CN110649385B

CN110649385B - Microstrip antenna

Info

Publication number: CN110649385B
Application number: CN201911064730.7A
Authority: CN
Inventors: 方宜娇; 范丽莉; 徐宏贵; 钟将为
Original assignee: Lenovo Beijing Ltd
Current assignee: Lenovo Beijing Ltd
Priority date: 2019-11-01
Filing date: 2019-11-01
Publication date: 2021-01-15
Anticipated expiration: 2039-11-01
Also published as: CN110649385A

Abstract

The present disclosure provides a microstrip antenna. The microstrip antenna includes: a ground plate; the dielectric substrate is arranged on the surface of the grounding plate; the first patch is arranged on the top surface of the dielectric substrate; and a second patch; the medium substrate comprises a target area and a mixed medium structure, the target area is an area where the electric field intensity of an electric field generated by the first patch in the medium substrate is smaller than a threshold value, the mixed medium structure is arranged in the target area, and the second patch is arranged on the top surface of the mixed medium structure.

Description

Microstrip antenna

Technical Field

The present disclosure relates to the field of communications, and more particularly, to a microstrip antenna.

Background

Current mobile communication systems mainly implement separation of a Reception (RX) channel and a Transmission (TX) channel by means of time division duplex or frequency division duplex. Time Division Duplexing (TDD) refers to that a receiving channel and a transmitting channel respectively work in different Time slots to ensure that a certain isolation exists between the two channels, and GSM and TD-SCDMA in 3GPP standards adopt a TDD mode. Frequency-division Duplex (FDD) means that a receiving channel and a transmitting channel respectively work at different frequencies to ensure that a certain isolation exists between the two channels, and WCDMA and CDMA2000 in the 3GPP standard adopt an FDD mode. With the advent of the 5G era, the concept of Full Duplex (Full Duplex) was increasingly being addressed. Full duplex means that a receiving channel and a transmitting channel can simultaneously work at the same frequency, and when the two channels simultaneously work at the same frequency, a certain degree of isolation still exists between the two channels. Full duplex realizes the simultaneous bidirectional transmission of signals, and can double the transmission rate of a communication system under the same time and bandwidth. Therefore, how to realize full duplex has become a very important issue in the 5G era. The difficulty in implementing full duplex is how to eliminate self-interference (self interference) generated by a transmitting signal to a receiving signal at the same frequency.

The related art adopts the following scheme to solve the problem that the transmission signals generate self-interference on the receiving signals at the same frequency.

Scheme 1: as shown in fig. 1A, the isolation is increased by using different transceiving antennas for the Rx end and the Tx end, respectively.

Scheme 2: a circulator (a device for unidirectional ring transmission of electromagnetic waves) is arranged between the Rx end and the Tx end, and the isolation between the Rx end and the Tx end is realized by utilizing the principle of the circulator. For example, as shown in fig. 1B, Cirulator represents a circulator, and according to the principle of the circulator, a signal of 1 port can be transmitted to 2 ports, and a signal of 2 ports can be transmitted to 3 ports, but signals from 2 ports to 1 port, from 3 ports to 2 ports, and between 1 port and 3 ports cannot pass through.

Scheme 3: the improvement of scheme 2 is that, as shown in fig. 1C, there are two paths from the Tx end to the Rx end, one path directly transmits the Tx signal, and the other path connects to an inverter to invert the phase of the Tx signal by pi, so that for the Rx end, a Tx signal and an inverted Tx signal are received at the same time, and the two signals cancel each other, thereby eliminating the influence of the Tx end transmitted at the same time at the Rx end, and realizing full duplex.

Scheme 4: the Tx end and Rx end regions are separated by the main polarization (Co-Pol) and cross polarization (X-Pol) of the antenna. As shown in fig. 1D, due to the difference in radiation directivity of the antennas, the electric field generated by one antenna is along the x direction and the electric field generated by the other antenna is along the y direction, so that the electromagnetic field distributions on both sides have orthogonal characteristics.

The above related art solution has at least the following problems: for scheme 1, the Tx end has a large influence on the Rx end, and the isolation is not good. For schemes 2-4: the circuit structure is complicated and difficult to realize.

Disclosure of Invention

One aspect of the present disclosure provides a microstrip antenna, including: a ground plate; the dielectric substrate is arranged on the surface of the grounding plate; the first patch is arranged on the top surface of the dielectric substrate; and a second patch; the medium substrate comprises a mixed medium structure, the mixed medium structure is arranged in a target area, the target area is an area where the electric field intensity of an electric field generated by the first patch in the medium substrate is smaller than a threshold value, and the second patch is arranged on the top surface of the mixed medium structure.

Optionally, the first patch and the second patch are respectively coupled with the ground plate.

Optionally, the microstrip antenna further includes: a first feed line connected to the first patch; and a second power feed line connected to the second patch, the first power feed line extending in the same direction as the second power feed line.

Optionally, the characteristic impedance of the first and second feed lines is 50 Ω

Optionally, the thickness of the mixed dielectric structure in the direction perpendicular to the ground plane is greater than half the thickness of the dielectric substrate in the direction perpendicular to the ground plane.

Optionally, the mixed media structure comprises a plurality of first media and a plurality of second media arranged alternately.

Optionally, the dielectric constant and thickness of the first medium and the dielectric constant and thickness of the second medium satisfy the following equations: epsilon 1 and d1 plus epsilon 2 and d2 is K (lambda/2), wherein d1 is the thickness of the first medium, epsilon 1 is the dielectric constant of the first medium, d2 is the thickness of the second medium, epsilon 2 is the dielectric constant of the second medium, lambda is the wavelength corresponding to the central frequency of the microstrip antenna, and K is a positive integer.

Optionally, the second patch is rectangular, and the length of the long side of the second patch is set to be a positive integer multiple of the sum of the thickness d1 of the first medium and the thickness d2 of the second medium.

Optionally, the extending direction of the second patch is the same as the arrangement direction of the first medium and the second medium, and the edge of the second patch is located at the seam of the first medium and the second medium.

According to the microstrip antenna of the embodiment of the present disclosure, the mixed dielectric structure is disposed in the target area, and the second patch is disposed on the top surface of the mixed dielectric structure. The target area is an area with smaller electric field intensity generated by the first patch, and the first patch and the second patch have larger isolation, so that full duplex of the first patch and the second patch is realized. In addition, the microstrip antenna does not need a circulator or a polarized antenna, and the structure is simpler.

Drawings

For a more complete understanding of the present disclosure and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:

fig. 1A to 1D schematically show structural diagrams of a related art full-duplex antenna.

FIG. 2 schematically illustrates a full-duplex system;

figure 3 schematically illustrates a structural schematic of a microstrip antenna according to an embodiment of the present disclosure;

FIG. 4 schematically illustrates an electric field distribution of eigenmodes excited by a first patch in a dielectric substrate, in accordance with an embodiment of the disclosure;

FIG. 5 schematically illustrates a structural schematic of a dielectric substrate according to an embodiment of the disclosure FIG. 4 schematically illustrates a structural schematic of a dielectric substrate according to an embodiment of the disclosure;

FIG. 6 schematically illustrates a structural schematic of a hybrid media according to an embodiment of the disclosure;

figure 7 schematically illustrates a network simulation diagram of a microstrip antenna according to an embodiment of the present disclosure; and

fig. 8 schematically illustrates a structural schematic diagram of a microstrip antenna according to another embodiment of the present disclosure.

Detailed Description

Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. It should be understood that the description is illustrative only and is not intended to limit the scope of the present disclosure. In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the embodiments of the disclosure. It may be evident, however, that one or more embodiments may be practiced without these specific details. Moreover, in the following description, descriptions of well-known structures and techniques are omitted so as to not unnecessarily obscure the concepts of the present disclosure.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The terms "comprises," "comprising," and the like, as used herein, specify the presence of stated features, steps, operations, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, or components.

All terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art unless otherwise defined. It is noted that the terms used herein should be interpreted as having a meaning that is consistent with the context of this specification and should not be interpreted in an idealized or overly formal sense.

Where a convention analogous to "at least one of A, B and C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B and C" would include but not be limited to systems that have a alone, B alone, C alone, a and B together, a and C together, B and C together, and/or A, B, C together, etc.). Where a convention analogous to "A, B or at least one of C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B or C" would include but not be limited to systems that have a alone, B alone, C alone, a and B together, a and C together, B and C together, and/or A, B, C together, etc.).

Fig. 2 schematically shows a full duplex system. As shown in fig. 2, TX denotes a transmission signal, RX denotes a reception signal, ANT denotes an antenna, PA denotes a power amplifier, DAC denotes a digital-to-analog converter, LNA denotes a low noise amplifier, and ADC denotes an analog-to-digital converter. For the full duplex system, the TX signals at the same time and frequency have an effect of over 100dB on the RX signals. The full-duplex system is divided into three subsystems to eliminate these effects and thereby successfully demodulate the RX signal. The three subsystems are an antenna system 110, an Analog Cancellation Circuit (Analog Cancellation Circuit)120, and a digital Cancellation Circuit (digital Cancellation Circuit) 130. The antenna system 110 is used to realize isolation between the receiving antenna and the transmitting antenna, and the analog signal interference cancellation circuit 120 is used to cancel interference of the analog signal portion. The digital signal interference cancellation circuit 130 is used to cancel interference of the digital signal portion. The microstrip antenna of the embodiments of the present disclosure is an improvement to the antenna system 110 to achieve isolation of the receive antenna and the transmit antenna.

Embodiments of the present disclosure provide a microstrip antenna. The microstrip antenna includes a ground plane; the dielectric substrate is arranged on the surface of the grounding plate; the first patch is arranged on the top surface of the dielectric substrate; and a second patch; the medium substrate comprises a target area and a mixed medium structure, the target area is an area where the electric field intensity of an electric field generated by the first patch in the medium substrate is smaller than a threshold value, the mixed medium structure is arranged in the target area, and the second patch is arranged on the top surface of the mixed medium structure.

The microstrip antenna of the embodiments of the present disclosure is specifically described below with reference to fig. 3.

Fig. 3 schematically illustrates a structural schematic diagram of a microstrip antenna according to an embodiment of the present disclosure.

As shown in fig. 3, the microstrip antenna includes a ground plane 310, a dielectric substrate 320, a first patch 330 disposed on a top surface of the dielectric substrate 320, and a second patch 340.

Wherein, the dielectric substrate 320 is disposed on the surface of the ground plate 310 and includes a mixed dielectric structure 322. The first patch 330 is disposed on the top surface of the dielectric substrate 320. The second patch 340 is disposed with the top surface of the mixed media structure 322.

The first patch 330 is coupled with the ground plate 310 and may be used to transmit signals or receive signals according to an embodiment of the present disclosure. The material of the first patch 330 may be a conductor such as metal, for example. The size of the first patch 330 may be determined according to the wavelength corresponding to the center frequency of the microstrip antenna and the dielectric constant of the dielectric substrate.

According to the embodiment of the present disclosure, when the first patch 330 is used as a transmitting port, the electric field distribution of the eigenmode excited by the first patch in the dielectric substrate 320 is as shown by the arrow mark in fig. 4, and the electric field intensity is uniform along the y direction and is small in the middle and large in the x direction. The region of the dielectric substrate 320 where the electric field strength is less than the threshold is the target region 321. The threshold may be determined according to actual needs, and the smaller the threshold is, the smaller the target area 321 is, and the smaller the interference generated in the target area 321 when the first patch 330 transmits the signal is.

FIG. 5 schematically illustrates a structural schematic of a dielectric substrate according to an embodiment of the disclosure.

As shown in fig. 5, a mixed media structure 322 is disposed in the target area 321. The second patch 340 is disposed on the top surface of the mixed media structure 322 and attached to the mixed media structure 322. By this arrangement, when the first patch 330 and the second patch 340 transmit and receive signals at the same frequency, the difference between the electric field generated by the first patch 330 in the dielectric substrate 320 and the electric field generated by the second patch 340 in the mixed dielectric structure 322 is larger, so that a larger isolation can be achieved.

According to an embodiment of the present disclosure, the hybrid dielectric structure 322 is proximate to the ground plane 310 and has a thickness in a direction perpendicular to the ground plane that is greater than half the thickness of the dielectric substrate in the direction perpendicular to the ground plane. It is understood that the thickness of the hybrid media structure 322 does not exceed the thickness of the media substrate 320. Since the electric field excited by the eigenmode of the first patch 330 is smaller at a position close to the ground plane 310, the interference of the first patch 330 can be further reduced by disposing the mixed dielectric structure 322 at a position close to the ground plane 310.

Fig. 6 schematically illustrates a structural schematic of a hybrid media according to an embodiment of the disclosure.

As shown in fig. 6, the mixed media structure 322 includes a plurality of first media 3221 and a plurality of second media 3222 alternately arranged. Wherein, the dielectric constant and thickness of the first medium 3221 and the dielectric constant and thickness of the second medium 3222 need to satisfy the following formula:

ε1*d1+ε2*d2＝K*(λ/2)，

wherein d1 is the thickness of the first medium 3221, epsilon 1 is the dielectric constant of the first medium 3221, d2 is the thickness of the second medium 3222, epsilon 2 is the dielectric constant of the second medium 3222, lambda is the electromagnetic wave wavelength corresponding to the center frequency of the microstrip antenna, K is a positive integer, and the value of K can be specifically set as required. The center frequency may be, for example, 2GHz to 3 GHz.

Referring now to fig. 3 and 5, a second patch 340 in accordance with an embodiment of the present disclosure is specifically set forth.

The second patch 340 is coupled to the ground plate 310 and may be used to transmit signals or receive signals, according to an embodiment of the present disclosure. The material of the second patch 340 may be a conductor such as metal, for example.

As shown in fig. 5, the second patch 340 may be rectangular. The length of the long side of the second patch 340 in the y direction is set to a positive integer multiple of the sum of the thickness d1 of the first medium 3221 and the thickness d2 of the second medium 3222. Illustratively, in the present embodiment, the length of the long side of the second patch 340 is set to be 2 times the sum of the thickness d1 of the first medium 3221 and the thickness d2 of the second medium 3222. The length of the short side of the second patch 340 in the x direction may be set according to design requirements, and the length of the short side does not exceed the width of the mixed medium in the x direction at most. In addition, the extending direction of the second patch 340 in the y direction is the same as the arrangement direction of the first medium 3221 and the second medium 3222 in the x direction, and the edge of the second patch 340 is located at the seam of the first medium 3321 and the second medium 3322. The midline of the second patch 340 in the x-direction coincides with the midline of the mixed media structure in the x-direction. Through the above arrangement, the excitation efficiency of the second patch 340 can be improved.

According to the microstrip antenna of the embodiment of the present disclosure, the hybrid dielectric structure 322 is disposed at the target area 321, and the second patch 340 is disposed on the top surface of the hybrid dielectric structure 322. Since the target region 321 is a region where the field intensity of the electric field generated by the first patch 330 is small, if the first patch 330 is used as a transmitting end and the second patch 340 is used as a receiving end, the difference in field distribution between the electric field generated by the second patch 340 and the electric field generated by the first patch 330 is large, that is, the first patch 330 and the second patch 340 have a large isolation degree.

Figure 7 schematically illustrates a network simulation diagram of a microstrip antenna according to an embodiment of the present disclosure. Wherein the first patch 330 is port 1 and the second patch 340 is port 2. S11 indicates the reflection coefficient of port 1 when port 2 is matched; s22 indicates the reflection coefficient of port 2 when port 1 is matched; s12 indicates the reverse transmission coefficient from port 2 to port 1 when port 1 is matched; s21 indicates the forward transmission coefficient from port 1 to port 2 when port 2 is matched. As shown in FIG. 8, the isolation between ports 1 and 2 can be-35 dBm or more at a frequency of about 2.46 GHz.

Therefore, the first patch 330 has less influence on the received signal of the second patch 340 when transmitting a signal, thereby realizing full duplex of the transmitted signal and the received signal.

In addition, according to the microstrip antenna implemented by the present disclosure, a circulator or a polarized antenna is not required when the microstrip antenna is implemented, and the structure is simpler.

Referring to fig. 3 and 5, according to an embodiment of the present disclosure, the microstrip antenna further includes: a first feed line 350 and a second feed line 360. Wherein the first feed line 350 is connected to the first patch 330 and the second feed line 360 is connected to the second patch 340. The first and second

power feeding lines

350 and 360 may be used to transmit signals, and may be made of a conductor such as metal.

According to the embodiment of the present disclosure, the lengths of the first and second

power feeding lines

350 and 360 may be set as required. The widths and heights of the first and second

power feeding lines

350 and 360 can be adjusted according to their characteristic impedances. According to the embodiment of the present disclosure, the characteristic impedance of the first and second

power feeding lines

350 and 360 is set to 50 ohms, that is, the width and height of the first and second

power feeding lines

350 and 360 may be arbitrarily set as long as the characteristic impedance of 50 ohms is satisfied.

According to an embodiment of the present disclosure, the extending direction of the second power feeding line 360 may be the same as the extending direction of the first power feeding line 350, and may also be at an angle to the extending direction of the first power feeding line 350.

As shown in fig. 8, when the extending direction of the second power feeding line 360 is the same as that of the first power feeding line 350, the first power feeding line 350 and the second power feeding line 360 are located on the same side of the dielectric substrate, so that the space of the step line can be saved. It should be noted that the relative position of the second power feed line 360 and the first power feed line 350 can be flexibly set. For example, after the position of the first feed line 350 is fixed, the second feed line 360 may be adjusted in position in the y direction as shown by the arrow in fig. 7, and it will be appreciated that while the second feed line 360 is adjusted in position, the second patch 340 connected to the second feed line 360 may also adjust its position relative to the mixed media structure 322 in the y direction as shown by the arrow accordingly, thereby meeting different design requirements.

Those skilled in the art will appreciate that various combinations and/or combinations of features recited in the various embodiments and/or claims of the present disclosure can be made, even if such combinations or combinations are not expressly recited in the present disclosure. In particular, various combinations and/or combinations of the features recited in the various embodiments and/or claims of the present disclosure may be made without departing from the spirit or teaching of the present disclosure. All such combinations and/or associations are within the scope of the present disclosure.

While the disclosure has been shown and described with reference to certain exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the disclosure as defined by the appended claims and their equivalents. Accordingly, the scope of the present disclosure should not be limited to the above-described embodiments, but should be defined not only by the appended claims, but also by equivalents thereof.

Claims

1. A microstrip antenna comprising:

a ground plate;

the dielectric substrate is arranged on the surface of the grounding plate;

the first patch is arranged on the top surface of the dielectric substrate; and

a second patch;

the dielectric substrate comprises a mixed dielectric structure, the mixed dielectric structure is arranged in a target area, the target area is an area where the electric field intensity of an electric field generated by a first patch in the dielectric substrate is smaller than a threshold value, the second patch is arranged on the top surface of the mixed dielectric structure, the bottom surface of the mixed dielectric structure is in contact with the grounding plate, the thickness of the mixed dielectric structure in the direction perpendicular to the grounding plate is smaller than that of the dielectric substrate in the direction perpendicular to the grounding plate, and the mixed dielectric structure comprises a plurality of first dielectrics and a plurality of second dielectrics which are alternately arranged.

2. The microstrip antenna according to claim 1, wherein said first and second patches are respectively coupled to said ground plane.

3. The microstrip antenna of claim 1, further comprising:

a first feed line connected with the first patch; and

and a second power supply line connected to the second patch, the first power supply line extending in the same direction as the second power supply line.

4. The microstrip antenna according to claim 3, wherein the characteristic impedance of the first and second feed lines is 50 Ω.

5. The microstrip antenna according to claim 1, wherein the thickness of said hybrid dielectric structure in a direction perpendicular to the ground plane is greater than half the thickness of said dielectric substrate in a direction perpendicular to the ground plane.

6. The microstrip antenna according to claim 1, wherein the dielectric constant and thickness of said first medium and the dielectric constant and thickness of said second medium satisfy the following formula:

ε1*d1+ε2*d2＝K*(λ/2)，

the d1 is the thickness of the first medium, the epsilon 1 is the dielectric constant of the first medium, the d2 is the thickness of the second medium, the epsilon 2 is the dielectric constant of the second medium, the lambda is the wavelength corresponding to the central frequency of the microstrip antenna, and the K is a positive integer.

7. The microstrip antenna according to claim 6, wherein said second patch is rectangular, the length of the long side of said second patch being set to a positive integer multiple of the sum of the thickness d1 of the first medium and the thickness d2 of the second medium.

8. The microstrip antenna according to claim 7, wherein the second patch extends in the same direction as the first and second media and has an edge at the seam of the first and second media.