CN111327345A

CN111327345A - Antenna isolation method, time delay network and equipment thereof

Info

Publication number: CN111327345A
Application number: CN201910633600.4A
Authority: CN
Inventors: 张闯; 刘一鸿; 苏笛; 林鹏; 钱辰; 喻斌; 李维实; 沈莹
Original assignee: Beijing Samsung Telecommunications Technology Research Co Ltd; Samsung Electronics Co Ltd
Current assignee: Beijing Samsung Telecommunications Technology Research Co Ltd; Samsung Electronics Co Ltd
Priority date: 2018-12-14
Filing date: 2019-07-12
Publication date: 2020-06-23
Anticipated expiration: 2039-07-12
Also published as: CN111327345B

Abstract

The embodiment of the application provides an antenna isolation method, which realizes isolation of a transmitting antenna and a receiving antenna by adding a plurality of metal chokes between the transmitting antenna and the receiving antenna to form a choke groove. An embodiment of the present application further provides a delay network, including: the time delay selection module comprises a plurality of time delay selection modules and at least one switch, wherein each time delay selection module comprises a time delay device and a microstrip line which are connected in parallel, and the switch is used for selecting whether a signal passes through the time delay device or the microstrip line; and at least one power divider, configured to be connected to one or more delay selection modules of the multiple delay selection modules. Antenna systems, analog cancellation modules, and devices are also provided.

Description

Antenna isolation method, time delay network and equipment thereof

Technical Field

The present application relates to the field of radio frequency communication technologies, and in particular, to an antenna isolation method, a delay network, and an apparatus thereof.

Background

The duplex mode of the traditional communication system is half duplex, which is mainly divided into a Time Division Duplex (TDD) mode and a Frequency Division Duplex (FDD) mode, wherein the time division duplex distinguishes uplink and downlink transmission through a time domain, and the frequency division duplex distinguishes uplink and downlink transmission through a frequency domain. The two half-duplex modes can avoid self-interference of transmission to reception of the same equipment, however, because only one direction of transmission is allowed on the same time-frequency resource, the utilization rate of the two modes to frequency spectrum is not high. To further improve the spectrum utilization of the system, a simultaneous same frequency Full Duplex (FD) technique may be used.

Theoretically, full-duplex technology can achieve twice the spectrum utilization of half-duplex technology. However, since the transmission and reception of the same device are simultaneously on the same frequency in the full-duplex mode, the reception of the device may suffer from self-interference of the transmission, and the strength of the self-interference is even 120 dB higher than that of the bottom noise, so in order for the full-duplex device to normally communicate, the self-interference needs to be reduced to the level of the bottom noise.

Therefore, a radio frequency self-interference cancellation technique with good performance is needed.

Disclosure of Invention

Therefore, the embodiment of the application provides an antenna isolation method, a time delay network, a self-interference elimination system and equipment.

According to a first aspect of the present application, there is provided an antenna isolation method, comprising:

arranging a plurality of choke plates made of metal materials, wherein the choke plates are positioned between a sending antenna and a receiving antenna, two adjacent choke plates form a choke groove, and each choke plate in the choke plates is fixed on a metal antenna panel.

In some embodiments, the plurality of chokes are parallel to each other and perpendicular to a line between the transmit antenna and the receive antenna.

In some embodiments, two or more of the plurality of chokes may have different heights.

In some embodiments, the height of the plurality of chokes is between one quarter and one half of a wavelength corresponding to a center frequency of an operating band of the transmit antenna and the receive antenna.

In some embodiments, the distance between the transmitting antenna and the nearest choke plate is a quarter of a wavelength corresponding to the center frequency of the antenna operating band, and the distance between the receiving antenna and the nearest choke plate is also a quarter of a wavelength corresponding to the center frequency of the antenna operating band.

In some embodiments, a spacing between adjacent chokes of the plurality of chokes is less than half a wavelength corresponding to a center frequency of an operating band of the transmit antenna and the receive antenna.

In some embodiments, the plurality of chokes are symmetrically distributed in height with respect to a midpoint of a line connecting the transmitting antenna and the receiving antenna, and the chokes located near the transmitting antenna and the receiving antenna have a highest height.

In some embodiments, the plurality of chokes are symmetrically distributed in height with respect to a midpoint of a line between the transmitting antenna and the receiving antenna, and a middle choke has a highest height.

According to a second aspect of the present application, there is provided an antenna system comprising: a receiving antenna; a transmitting antenna; and a plurality of chokes arranged according to the method of the first aspect between the receive antennas and the transmit antennas.

In some embodiments, the distance between the transmitting antenna and the choke plate closest to the transmitting antenna in the plurality of choke plates is a quarter of a wavelength corresponding to a center frequency of the antenna operating band, and the distance between the receiving antenna and the choke plate closest to the receiving antenna in the plurality of choke plates is a quarter of a wavelength corresponding to a center frequency of the antenna operating band.

According to a third aspect of the present application, a delay network is provided, comprising:

a plurality of latency selection modules, each of the plurality of latency selection modules comprising:

a time delay;

the microstrip line is connected with the time delay unit in parallel; and

at least one switch for selecting whether a signal passes through the delay or the microstrip line;

and

and the power divider is used for being connected with one or more delay selection modules in the plurality of delay selection modules.

In some embodiments, the delay network further includes at least one combiner, which is connected to the plurality of delay selection modules and/or the at least one power divider.

According to a fourth aspect of the present application, there is provided a latency network, comprising:

a plurality of delay subnetworks; and

at least one power divider and/or combiner, wherein one or more power dividers and/or combiners of the at least one power divider and/or combiner are connected between the plurality of delay sub-networks in the transmission direction of signals.

In some embodiments, one or more of the plurality of latency sub-networks comprises a latency network according to the third aspect described above.

According to a fifth aspect of the present application, there is provided an analog cancellation module comprising the delay network according to the third or fourth aspect; the attenuator and the phase shifter are connected in series on each output branch of the time delay network; and a control circuit for controlling the delay selection of the delay network and the settings of the attenuator and phase shifter.

According to a sixth aspect of the present application, there is provided an electronic device comprising an antenna system according to the second aspect described above and/or an analog cancellation module according to the fifth aspect described above.

The embodiment of the application improves the adaptability to the environment by constructing the time delay network capable of being adjusted in a program control mode, and simultaneously realizes the effect of increasing the virtual reconstruction channel indirectly by generating superposed signals with different time delays through the network under the condition of not increasing the number of physical reconstruction channels. Furthermore, by using an antenna isolation structure in the form of a choke groove having a choke plate composition, interference between the transmitting antenna and the receiving antenna is greatly reduced.

Drawings

The foregoing and additional aspects and advantages of the present application will become more apparent and readily appreciated from the following description, taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a schematic diagram illustrating a transceiving antenna coupling scenario;

FIG. 2 shows a schematic of a prior art circulator isolation scheme;

fig. 3 shows a schematic diagram of a prior art interference cancellation scheme for multiple transmit antennas;

FIG. 4 shows a schematic diagram of a prior art analog self-interference cancellation solution;

FIG. 5 is a schematic diagram showing the propagation of electromagnetic waves on a metal-textured surface;

FIG. 6 shows a schematic of choke parameters;

FIG. 7 illustrates a model diagram of an antenna design including an antenna isolation device according to an embodiment of the present application;

FIG. 8 shows a schematic diagram of the transmit antenna to choke distance;

figure 9 shows a schematic diagram of an antenna structure configuration;

fig. 10 shows a specific parameter configuration diagram of an antenna structure;

figure 11 shows a schematic view of another antenna configuration;

fig. 12 shows a schematic diagram of another antenna structure specific parameter configuration;

fig. 13 shows a schematic diagram of another antenna structure specific parameter configuration;

fig. 14 shows a schematic diagram of another antenna structure specific parameter configuration;

fig. 15 shows a schematic diagram of another antenna structure specific parameter configuration;

FIG. 16 shows a schematic diagram of a latency selection module according to an embodiment of the application;

FIG. 17 shows a schematic diagram of a latency network according to an embodiment of the present application;

FIG. 18 shows a schematic diagram of another latency network according to an embodiment of the present application;

FIG. 19 shows a schematic diagram of another latency network according to an embodiment of the present application; and

fig. 20 shows a schematic diagram of a radio frequency domain self-interference cancellation scheme including an antenna isolation device and a delay network according to the present embodiment.

In the drawings, the same or similar structures are identified by the same or similar reference numerals.

Detailed Description

Reference will now be made in detail to embodiments of the present application, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary only for the purpose of explaining the present application and are not to be construed as limiting the present application.

As used herein, the singular forms "a", "an", "the" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements may also be present. Further, "connected" or "coupled" as used herein may include wirelessly connected or wirelessly coupled. As used herein, the term "and/or" includes all or any element and all combinations of one or more of the associated listed items.

It will be understood by those within the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

It will be understood by those skilled in the art that "electronic device" as used herein may include any device that requires the transmission and reception of radio frequency signals simultaneously at the same frequency. Such a device may include: a cellular or other communication device having a single line display or a multi-line display or a cellular or other communication device without a multi-line display; PCS (Personal Communication Service), which may combine voice, data processing, facsimile and/or data Communication capabilities; a PDA (Personal Digital Assistant), which may include a radio frequency receiver, a pager, internet/intranet access, a web browser, a notepad, a calendar and/or a GPS (global positioning System) receiver; a conventional laptop and/or palmtop computer or other device having and/or including a radio frequency receiver. As used herein, an "electronic device" may be portable, transportable, installed in a vehicle (aeronautical, maritime, and/or land-based), or situated and/or configured to operate locally and/or in a distributed fashion, and/or in any other location(s) on earth and/or in space. The "electronic Device" used herein may also be a communication terminal, a web terminal, a music/video playing terminal, such as a PDA, an MID (Mobile Internet Device) and/or a Mobile phone with music/video playing function, and may also be a smart tv, a set-top box, and the like. Further, the devices described herein may also be access network devices such as base stations, relay stations, and the like.

The current self-interference cancellation techniques mainly include: antenna isolation techniques, analog self-interference cancellation techniques and digital self-interference cancellation techniques. The antenna isolation technique uses physical isolation of antennas or beamforming techniques to achieve the purpose of reducing the power of self-interference signals. Analog self-interference cancellation techniques operate before an analog-to-digital conversion module (ADC), which reconstructs the self-interference signal using the analog signal and subtracts the reconstructed signal from the received signal. The digital self-interference cancellation technique works after the ADC, and uses the digital signal to reconstruct the self-interference signal and subtracts the reconstructed signal from the received signal. Due to the limitation of the dynamic range of the ADC, the sum of the antenna isolation and the analog self-interference cancellation needs to be larger than a certain value to ensure that the quantization error of the effective signal received by the ADC is at the level of the noise floor.

The main reason for strong self-interference signal is the coupling between the transmitting and receiving antenna units, and the source of mutual coupling between the transmitting and receiving antenna units mainly includes two parts: one part is antenna unit space coupling; one part by floor surface currents or surface waves.

As shown in fig. 1, a transmitting antenna 1 as a radiating element radiates electromagnetic waves into free space, and a receiving antenna element 2 is connected to a matching load. The mutual coupling effect is mainly divided into the following parts:

(1) the electromagnetic wave radiated by the antenna element 1 affects the surface current distribution of the antenna element 2 by spatial coupling.

(2) The distributed currents on the antenna element 2 radiate into space and influence the radiation of the antenna element 1.

(3) Feeding the transmit antenna through the feed point will induce a distributed current in the common floor and into the ports of the antenna element 2.

Mutual coupling between antenna elements will cause a change in the current distribution over the antenna, the current being the source of the radiation, which will change the radiation pattern of the antenna elements. The directional diagram function of a single antenna element can be used

It is shown that the directional pattern of a single antenna In the far zone should be such that when fed with current In

Through mutual coupling analysis among the antenna units, it can be known that an electromagnetic field radiated by the excited antenna unit is coupled to the non-excited antenna unit to generate induced current, a part of energy of the induced current on the non-excited antenna unit is consumed by a matching load connected to the port, and another part of the induced current is radiated into free space. Therefore, the electromagnetic wave somewhere in the free space is formed by superposing a plurality of electromagnetic wave vectors, which is different from the electromagnetic wave radiated by a single antenna. In a multiport network, the directional pattern function of the jth cell is:

in which the jth element corresponds to mm and the remaining elements to mn (m ≠ n), which is related to the directional diagram function of a single antenna element

Different. The antenna element cross-coupling affects not only the directional pattern but also the input impedance, polarization characteristics, gain, etc. of the antenna, thereby deteriorating the overall performance of the system.

When the antenna element pitch is small, the coupling between the antenna elements is mainly caused by near-field coupling and floor surface currents.

The existing main methods for suppressing the coupling of the antenna unit include:

1. a shielding structure. Such as choke rings, metal fences, etc., shield the cross-talk of energy between antenna elements.

2. A gap with a special structure is arranged on the floor to block surface wave propagation so as to realize mutual coupling suppression.

3. A special material. Such as wave-absorbing materials, left-handed materials, FSS, EBG, etc.

In addition, in order to effectively isolate the transmitting antenna from the receiving antenna, the conventional full-duplex antenna also adopts the following modes:

1. and isolating the transceiving ports by adopting a circulator. As shown in fig. 2, the port 1 is a transmitting antenna port, the port 3 is a receiving antenna port, the port 2 is a common antenna port, a transmitting signal is radiated out through the port 1 and the port 2, a receiving signal is received through the port 2 and the port 3, the transmitting port 1 and the receiving port 3 are isolated through the common port 2, the transmitting signal is prevented from directly entering a receiving loop, and therefore the effect of transmitting and receiving isolation is achieved.

2. The transmitting antenna and the receiving antenna are isolated by adopting different polarization modes. For example, the transmitting antenna uses horizontal polarization, and the receiving antenna uses vertical polarization, so that the transmitting signal can be effectively suppressed from entering the receiving loop.

3. The transmit antenna and the receive antenna are separated by distance. I.e. the transmitting antenna and the receiving antenna are separated by a certain distance, the longer the distance is, the higher the corresponding isolation is.

4. Signals passing through multiple transmit antennas are cancelled out at the receive antennas for isolation. As shown in fig. 3, the distance of the transmitting antenna 2 from the receiving antenna is more than half a wavelength from the transmitting antenna 1 to the receiving antenna, and then the two transmitting antennas cancel each other out when transmitting the same signal at the receiving antenna.

The antenna design scheme as described above can solve the problem of isolation of the transmitting and receiving antennas to some extent, however, the inventors of the present application found that these design schemes have problems. For example, the circulator solution can only achieve 15dB isolation; the way of antenna polarization can only achieve about 20 dB more isolation; although the distance for isolating the transceiving antennas can achieve higher isolation, the distance between the transceiving antennas is far enough, and the size of the corresponding antennas is larger; the scheme of isolating by overlapping multiple antenna signals is only suitable for narrow-band signals, such as 5MHz, and when the signal bandwidth is wide, the isolation of the bandwidth part with the farther center frequency point is poor.

The existing analog self-interference cancellation technology is mainly a direct coupling radio frequency interference cancellation mode. As shown in fig. 4, in this method, a path of signal is coupled from the power amplifier output of the transmitting end as a reconstructed signal, the reconstructed signal is divided into multiple paths of signals by a power divider, and each path of signal passes through a coaxial line with different lengths or a time delay chip with different time delay sizes, and is combined and output by a combiner after being subjected to amplitude modulation and phase modulation. The reconstructed signal is used to cancel the received signal, so as to achieve the purpose of eliminating the self-interference signal.

The self-interference signal contains a signal directly received between the transmitting antenna and the receiving antenna and also contains a multi-path signal formed by reflection of an object in the environment. In the process of simulating self-interference cancellation, the environment and the multipath distribution condition need to be analyzed in advance, and the time delay of the signal input into the reconstruction channel needs to be adjusted manually to be approximately the same as the time delay of the multipath signal.

The inventors of the present invention found that this technique has the following problems:

(1) the time delay of each reconstruction channel is fixed, and different environments cannot be fitted;

(2) the number of reconstruction channels should be approximately the same as the number of strong multipath signals in the environment, and if the number of physical reconstruction channels is directly increased, the volume and complexity of the reconstruction plate will be increased.

To solve some of the above problems, there is provided an antenna isolation method including:

In some embodiments, the plurality of chokes have a thickness that is substantially less than a spacing between adjacent chokes.

To solve some of the above problems, there is provided an antenna system comprising: a receiving antenna; a transmitting antenna; and a plurality of chokes arranged according to the above method between the receiving antenna and the transmitting antenna.

To solve some of the above problems, an embodiment of the present application provides a delay network, including:

a time delay;

the microstrip line is connected with the time delay unit in parallel; and

and

In the above embodiment, the delay units included in each delay selection module may be the same or different, and the number of the delay units included in each delay selection module may be one or multiple.

To address some of the above issues, there is provided a latency network comprising:

a plurality of delay subnetworks; and

In some embodiments, one or more of the plurality of delay sub-networks comprises a delay network as described above.

The phrase "a plurality of C are connected between a plurality of a and a plurality of B in the transmission direction of a signal" as used herein means that any one C of the plurality of C is not a termination point (e.g., a start point and an end point) of a network for a network including at least the plurality of a, the plurality of B, and the plurality of C.

To solve some of the above problems, there is provided an analog cancellation module comprising any of the above delay networks; the attenuator and the phase shifter are connected in series on each output branch of the time delay network; and a control circuit for controlling the delay selection of the delay network and the settings of the attenuator and phase shifter.

To address some of the above issues, an electronic device is provided that includes the above antenna system and/or analog cancellation module.

The technical solutions of the present application will be discussed in more detail below with respect to specific embodiments, and it should be noted that the specific technical solutions provided in the following embodiments are only examples and should not be considered as limitations on the technical solutions of the present application.

Example one

This embodiment designs an antenna isolation structure, characterized by: the high-frequency and high-frequency choke type antenna comprises at least two metal chokes, each two adjacent chokes form a choke groove, the heights of the different chokes can be different, the height and the thickness of each choke and the distance between the adjacent chokes depend on the frequency and the bandwidth to be supported by the antenna, and the high-frequency and high-frequency choke type antenna can be further optimized through simulation. By utilizing the antenna isolation structure, the near-field coupling and the surface wave of the receiving and transmitting antenna can be inhibited, so that the self-interference of the transmitting antenna of the same equipment to the receiving antenna is inhibited.

Design of choke height

The working principle and design of the choke can be analyzed by the metal corrugated surface theory, as shown in fig. 5, and a general surface wave is composed of two modes of TE and TM. From the boundary conditions of electromagnetic wave propagation, the surface of a flat floor approximates the PEC characteristics, its tangential electric field E _t0, i.e. TE mode, but TM mode electromagnetic waves can be propagated by a planar floor surfaceA wave. Similarly, for a PMC surface that does not actually exist, its tangential magnetic field H _t0, so that the TM wave is cut off and the TE wave is propagated.

As shown in fig. 6, the metal corrugated surface structure with a depth d of a quarter wavelength is formed by arranging PEC and equivalent PMC surfaces at intervals periodically distributed along the x-axis. The PEC surface is a metal plane located on the xoy surface, the equivalent PMC surface is composed of a quarter-wavelength parallel metal wall of a terminal short circuit (terminal-short), and according to the transmission line basic theory, the surface impedance of the short circuit metal wall is approximately infinite after the short circuit metal wall is transformed by the quarter-wavelength parallel transmission line, and the short circuit metal wall is equivalent to the PMC surface, so that the parallel metal wall can effectively block the propagation of surface waves.

The height of the choke can be obtained according to the surface impedance model proposed by a.d. olver, and the surface admittance of the metal corrugated surface can be expressed as

Wherein, J₁And Y₁First and second bessel functions of first order are respectively expressed, k is the free space wavenumber, d is the groove depth d ═ b-a, as shown in fig. 6, w is the groove width, η₀Is the free space wave impedance.

Substituting the relevant data, calculating to obtain:

where Z is₀377 Ω is the wave impedance in free space, k is the wave number in free space, Z_bThe impedance at the bottom of the trench, for a metal structure, is zero, so that:

Z_s＝jZ₀tan kd

to further solve for the surface attenuation factor α of the corrugated metal surface, the surface wave impedance Z is assumed to be present with an electric field component in the propagation direction_sThe available boundary conditions are expressed as:

according to Harrington's study, the surface wave at this time can be expressed as:

the above formula can be obtained by combining the Maxwell equation and Helmholtz equation:

namely:

according to the variation of the groove depth d, the propagation condition of the surface wave on the metal corrugated surface can be summarized as follows:

1) when d is less than λ/4, the attenuation factor α is greater than 0, so that the surface wave propagates at a slow wave speed less than the speed of light, and the transmission of the surface wave is not suppressed by the metal corrugated surface.

2) When λ/4 < d < λ/2, the attenuation factor α < 0 can be obtained from the above formula, and when a surface wave having a negative attenuation factor does not exist, the propagation of the surface wave is suppressed by the metal corrugated surface.

3) When d > λ/2, the attenuation factor α, which can be determined from the above formula, will vary periodically according to the tan function curve, repeating the above two cases.

From the above analysis, it can be seen that the choke height satisfies the condition of λ/4 < d < λ/2 in order to suppress the surface wave propagation. A choke height of between 3 λ/4 < d < λ is also possible due to the periodic variation of the attenuation factor, but from the viewpoint of reducing the antenna size, a choke height of λ/4 < d < λ/2 is preferable. The inventors of the present invention have also found that when the heights of all the chokes are the same, there is better suppression of surface waves for single frequency signals or signals with relatively narrow bandwidths. Therefore, in order to suppress surface waves over a larger bandwidth, it is proposed in some embodiments of the present application to employ chokes of different heights, the specific value of the height of each choke being determinable from the results of the simulation.

Design of the choke plate spacing and thickness

In order to ensure that only TE mode electromagnetic waves exist between choke plates, the distance and thickness of the choke plates need to satisfy: thickness < spacing + thickness < half wavelength. Therefore, in the actual design, the distance between the chokes is smaller than a half wavelength, and the thickness of the chokes is far smaller than the distance between the chokes.

In summary, the embodiment of the present application proposes that no less than two metal chokes are used to suppress the spatial coupling and the surface wave coupling between the transmitting antenna and the receiving antenna, wherein the plurality of chokes are parallel to each other, two adjacent chokes and the metal antenna panel form a choke groove, the heights of different chokes may be different, and the height of each choke is between a quarter wavelength and a half wavelength, or between three quarters wavelength and a full wavelength, the distance between two adjacent chokes is smaller than a half wavelength, and the thickness of the choke plate is much smaller than the distance between the chokes.

It should be noted that, when determining the number of chokes, the height of each choke, the spacing between chokes, and the thickness of each choke, many non-ideal factors existing in the antenna design, the size requirement of the antenna, the compromise between the antenna pattern and the isolation, and the like need to be comprehensively considered for further optimization through simulation.

Example two

This embodiment proposes an antenna structure, which utilizes the antenna isolation structure described in the first embodiment to suppress the interference of the transmitting antenna to the receiving antenna, and at the same time, sets the distance between the transmitting antenna and the nearest choke plate to be a quarter of the wavelength corresponding to the antenna center frequency, and sets the distance between the receiving antenna and the nearest choke plate to be also a quarter of the wavelength corresponding to the antenna center frequency, so as to ensure the radiation pattern of the antenna.

Specifically, the structure of the antenna can be as shown in fig. 7, where the antenna is a two-transmit and two-receive antenna, where port 1 and port 2 are transmit antenna ports and respectively adopt +450 and-450 polarization modes, and port 3 and port 4 are receive antenna ports and respectively adopt +450 and-450 polarization modes. In order to improve the isolation between the transmitting antenna and the receiving antenna, i.e. reduce the influence of the

ports

1 and 2 on the

ports

3 and 4 when transmitting signals, an enclosure is introduced around the transmitting and receiving antenna, and the choke structure described in the first embodiment is added between the two transmitting antenna ports and the two receiving antenna ports.

Design of the spacing of the antenna from the nearest choke

The distance between the transmitting antenna and the nearest choke is designed mainly in consideration of avoiding the radiation wave of the antenna from being cancelled out in reverse phase with the reflected wave of the choke. As shown in fig. 8, when the radiation wave of the transmission antenna is reflected by the choke plate made of a metal material, a phase shift of 1800 is caused, and if the transmission antenna is relatively close to the choke plate, the radiation wave on the left side of the transmission antenna and the reflected wave from the choke plate cancel each other out in opposite phases, and in order to avoid this, the distance between the transmission antenna and the choke plate is made a quarter wavelength, and the phase of the reflected wave to the radiation wave on the left side of the antenna is 0 and the reflected wave are added in phase. Therefore, the distance between the transmitting antenna and the nearest choke is set to a quarter wavelength, and similarly, the distance between the receiving antenna and the nearest choke is also set to a quarter wavelength.

Based on the antenna structure, if 1 transmit and 1 receive are adopted, the transmit antenna and the receive antenna can also adopt different polarization modes, for example, in fig. 7, the transmit antenna and the receive antenna adopt port 1 for transmission and port 4 for reception, or adopt port 2 for transmission and port 3 for reception, and then the isolation between the transmit antenna and the receive antenna is caused by different polarization modes in addition to the isolation of a choke plate.

EXAMPLE III

Based on the antenna structure of the second embodiment, the present embodiment provides a specific antenna parameter configuration scheme.

In this embodiment, two kinds of high chokes are used, wherein the chokes on both sides are high chokes, and the choke in the middle is a low choke and a high choke alternately arranged. For example, fig. 9 shows 5 chokes in total, two chokes on both sides (1 st and 5 th) are high chokes, and the three chokes in the middle (2 nd, 3 rd and 4 th) are low chokes, high chokes and low chokes, respectively.

By adding a plurality of chokes with different heights between the transmitting and receiving antennas, the space coupling between the transmitting and receiving antennas and the surface wave coupling on the metal antenna panel can be reduced in a larger bandwidth, and the port isolation between the transmitting and receiving antennas is effectively improved.

Based on the structure of the choke, a specific parameter configuration is shown in fig. 10. There are 5 chokes between the receiving antenna, wherein, the height of board 1, board 3, board 5 is 32mm, and the height of board 2 and board 4 is 12mm, and the interval of board is 28.25mm, and thickness is 2mm, and the distance of sending antenna and board 1 is 38.5mm, and the distance of receiving antenna and board 5 is 38.5mm, and the thickness of metal antenna panel is 3 mm. The parameter configuration can effectively isolate the transceiving antennas in the frequency band of 3.4-3.6GHz, for example.

It should be noted that the above structures and values are only examples, and even for the transmitting and receiving antennas in the same frequency band, more or fewer chokes may be used, and at least some of the above values may have different values. The embodiment is not limited by the specific number of chokes and the value of the specific parameter.

Example four

Based on the antenna structure of the second embodiment, the present embodiment provides another specific antenna parameter configuration scheme.

In this embodiment, two kinds of chokes are used, and the height of the chokes at both ends is smaller than that of the choke at the middle. As shown in fig. 11, there are 5 chokes in total between the transmitting and receiving antennas, and the two chokes on both sides (1 st, 2 nd, 4 th and 5 th) are low chokes, and the choke in the middle (3 rd) is high chokes.

Based on the structure of the choke, a specific parameter configuration scheme is shown in fig. 12. There are 5 chokes between the receiving and dispatching antenna, wherein, the height of board 1, board 2, board 4, board 5 is 57mm, and the height of board 3 is 67mm, and the interval of board is 23mm, and thickness is 2mm, and the distance of sending antenna and board 1 is 31mm, and the distance of receiving antenna and board 5 is 31mm, and the thickness of metal antenna panel is 3 mm. The parameter configuration can effectively isolate the transceiving antennas in the frequency band of 2.35-2.55GHz, for example.

EXAMPLE five

In this embodiment, two kinds of high chokes are used, wherein the chokes on both sides are high chokes, and the choke in the middle is a low choke and a high choke alternately arranged. For example, fig. 13 shows 5 chokes in total, two chokes on both sides (1 st and 5 th) are high chokes, and the three chokes in the middle (2 nd, 3 rd and 4 th) are low chokes, high chokes and low chokes, respectively.

Based on the structure of the choke, a specific parameter configuration scheme is shown in fig. 13. There are 5 chokes between the receiving and dispatching antenna, wherein, the height of board 1, board 3, board 5 is 4mm, and the height of board 2 and board 4 is 1.5mm, and the interval of board is 3.5mm, and thickness is 1mm, and the distance of sending antenna and board 1 is 4.8mm, and the distance of receiving antenna and board 5 is 4.8mm, and the thickness of metal antenna panel plate is 3 mm. The parameter configuration can effectively isolate the transceiving antenna in the 28GHz band, for example.

EXAMPLE six

In this embodiment, two kinds of chokes are used, and the height of the chokes at both ends is smaller than that of the choke at the middle. As shown in fig. 14, there are 5 chokes in total between the transmitting and receiving antennas, and the two chokes on both sides (1 st, 2 nd, 4 th and 5 th) are low chokes, and the choke in the middle (3 rd) is high chokes.

Based on the structure of the choke, a specific parameter configuration is shown in fig. 14. There are 5 chokes between the receiving antenna, wherein, the height of board 1, board 2, board 4, board 5 is 5mm, and the height of board 3 is 5.9mm, and the interval of board is 2mm, and thickness is 1mm, and the distance of sending antenna and board 1 is 2.7mm, and the distance of receiving antenna and board 5 is 2.7mm, and the thickness of metal antenna panel is 3 mm. The parameter configuration can effectively isolate the transceiving antenna in the 28GHz band, for example.

EXAMPLE seven

In this embodiment, two kinds of chokes are used, and the height of the chokes at both ends is smaller than that of the choke at the middle. As shown in fig. 15, 3 chokes are shared between the transmitting and receiving antennas, and a low choke is used for two chokes (1 st and 3 rd) on both sides, and a high choke is used for a choke (2 nd) in the middle. Based on the structure of the choke, a specific parameter configuration is shown in fig. 15. The height that has 3 chokes between the receiving and dispatching antenna is 5mm respectively, 5.9mm, 5mm, and the interval of choke is 2mm, and thickness is 1mm, and the distance of sending antenna and board 1 is 2.7mm, and the distance of receiving antenna and board 3 is 2.7mm, and the thickness of metal antenna panel is 3 mm. The parameter configuration can effectively isolate the transceiving antenna in the 28GHz band, for example.

Example eight

This embodiment introduces a delay network structure with adjustable delay.

The basic unit of the delay network structure is a delay selection module as shown in fig. 16, and the delay selection module is composed of one or two switches, a delay unit and a microstrip line. The time delay device generates fixed time delay, the length of the microstrip line is extremely short, the introduced time delay is approximately 0, and the time delay device is connected with the microstrip line in parallel. The switch is used for selecting whether the signal passes through the delayer or the microstrip line, the signal has fixed time delay when passing through the delayer, and the signal has no time delay approximately when passing through the microstrip line.

The time delay network is composed of not less than 1 time delay selection module and not less than 1 power divider. The time delay selection module outputs the input signal without time delay or after fixed time delay; the power divider converts 1 path of input signals into a plurality of paths of output signals with the same or different powers, and the time delay of the output signals relative to the input signals is approximately 0. The time delay selection modules are connected in series to form a branch circuit with adjustable time delay, and the time delay of the branch circuit is adjusted by adjusting the on and off of a switch of each time delay selection module; one branch is divided into a plurality of branches through the power divider, each branch can be continuously connected with a plurality of time delay selection modules in series and is divided into a plurality of branches through the power divider, and any number of time delay adjustable output branches can be generated by introducing the power divider into the time delay adjustable branch. The number of the time delay selection modules is determined according to the time delay range required to be adjusted by the branches, and the number of the power dividers is determined according to the number of the branches required. When the signal passes through the time delay network, the signal after a certain time delay is obtained according to the state of each time delay selection module when the signal passes through one branch circuit; when the signals pass through the power divider, the signals are divided into multiple paths of signals with the same or different powers according to the power distribution condition of the power divider, and the time delays of the signals are the same.

Fig. 17 shows an example of the delay network with adjustable delay, where a main branch is formed by connecting 4 delay selection modules in series, and then is divided into two branches by a power divider, each branch is connected with 4 delay selection modules in series, and then is divided into two branches by the power divider, and the four branches are connected with 4 delay selection modules in series, so as to finally generate four output branches. Assuming that the delay of each delay selection module is D, since there are 12 delay selection modules on each output branch, the adjustable delay range on each output branch is 0 to 12D, and the adjusted granularity is 1D.

If the delay of each fixed delayer is 2 ns. Assume that the switch selections of the delay selection blocks in the first row of the delay network in fig. 17 are sequentially (0, 1, 0, 1), where 0 denotes no delay and 1 denotes a delay. The delay output for the first row is 4 ns. Similarly, the switch selections of the second row and the third row are (1, 0, 0, 0) and (1, 1, 1, 0), respectively, and the time delay outputs of the second row and the third row are 6ns and 10 ns. The selection modes of the fourth line, the fifth line, the sixth line and the seventh line are respectively as follows: (0,0,0,0)(1,0,0,0)(1,0,0,0)(1,1,1,1). Finally, the time delays of the 4 paths of signals output by the time delay network of fig. 17 are respectively: 6ns, 8ns, 12ns, 18 ns.

It should be noted that fig. 17 is only an example of the latency network of the present application, and should not be considered as a limitation to the technical solution of the present application. For example, in other implementations, the power divider may be connected to another power divider, and is not limited to only being connected to the delay selection module as shown in fig. 17.

Example nine

This embodiment introduces another delay network structure based on the eighth embodiment. Different from the eighth embodiment, a combiner is introduced into the delay network, and the combiner has a function of combining multiple input signals into 1 output signal in an equal power or unequal power manner, and the delay of the output signal relative to the input signal is approximately 0. By introducing the combiner, the 1-path output signal can contain multiple paths of signals with different time delays. Specifically, the delay network is first divided into multiple branches by 1 power divider, then each branch is connected in series with 1 or more delay adjustable modules, and is further divided into multiple branches by the power divider, then the output of the power dividers is combined into 1 path by the combiner, the output of the combiner can be used as the final output, and the delay adjustable modules, the power dividers and the combiner can also be connected in series continuously in the manner. The number of the delay adjustable modules, the number of the power dividers, the number of the combiners, and the connection mode of the delay adjustable modules and the power dividers are determined by the range of the adjustable delay which needs to be generated finally, the number of branches which need to be output finally, and the number of signals which need to be superposed by each output branch.

Fig. 18 is an example of the structure of the delay network, in which 1 branch is first divided into 3 branches by 1 power divider, then 1 delay adjustable module and 1 power divider are connected in series in each branch, the power divider connected in series further divides the branch into 3 branches, then each combiner respectively takes 1 path from the outputs of the 3 power dividers to form 3 paths of inputs, in addition, 1 switch is connected in series before each path of input, the path is selected as an input or not by closing or opening the switch, 3 combiners generate 3 paths of outputs in total, and the 3 paths of outputs are respectively connected in series with 1 delay selection module as a final output. The flow of the signal through the time delay network is as follows: the signal is divided into 3 paths of signals by the power divider, each path of signal generates a signal with certain time delay by a time delay selection module, then each path of signal is divided into 3 paths of signals with different time delays by the power divider, then the signal is determined not to enter the combiner according to the switching state in front of the combiner, the signals input into the combiner are superposed into one path of output signal, and the output signal is generated as a final output signal after a certain time delay by the time delay selection modules connected in series.

If the input signal is x (t), the time delays of the

time delay units

1, 2 and 3 are respectively D₁、D₂、D₃And the gains of the power divider and the combiner are both 1. ThenAfter passing through the first row of time delay devices, the output signals of the three power dividers are x (t + S) respectively₁₁D₁₁)，x(t+S₁₂D₁₂)，x(t+S₁₃D₁₃) The three signals input to any one combiner are respectively as follows:

wherein S_ijAnd selecting a switch corresponding to the jth time delay selection module in the ith column, namely selecting whether a signal passes through the time delay chip or the microstrip line. Provision of S_ijA value of 0 indicates that the signal does not increase the delay without passing through the fixed delay chip. S_ijAnd 1, the signal is added with the fixed time delay through the fixed time delay chip. D_ijRepresenting the delay of the jth fixed delay chip of the ith column. The signals output by the combiner are combined and output to the next column of delay selection modules, so that the signals output by the combiner can be represented as:

C₁₁x(t+S₁₁D₁₁)+C₁₂x(t+S₁₂D₁₂)+C₁₃x(t+S₁₃D₁₃)

wherein C is_ijThe selection method of the j-th switch before each i-th combiner is shown, wherein 0 is defined as open and 1 is defined as closed. Therefore, the signals input to the delay selection modules in the next column are respectively:

after passing through the second row of delay selection modules, the finally output 3 paths of signals are:

the signal output of various time delay superposition and various time delay distribution can be achieved by controlling the switch S and the switch C.

The time delay of a single fixed time delay chip is assumed to be 1ns, 2ns and 5ns respectively. I.e. D_i1＝1ns，D _i2＝2ns，D_i3＝5ns. Let C₁₁＝1，C₁₂＝0，C₁₃＝0。S₁₁＝1，S₁₂＝1，S₁₃＝1，S₂₁And when the output delay of the first path of the matrix delay network is 1, the output delay of the first path of the matrix delay network is 2 ns. Let C₂₁＝1，C₂₂＝1，C₂₃＝1，S₁₁＝1，S₁₂＝1，S₁₃＝1，S₂₂And (1), the second output of the matrix delay network is a superposed signal of signals with the delay of (3ns, 4ns, 7 ns). Let C₃₁＝1，C₃₂＝0，C₃₃＝1。S₁₁＝1，S₁₂＝1，S₁₃＝1，S₂₃And (0), the third path output of the matrix time delay network is a superposed signal of signals with time delays of (1ns, 5 ns). Therefore, the final output signals are:

it should be noted that fig. 18 is only an example of the latency network of the present application, and should not be considered as a limitation to the technical solution of the present application. For example, in other implementations, the power divider may be connected to another power divider, not limited to only the delay selection module and the combiner shown in fig. 17, and the combiner may send its output to a splitter or another combiner to form a more complex delay network.

Example ten

In this embodiment, a cascade structure of a delay network is introduced, and two or more stages of delay networks are cascaded through a combiner and/or a power divider, so that more branches including different delay outputs can be generated with fewer delay units.

Specifically, the cascaded delay network is composed of delay networks, combiners and/or power dividers, where each delay network generates 1 input path to multiple output paths with different delays, the delay network may adopt the delay network with adjustable delay described in the eighth embodiment or the ninth embodiment, or may adopt a fixed delay network shown in fig. 16, the combiners combine the multiple input paths into 1 output path according to equal power or unequal power, and the power dividers divide the 1 input path into multiple output paths with equal power or unequal power. The multi-path output of a delay network is combined into 1 path output through a combiner, so that 1 path output containing different time delays can be obtained, then the output of the combiner can be directly connected to the input of the next stage delay network in series, or the output of the combiner is divided into a plurality of branches through a power divider, each branch is connected with a delay network in series, the finally obtained time delay of each output branch is the sum of the time delays of each stage of the multi-stage delay network passed by the branch from the initial input to the final output, and if the branch combined by the combiner exists on the branch, the output of the branch comprises the superposition of the signals of the combined branches. It should be noted that the delay network cascade structure is not limited to two-stage cascade, and may also be three-stage or more-stage cascade, the adjacent two-stage cascade mode is the same as the two-stage cascade mode, and the stage number of the delay network, the number of the delay network in each stage, the number of the combiner, the number of the power divider, and the connection mode of the delay network, the combiner, and the power divider are determined according to the number of output branches finally required and the delay requirement of each branch. When a signal passes through the cascade time delay network, 1 path of signal generates multiple paths of signals with different time delays when the signal passes through each time delay network, when the signal passes through the combiner, multiple paths of input signals are superposed into 1 path of output signals, when the signal passes through the power divider, 1 path of input signal generates signals with the same multiple paths of time delays and the same or different powers, the signal finally output by one branch is the superposition of all signals reaching the branch, the time delay of each signal is the sum of the time delays of the passing cascade networks, and the power is the product of the initial input power and the gains of the passing combiner and the power divider.

FIG. 19 is an example of the cascaded delay network, where the first stage delay network generates 1 input to 4 outputs with different delays, and the delays of the 4 outputs are D₁₁，D₁₂，D₁₃，D₁₄Then, the combiner combines 4-path signals into 1-path signal, the power divider divides the 1-path signal output by the combiner into 2-path signals, then the 2-path signals are respectively sent to the next-stage time delay network, the two time delay networks respectively have 4-path output, wherein the two time delay networks output by the time delay network 2The time delays of the 4 paths of signals are respectively D₂₁，D₂₂，D₂₃，D₂₄The time delay of 4 paths of signals output by the time delay network 3 is respectively D₃₁，D₃₂，D₃₃，D₃₄. Each path of signal of the finally output 8 paths of signals is formed by overlapping 4 paths of signals, assuming that an input signal is x (t), and gains of the time delay network, the combiner and the power divider are all 1, then the output 8 paths of signals are respectively:

in the cascaded delay network of fig. 19, if the delay networks (1), (2) and (3) all adopt the delay network shown in fig. 17, and the delays of the 4 paths are (6ns, 8ns, 12ns, 18ns), respectively, the output signal of the 1 st path of the delay network (2) is a superimposed signal of the signals with the delays of (12ns, 14ns, 18ns, 24ns), respectively. Similarly, the output signal of the 2 nd path is a superimposed signal of signals with time delays of (14ns, 16ns, 20ns, 26ns), the output signal of the 3 rd path is a superimposed signal of signals with time delays of (18ns, 20ns, 24ns, 30ns), and the output signal of the 4 th path is a superimposed signal of signals with time delays of (24ns, 26ns, 30ns, 36 ns). The output signal of the delay network (3) can be obtained similarly.

EXAMPLE eleven

This embodiment introduces a radio frequency domain self-interference cancellation scheme for full-duplex devices. The self-interference cancellation scheme is composed of antenna isolation and analog self-interference cancellation, where at least the antenna isolation scheme adopts the antenna structure with the choke plate described in the second embodiment, or at least the analog domain self-interference scheme adopts the structure of the delay network described in the eighth, ninth, and tenth embodiments.

Fig. 20 is an example of the radio frequency domain self-interference cancellation scheme, where an antenna of the scheme adopts an antenna structure with isolated chokes as described in the second embodiment, a delay network for analog domain cancellation adopts a delay network structure as described in the eighth, ninth, and tenth embodiments, each output branch of the delay network is respectively connected in series with an amplitude modulator and a phase shifter, a control unit adjusts the delay of each output branch by adjusting the switch selection of the delay network, adjusts the gain of each branch by adjusting a phase modulator, and adjusts the phase of each branch by adjusting the phase shifter. The scheme shown in fig. 20 has an advantage that the radio frequency domain self-interference cancellation capability of the full-duplex device can be effectively improved by using the antenna scheme and the delay network provided by the present application in combination.

The foregoing is only a partial embodiment of the present application, and it should be noted that, for those skilled in the art, several modifications and decorations can be made without departing from the principle of the present application, and these modifications and decorations should also be regarded as the protection scope of the present application.

Claims

1. An antenna isolation method, comprising:

2. The antenna isolation method of claim 1, wherein the plurality of chokes are parallel to each other and perpendicular to a line between the transmit antenna and the receive antenna.

3. The antenna isolation method of claim 1, wherein two or more of the plurality of chokes have different heights.

4. The antenna isolation method of claim 1, wherein the heights of the plurality of chokes are between one quarter and one half of a wavelength corresponding to a center frequency of an operating band of the transmit antenna and the receive antenna.

5. The antenna isolation method of claim 1, wherein a spacing between adjacent chokes in the plurality of chokes is less than half a wavelength corresponding to a center frequency of an operating band of the transmit antenna and the receive antenna.

6. The antenna isolation method of claim 5, wherein a thickness of each choke of the plurality of chokes is substantially less than a spacing between the adjacent chokes.

7. The antenna isolation method of claim 1, wherein the plurality of chokes are symmetrically distributed in height with respect to a midpoint of a line connecting the transmitting antenna and the receiving antenna, and the choke located near the transmitting antenna and the receiving antenna has a highest height.

8. The antenna isolation method of claim 1, wherein the plurality of chokes are symmetrically distributed in height with respect to a midpoint of a line between the transmitting antenna and the receiving antenna, and a middle choke has a highest height.

9. An antenna system, comprising:

a receiving antenna;

a transmitting antenna;

a plurality of chokes arranged according to the method of any one of claims 1 to 8 between the receive antennas and the transmit antennas.

10. The antenna system of claim 9, wherein the transmitting antenna is located a quarter of a wavelength corresponding to a center frequency of the antenna operating band from a choke of the plurality of chokes that is closest to the transmitting antenna, and the receiving antenna is located a quarter of a wavelength corresponding to a center frequency of the antenna operating band from a choke of the plurality of chokes that is closest to the receiving antenna.

11. A latency network, comprising:

a time delay;

the microstrip line is connected with the time delay unit in parallel; and

at least one switch for selecting whether a signal passes through the delay or the microstrip line; and

12. The latency network of claim 11, further comprising:

and the combiner is used for being connected with the plurality of time delay selection modules and/or the at least one power divider.

13. A latency network, comprising:

a plurality of delay subnetworks; and

14. The latency network of claim 13, wherein one or more of the plurality of latency sub-networks comprises the latency network of claim 11 or 12.

15. An analog cancellation module, comprising:

the latency network of any one of claims 11 to 14;

the attenuator and the phase shifter are connected in series on each output branch of the time delay network; and

and the control circuit is used for controlling the time delay selection of the time delay network and the setting of the attenuator and the phase shifter.

16. An electronic device, comprising:

the antenna system of claim 9 and/or the analog cancellation module of claim 15.