along The circuit boards are spaced apart in the longitudinal direction.
11. A mobile terminal, comprising an electromagnetic multiple input multiple output antenna system, the electromagnetic multiple input multiple output antenna system being the electromagnetic multiple input multiple output antenna system according to any one of claims 1-10.

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