CN118156775A - Small electric antenna and terminal equipment - Google Patents

Abstract

The present disclosure provides an electrically small antenna, comprising an antenna radiator, a feed probe, a first capacitive load component, a second capacitive load component, and a ground plate, the feed probe being connected to the antenna radiator; the middle position of the antenna radiator is connected with the grounding plate, the first capacitive load component is connected with the first position of the antenna radiator and is grounded, and the second capacitive load component is connected with the second position of the antenna radiator and is grounded; according to the embodiment of the disclosure, the near field electric field intensity and SAR can be reduced and the beam width can be increased on the premise of not increasing the antenna size and ensuring the antenna efficiency, so that a larger beam scanning range can be obtained when the antenna is applied to array. The embodiment of the disclosure also provides a terminal device.

Description

Small electric antenna and terminal equipment

Technical Field

The disclosure relates to the technical field of communication equipment, in particular to an electric small antenna and terminal equipment.

Background

As a small-sized antenna, an electrically small antenna is often used in various terminal devices, which has a small occupied space and a certain radiation capability, and the advantages are obvious. Common small electric antennas include inverted-L antennas, inverted-F antennas, small loop antennas, monopole antennas, and the like. The inverted L antenna and the inverted F antenna are asymmetric radiation antennas, the electric field intensity of the near field of the small electric antenna is high, the beam width is narrow, the beam is difficult to widen, and the small electric antenna is difficult to apply to an antenna array with larger requirements on the beam scanning range.

Disclosure of Invention

The disclosure provides an electrically small antenna and terminal equipment.

In a first aspect, embodiments of the present disclosure provide an electrically small antenna, including an antenna radiator, a feed probe, a first capacitive load component, a second capacitive load component, and a ground plane, the feed probe being connected to the antenna radiator;

The middle position of the antenna radiator is connected with the grounding plate, the first capacitive load component is connected with the first position of the antenna radiator and grounded, and the second capacitive load component is connected with the second position of the antenna radiator and grounded.

In yet another aspect, an embodiment of the disclosure further provides a terminal device including the electrically small antenna as described above.

The embodiment of the disclosure provides an electrically small antenna, which comprises an antenna radiator, a feed probe, a first capacitive load component, a second capacitive load component and a grounding plate, wherein the feed probe is connected with the antenna radiator; the middle position of the antenna radiator is connected with the grounding plate, the first capacitive load component is connected with the first position of the antenna radiator and is grounded, and the second capacitive load component is connected with the second position of the antenna radiator and is grounded; according to the embodiment of the disclosure, the near field electric field intensity and SAR can be reduced and the beam width can be increased on the premise of not increasing the antenna size and ensuring the antenna efficiency, so that a larger beam scanning range can be obtained when the antenna is applied to array.

Drawings

Fig. 1 is a schematic structural diagram of an electrically small antenna according to an embodiment of the present disclosure;

FIG. 2 is a schematic diagram of standing wave field distribution of a symmetric array antenna;

FIG. 3 is a schematic diagram of standing wave field distribution of an inverted F antenna;

Fig. 4 is a schematic structural diagram of an electrically small antenna according to another embodiment of the present disclosure;

FIG. 5a is a schematic diagram of the return loss of the electrically small antenna of FIG. 4;

FIG. 5b is a diagram of the electrically small antenna of FIG. 4;

FIG. 5c is a schematic SAR diagram of the electrically small antenna shown in FIG. 4;

FIG. 6a is a schematic diagram of the return loss of the electrically small antenna of FIG. 1;

FIG. 6b is a diagram of the electrically small antenna of FIG. 1;

FIG. 6c is a schematic SAR diagram of the electrically small antenna shown in FIG. 1;

fig. 7a is a schematic diagram of return loss of an inverted F antenna;

fig. 7b is a pattern of an inverted F antenna;

fig. 7c is a SAR schematic of an inverted F antenna.

Detailed Description

Example embodiments will be described more fully hereinafter with reference to the accompanying drawings, but may be embodied in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms "a," "an," 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.

Embodiments described herein may be described with reference to plan and/or cross-sectional views with the aid of idealized schematic diagrams of the present disclosure. Accordingly, the example illustrations may be modified in accordance with manufacturing techniques and/or tolerances. Thus, the embodiments are not limited to the embodiments shown in the drawings, but include modifications of the configuration formed based on the manufacturing process. Thus, the regions illustrated in the figures have schematic properties and the shapes of the regions illustrated in the figures illustrate the particular shapes of the regions of the elements, but are not intended to be limiting.

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. 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 relevant art and the present disclosure, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Because the terminal equipment is close to the ground plane, the inverted-L antenna is difficult to resonate, and the common antenna is an inverted-F antenna. In the research and development project of the terminal, the situation that the input power of the antenna needs to be reduced or the shape of the antenna needs to be changed because SAR (Specific Absorpt ion Rate, electromagnetic wave absorption ratio) exceeds the standard often occurs, and the SAR is difficult to be reduced by simply changing the shape of the antenna. The near field electric field strength of an antenna is strongly related to the antenna performance and input power, and the shape is changed without changing the antenna type, with the general result that the antenna performance is sacrificed to reduce the near field electric field strength, and the lower the near field electric field strength peak value is, the more dispersed, the smaller the SAR is.

In the related art, an electronic control system is generally used to reduce the antenna performance when the terminal is close to the human body, or to perform antenna switching to reduce the electric field intensity near the human body, and the terminal structure is modified to reduce the electric field intensity of the near field of the antenna, so that the SAR is reduced. But the cost of adopting the electric control system is higher, the income of terminal products is reduced, and changing the terminal structure can increase the constraint on the overall design of the terminal, and the design difficulty is increased.

In order to solve the above-described problems, the presently disclosed embodiment provides an electrically small antenna, which includes an antenna radiator 1, a feed probe 2, a first capacitive load member 31, a second capacitive load member 32, and a ground plate 4, as shown in fig. 1, the feed probe 2 being connected to the antenna radiator 1; the middle position of the antenna radiator 1 is connected to the ground plate 4, the first capacitive load member 31 is connected to the first position M1 of the antenna radiator 1 and is grounded, and the second capacitive load member 32 is connected to the second position M2 of the antenna radiator 1 and is grounded.

The first capacitive load component 31 and the second capacitive load component 32 may be, but are not limited to, grounded through the ground plane 4. The specific structures of the antenna radiator 1 and the feed probe 2, and the connection manner of the antenna radiator 1 and the feed probe 2 can be implemented by adopting the existing scheme, and will not be described herein again.

The first capacitive load member 31 and the second capacitive load member 32 are members capable of generating reactance, the first capacitive load member 31 is capable of generating near-field electric field intensity with the ground portion of the antenna radiator 1, and the second capacitive load member 32 is capable of generating near-field electric field intensity with the ground portion of the antenna radiator 1, and the two near-field electric field intensities are close to each other and opposite to each other. The first capacitive load part 31, the second capacitive load part 32 and the antenna radiator 1 cooperate to generate resonance at a predetermined frequency point.

The embodiment of the disclosure provides an electrically small antenna, which comprises an antenna radiator 1, a feed probe 2, a first capacitive load component 31, a second capacitive load component 32 and a grounding plate 4, wherein the feed probe 2 is connected with the antenna radiator 1 and the grounding plate 4; the middle position of the antenna radiator 1 is connected with the grounding plate 4, two ends of the first capacitive load component 31 are respectively connected with the first position M1 of the antenna radiator 1 and the grounding plate 4, and two ends of the second capacitive load component 32 are respectively connected with the second position M2 of the antenna radiator 1 and the grounding plate 4; according to the embodiment of the disclosure, the near field electric field intensity and SAR can be reduced and the beam width can be increased on the premise of not increasing the antenna size and ensuring the antenna efficiency, so that a larger beam scanning range can be obtained when the antenna is applied to array.

The size of a common electrically small antenna in a terminal is a quarter wavelength (lambda), and in order to obtain a wide beam and a low near field electric field strength, the radiation structure of the electrically small antenna needs to be in a symmetrical form. Embodiments of the present disclosure refer to standing wave field distribution of a symmetric dipole antenna with a minimum dimension of one-half wavelength, artificially limiting boundary conditions on an electrically small antenna of one-quarter wavelength, causing it to form resonance.

Fig. 2 is a schematic diagram of standing wave field distribution of a symmetric array antenna, as shown in fig. 2, in which Feed is an end point of a Feed probe, emax1 is a voltage wave antinode, a quarter wavelength distance is passed to the right direction by a voltage wave node, and then the quarter wavelength voltage wave antinode Emax2 is passed back. The voltage antinode Emax1 and Emax2 have the same phase difference of 180 DEG, and the standing wave field distribution generates symmetrical radiation.

In contrast to quarter-wavelength electrically small antennas, taking an inverted-F antenna as an example, fig. 3 shows the standing wave field distribution of an inverted-F antenna, which generates asymmetric radiation. As shown in fig. 3, a voltage wave node is first set, the center of the quarter-wavelength electrically small antenna is Grounded (GND) to make its potential 0, then the open ends on the left and right sides are set, for the microstrip antenna, the open ends are voltage antinode Emax, the distance between the voltage antinode Emax and the voltage wave node (GND) is typically quarter-wavelength, so the left and right ends of the antenna cannot be used as the open ends, otherwise, the resonance will be at the frequency doubling point of the required frequency point.

It should be noted that, the pure reactance device is used as the antenna end, and the boundary of the standing wave field of the symmetrical array antenna is made for setting. The symmetrical array antenna ends are 0 phase difference total reflection, so that an inductive device cannot be used, and a capacitive device is needed to be used as a load.

In the embodiments of the present disclosure, the principles of the embodiments of the present disclosure are described by taking a quarter-wavelength electrically small antenna common to terminals as an example. Since the antenna is a microstrip antenna, the antenna can be used as a microstrip line for analysis when a standing wave field is formed, and in order to enable the reflection coefficient of the tail end to be 1, the load of the tail end of the small electric antenna is required to be-jX, and the impedance relation is shown as a formula (1):

where Z0 is the characteristic impedance of the microstrip line, the value is generally 50Ω, X is reactance, and it cannot take an infinite value, but if Z0 is far greater, the value of equation (1) can be made to approach 1.

When the capacitive device is used as the end load of the small electric antenna, the distance from the end of the small electric antenna to the center position is one eighth wavelength according to a transmission line impedance calculation formula.

The equivalent impedance from the tail end of the small electric antenna to the central position is jZ0, the central position is equivalent to the load impedance, the reflection coefficient is-j, the central position of the small electric antenna is provided with a grounding component, the reflection coefficient of the grounding component is-1 as a load, the reflection coefficient is equal in module value, and the phase difference is pi. The load at the two ends of the small electric antenna and the grounding part at the central position can be mutually converted according to a transmission line equation, and the standing wave field distribution and the anti-phase difference of two open-circuit end voltage wave antinodes of the obtained microstrip small electric antenna are similar to those of the symmetrical array antenna.

In some embodiments, as shown in fig. 1, the antenna radiator 1 includes a ground portion 10, a first extension portion 11 and a second extension portion 12, the first extension portion 11 and the second extension portion 12 are connected, and the first extension portion 11 and the second extension portion 12 extend in opposite directions, a connection position of the first extension portion 11 and the second extension portion 12 is connected to one end of the ground portion 10, and the other end of the ground portion 10 is connected to the ground plate 4; the first capacitive load member 31 is connected to the first extension 11, the second capacitive load member 32 is connected to the second extension 32, and the feed probe 2 may be connected to either the first extension 11 or the second extension 12, and in the embodiment of the present disclosure, the feed probe 2 is connected to the second extension 12 is described as an example.

The first extension 11 and the second extension 12 may be integrally formed to form a laterally disposed member, and the grounding portion 10 may be located at a central position of the laterally disposed member.

In some embodiments, the antenna radiator 1 is T-shaped, and the antenna radiator 1, the first capacitive load part 31 and the second capacitive load part 31 form an E-shaped structure.

In some embodiments, at least one of the first extension 11 and the second extension 12 is in a strip shape, or at least one of the first extension 11 and the second extension 12 is in an arc shape. That is, the first extension 11 and the second extension 12 are both in a strip shape, and the connection of the two may form a strip structure, so that the antenna radiator 1 integrally forms a standard T-shaped structure; or the first extension part 11 and the second extension part 12 are arc-shaped, and the two extension parts are connected to form an arc-shaped structure, so that the antenna radiator 1 integrally forms a T-shaped structure with an arc-shaped horizontal part; or one of the first extension part 11 and the second extension part 12 is arc-shaped, the other one of the first extension part 11 and the second extension part 12 is strip-shaped, and the two parts are connected to form a combined structure of one section of arc shape and one section of strip shape, so that the antenna radiator 1 integrally forms a T-shaped structure, and the horizontal part of the T-shaped structure is a combined structure comprising the arc shape and the strip shape. In the case where the first extension portion 11 and the second extension portion 12 are each arc-shaped, the shapes of the first extension portion 11 and the second extension portion 12 may be the same or different.

The further the feed probe 2 is from the ground 10, the poorer the resonance effect and therefore, in order to ensure that a better resonance effect is achieved, in some embodiments, the feed probe 2 is disposed adjacent to the ground 10 as shown in fig. 1. That is, the distance S1 between the feeding probe 2 and the ground portion 10 is smaller than the distance S2 between the feeding probe 2 and the corresponding capacitive load member, as shown in fig. 1, the feeding probe 2 is connected to the second extension portion 12, and the corresponding capacitive load member is the second capacitive load member 32; if the feed probe 2 is connected to the first extension 11, the corresponding capacitive load component is the first capacitive load component 31.

In some embodiments, the distance S1 between the feed probe 2 and the ground 10 is greater than 0.2L and less than 0.32L, where L is the length of the extension to which the feed probe 2 is connected, and the extension is one of the first extension 11 and the second extension 12. The feed probe 2 may be disposed within a certain range, i.e., 0.2l < s1<0.32l, adjacent to the ground 10. For a quarter-wavelength electrically small antenna, the lengths l=1/8λ of the first extension portion 11 and the second extension portion 12 take the position of the grounding portion 10 as the origin, and the value range of the position P of the feeding probe 2 is (0.025 λ,0.04 λ) or (-0.025 λ, -0.04 λ).

In some embodiments, as shown in fig. 1, a distance S3 between the first location M1 and the ground portion 10 is greater than 0.92L1, and L1 is a length of the first extension portion 11; the distance S4 between the second position M2 and the grounding portion 10 is greater than 0.92L2, and L2 is the length of the second extension portion 12. In the presently disclosed embodiments, l1=l2=l.

The first capacitive load part 31 and the second capacitive load part 32 may be provided within a certain range adjacent to both ends of the radiator 1, i.e., 0.92l1< s3< =l1, 0.92l2< s4< =l2. For a quarter-wavelength electrically small antenna, the lengths l=1/8λ of the first extension portion 11 and the second extension portion 12 take the position of the ground portion 10 as the origin, the range of the value of the position M1 of the first capacitive load member 31 is (0.115 λ,0.125 λ), and the range of the value of the position M2 of the second capacitive load member 32 is (-0.115 λ, -0.125 λ).

Since the application environment of the small electric antenna has a great influence on the antenna performance, in order to adapt the small electric antenna to different environments, in some embodiments, the feeding probe 2 is detachably connected to the first extension 11 or the second extension 12, so that the position of the feeding probe 2 can be determined according to the use condition of the terminal device and connected to the radiator 1.

In some embodiments, the first capacitive load component 31 and/or the second capacitive load component 32 are capacitive devices.

In some embodiments, the first capacitive load component 31 and/or the second capacitive load component 32 may also be conductor structures.

Fig. 4 is a schematic structural view of an electrically small antenna according to another embodiment of the present disclosure, in which the first capacitive load part 31 and the second capacitive load part 32 are capacitive devices.

The electrically small antenna shown in fig. 1 has a structure in which the first capacitive load part 31 and the second capacitive load part 32 are conductors having a certain thickness as compared with the capacitive device, and other structures of the electrically small antenna shown in fig. 1 are the same as those of the electrically small antenna shown in fig. 4.

Simulation experiments are performed on the near field electric field intensity and the beam width of the electric small antenna and the traditional inverted-F antenna of the embodiment of the present disclosure. The resonance frequency of the small electric antenna is 2.6GHz, the capacitive load component is arranged at the open end of the radiator, and the length of the antenna is smaller than and close to a quarter wavelength of 2.6 GHz. As can be seen from simulation results, compared with the traditional inverted F antenna, the small electric antenna of the embodiment of the disclosure has the advantages of increasing the beam width and reducing SAR.

Fig. 5a-5c are return loss diagrams, patterns and SAR diagrams of electrically small antennas employing capacitive devices as capacitive loading components. Fig. 6a-6c are return loss diagrams, patterns and SAR diagrams of electrically small antennas with conductor structures as capacitive loading components. Fig. 7a-7c are conventional return loss diagrams, patterns and SAR diagrams for an F antenna. For convenience of description, the antenna corresponding to fig. 5a to 5c will be referred to as an antenna A1, the antenna corresponding to fig. 6a to 6c will be referred to as an antenna A2, and the antenna corresponding to fig. 7a to 7c will be referred to as an antenna B.

As shown in fig. 5a, 6a and 7a, resonances of the antennas A1, A2 and B all occur around 2.6GHz, and the antenna efficiency is about-0.2 dB.

As shown in fig. 5B, the 3dB beamwidth of the antenna A1 at resonance is 86 °, as shown in fig. 6B, the 3dB beamwidth of the antenna A2 at resonance is 92 °, as shown in fig. 7B, the 3dB beamwidth of the antenna B at resonance is 64 °, the antenna A1 is one third of the beamwidth than the antenna B, and the antenna A2 is about 40% of the beamwidth than the antenna B.

The human body can generate an induction electromagnetic field due to the action of the external electromagnetic field, so that heat is generated in the human body, the larger the external electromagnetic field is, the larger the induction electromagnetic field generated by the human body is, and the damage to the human body can be caused by the overlarge induction electromagnetic field. In this regard, the electromagnetic energy absorbed by the human body per kilogram in six minutes is internationally defined as SAR, which is in units of W/kg, and the lower the peak value of the near-field electric field intensity, the more dispersed, the smaller the SAR. The calculation formula of SAR is formula (2):

Wherein delta is the human body conductivity, E (r) is the near field electric field intensity incident to the human body, E (r) is related to the human body dielectric constant, ρ is the human body density, and for a fixed human body, when the two electromagnetic wave frequencies are the same, the human body dielectric constant and the conductivity are the same.

Through simulation experiments, under the condition of the same input power, the square of the near field electric field intensity of the antenna B is 3.3 times of the square of the near field electric field intensity of the antenna A1, and the square of the near field electric field intensity of the antenna B is 5.84 times of the square of the near field electric field intensity of the antenna A2.

As shown in fig. 5c, the SAR peak of the antenna A1 is 0.7338W/kg, as shown in fig. 6c, the SAR peak of the antenna A2 is 0.6011W/kg, and as shown in fig. 7c, the SAR peak of the antenna B is 1.4599W/kg, whereby it can be seen that the SAR of both the antenna A1 and the antenna A2 is smaller than the SAR of the antenna B, the SAR is reduced by about more than half, and the SAR of the antenna A2 is lower than the SAR of the antenna A1. That is, the electrically small antenna using the conductor structure has better SAR index than the electrically small antenna using the capacitive device, and can reduce the near field electric field intensity and SAR and increase the beam width, with high reliability, regardless of the type of the electrically small antenna using the capacitive load member.

The embodiment of the disclosure also discloses a terminal device, which comprises the small electric antenna. The small electric antenna comprises an antenna radiator 1, a feed probe 2, a first capacitive load component 31, a second capacitive load component 32 and a grounding plate 4, wherein the feed probe 2 is connected with the antenna radiator 1 and the grounding plate 4; the middle position of the antenna radiator 1 is connected with the grounding plate 4, two ends of the first capacitive load component 31 are respectively connected with the first position M1 of the antenna radiator 1 and the grounding plate 4, and two ends of the second capacitive load component 32 are respectively connected with the second position M2 of the antenna radiator 1 and the grounding plate 4; according to the embodiment of the disclosure, the near field electric field intensity and SAR can be reduced and the beam width can be increased on the premise of not increasing the antenna size and ensuring the antenna efficiency, so that a larger beam scanning range can be obtained when the antenna is applied to array.

The small electric antenna provided by the embodiment of the disclosure has a symmetrical radiation structure and stable performance. The beam width is wider than that of an electric small antenna with the same size, and the SAR is 0.5 times of that of an inverted F antenna under the condition of the same input power and antenna efficiency, so that the SAR index is better.

Those of ordinary skill in the art will appreciate that all or some of the steps of the methods, functional modules/units in the apparatus disclosed above may be implemented as software, firmware, hardware, and suitable combinations thereof. In a hardware implementation, the division between the functional modules/units mentioned in the above description does not necessarily correspond to the division of physical components; for example, one physical component may have multiple functions, or one function or step may be performed cooperatively by several physical components. Some or all of the physical components may be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application specific integrated circuit. Such software may be distributed on computer readable media, which may include computer storage media (or non-transitory media) and communication media (or transitory media). The term computer storage media includes both volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data, as known to those skilled in the art. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital Versatile Disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can be accessed by a computer. Furthermore, as is well known to those of ordinary skill in the art, communication media typically embodies computer readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism and includes any information delivery media.

Example embodiments have been disclosed herein, and although specific terms are employed, they are used and should be interpreted in a generic and descriptive sense only and not for purpose of limitation. In some instances, it will be apparent to one skilled in the art that features, characteristics, and/or elements described in connection with a particular embodiment may be used alone or in combination with other embodiments unless explicitly stated otherwise. It will therefore be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the scope of the present invention as set forth in the following claims.

Claims (11)

1. An electrically small antenna is characterized by comprising an antenna radiator, a feed probe, a first capacitive load component, a second capacitive load component and a grounding plate, wherein the feed probe is connected with the antenna radiator;

The middle position of the antenna radiator is connected with the grounding plate, the first capacitive load component is connected with the first position of the antenna radiator and grounded, and the second capacitive load component is connected with the second position of the antenna radiator and grounded.

2. The electrically small antenna according to claim 1, wherein the antenna radiator includes a ground portion, a first extension portion and a second extension portion, the first extension portion and the second extension portion are connected, and the first extension portion and the second extension portion extend in opposite directions, a connection position of the first extension portion and the second extension portion is connected to one end of the ground portion, and the other end of the ground portion is connected to the ground plate;

The first capacitive load component is connected with the first extension part, the second capacitive load component is connected with the second extension part, and the feed probe is connected with the first extension part or the second extension part.

3. The electrically small antenna of claim 2, wherein the antenna radiator is T-shaped, and the antenna radiator, the first capacitive load member, and the second capacitive load member form an E-shaped structure.

4. The electrically small antenna as in claim 3, wherein at least one of said first extension and said second extension is in the shape of a strip or at least one of said first extension and said second extension is in the shape of an arc.

5. The electrically small antenna as in claim 3, wherein said feed probe is disposed adjacent said ground.

6. The electrically small antenna as in claim 5, wherein a distance between the feed probe and the ground is greater than 0.2L and less than 0.32L, wherein L is a length of an extension to which the feed probe is connected, the extension being one of the first extension and the second extension.

7. The electrically small antenna according to claim 3, wherein a distance between the first location and the ground is greater than 0.92L1, L1 being a length of the first extension;

The distance between the second position and the grounding part is larger than 0.92L2, and L2 is the length of the second extension part.

8. The electrically small antenna of claim 2, wherein the feed probe is detachably connected to the first extension or the second extension.

9. The electrically small antenna as claimed in any one of claims 1-8, wherein said first capacitive loading means and/or said second capacitive loading means are capacitive devices.

10. The electrically small antenna as claimed in any one of claims 1-8, wherein said first capacitive loading means and/or said second capacitive loading means are conductor structures.

11. A terminal device comprising an electrically small antenna according to any of claims 1-10.