阅读说明：本技术 一种应用于4g-mimo智能眼镜的双环天线 (Be applied to dicyclo antenna of 4G-MIMO intelligent glasses ) 是由 王艳艳 班永灵 赵星影 公晓庆 李肖飞 王冰 于 2019-08-29 设计创作，主要内容包括：本发明属于可穿戴天线技术领域,具体涉及一种应用于4G-MIMO智能眼镜的双环天线,该天线充分利用了眼镜的形状,将环天线印刷在眼镜框上,并且根据眼镜的对称性能,形成MIMO天线结构；本发明通过加载匹配电路的实现GSM850/900、GSM1800/1900、UMTS2100和LTE2300/2500等频段的覆盖；更进一步的,本发明通过加载一个去耦的寄生元有效减小两个天线之间的近场耦合,使得两个天线在低频段的最小隔离也达到了-15dB以下；并且,去耦寄生元的引入对天线本身的自阻抗影响也很小,带宽仍然能够覆盖4G的两个频段824-960MHz和1710-2690MHz。由此可见,本发明双环天线不仅符合智能眼镜的应用,并且满足去耦的要求。(the invention belongs to the technical field of wearable antennas, and particularly relates to a double-loop antenna applied to 4G-MIMO intelligent glasses, which fully utilizes the shape of the glasses, prints the loop antenna on a glasses frame, and forms an MIMO antenna structure according to the symmetry performance of the glasses; the invention realizes the coverage of frequency bands such as GSM850/900, GSM1800/1900, UMTS2100, LTE2300/2500 and the like by loading a matching circuit; furthermore, the invention effectively reduces the near-field coupling between the two antennas by loading a decoupling parasitic element, so that the minimum isolation of the two antennas at a low frequency band is also less than-15 dB; moreover, the influence of the introduction of the decoupling parasitic element on the self-impedance of the antenna is small, and the bandwidth can still cover the two frequency bands 824-960MHz and 1710-2690MHz of 4G. Therefore, the double-loop antenna not only meets the application of the intelligent glasses, but also meets the decoupling requirement.)

1. The utility model provides a be applied to dicyclo antenna of 4G-MIMO intelligent glasses, dicyclo antenna is bilateral symmetry structure, includes: the glasses frame comprises a glasses frame dielectric substrate (1), a glasses leg dielectric substrate (2) vertically connected with the glasses frame dielectric substrate (1), a metal ring (3) arranged on the front surface of the glasses frame dielectric substrate (1), a metal floor (4) arranged on the outer side of the glasses leg dielectric substrate (2), a microstrip feeder line (5), a ground short circuit line (6) and a matching circuit (7); characterized in that the metal ringAn opening metal ring is adopted, and the opening position is opposite to the connection position of the glasses frame medium substrate and the glasses leg medium substrate; the upper opening end of the opening metal ring is connected with the metal floor through a grounding short circuit line, the lower opening end of the opening metal ring is connected with the metal floor through a microstrip feeder line, and the joint of the microstrip feeder line and the metal floor is used as a feed port; the microstrip feed line is characterized in that a matching circuit is arranged on the microstrip feed line and comprises a capacitor C_H1Capacitor C_H2Inductor L_H1Inductor L_L2Inductor L_L1And a capacitor C_L1(ii) a Wherein the capacitance C_H2One end of the capacitor is connected with the metal ring 3, and the other end is sequentially connected with the capacitor C in series_H1Inductor L_L2Inductor L_L1said inductance L_L1The other end of the first power supply is connected with the feed port; the capacitor C_L1One terminal and an inductor L_L1Inductor L_L2The other ends are connected with the ground; the inductance L_H1One terminal and a capacitor C_H1Capacitor C_H1Connected and the other end is grounded.

2. The dual-loop antenna applied to 4G-MIMO smart glasses according to claim 1, wherein the dual-loop antenna further comprises a decoupling parasitic element (8), the decoupling parasitic element is arranged along the upper edge of the dielectric substrate of the glasses frame and maintains a uniform gap with the metal ring.

3. The dual-loop antenna applied to 4G-MIMO smart glasses according to claim 1, wherein the width of the metal loop is 2 mm.

4. The dual-loop antenna applied to 4G-MIMO smart glasses according to claim 1, wherein the width of the decoupling parasitic element is 1mm, the length of the decoupling parasitic element is 200mm, and the gap between the metal loop and the decoupling parasitic element is 1 mm.

5. The dual-loop antenna for 4G-MIMO smart glasses according to claim 1, wherein the microstrip feed line is composed of a 50 ohm rf line.

Technical Field

The invention belongs to the technical field of wearable antennas, and particularly relates to a double-ring antenna applied to 4G-MIMO intelligent glasses.

Background

In recent years, a multiple-input multiple-output MIMO technology has been proposed, which can effectively improve the performance of a wireless communication system, and improve the channel capacity and communication quality of the system by using the characteristics of multiple paths; in this technology, the design of the antenna plays a very important role, since it is the transmission tool for communication between the transmitter and the receiver. Whereas to obtain the performance of a MIMO system, the antennas at the transmitter and receiver should be uncorrelated; theoretically, when the distance between two antennas reaches more than half wavelength of the antennas, the antennas cannot affect each other, but the distance cannot be realized by miniaturized intelligent equipment; therefore, it is necessary to reduce the coupling using decoupling techniques.

two difficulties exist in the process of designing the MIMO antenna, one is that the bandwidth is narrow for a simple antenna structure, multiple frequency bands are difficult to cover, extra resonance is generated by generally adding parasitic branches, and then broadband coverage is obtained; for the intelligent glasses antenna, the structure and the form are fixed, and the scheme of adding the parasitic branches is limited, so that the resonant frequency of the antenna can be adjusted by a method of loading the matching circuit, and the required frequency band requirement can be met.

Another technical problem of MIMO antennas is that mutual coupling exists between antennas, and the methods of reducing coupling between antennas can be divided into external decoupling and internal decoupling. External decoupling including parasitic element decoupling, matching circuit decoupling, floor printing seam decoupling, and neutral line decoupling, which are added in the antenna structure; the antenna bandwidth obtained by adding the matching circuit to reduce the coupling is narrower, and in addition, most matching circuits are similar to a filter structure, so that multi-mode decoupling can be realized by referring to a multi-mode filter theory, but if the number of decoupling modes is increased, the design becomes difficult, and a matrix corresponding to the filter becomes complicated; floor print slot decoupling, which is actually for antenna elements sharing a floor, reduces the flow of floor current between two antenna elements through a slot, thereby reducing coupling; the design of the neutralization line does not have a standard criterion, and the reduction of the broadband mutual coupling is difficult to realize. The internal decoupling comprises odd-even mode decoupling, mirror image antenna element decoupling, characteristic mode theory decoupling and multi-polarization decoupling; good isolation of the eigenmodes can be achieved for frequency bands below 1GHz, but it is difficult to control the frequency of the multi-eigenmode because flexibility in adapting the radiator is limited; in addition, there is a method of defectively decoupling for antennas sharing a floor, but this structure is too bulky for mobile terminals.

For the double-loop antenna applied to the 4G-MIMO intelligent glasses, the two simple loop antennas realize the coverage of the frequency band through the matching circuit; since the two antennas do not share a common floor structure, neither of the two decoupling methods of defected ground and floor slotting can achieve a reduction in mutual coupling; and, since the form of the glasses is single and the structure is fixed, the required design space of the decoupling scheme of the matching circuit is also greatly limited.

Disclosure of Invention

The invention aims to solve the design difficulty of a double-loop antenna applied to 4G-MIMO intelligent glasses, provides the double-loop antenna applied to the 4G-MIMO intelligent glasses, realizes the coverage of frequency bands such as GSM850/900, GSM1800/1900, UMTS2100, LTE2300/2500 and the like on a 4G-MIMO intelligent glasses frame, effectively reduces the coupling between the two antennas and greatly improves the performance parameters of the antennas.

In order to achieve the purpose, the invention adopts the technical scheme that:

The utility model provides a be applied to dicyclo antenna of 4G-MIMO intelligent glasses, dicyclo antenna is bilateral symmetry structure, includes: the spectacle frame comprises a spectacle frame dielectric substrate 1, a spectacle leg dielectric substrate 2 vertically connected with the spectacle frame dielectric substrate 1, a metal ring 3 arranged on the front surface of the spectacle frame dielectric substrate 1, a metal floor 4 arranged on the outer side of the spectacle leg dielectric substrate 2, a microstrip feeder line 5, a ground short circuit line 6 and a matching circuit 7; the glasses frame is characterized in that the metal ring 3 is an open metal ring, and the open position of the metal ring is over against the connection position of the glasses frame medium substrate 1 and the glasses leg medium substrate 2; the upper opening end of the opening metal ring is connected with the metal floor through a grounding short circuit line 6, the lower opening end is connected with the metal floor 4 through a microstrip feeder line 5, and the joint of the microstrip feeder line 5 and the metal floor 4 is used as a feed port to realize feed; the microstrip feed line is characterized in that a matching circuit is arranged on the microstrip feed line and comprises a capacitor C_H1Capacitor C_H2Inductor L_H1Inductor L_L2Inductor L_L1And a capacitor C_L1(ii) a Wherein the capacitance C_H2One end of the capacitor is connected with the metal ring 3, and the other end is sequentially connected with the capacitor C in series_H1Inductor L_L2Inductor L_L1Said inductance L_L1The other end of the first power supply is connected with the feed port; the capacitor C_L1One terminal and an inductor L_L1Inductor L_L2The other ends are connected with the ground; the inductance L_H1One terminal and a capacitor C_H1Capacitor C_H1Connected and the other end is grounded.

Further, the double-loop antenna further comprises a decoupling parasitic element 8, wherein the decoupling parasitic element 8 is arranged along the upper edge of the dielectric substrate of the glasses frame, and a uniform gap is kept between the decoupling parasitic element 8 and the metal ring 3.

Further, the width of the metal ring is 2 mm.

The width of parasitic element of decoupling is 1mm, length is 200mm, the clearance between metal ring and the parasitic element of decoupling is 1 mm.

The microstrip feed line 5 is composed of a 50 ohm radio frequency line.

The invention has the beneficial effects that:

The double-loop antenna applied to the 4G MIMO intelligent glasses fully utilizes the shape of the glasses, the loop antenna is printed on a glasses frame, and an MIMO antenna structure is formed according to the symmetry performance of the glasses; the invention can cover 4G high and low frequency bands by loading the matching circuit, and meanwhile, no breakpoint is arranged on the loop antenna, thus the invention conforms to the beauty and the obdurability of the design of the all-metal frame. Furthermore, because near-field coupling exists between the two loop antennas, the invention combines the shape of the glasses, loads a decoupled parasitic element on the upper edges of the two loop antennas, the width of the parasitic element is 1mm, the length of the parasitic element is 200mm, and the distance between the parasitic element and the loop antennas is 1 mm; and, the decoupling element matches the shape of the glasses, the middle part is sunken downwards, and the sunken degree is 10 mm. In the invention, before a decoupling parasitic element is not added, the intelligent glasses antenna can cover two frequency bands 824-; the added decoupling parasitic element is equivalent to a dipole which resonates at 0.86GHz, so that the amplitude of S12 of the two antennas generates a coupling zero point at 0.86GHz, the coupling zero point is about-35 dB, and the minimum isolation at a low frequency band is also less than-15 dB; moreover, the influence of the introduction of the decoupling parasitic element on the self-impedance of the antenna is small, and the bandwidth can still cover the two frequency bands 824-960MHz and 1710-2690MHz of 4G.

Drawings

Fig. 1 is a schematic structural diagram of a dual-ring antenna applied to 4G MIMO smart glasses according to embodiment 1 of the present invention;

Fig. 2 is a schematic structural diagram of a dual-loop antenna loaded with decoupling parasitic elements and applied to 4G MIMO smart glasses according to embodiment 2 of the present invention;

FIG. 3 is an abstract circuit schematic of the matching circuit loaded by the present invention, including a high pass matching circuit and a low pass matching circuit;

FIG. 4 is a graph of the test and simulated return loss of the dual-loop antenna applied to 4G MIMO smart glasses in example 1;

FIG. 5 is a diagram of the test and simulation return loss of the dual-loop antenna applied to 4G MIMO smart glasses loaded with decoupling parasitic elements in embodiment 2;

Wherein: the structure comprises a spectacle frame dielectric substrate 1, a spectacle leg dielectric substrate 2, a metal ring 3, a metal floor 4, a microstrip feeder line 5, a ground short-circuit line 6, a matching circuit 7 and a decoupling parasitic element 8.

Detailed Description

The invention is further described below with reference to the figures and examples.