Memory metal frequency-adjustable antenna circuit, antenna system and communication equipment

Abstract

The invention relates to the technical field of antennas, and provides a memory metal frequency-adjustable antenna circuit, an antenna system and communication equipment, the circuit comprises a control module, a plurality of memory metal elements, a power supply link and a radio frequency link; the power supply link comprises a power supply module, and the radio frequency link comprises an antenna; the memory metal element has a power-on shrinkage characteristic; the control module sends a power supply control signal according to the antenna regulation requirement; the antenna regulation and control requirements are the working frequency band and bandwidth requirements of the antenna; the power supply module outputs power supply current to the memory metal element based on the power supply control signal; the memory metal element shrinks under the power supply current, and the impedance of the memory metal element is dynamically adjusted so as to dynamically adjust the characteristic impedance of the antenna. According to the invention, the circuit is more simplified, the cost is lower, the use is more flexible, the resonant frequency and bandwidth of the antenna can be effectively adjusted on the premise of not increasing the equipment size, the multi-band requirement is met, and the communication performance is improved.

Description

Technical Field

[0001] The present invention relates to the field of antenna technology, and in particular to a memory metal frequency-adjustable antenna circuit, an antenna system and communication equipment. Background Art

[0002] With the rapid development of wireless communication technology, wireless communication devices have become an indispensable part of modern life. In these devices, antennas, as key signal transceiver devices, play a vital role. The main function of the antenna is to convert the guided waves on the transmission line into electromagnetic waves in free space, or vice versa. Although the role of the antenna in wireless communication equipment is crucial, its performance is limited by its own electromagnetic characteristics and has a certain working bandwidth and working frequency. Once these ranges are exceeded, the performance of the antenna will drop sharply, affecting the communication effect. Since wireless communication equipment often needs to support multiple frequency bands or different transceiver bands of the same standard, the antenna is required to support multiple frequency bands at the same time to reduce the number of antennas and reduce the size of communication equipment.

[0003] In order to meet the needs of multiple frequency bands, the existing technology usually designs multiple antennas, each of which supports one frequency band. Although this solution can meet the needs of multiple frequency bands, it will significantly increase the size of the device because each antenna requires a certain amount of space. In addition, this design also limits the expansion of the antenna bandwidth, and when the isolation between the antennas is insufficient, the performance will be affected by each other.

[0004] Given the limitations of existing technologies, there is an urgent need for a new antenna design that can simultaneously support multiple frequency bands without increasing the size of the device, and has a wider operating bandwidth and higher performance. Summary of the invention

[0005] The present invention provides a memory metal frequency-adjustable antenna circuit, antenna system and communication equipment, which are used to solve the defects in the prior art that the size of the equipment is significantly increased, the expansion of the antenna bandwidth is limited, and when the isolation between the antennas is insufficient, the performance will be affected by each other. The circuit of the present invention is simpler, the cost is lower, and the use is more flexible. Without increasing the size of the equipment, the resonant frequency and bandwidth of the antenna can be effectively adjusted to meet the requirements of multiple frequency bands and improve the communication performance.

[0006] The present invention provides a memory metal frequency-adjustable antenna circuit, comprising a control module, a plurality of memory metal elements, a power supply link and a radio frequency link; the power supply link comprises a power supply module, the radio frequency link comprises an antenna; the memory metal element has a power-on contraction characteristic; the control end of the control module is connected to the control end of the power supply module, the first power supply end of the power supply module is connected to the first end of the memory metal element, the second power supply end of the power supply module and the connection end of the antenna are both connected to the second end of the memory metal element; the control module is used to send a power supply control signal according to antenna control requirements; the antenna control requirements are the frequency band and bandwidth requirements for the antenna to work; the power supply module is used to output a power supply current to the memory metal element based on the power supply control signal; the memory metal element is used to contract under the power supply current, dynamically adjust its own impedance, so as to dynamically adjust the characteristic impedance of the antenna.

[0007] According to a memory metal tunable frequency antenna circuit provided by the present invention, the radio frequency link also includes a plurality of DC isolation elements, which are arranged at both ends of the memory metal element to isolate the interference of the power supply current of the memory metal element on the radio frequency link.

[0008] According to a memory metal tunable frequency antenna circuit provided by the present invention, the power supply link also includes a filter element, which is arranged between the power supply module and the memory metal element to filter out interference and noise of the power supply link to the radio frequency link.

[0009] According to a memory metal frequency-adjustable antenna circuit provided by the present invention, the radio frequency link also includes a radio frequency wireless transceiver, a first end of the radio frequency wireless transceiver is connected to the input end of the control module, and a second end of the radio frequency wireless transceiver is connected to the connection end of the antenna, for determining the antenna control requirements and transmitting and receiving wireless signals.

[0010] According to a memory metal frequency-adjustable antenna circuit provided by the present invention, the radio frequency link also includes a radio frequency matching module, which is connected to the memory metal element and is used to match the memory metal element to adjust the characteristic impedance of the antenna.

[0011] According to a memory metal frequency-adjustable antenna circuit provided by the present invention, the memory metal element is a nickel-titanium alloy memory metal inductor.

[0012] According to a memory metal tunable frequency antenna circuit provided by the present invention, the nickel-titanium alloy memory metal inductor is connected to the edge connection end of the antenna by series and / or parallel matching.

[0013] According to a memory metal frequency-adjustable antenna circuit provided by the present invention, the nickel-titanium alloy memory metal inductor is connected to the middle connection end of the antenna by means of series and / or parallel matching.

[0014] The present invention also provides an antenna system, comprising the above-mentioned memory metal frequency-adjustable antenna circuit.

[0015] The present invention also provides a communication device, comprising the above antenna system.

[0016] The present invention provides a memory metal frequency-adjustable antenna circuit, antenna system and communication equipment, the circuit includes a control module, a plurality of memory metal elements, a power supply link and a radio frequency link; the power supply link includes a power supply module, and the radio frequency link includes an antenna; the memory metal element has a power-on contraction characteristic; the control module sends a power supply control signal according to the antenna control requirements; the antenna control requirements are the frequency band and bandwidth requirements for the antenna operation; the power supply module outputs a power supply current to the memory metal element based on the power supply control signal; the memory metal element contracts under the power supply current, dynamically adjusts its own impedance, and dynamically adjusts the characteristic impedance of the antenna. The circuit of the present invention is simpler, has lower cost, and is more flexible to use. Without increasing the size of the device, it can effectively adjust the resonant frequency and bandwidth of the antenna, meet multi-band requirements, and improve communication performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 The present invention provides a schematic structural diagram of a memory metal frequency-adjustable antenna circuit.

[0019] Figure 2 It is a schematic diagram of the principle of the memory metal element provided by the present invention.

[0020] Figure 3 It is a schematic diagram of the principle of a circuit for adjusting the resonant operating frequency of an antenna by a series matching method provided by the present invention.

[0021] Figure 4 It is a schematic diagram of the principle of a circuit for adjusting the resonant operating frequency of an antenna by a parallel matching method provided by the present invention.

[0022] Figure 5 It is a schematic diagram of the principle of a circuit for adjusting the resonant operating frequency of an antenna by a series plus parallel joint matching method provided by the present invention.

[0023] Figure 6 It is a schematic diagram of the principle of a circuit for adjusting the resonant operating frequency of an antenna by a middle series loading tuning method provided by the present invention.

[0024] Figure 7 It is a schematic diagram of the principle of a circuit for adjusting the resonant operating frequency of an antenna by a parallel loading tuning method in the middle of the antenna provided by the present invention.

[0025] Figure 8 It is a schematic diagram of the principle of the adjustable inductor series loaded antenna branch model provided by the present invention.

[0026] Fig. 9 It is a resonant frequency diagram of the adjustable inductor series loading antenna provided by the present invention.

[0027] Fig.10 It is a distribution curve diagram of the radiation efficiency of the antenna with adjustable inductor series loading provided by the present invention.

[0028] Fig.11 These are two limit state diagrams of the maximum and minimum values ​​of the adjustable inductance provided by the present invention. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] Please refer to Figure 1 , Figure 1 The present invention provides a schematic structural diagram of a memory metal frequency-adjustable antenna circuit.

[0031] The present invention provides a memory metal frequency-adjustable antenna circuit, comprising a control module 1, a plurality of memory metal elements 2, a power supply link and a radio frequency link; the power supply link comprises a power supply module 3, and the radio frequency link comprises an antenna 4; the memory metal element 2 has a power-on contraction characteristic; the control end of the control module 1 is connected to the control end of the power supply module 3, the first power supply end of the power supply module 3 is connected to the first end of the memory metal element 2, and the second power supply end of the power supply module 3 and the connection end of the antenna 4 are both connected to the second end of the memory metal element 2; the control module 1 is used to send a power supply control signal according to the control requirements of the antenna 4; the control requirements of the antenna 4 are the frequency band and bandwidth requirements for the antenna 4 to work; the power supply module 3 is used to output a power supply current to the memory metal element 2 based on the power supply control signal; the memory metal element 2 is used to contract under the power supply current and dynamically adjust its own impedance to dynamically adjust the characteristic impedance of the antenna 4.

[0032] In order to solve the technical problems existing in the prior art, the present invention provides a memory metal adjustable frequency antenna circuit, including a control module 1, a plurality of memory metal elements 2, a power supply link and a radio frequency link. The control module 1 calculates the required power supply current value according to the working frequency band and bandwidth requirements of the antenna 4, and generates a power supply control signal. The current value is used to adjust the impedance of the memory metal element 2, thereby changing the characteristic impedance of the antenna 4. The control module 1 pre-sets the current values ​​corresponding to different working frequency bands and bandwidths through an algorithm, and these values ​​are stored in the memory of the microcontroller. The power supply module 3 can be a precise current source, and the power supply module 3 receives the power supply control signal sent by the control module 1 and outputs the corresponding power supply current to the memory metal element 2. The design of the current source can provide a stable current and is not affected by the fluctuation of the power supply voltage. The memory metal element 2 is made of nickel-titanium alloy material, for example, and the memory metal element 2 has the characteristic of power-on contraction. Under the action of different currents, the length of the memory metal element 2 will change, thereby changing its impedance. The characteristic impedance of the antenna 4 in the radio frequency link matches the impedance of the memory metal element 2. By adjusting the impedance of the memory metal element 2, the operating frequency of the antenna 4 can be dynamically adjusted, the bandwidth of the antenna 4 can be expanded, and the bandwidth can even be expanded to support multi-band operation. The antenna 4 can quickly adapt to different communication needs and improve the performance and flexibility of the communication system.

[0033] The control module 1 may be a CPU (Central Processing Unit) main control chip, which is not particularly limited in the present invention.

[0034] As a preferred embodiment, the radio frequency link further includes a plurality of DC isolation elements, which are arranged at both ends of the memory metal element 2 to isolate the interference of the power supply current of the memory metal element 2 on the radio frequency link.

[0035] In this embodiment, the memory metal frequency-adjustable antenna circuit further improves performance by integrating several DC isolation elements in the RF link. These DC isolation elements are set at both ends of the memory metal element 2, and their main function is to isolate the interference of the power supply current of the memory metal element 2 on the RF link, ensuring the quality of the RF signal and the communication quality. It is not only suitable for communication environments with a single frequency band, but also for complex communication environments that need to work on multiple frequency bands.

[0036] The DC blocking element can be a DC blocking capacitor, because the capacitor can block the DC current while allowing the AC (RF) signal to pass. Each DC blocking element is connected between one end of the memory metal element 2 and the RF link, thereby forming an isolation barrier between the DC supply current and the RF signal. This configuration allows the memory metal element 2 to adjust its shape and impedance under the action of the changing DC current without affecting the transmission of the RF signal.

[0037] In practical applications, the control module 1 dynamically adjusts the size of the power supply current according to the operating frequency band and bandwidth requirements of the antenna 4. Since the memory metal element 2 requires a DC current to achieve changes in shape and impedance, these currents may interfere with the RF signal if they flow directly into the RF link. Therefore, the DC isolation elements play a vital role here. They not only protect the RF link from interference from the DC power supply current, but also ensure that the memory metal element 2 can accurately respond to the instructions of the control module 1, achieve precise adjustment of the characteristic impedance of the antenna 4, and improve the stability and reliability of the memory metal adjustable frequency antenna circuit.

[0038] As a preferred embodiment, the power supply link further includes a filter element, which is disposed between the power supply module 3 and the memory metal element 2 and is used to filter out interference and noise of the power supply link to the radio frequency link.

[0039] In this embodiment, the memory metal tunable frequency antenna circuit further includes a filter element, which is integrated in the power supply link, specifically, arranged between the power supply module 3 and the memory metal element 2. The main function of the filter element is to filter out any noise and interference signals introduced by the power supply link that may interfere with the radio frequency link, and ensure that the antenna 4 can maintain the quality of the communication signal under different working conditions.

[0040] The filter element can be a filter inductor, and the memory metal element 2 can be a memory metal inductor. The positive and negative poles of the power supply are connected between the memory metal inductor and the DC blocking capacitor through the filter inductor. The self-resonant frequency of the filter inductor matches the operating frequency range of the antenna 4. The filter inductor presents a high impedance in the high frequency band, which is equivalent to an open circuit state, eliminating the influence of the power supply link on the radio frequency link.

[0041] As a preferred embodiment, the RF link also includes a RF wireless transceiver, a first end of the RF wireless transceiver is connected to the input end of the control module 1, and a second end of the RF wireless transceiver is connected to the connection end of the antenna 4, for determining the control requirements of the antenna 4 and sending and receiving wireless signals.

[0042] In this embodiment, the memory metal frequency-adjustable antenna circuit further integrates a radio frequency transceiver to achieve the determination of the control requirements of the antenna 4 and the transmission and reception of wireless signals. The radio frequency transceiver is a core component in the wireless communication system and is responsible for processing the transmission and reception of wireless signals.

[0043] In practical applications, an RF wireless transceiver can be a complete radio system that includes components such as modulators, demodulators, mixers, filters, and amplifiers. These components work together to ensure the effective transmission and reception of wireless signals. For example, the modulator converts the digital signal into an RF signal suitable for wireless transmission, the amplifier boosts the power of the signal, and the demodulator converts the received RF signal back into a digital signal.

[0044] As a preferred embodiment, the radio frequency link further includes a radio frequency matching module, which is connected to the memory metal element 2 and is used to match the memory metal element 2 to adjust the characteristic impedance of the antenna 4 .

[0045] In this embodiment, the memory metal frequency-adjustable antenna circuit optimizes the characteristic impedance matching of the antenna 4 by integrating a radio frequency matching module. For example, the front end and the rear end of the memory metal element 2 can be used together with the radio frequency matching module to ensure that the antenna 4 is more flexible in matching.

[0046] As a preferred embodiment, the memory metal element 2 is a nickel-titanium alloy memory metal inductor.

[0047] Please refer to Figure 2 , Figure 2 A schematic diagram of the principle of the memory metal element provided by the present invention.

[0048] In this embodiment, the memory metal element 2 uses a nickel-titanium alloy memory metal inductor. Nickel-titanium alloy, also known as NiTi alloy, is widely used in the manufacture of adjustable inductors due to its unique shape memory effect and superelasticity. This material undergoes a phase change when heated (for example, when an electric current passes through it), causing its length to shrink, thereby changing the inductance value. The larger the current, the greater the shrinkage ratio. When the maximum shrinkage current is reached, it no longer shrinks. The nickel-titanium alloy memory metal shrink wire can achieve a shrinkage ratio of 20% at the maximum shrinkage current.

[0049] Therefore, a winding inductor is made of nickel-titanium alloy shrinkable wire, a DC current is added to the shrinkable wire winding inductor, and the shrinkage ratio length of the shrinkable wire is controlled by adjusting the current value, thereby adjusting the value of the winding inductance to make an adjustable inductor controlled by DC current.

[0050] By adding this shrinkable wire adjustable inductor to the design of antenna 4, the resonant frequency of antenna 4 can be adjusted through the characteristic that the inductance value can be adjusted when it is energized, and the bandwidth of antenna 4 can be expanded, and the bandwidth can even be expanded to support multi-band operation.

[0051] According to the calculation formula of the inductance of the hollow winding coil, the coil wire diameter w (mm), the wire spacing s (mm), the number of turns n and the coil diameter D (mm), the coil height H (mm) = n × (w + s), the coil inductance L (uH) can be calculated as: L = (D2 ×n 2 ) / ((18×D+40×H)×25.4).

[0052] As a preferred embodiment, the nickel-titanium alloy memory metal inductor is connected to the edge connection end of the antenna 4 by series and / or parallel matching.

[0053] Please refer to Figure 3 , Figure 3 This is a schematic diagram of the principle of a circuit for adjusting the resonant operating frequency of an antenna by a series matching method provided by the present invention.

[0054] In this embodiment, a coil made of nickel-titanium alloy memory metal shrink wire material is added to the antenna 4 design scheme, and the antenna 4 operating frequency is adjusted by connecting the antenna 4 in series with a matching circuit, that is, the edge connection end of the antenna 4 is connected to the shrink wire adjustable inductor, and a DC blocking capacitor is connected in series on both sides of the adjustable inductor to isolate the influence of the DC current applied to the shrink wire adjustable inductor on the RF path. The adjustable inductor and the two DC blocking capacitors are connected to the positive and negative poles of the power supply through two filter inductors respectively. The filter inductor presents a high impedance in the high frequency band, which is equivalent to an open circuit state to eliminate the influence of the power supply link on the RF path. The CPU main control chip control signal is connected to the power supply, and the power supply output current is adjusted according to the working frequency band requirements of the antenna 4, thereby controlling the adjustable inductance, thereby adjusting the series matching inductance of the antenna 4. According to the impedance calculation formula Z of the inductor L =j×2×π×f×L (f is the operating frequency of antenna 4, L is the inductance of the coil). Assume that the characteristic impedance of antenna 4 is Z ANT =A+j×B, where A is the real part of the characteristic impedance of antenna 4, i.e., the electrical impedance, which is related to the loss of antenna 4; B is the imaginary part of the characteristic impedance of antenna 4, i.e., the reactance, which is related to the inductance and capacitance of antenna 4. According to the calculation formula for the characteristic impedance of antenna 4 series matching, the characteristic impedance of antenna 4 after series matching with adjustable inductance is Z K =Z ANT +Z L =A+j×B+j×2×π×f×L, and the CPU main control chip controls the power supply to output different current values ​​to adjust the adjustable inductance of the shrink wire according to the frequency band and bandwidth of the antenna 4 required by the RF wireless transceiver, or different channel frequencies in the same frequency band, and controls the characteristic impedance Z of the antenna 4 after the adjustable inductance is matched in series through the change of the adjustable inductance. k value, to achieve the purpose of adjusting the bandwidth or working frequency of antenna 4, the adjustable inductor front end and back end can also be used simultaneously with other RF matching circuits to ensure that the matching of antenna 4 is more flexible.

[0055] Please refer to Figure 4 , Figure 4This is a schematic diagram of the principle of a circuit for adjusting the resonant operating frequency of an antenna using a parallel matching method provided by the present invention.

[0056] In this embodiment, the working frequency of antenna 4 is adjusted by connecting the edge connection end of antenna 4 in parallel with the matching circuit of the adjustable inductor. Similarly, a DC blocking capacitor is connected in series on both sides of the adjustable inductor to isolate the influence of the DC current applied to the shrink wire adjustable inductor on the radio frequency path. The adjustable inductor and the two DC blocking capacitors are respectively connected to the positive and negative poles of the power supply through two filter inductors. The filter inductor presents a high impedance in the high frequency band, which is equivalent to an open circuit state to eliminate the influence of the power link on the radio frequency path. The control signal of the CPU main control chip is connected to the power supply, and the power output current is adjusted according to the working frequency band requirement of antenna 4, so as to control the adjustable inductance, thereby realizing the function of adjusting the parallel matching inductance of antenna 4. According to the impedance calculation formula Z of the inductor L =j×2×π×f×L (f is the operating frequency of antenna 4, L is the inductance of the coil), assuming that the characteristic impedance of antenna 4 is Z ANT =A+j×B, according to the calculation formula of the characteristic impedance of the parallel matching of antenna 4, the characteristic impedance of antenna 4 after parallel matching with adjustable inductance is Z K =Z ANT ×Z L / (Z ANT +Z L )=((A+j×B)×(j×2×π×f×L)) / ((A+j×B)+(j×2×π×f×L)).

[0057] Please refer to Figure 5 , Figure 5 This is a schematic diagram of the principle of a circuit for adjusting the resonant operating frequency of an antenna by a series plus parallel joint matching method provided by the present invention.

[0058] In this embodiment, the operating frequency of antenna 4 is adjusted by connecting multiple adjustable inductors in series and in parallel at the edge connection end of antenna 4 and combining matching circuits. Similarly, a DC blocking capacitor is connected in series on both sides of the two adjustable inductors to isolate the influence of the DC current applied to the shrink wire adjustable inductor on the radio frequency path. The adjustable inductor and the two DC blocking capacitors are respectively connected to the positive and negative poles of the power supply through two filter inductors. The filter inductor presents a high impedance in the high frequency band, which is equivalent to an open circuit state to eliminate the influence of the power supply link on the radio frequency path. The CPU main control chip control signal is connected to the power supply, and the power supply output current is adjusted according to the working frequency band requirements of antenna 4, thereby controlling the adjustable inductance, thereby achieving the function of adjusting the inductance of the antenna 4 series and parallel matching multiple devices. According to the impedance calculation formula Z of the inductor L =j×2×π×f×L (f is the operating frequency of antenna 4, L is the inductance of the coil), assuming that the characteristic impedance of antenna 4 is Z ANT=A+j×B, according to the calculation formula of the characteristic impedance of the series and parallel matching of the antenna 4, the characteristic impedance of the antenna 4 after the series and parallel matching of multiple adjustable inductors is Z K =((Z ANT +Z L1 )×Z L2 ) / ((Z ANT +Z L1 )+Z L2 )=((A+j×B+j×2×π×f×L1)×(j×2×π×f×L2)) / ((A+j×B+j×2×π×f×L1)+(j×2×π×f×L2)), where Z L1 is the series adjustable inductor impedance, L1 is the series adjustable quantity, Z L2 is the parallel adjustable inductor impedance, L2 is the parallel adjustable value, and the CPU main control chip controls the power supply to output different current values ​​to adjust the adjustable inductance of the shrink wire according to the frequency band and bandwidth of the antenna 4 required by the RF wireless transceiver, or different channel frequencies in the same frequency band, and through the change of the adjustable inductance, the characteristic impedance Z after the antenna 4 is matched with the series adjustable inductor is controlled. k value, to achieve the purpose of adjusting the bandwidth or working frequency of antenna 4. The adjustable inductor front end and back end can also be used in conjunction with other matching circuits (RF matching module) to ensure that the matching of antenna 4 is more flexible.

[0059] The above is a method for adjusting the characteristic impedance of the antenna 4 by adjusting the adjustable inductor in the matching circuit of the antenna 4, thereby realizing the adjustable antenna 4, expanding the bandwidth of the antenna 4, and improving the communication performance.

[0060] As a preferred embodiment, the nickel-titanium alloy memory metal inductor is connected to the middle connecting end of the antenna 4 by means of series and / or parallel matching.

[0061] Please refer to Figure 6 , Figure 6 This is a schematic diagram of the principle of a circuit for adjusting the resonant operating frequency of an antenna by means of a middle-series loading tuning method provided by the present invention.

[0062] Please refer to Figure 7 , Figure 7 This is a schematic diagram of the principle of a circuit for adjusting the resonant operating frequency of an antenna by a parallel loading tuning method in the middle of the antenna provided by the present invention.

[0063] In this embodiment, a nickel-titanium alloy memory metal adjustable shrink wire adjustable inductor is added to the antenna 4 as a loading and tuning method for the antenna 4 to adjust the working frequency band of the antenna 4 and expand the bandwidth of the antenna 4. Similarly, a DC blocking capacitor is connected in series on both sides of the adjustable inductor to isolate the influence of the DC current applied to the adjustable inductor of the shrink wire on the RF path. The adjustable inductor and the two DC blocking capacitors are respectively connected to the positive and negative poles of the power supply through two filter inductors. The filter inductor presents high impedance in the high frequency band, which is equivalent to an open circuit state to eliminate the influence of the power link on the RF path. The CPU main control chip control signal is connected to the power supply, and the power output current is adjusted according to the working frequency band requirements of the antenna 4, so as to control the adjustable inductance. This adjustable inductance is directly loaded onto the middle connection end of the antenna 4. When loaded in series, it plays the role of extending the antenna 4. The shorter the shrink wire length, the smaller the adjustable inductance. The shorter the equivalent length of the antenna 4, the working frequency shifts to the high frequency, and vice versa. When loaded in parallel, it plays the role of offsetting the capacitance between the antenna 4 and the ground. The shorter the shrink wire length, the smaller the adjustable inductance. The working frequency of the antenna 4 shifts to the high frequency, and vice versa. In this way, the adjustable antenna 4 is realized by loading tuning on the branches of the antenna 4 through the adjustable inductor, thereby expanding the bandwidth of the antenna 4 and improving the communication performance.

[0064] In addition, a series plus parallel joint antenna 4 intermediate loading mode may also be provided, and in specific applications, it may be used in multiple stages for expansion, which will not be described in detail in the present invention.

[0065] The present invention adds an adjustable inductor made of the shrinkage wire characteristics of nickel-titanium alloy to the design of antenna 4, and designs an adjustable antenna 4 to improve the working bandwidth of antenna 4. It can also be adjusted step by step by channel. The antenna 4 adjusts the bandwidth to be wider, the distribution is finer, or it works in multiple frequency bands, thereby improving the performance of antenna 4 and ensuring the wireless communication RF broadband and multi-band working communication effects.

[0066] As the inductance length of the winding coil shrinks, the corresponding diameter of the coil shrinks in proportion. The maximum shrinkage ratio of the coil diameter D (mm) can be adjusted from 80% to 100%.

[0067] Assuming that the diameter of the adjustable winding inductor is w=0.2(mm), the wire spacing is s=0.3(mm), the number of turns is n=10 and the coil diameter is D=2(mm), the coil height is H(mm)=n×(w+s)=5(mm), and the adjustable inductor expansion ratio is K, the relationship between the inductance and the expansion ratio K is calculated as: L(uH)=((D×K)^2×n^2) / ((18×(D×K)+40×H)×25.4).

[0068] The corresponding inductance values ​​for each 4% interval distribution according to the shrinkage ratio K corresponding to the expansion ratio are shown in Table 1.

[0069] Table 1 Correspondence between shrinkage ratio of adjustable inductance of shrinkable wire and coil inductance

[0070] Please refer to Figure 8 , Figure 8 This is a schematic diagram of the principle of the adjustable inductor series-loaded antenna branch model provided by the present invention.

[0071] Please refer to Fig. 9 , Fig. 9 The resonant frequency diagram of the antenna with adjustable inductance series loading provided by the present invention.

[0072] Please refer to Fig.10 , Fig.10 This is a distribution curve diagram of the radiation efficiency of the antenna with adjustable inductor series loading provided by the present invention.

[0073] Please refer to Fig.11 , Fig.11 The invention provides two limit state diagrams of the maximum and minimum values ​​of the adjustable inductance.

[0074] The model of the antenna branch section with adjustable inductance series loading includes a simulated feeding point and a simulated adjustable inductance series loading on antenna 4. The upper and lower loading positions of the adjustable inductance have different corresponding adjustment effects and can be adjusted according to actual application requirements. The bottom plane is the reference ground plane of antenna 4, and the two cylinders are the main branches of antenna 4. When the adjustable inductance is adjusted in the range of 44.1 (nH) to 66.7 (nH) as shown in Table 1, the corresponding antenna 4 resonant frequency S11 and antenna 4 radiation efficiency distribution curves are shown. According to the simulation model results, it can be seen that the corresponding antenna 4 resonant frequency is adjusted from 0.379 (GHz) to 0.342 (GHz), and S11 below -10dB is used as the bandwidth of antenna 4. The maximum and minimum values ​​of the adjustable inductance are taken to compare the bandwidth of antenna 4. The adjustable inductor is not powered by a DC power supply, and the original state is equivalent to the maximum inductance of the ordinary fixed value inductor. The bandwidth of antenna 4 is mark5-mark6=0.35 (GHz)-0.335 (GHz)=15 (MHz). After the adjustable inductor is powered by a DC power supply, the total inductance of antenna 4 in different contraction states from the maximum to the minimum adjustable range is The bandwidth is mark2-mark6=0.39(GHz)-0.335(GHz)=55(MHz), 55-15=40(MHz), and the bandwidth of antenna 4 is extended by nearly 40(MHz). This confirms that when the series adjustable inductor is loaded to antenna 4, the operating frequency of antenna 4 is constantly changing with the change of the loaded adjustable inductor, and the corresponding working bandwidth of antenna 4 is effectively extended. Therefore, the CPU main control chip control signal is connected to the power supply, and the power supply output current is adjusted according to the working frequency bandwidth requirement of antenna 4, thereby controlling the adjustable inductor, thereby adjusting the working frequency of antenna 4 and extending the bandwidth of antenna 4.

[0075] The above is only one way of adjusting the working frequency of the antenna 4 by series adjustable inductor loading tuning. Other extended series and parallel joint loading tuning, or joint matching circuit tuning methods can be implemented through the above technical expansion, and the control is more flexible.

[0076] The antenna system provided by the present invention is described below. The antenna system described below and the memory metal tunable frequency antenna circuit described above can be referred to each other.

[0077] The present invention also provides an antenna system, comprising the above-mentioned memory metal frequency-adjustable antenna circuit.

[0078] The communication device provided by the present invention is described below. The communication device described below and the memory metal tunable frequency antenna circuit described above can be referred to each other.

[0079] The present invention also provides a communication device, comprising the above antenna system.

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A memory metal frequency-adjustable antenna circuit, characterized in that: It includes a control module, a plurality of memory metal elements, a power supply link and a radio frequency link; the power supply link includes a power supply module, the radio frequency link includes an antenna; the memory metal element has a power-on contraction characteristic; The control end of the control module is connected to the control end of the power supply module, the first power supply end of the power supply module is connected to the first end of the memory metal element, and the second power supply end of the power supply module and the connection end of the antenna are both connected to the second end of the memory metal element; The control module is used to send a power supply control signal according to the antenna control requirements; the antenna control requirements are the frequency band and bandwidth requirements for the antenna operation; The power supply module is used to output a power supply current to the memory metal element based on the power supply control signal; The memory metal element is used to shrink under the supply current and dynamically adjust its own impedance to dynamically adjust the characteristic impedance of the antenna.

2. The memory metal tunable frequency antenna circuit according to claim 1, characterized in that: The radio frequency link also includes a plurality of direct current isolating elements, which are arranged at both ends of the memory metal element and are used to isolate the interference of the power supply current of the memory metal element on the radio frequency link.

3. The memory metal tunable frequency antenna circuit according to claim 1, characterized in that: The power supply link further includes a filter element, which is disposed between the power supply module and the memory metal element and is used to filter out interference and noise of the power supply link to the radio frequency link.

4. The memory metal tunable frequency antenna circuit according to claim 1, characterized in that: The RF link also includes a RF transceiver, a first end of the RF transceiver is connected to the input end of the control module, and a second end of the RF transceiver is connected to the connection end of the antenna, for determining the antenna control requirements and transmitting and receiving wireless signals.

5. The memory metal frequency-adjustable antenna circuit according to claim 1, characterized in that: The radio frequency link further includes a radio frequency matching module, which is connected to the memory metal element and is used to match the memory metal element to adjust the characteristic impedance of the antenna.

6. The memory metal tunable frequency antenna circuit according to any one of claims 1 to 5, characterized in that: The memory metal element is a nickel-titanium alloy memory metal inductor.

7. The memory metal frequency-adjustable antenna circuit according to claim 6, characterized in that: The nickel-titanium alloy memory metal inductor is connected to the edge connection end of the antenna by series and / or parallel matching.

8. The memory metal frequency-adjustable antenna circuit according to claim 6, characterized in that: The nickel-titanium alloy memory metal inductor is connected to the middle connecting end of the antenna by series and / or parallel matching.

9. An antenna system, characterized in that: The invention comprises the memory metal frequency-adjustable antenna circuit as claimed in any one of claims 1 to 8.

10. A communication device, characterized in that: Comprising the antenna system as claimed in claim 9.

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