Multiple access signal search antenna and electronic device for wireless communication system

Abstract

This invention provides a multiple access signal search antenna and electronic device for a wireless communication system. The multiple access signal search antenna includes multiple antenna elements, each of which can switch between a radiating state and a non-radiating state under the control of its control element. The radiating position of the multiple access signal search antenna is determined by the antenna elements in the radiating state, such that by controlling the radiating or non-radiating state of each antenna element, the radiating position of the multiple access signal search antenna can be adjusted to improve signal reception quality. This invention can flexibly receive and reflect signals from different paths, effectively increasing the strength of the received signal, reducing interference, and providing more stable signal quality in scenarios with significant multipath effects.

Description

Technical Field

[0001] This invention relates to the field of wireless communication technology, and in particular to a multiple access signal search antenna and electronic device for wireless communication systems. Background Technology

[0002] The Internet of Things (IoT) represents the future of wireless communication, and 5G, as we know it, is a crucial part of mobile communication. However, as signals propagate, various interferences along the way are unavoidable, leading to signal attenuation, poor reception, and even information loss or corruption. Interference and scattering are common problems in current ultra-dense networks (such as 6G networks), and these issues are generally considered detrimental. Traditional solutions such as Multiple-Input Multiple-Output (MIMO) and AI-assisted signal processing can address these problems, but they often involve high power consumption, high hardware complexity, and require wide bandwidth, resulting in scalability challenges and hindering large-scale deployment.

[0003] It should be noted that the information disclosed in the background section of this invention is intended only to enhance the understanding of the general background of this invention, and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0004] The purpose of this invention is to provide a multiple access signal search antenna and electronic device for wireless communication systems, which can flexibly receive and reflect signals from different paths, effectively increase the strength of the received signal, reduce interference, and provide more stable signal quality in scenarios with significant multipath effects.

[0005] To achieve the above objectives, the present invention provides a multiple access signal search antenna for a wireless communication system, comprising a plurality of antenna elements, each of which can switch between a radiating state and a non-radiating state under the control of its control element; the radiating position of the multiple access signal search antenna is determined by the antenna elements in the radiating state, such that by controlling the radiating or non-radiating state of each antenna element, the radiating position of the multiple access signal search antenna can be adjusted to improve signal reception quality.

[0006] Optionally, the multiple access signal search antenna provided by the present invention further includes a control board, which is electrically connected to each of the control elements to control the switching state of the control elements.

[0007] Optionally, the control board is configured to dynamically control the antenna element with the largest signal-to-interference-plus-noise ratio to switch to the radiation state based on the real-time signal-to-interference-plus-noise ratio.

[0008] Optionally, the control element of each antenna unit includes at least one PIN diode, and for each antenna unit, the antenna unit is dynamically switched to a radiating state or a non-radiating state by controlling the switching state of the PIN diode in the antenna unit.

[0009] Optionally, the control board is electrically connected to each of the PIN diodes via a bias via.

[0010] Optionally, the multiple access signal search antenna provided by the present invention further includes a DC bias circuit, which is configured to provide DC current to the PIN diode.

[0011] Optionally, the plurality of antenna elements are arranged in a two-dimensional array on the same plane.

[0012] Optionally, any two adjacent antenna elements in the same column can be configured not to be in a radiating state at the same time.

[0013] Optionally, the multiple access signal search antenna provided by the present invention further includes a millimeter-wave feed waveguide that provides energy to the plurality of antenna elements. The millimeter-wave feed waveguide is provided with a plurality of slots, and the plurality of slots are configured one-to-one with the plurality of antenna elements.

[0014] To achieve the above objectives, the present invention also provides an electronic device, the electronic device comprising the multiple access signal search antenna described in any of the preceding claims.

[0015] Compared with the prior art, the multiple access signal search antenna and electronic device for wireless communication systems provided by the present invention have the following advantages:

[0016] The multiple access signal search antenna for a wireless communication system provided by this invention includes multiple antenna elements, each of which can switch between a radiating state and a non-radiating state under the control of its control element. The radiating position of the multiple access signal search antenna is determined by the antenna element in the radiating state, so that by controlling the radiating or non-radiating state of each antenna element, the radiating position of the multiple access signal search antenna can be adjusted to improve signal reception quality. Therefore, the multiple access signal search antenna provided by this invention can dynamically change the position of its radiating aperture within a specified area, flexibly receive and reflect signals from different paths, effectively increase the strength of the received signal, reduce interference, and thus provide more stable signal quality in scenarios with significant multipath effects, achieving optimal signal reception quality. Furthermore, the multiple access signal search antenna provided by this invention can operate effectively in millimeter-wave bands and high-frequency communication conditions, adapting to complex propagation environments and improving communication reliability and transmission efficiency. In 5G / 6G networks with high-speed, low-latency requirements, the multiple access signal search antenna provided by this invention can effectively improve communication quality and ensure user experience. In the millimeter-wave band, the multiple access signal search antenna provided by this invention can effectively address multipath attenuation and interference issues in high-frequency propagation, making it suitable for satellite communications, the Internet of Things (IoT), and high-speed wireless transmission. In high-density interference scenarios (such as urban environments and large event venues), the multiple access signal search antenna provided by this invention can automatically adjust its radiation position, thereby optimizing signal reception quality. Furthermore, the multiple access signal search antenna provided by this invention has a compact structure, allowing for easy integration into existing platforms while maintaining compatibility with current installation methods. This enables upgrades to 5G or IoT systems without significant modifications to existing infrastructure. The multiple access signal search antenna provided by this invention is not only suitable for conventional communications but can also be arrayed to form MU-MIMO (Multi-User Multiple-Input Multiple-Output) and MIMO (Multi-Input Multiple-Output) architectures, meeting the multi-user requirements of WiFi 6 and 5G communications and improving system capacity and communication efficiency.

[0017] Since the electronic device provided by this invention includes the multiple access signal search antenna for wireless communication system provided by this invention, the electronic device provided by this invention has at least all the beneficial effects of the multiple access signal search antenna for wireless communication system provided by this invention. For details, please refer to the relevant description above. Therefore, the beneficial effects of the electronic device provided by this invention will not be described in detail here. Attached Figure Description

[0018] Figure 1a This is a schematic diagram of a downlink communication system;

[0019] Figure 1b This is a schematic diagram of the multipath effect;

[0020] Figure 2a A schematic diagram of the layered structure of a multiple access signal search antenna provided in one embodiment of the present invention;

[0021] Figure 2b A schematic diagram of the distribution of antenna elements in a multiple access signal search antenna for a wireless communication system according to an embodiment of the present invention;

[0022] Figure 2c A schematic diagram illustrating the working principle of a multiple access signal search antenna provided in one embodiment of the present invention;

[0023] Figure 2d A schematic diagram of the energy in the radiating waveguide of an antenna element in a radiating state in a multiple access signal search antenna according to an embodiment of the present invention;

[0024] Figure 2e A schematic diagram of four possible states of a primitive atom in a multiple access signal search antenna provided according to an embodiment of the present invention;

[0025] Figure 2f A schematic diagram of the electric field distribution of elementary atoms in a multiple access signal search antenna under three possible states, provided in an embodiment of the present invention.

[0026] Figure 2g A schematic diagram of the simulated electric field results of elementary atoms in a multiple access signal search antenna provided in one embodiment of the present invention;

[0027] Figure 2h A schematic diagram of the electric field distribution on the surface of a multiple access signal search antenna at different time points and when different antenna elements are activated, according to an embodiment of the present invention.

[0028] Figure 3a A schematic diagram of three rich scattering generators;

[0029] Figure 3b A schematic diagram showing the electric field distribution received by a multiple access signal search antenna from each generator at different locations and the electric field distribution received from all generators, according to an embodiment of the present invention.

[0030] Figure 3c A schematic diagram of the electric field distribution received by the multiple access signal search antenna from all generator transmitters in all 10 cases according to an embodiment of the present invention;

[0031] Figure 3d A schematic diagram illustrating the correlation coefficient matrix of all electric field data generated by the scattering generator;

[0032] Figure 4a A schematic diagram showing the experimental setup for the FAMA system;

[0033] Figure 4b A schematic diagram of the rich scattering generator used as the transmitter and the multiple access signal search antenna used in the measurement;

[0034] Figure 4c A front view of a multiple access signal search antenna provided according to an embodiment of the present invention;

[0035] Figure 4d A rear view of a multiple access signal search antenna provided according to an embodiment of the present invention;

[0036] Figure 5a A schematic diagram of SINR measured at different frequencies with transmitter Tx1 as the target user and transmitters Tx2 and Tx3 as interference sources.

[0037] Figure 5b This diagram illustrates the SINR measurements at different frequencies when transmitter Tx2 is the target user and transmitters Tx1 and Tx3 are interference sources.

[0038] Figure 5c A schematic diagram of SINR measured at different frequencies when transmitter Tx3 is the target user and transmitters Tx1 and Tx2 are interference sources.

[0039] Figure 5d A schematic diagram of the complete experimental setup for connecting the multiple access signal search antenna and transmitter group provided by this invention to a vector network analyzer for measurement;

[0040] Figure 6a A schematic diagram of the SINR range observable in all cases when the transmitter Tx1 is the target user, provided by a multiple access signal search antenna according to an embodiment of the present invention;

[0041] Figure 6b A schematic diagram of the SINR range observable in all cases when the transmitter Tx1 is the target user, provided by a multiple access signal search antenna according to an embodiment of the present invention;

[0042] Figure 6c The diagram shows the observable SINR range of the multiple access signal search antenna provided in one embodiment of the present invention when the target user is the transmitter Tx3, and the actual SINR at all antenna element locations in the scenario of Case 2.

[0043] Figure 6d This is a schematic diagram comparing the maximum SINR achievable by a multiple access signal search antenna according to an embodiment of the present invention with the SINR received by a conventional fixed-position antenna.

[0044] The reference numerals in the attached figures are explained as follows: Elemental fluid antenna - 100; Antenna element - 110; Control element - 111; PIN diode - 1111; Millimeter wave feed waveguide - 120; Control board - 130; FPGA controller - 131; Abundant scattering generator - 200; Vector network analyzer - 300; Laptop computer - 400. Detailed Implementation

[0045] The following detailed description, in conjunction with the accompanying drawings and specific embodiments, further illustrates the multiple access signal search antenna and electronic device for wireless communication systems proposed in this invention. The advantages and features of this invention will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, used only to facilitate and clarify the explanation of the invention's purpose. Please refer to the drawings for a clearer understanding of the invention's objectives, features, and advantages. It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are only for illustrative purposes and to enable those skilled in the art to understand and read the invention, and are not intended to limit the implementation conditions of the invention. Any modifications to the structure, changes in proportions, or adjustments to the size, provided they produce the same or similar effects and achieve the same objectives as this invention, should still fall within the scope of the technical content disclosed in this invention.

[0046] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. The singular forms “a,” “an,” and “the” include plural objects. The term “or” is generally used to mean “and / or,” the term “several” is generally used to mean “at least one,” and the term “at least two” is generally used to mean “two or more.” Furthermore, the terms “first,” “second,” and “third” are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated.

[0047] Furthermore, in the description of this specification, the reference to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., means that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0048] To facilitate understanding, a brief introduction to the research background of this invention will be given first.

[0049] Despite being touted as a revolutionary technology, fifth-generation (5G) mobile communication systems have yet to deliver significant improvements in the user experience for the average smartphone user. The dazzling applications showcased in 5G rollouts, such as holographic communication and haptic internet, have yet to materialize. This is because promotional campaigns typically emphasize securing ample spectrum and energy resources to realize these applications, whereas in reality, limited resources prevent the large-scale provision of such high-demand services. This situation has prompted practitioners, researchers, and scientists in the communications field to consider the improvements needed for the next generation of communication systems (i.e., sixth-generation systems, 6G). Among the many ambitious key performance indicators (KPIs), a prominent goal for 6G is to achieve spectral efficiency exceeding 1000 bps / Hz. This goal implies that, considering only single-user point-to-point systems, communication links would need to operate at extreme SNR levels of up to 3000 dB. A more plausible explanation is that this goal requires networks capable of sharing spectrum among a large number of users while ensuring that each user still receives acceptable performance.

[0050] Spectral efficiency is a metric that measures the bit rate (bits per second) achievable per hertz of bandwidth. According to Shannon's formula, the classic expression for spectral efficiency is log2(1+SNR), where SNR is the signal-to-noise ratio of the received signal. When U users share the same physical channel, this expression becomes Ulog2(1+SINR), where SINR represents the signal-to-interference-to-noise ratio (SINR) for each user, assuming that each user has the same performance. Clearly, the above discussion assumes that each user has only one antenna. However, if each user has a multiple-input multiple-output (MIMO) channel, the spectral efficiency for each user becomes rlog2(1+SNR), where r = min(n T ,n R ), n T and nR These represent the number of antennas at the transmitting and receiving ends, respectively. However, due to space and cost limitations, n R Typically, the value of r is small, and in practice, it is also small. Therefore, regardless of whether MIMO is used, if a network needs to achieve a spectral efficiency exceeding 1000 bps / Hz, the conclusion remains that it must be achieved through spectrum sharing among a large number of users.

[0051] Multiple access technologies determine how users obtain available spectrum resources for communication. Traditional methods rely on Time Division Multiple Access (TDMA) and Frequency Division Multiple Access (FDMA) to provide users with orthogonal and non-overlapping communication channels because this approach is relatively simple in terms of interference management. However, as mobile networks attempt to meet growing demands within limited spectrum, multi-user sharing on the same time-frequency channel becomes increasingly necessary. In this process, proper interference management is required to ensure reliable communication. In 5G New Radio (NR), this is achieved through Massive Multi-User Multiple-Input Multiple-Output (MU-MIMO) technology. The principle of MU-MIMO is simple. Assuming available user channel state information (CSI), a multi-antenna base station (BS) can use signal processing techniques to cleverly mix the signals from its antennas before transmitting them to the user; this method is called MU-MIMO precoding. Channel state information (CSI) refers to the amplitude and phase changes of the received signal after passing through the wireless channel, and, where appropriate, may also include the angle of departure (AoD) and / or angle of incidence (AoA) for each propagation path.

[0052] However, the performance of massive MU-MIMO in 5G-NR has been somewhat disappointing, raising questions about the potential of ultra-large MIMO (XL-MIMO) in 6G. The main challenge lies in scalability, particularly the difficulty of extending the Channel State Information (CSI) acquisition process in multi-user scenarios and the complexity of precoding computation. Reliable CSI acquisition is crucial for effective MU-MIMO precoding, but the rapid changes in radio channels make maintaining CSI accuracy increasingly difficult as the number of users increases. Also worth mentioning are two emerging multiple access technologies: Non-Orthogonal Multiple Access (NOMA) and Rate Split Multiple Access (RSMA). They enable users to overlap communication on the same physical channel through advanced coding and decoding schemes. While NOMA has received significant attention in the 5G development cycle, RSMA is currently under discussion in 3GPP (3rd Generation Partnership Project) as a candidate technology for post-5G and 6G standardization. However, both NOMA and RSMA face challenges related to CSI feedback and high decoding complexity, limiting their potential as large-scale spectrum sharing solutions. Therefore, a fundamentally different approach is needed to complement existing and emerging MU-MIMO technologies.

[0053] With the rapid development of artificial intelligence (AI), some are optimistic about solving the scalability problem in MU-MIMO. Indeed, deep learning has already been used to reduce CSI feedback in massive MIMO systems in 5G. Deep learning is also expected to be applied to a range of design problems in the 6G physical layer. However, it should be noted that system performance fundamentally depends on the physical signal itself, and AI cannot change this physical limitation. Therefore, the goal of this invention is to break through the physical boundaries of existing communication systems and explore innovative opportunities for wireless communication multiple access technologies that can scale with the number of users.

[0054] To rethink the possibilities of multiple access, a recently introduced concept of a novel reconfigurable antenna—known as the “Fluorescent” Antenna System (FAS)—has attracted particular attention and has become a key technology for 6G. FAS stands for any software-controllable, shape-flexible, and location-flexible wireless communication antenna system. FAS is a first in the field of reconfigurable antennas. From an information theory perspective, FAS can be viewed as a new physical-layer degree of freedom that enhances communication performance. A recent tutorial article provides comprehensive coverage of many topics related to FAS. Notably, through its location reconfigurability, FAS gives transceivers the ability to access received signals with fine resolution in space. Unlike traditional fixed-location antennas that receive signals at a single “point” in space, FAS can receive signals from a predetermined “spatial area” with fine resolution. This change is fundamental because it expands the dimension of the received signal without requiring a corresponding increase in the number of radio frequency (RF) chains. More importantly, this capability allows FAS to access the fluctuating characteristics of wireless channels in space and utilize them for multiple access. In particular, wireless channels are typically modeled as complex coefficients, characterizing amplitude attenuation and phase shift, reflecting the overall effect of radio wave propagation in a wireless environment. This can also be interpreted as the superposition of multipath propagation paths between the transmitter and receiver. A classic phenomenon is that when multipath signals cancel each other out, the wireless channel randomly attenuates or even disappears; this is called fading. When the receiver location changes, the combination of propagation paths also changes, thus altering the channel fading coefficient. FAS has a unique advantage in this regard. Specifically, FAS can observe the changes in the wireless channel within a given spatial area with fine resolution, and fading means that the channel may disappear at certain locations. Therefore, in multi-user scenarios, locations where the total interference channel disappears (or becomes extremely weak) can be selectively activated, which is the "Fluorescent Antenna Multiple Access" (FAMA) concept proposed in one paper. An exciting result is that FAMA can achieve interference avoidance without relying on base station-side CSI like MU-MIMO precoding, or on complex encoding and decoding like NOMA and RSMA. Our interpretation of FAMA is "using the fluctuations of radio waves and taking advantage of opportunities created by nature for spatial multiplexing," which is similar to Bruce Lee's famous martial arts philosophy, "Like water, my friend." If Bruce Lee used the adaptability of water to cope with combat, then FAMA uses the same concept for multiple access: "Like water, my antenna." The transceiver can be a base station, access point, mobile phone, tablet, or any Internet of Things (IoT) device with wireless connectivity. Spatial multiplexing refers to multiple access technology that separates users in the spatial domain. It's worth noting that fading is widely considered a "curse" in wireless communication, and decades of efforts have aimed to mitigate this phenomenon to restore communication stability and attempt to achieve good reception performance.

[0055] The concept of FAMA was first proposed by Wong et al. in 2022, and subsequent studies have further explored its challenges in signal processing and attempted to combine it with other techniques. However, existing research remains largely theoretical, lacking a deep understanding of how to implement FAMA in practice. One straightforward approach to implementing FAS is to use liquid antennas due to their shape flexibility. Recently, a paper has designed a position-flexible FAS using a liquid metal antenna and validated the feasibility of FAMA using obtained measurement data. While the results are positive, the main problem with liquid-based methods is their slow response time when changing the FAS position. The required response time should be in the millisecond range or less (i.e., channel coherence time), but the transposition time of the liquid-based radiator is close to one second even in the most ideal conditions. A promising alternative is to implement FAS using reconfigurable pixels. In this approach, a reconfigurable radiating surface consists of a tiny matrix of pixels, and the radiation characteristics are reconstructed by optimizing the connections between the pixels. However, this research is still in its very early stages, and it is unclear how the optimized connections between pixels relate to specific functions in the radiation characteristics. Furthermore, it remains unknown whether FAS implemented using reconfigurable pixels is effective for FAMA. The concepts of coded metasurfaces, leaky antennas, pixel-based antennas, and movable antennas are also applicable to the design of FAS, but currently, there are no attempts to implement FAS using these techniques other than reconfigurable pixels. It is speculated that positively and negatively doped (PIN) diodes could be used to control the operating state of each metasurface unit, while the theory of leaky antennas could be used to design integrated waveguides (SIWs) to manage radio wave propagation.

[0056] The principle of FAMA will be explained below.

[0057] Please refer to Figure 1a This is a schematic diagram of a downlink communication system where two distributed base stations (BS1 and BS2) are responsible for transmitting data to two mobile users in a typical rich scattering environment (both outdoor and indoor). The middle inset shows a user's laptop with a Fascinating Array (FAA) installed, allowing observation of the electric field distribution of signals from the two base stations. The inset on the right further illustrates the concept of Fascinating Array (FAMA), specifically focusing on a horizontal dimension of the FAS and showing the variation of wireless signal strength along that dimension. It can be clearly seen that the wireless signal strength fluctuates, providing the FAS with opportunities to avoid interference. Figure 1aAs shown, consider a wireless communication network where a base station (BS) provides services to U users via a shared physical channel in the downlink. The BS is equipped with U antennas at fixed locations, each dedicated to transmitting a communication signal to one of the users. In this paper, the allocation of BS antennas to users is not important, but such allocation can be easily implemented in practical applications. At the user end, each user is equipped with a "fluid" antenna (called a FAS), which is considered to have the ability to "ride the radio waves" and switch to a "favorable" radiation position according to changes in wireless channel conditions. Assume that each user's FAS has N preset selectable positions, arranged in a two-dimensional grid on a given plane, comprising I rows and J columns (N = I × J). All these selectable positions share a common radio frequency (RF) link. Under this model, the signal received by user u's FAS at position (i,j) is... It can be represented as:

[0058]

[0059] Among them u∈{1,2,…,U}, i∈{1,2,…,I}, j∈{1,2,…,J}. s u This represents the signal sent by user u. This represents the zero-mean additive white Gaussian noise (AWGN) at the user's position (i,j). Indicates from the first The fading channel from a BS antenna to the (i,j) location of user u. When When, it indicates interference with the channel; when Let represent the desired channel. For the sake of simplicity and without loss of generality, we will focus on the channel being considered as a static timescale. In reality, the channel does change, but the same process can be repeated each time the channel changes.

[0060] In FAMA, user u switches its FAS to the position that maximizes the signal-to-interference ratio (SIR); at high signal-to-noise ratio (SNR), when noise is negligible, this is also known as signal-to-interference-plus-noise ratio (SINR).

[0061] Specifically, the best location selected by the user (i * ,j * )| u It can be determined using the following formula:

[0062]

[0063] in This represents the expected value of the input random variable. The theoretical performance of FAMA, such as the interruption probability, has been studied in relevant literature, and the results show that it has a very promising future in multiple access communication.

[0064] However, experimental verification of FAMA's effectiveness is still lacking. This requires not only the design and fabrication of highly reconfigurable FAS hardware, but also the acquisition of measurement data through experiments to verify its performance in real-world environments.

[0065] Please continue to refer to this. Figure 1b This is a schematic diagram of the multipath effect. For example... Figure 1b As shown, multipath effects occur in daily communication, leading to signal attenuation. Statistics show that the attenuation caused by multipath effects is significant and seriously affects communication quality.

[0066] Based on this, the core idea of ​​this invention is to provide a multiple access signal search antenna and electronic device for wireless communication systems, which can flexibly receive and reflect signals from different paths, effectively increasing the strength of the received signal, reducing interference, and providing more stable signal quality in scenarios with significant multipath effects. This invention views scattering as a naturally provided opportunity, rather than eliminating scattering through cumbersome signal processing to restore channel stability. By combining a leaky antenna with metasurface coding, a novel reconfigurable antenna—called a metafluid antenna, or multiple access signal search antenna—is proposed to utilize fine spatial resolution to exploit interference nulls naturally formed by scattering. This idea adheres to Bruce Lee's martial arts philosophy of "like water, my friend," and is realized through a novel, fully electronically programmable metafluid architecture. This invention demonstrates for the first time the implementation of FAMA and shows its potential application scenarios, combining an artificially massively rich scattering transmitter with a novel receiver—the metafluid antenna (multiple access signal search antenna). By strategically activating the metasurface's elemental cells to the position of maximizing SINR, the power of electromagnetic wave (EM) dynamics in space and time is successfully utilized, thereby avoiding the need for expensive signal processing on the base station side. This new invention has a profound impact on the widespread application of wireless communication, sensor networks, and encryption technologies.

[0067] Please refer to Figure 2a and Figure 2b ,in, Figure 2a A schematic diagram of the layered structure of a multiple access signal search antenna provided in one embodiment of the present invention; Figure 2b This is a schematic diagram showing the distribution of antenna elements in a multiple access signal search antenna for a wireless communication system according to an embodiment of the present invention. Figure 2a and Figure 2bAs shown, the multiple access signal search antenna for a wireless communication system provided by the present invention includes a plurality of antenna elements 110, each of which can switch between a radiating state and a non-radiating state under the control of its control element 111; the radiating position of the multiple access signal search antenna is determined by the antenna element 110 in the radiating state, so that by controlling the radiating or non-radiating state of each antenna element 110, the radiating position of the multiple access signal search antenna can be adjusted to improve the signal reception quality.

[0068] Therefore, the multiple access signal search antenna provided by this invention can dynamically change the position of its radiating aperture within a specified area, flexibly receiving and reflecting signals from different paths, effectively increasing the strength of the received signal, reducing interference, and thus providing more stable signal quality in scenarios with significant multipath effects, achieving optimal signal reception quality. Furthermore, the multiple access signal search antenna provided by this invention can operate effectively in millimeter-wave bands and high-frequency communication conditions, adapting to complex propagation environments and improving communication reliability and transmission efficiency. In 5G / 6G networks with high-speed, low-latency requirements, the multiple access signal search antenna provided by this invention can effectively improve communication quality and ensure user experience. In the millimeter-wave band, the multiple access signal search antenna provided by this invention can effectively address multipath attenuation and interference problems in high-frequency propagation, making it suitable for satellite communication, IoT, and high-speed wireless transmission. In high-density interference scenarios (such as urban environments and large event venues), the multiple access signal search antenna provided by this invention can automatically adjust its radiation position, thereby optimizing signal reception quality. Furthermore, the multiple access signal search antenna structure provided by this invention is compact and can be easily integrated into existing platforms while maintaining compatibility with current installation methods. This allows it to be upgraded to 5G or IoT systems without significant modifications to existing infrastructure. The multiple access signal search antenna provided by this invention is not only suitable for conventional communications, but can also be arrayed to form MU-MIMO (Multi-User Multiple-Input Multiple-Output) and MIMO (Multi-Input Multiple-Output) architectures, meeting the multi-user requirements of WiFi 6 and 5G communications and improving system capacity and communication efficiency.

[0069] In summary, the multiple access signal search antenna provided by this invention utilizes channel fading to transform scattering and interference into advantages. By precisely moving the antenna's radiation position in space, and even reacting within a very short timeframe, the multiple access signal search antenna can freely search for multiple access signals amidst fluctuating radio waves, avoiding interference without relying on complex signal processing. This innovative design can effectively utilize radio wave fluctuations in space to achieve spatial multiplexing (i.e., simultaneous transmission of multiple signals) under multipath scattering conditions. Therefore, the multiple access signal search antenna provided by this invention can achieve lower complexity and greater channel capacity in practical applications.

[0070] Please continue to refer to this. Figures 2a to 2c ,in, Figure 2c This is a schematic diagram illustrating the working principle of a multiple access signal search antenna according to an embodiment of the present invention. Figures 2a to 2c As shown, the plurality of antenna elements 110 are arranged in a two-dimensional array on the same plane. Therefore, by arranging the plurality of antenna elements 110 in a two-dimensional array on the same plane, it is easier to integrate multiple independent antenna elements 110 into a single radio frequency chain, thereby facilitating the small-size configuration of the multiple access signal search antenna for wireless communication systems provided by this invention. It should be noted that, although... Figures 2a to 2c The example given is that the multiple access signal search antenna includes 120 antenna elements 110 (i.e., N=120), and these 120 antenna elements 110 are arranged in a two-dimensional array with I=8 rows and J=15 columns. However, as those skilled in the art will understand, this does not constitute a limitation on the present invention. The present invention does not limit the specific number of antenna elements 110 or the specific two-dimensional array form.

[0071] Please continue to refer to this. Figure 2c ,like Figure 2c As shown, in some exemplary embodiments, the control element 111 of each antenna element 110 includes at least one PIN diode 1111; for each antenna element 110, the antenna element 110 is dynamically switched to a radiating state or a non-radiating state by controlling the switching state of the PIN diode 1111 in that antenna element 110. Since each antenna element 110 includes at least one PIN diode 1111, the antenna element 110 can be dynamically switched to a radiating state or a non-radiating state by controlling the switching state of the PIN diode 1111 in that antenna element 110, thereby allowing energy to be radiated into the air through the antenna element 110 in the radiating state.

[0072] It should be noted that each antenna element 110 can be controlled to be turned on (radiating) or off (non-radiating) via a PIN diode 1111, thereby switching between the "radiating" and "non-radiating" states of the antenna element 110. This switching affects the intensity of the electromagnetic field and the direction of radiation. Each antenna element 110 can selectively enter "waveguide mode" or "free space mode," controlling how the antenna transmits or does not transmit signals.

[0073] Please continue to refer to this. Figure 2c ,like Figure 2cAs shown, the control element 111 of each antenna unit 110 includes a plurality of PIN diodes 1111 connected in series. Therefore, for each antenna unit 110, the antenna unit 110 can be dynamically switched to a radiating or non-radiating state by simultaneously controlling the switching states of the plurality of PIN diodes 1111 in that antenna unit 110, thereby effectively improving the control accuracy of each antenna unit 110. It should be noted that, although... Figure 2c The example given is that each antenna unit 110 includes four PIN diodes 1111 connected in series. However, as those skilled in the art will understand, this does not constitute a limitation on the present invention. The present invention does not limit the specific number of PIN diodes 1111 in each antenna unit 110.

[0074] Please continue to refer to this. Figure 2a and Figure 2d ,in, Figure 2d This is a schematic diagram of the energy in the radiating waveguide of antenna element 110 in a radiating state in a multiple access signal search antenna according to an embodiment of the present invention. Figure 2a and Figure 2d As shown, the multiple access signal search antenna provided by the present invention further includes a millimeter-wave feed waveguide 120 for providing energy to the plurality of antenna elements 110. The millimeter-wave feed waveguide 120 has a plurality of slots (not shown in the figure), and the plurality of slots are arranged one-to-one with the plurality of antenna elements 110. Therefore, by setting the millimeter-wave feed waveguide 120, the multiple access signal search antenna provided by the present invention can focus energy through the millimeter-wave feed waveguide 120, thus making it suitable for millimeter-wave band communication, effectively coping with complex propagation conditions in high-frequency environments, and achieving stable, high-quality communication. The response time of the multiple access signal search antenna provided by the present invention can reach 20MHz, thereby enabling rapid adaptation to signal changes and meeting the signal change requirements of mobile communication. Further, as... Figure 2d As shown, in free space, when an antenna element 110 is in a radiating state (PIN diode 1111 is in an open state), the free waveguide can transmit upwards and break through.

[0075] Please continue to refer to this. Figure 2a ,like Figure 2aAs shown, the multiple access signal search antenna provided by the present invention also includes a control board 130, which is electrically connected to each of the control elements 111 (PIN diodes 1111) to control the switching state of the control elements 111 (PIN diodes 1111). Thus, through the control board 130, a certain antenna element 110 can be selectively activated (switched to a radiating state) to radiate energy from the waveguide (millimeter-wave feed waveguide 120) into the air, while the remaining antenna elements 110 remain in a non-radiating state. This realizes the concept of a metafluid, which can be viewed as a radiating element moving in radio waves on a metasurface, and can dynamically activate specific positions for reception.

[0076] In some exemplary embodiments, the control board 130 includes an FPGA (Field Programmable Gate Array) controller. Thus, by employing the FPGA controller 131, the switching states of the PIN diodes 1111 in each antenna element 110 can be controlled more precisely.

[0077] In some exemplary embodiments, the control board 130 is configured to dynamically control the antenna element 110 with the highest signal-to-interference-plus-noise ratio (SNR) to switch to a radiating state based on the real-time SNR. Furthermore, by dynamically controlling the antenna element 110 with the highest SNR to switch to a radiating state based on the real-time SNR, the present invention can maximize the quality of the received signal, achieve optimal signal reception quality, and effectively improve the system's anti-interference capability.

[0078] In some exemplary embodiments, the control board 130 is electrically connected to each of the PIN diodes 1111 via bias vias. This connection method facilitates seamless integration between the PIN diodes 1111 and the antenna unit 110.

[0079] In some exemplary embodiments, the multiple access signal search antenna provided by the present invention further includes a DC bias circuit configured to provide DC current to the PIN diode 1111. Thus, the DC bias circuit can provide the necessary DC current to the PIN diode 1111 to switch between an "ON" and an "OFF" state.

[0080] In some exemplary embodiments, any two adjacent antenna elements 110 located in the same column are configured not to be in a radiating state at the same time. Since the radiation of any two adjacent antenna elements 110 located in the same column would cancel each other out when they are in a radiating state simultaneously, any two adjacent antenna elements 110 located in the same column are configured not to be in a radiating state at the same time.

[0081] Specifically, from a technical perspective, a single atom consists of two adjacent antenna elements 110 located in the same column, referred to as slot "+" antenna element 110A and slot "-" antenna element 110B, respectively. Figure 2c As shown. A key difference between atom-atoms and selectable positions is that each atom-atom contains two selectable positions, corresponding to two slots. Each antenna element 110 acts as a waveguide-fed magnetic dipole, extracting energy from the waveguide and radiating electromagnetic waves into the surrounding space. Since the lattice size of the atom-atom is much smaller than the wavelength, these antenna elements 110 can be considered as sampling points, capturing guided wave energy propagating in the waveguide at their respective locations. In the far-field region, the (k,l) atom-atom at a distance d... k,l The magnetic field generated at a certain position can be represented as:

[0082]

[0083] Where f0 is the carrier frequency, θ is the observation angle relative to the elementary fluid antenna 100 (multiple access signal search antenna), k0 is the propagation constant in free space, and m k,l It is the polarized magnetic dipole moment excited by elementary atoms at time t, and its expression is:

[0084]

[0085] Among them, P k,l H represents the complex magnetization polarization at the (k,l) position. k,l This represents the instantaneous magnetic field generated at position (k,l) within the waveguide structure. Furthermore, H0 is the amplitude of the magnetic field, and x... k,l Let ξ represent the propagation distance in the waveguide, and ξgw be the propagation constant of the guided wave, expressed as:

[0086]

[0087] Where μ and ε are the permeability and permittivity of the medium, respectively, ω is the carrier angular frequency, and W eff It is the effective width of the waveguide.

[0088] It is important to note that the magnetic current within the waveguide exhibits phase reversal between the upper and lower slots; for ease of distinction, we refer to them as slot "+" and slot "-", respectively. To differentiate between the two slots on the waveguide's longitudinal axis, the magnetic polarization of the upper slot and its distance to the far-field observation point are denoted as follows: and The magnetic polarization of the lower slot and the distance to the far-field observation point are denoted as follows: and The slots of the elementary atoms are controlled by PIN diode 1111. Different slot states lead to adjustments in radiation amplitude and phase, as expressed below:

[0089]

[0090] Related to the positionally flexible FAS function, the meta-atom has three states of interest: (1) OFF + &OFF - (2) ON + &OFF - (3) OFF + &ON - This corresponds to both slots being closed (case 1) or one of the two slots being open (cases 2 and 3), respectively. Figures 2e to 2f As shown, where, Figure 2e A schematic diagram of four possible states of a primitive atom in a multiple access signal search antenna provided according to an embodiment of the present invention; Figure 2f This is a schematic diagram of the electric field distribution of elementary atoms in the xy plane under three possible states in a multiple access signal search antenna provided according to an embodiment of the present invention. For each "ON" state, its magnetic field can be calculated by substituting equations (4) and (6) into (3). Therefore, the far-field expression of the (k,l) elementary atom in the "ON" state can be expressed as:

[0091]

[0092] By switching the PIN diode 1111 between the "ON" and "OFF" states, field radiation can be selectively blocked or allowed. Please refer to [link / reference needed]. Figure 2g This is a schematic diagram of the simulated electric field results of elementary atoms in a multiple access signal search antenna provided by an embodiment of the present invention. Figure 2gAs shown, focusing on frequency response, when the upper antenna element 110 is in the "ON" state and the lower element is in the "OFF" state, the results show that there is a difference of about 13dB in the electric field strength between the two elements. That is, the comparison of the electric field (E-field) difference between the antenna element 110 in the radiation state and the antenna element 110 in the non-radiation state shows that the difference in radiation intensity is significant. The ratio of the electric field strength in the "radiation" state (PIN diode 1111 is in the "on" state) is about 20 times that in the "non-radiation" state (PIN diode 1111 is in the "off" state). It can be seen that the antenna element 110 in the "on" state has a significantly stronger electric field strength than the antenna element 110 in the "off" state. This difference helps to achieve signal enhancement or suppression. In the metafluid antenna 100, slot "+" antenna element 110A and slot "-" antenna element 110B will not radiate simultaneously (i.e., any two adjacent antenna elements 110 located in the same column cannot be in a radiating state at the same time), because if slot "+" antenna element 110A and slot "-" antenna element 110B are both in the "ON" state, their radiation will cancel each other out. Furthermore, to illustrate the fluidized electric field, the field distribution on the surface of the metafluid antenna 100 (multiple access signal search antenna) is plotted at different time points and with different antenna elements 110 activated; please refer to [reference needed]. Figure 2h This is a schematic diagram of the electric field distribution on the surface of a multiple access signal search antenna provided in an embodiment of the present invention when different antenna elements 110 are activated at different time points. Figure 2h As shown, the electric field distribution resembles a rippled water surface, with a spike waveform appearing at the activated antenna element 110. This demonstrates that electromagnetic wave fluctuations on a metasurface can be accessed through the proposed metafluid architecture (multiple access signal search antenna).

[0093] To verify the feasibility of the multiple access signal search antenna provided by this invention for FAMA (Frequency and Position Adaptive Antenna), it is necessary to simulate the propagation conditions and characteristics of a real environment in a laboratory setting. Specifically, a waveguide-fed generator (rich scattering generator 200) was designed. This generator can radiate disordered beams, thereby generating diverse random electric field (E-field) distributions to simulate phenomena in a real rich scattering environment. The generator is a waveguide surface containing numerous randomly distributed slots. Please refer to [link to relevant documentation]. Figure 3a This is a schematic diagram of three abundant scattering generators 200. (See diagram for example.) Figure 3a As shown, there are three different rich scattering generators 200, each responsible for simulating the propagation environment from a user to the designed FAS receiver (i.e., the receiver containing the multiple access signal search antenna provided by this invention). Further, as... Figure 3aAs shown, these rich scattering generators 200 have arbitrarily arranged slots (slits). Enlarged detail images show that each rich scattering generator 200 has multiple rows of slots, each row consisting of randomly arranged upper and lower arrays of slots. Each slot represents a location where radio waves are emitted; therefore, the generator outputs a mixed signal of radio waves through these slots, simulating the scattering effect of a scatterer in a real propagation environment.

[0094] To accurately calculate the total surface radiation, the contribution of all slots to the far field needs to be considered. In this case, the generator's total far-field radiation H(θ) can be expressed as:

[0095]

[0096] Among them, 2M s ×N s This represents the total number of slots in the waveguide structure of the rich scattering generator 200. The definitions of the remaining variables and parameters are similar to those in the previous case of the elementary fluid antenna 100 (multiple access signal search antenna), but here the slots are fixed, rather than elementary atoms. Furthermore, the rich scattering generator 200 has M... s The rows of slots each contain an upper slot ("+") and a lower slot ("-"). It should be noted that the elementary atoms of the elementary fluid antenna 100 are tunable, while the slots in the rich scattering generator 200 are not.

[0097] For the generator, the radiating elements are discrete slots through which the input energy leaks out one by one. Therefore, we need to consider the radiative efficiency η of each radiating element. For a slot, its radiative efficiency η is related to the attenuation constant α in the y-direction. y (like Figure 3b As shown, this is a schematic diagram of the electric field distribution received by the multiple access signal search antenna from each rich scattering generator 200 at different locations and from all rich scattering generators 200, according to an embodiment of the present invention. The expression related to the offset distance Δl from the waveguide center is as follows:

[0098]

[0099] Suppose we are interested in a certain row in the waveguide (i.e., any M in the y-direction). s The radiation power of a certain slot (whether it's the upper or lower slot) is then determined by the radiation power of that slot (e.g., n). s radiated power It can be represented as:

[0100]

[0101] Among them, P in Indicates input power, η nIt can be calculated using equation (9). From equation (10), it can be seen that the radiated power is stronger closer to the input end and weaker further away from the input end. If all M values ​​in the waveguide feed generator are considered... s Line up, and use a power divider to distribute the input power to M. s One channel, then the slot (m) s ,n s radiated power It can be represented as:

[0102]

[0103] The variables here are expanded to accommodate the two-dimensional index in the waveguide-fed generator. Finally, substituting equation (11) into equation (8) yields the overall far-field radiation of the generator:

[0104]

[0105] To fully represent real-world environments, 30 such rich scattering generators 200 were fabricated, each with a different slot position. These generators were divided into three groups, each representing 10 independent wireless channels from a single transmitter. Therefore, these generators were sufficient to test the performance of a three-user FAMA system in 10 independent wireless environments.

[0106] like Figure 3c As shown, the disordered electric fields generated by these rich scattering generators 200 are transmitted to the receiver of the metafluid antenna 100 (multiple access signal search antenna). It can be observed that different transmitters radiate different radio waves through the rich scattering generators 200, simulating the radio wave propagation phenomenon on the metasurface of the metafluid antenna 100 (multiple access signal search antenna). To verify whether the radio waves generated by these rich scattering generators 200 conform to the theoretical rich scattering model, and whether these channels provide ideal conditions for FAMA interference avoidance, the correlation coefficients are evaluated using measurement data from the rich scattering generators 200 and the following formula:

[0107]

[0108] Among them, E i (i = 1, 2, ..., 30) represents the complex row vector received by the i-th generator from all switchable positions at the receiver of the elementary fluid antenna 100 (multiple access signal search antenna), H represents the conjugate transpose operation, and ||·|| returns the norm of the input vector. Therefore, ρ(E i E j The electric field E was measured. i and E jThe degree of correlation. Specifically, through numerical analysis of all 30 electric field data generated by the rich scattering generator 200 (from 3 emitters and 10 independent cases), the following can be obtained: Figure 3d This diagram illustrates the correlation coefficient matrix of all electric field data generated by the rich scattering generator 200. (See attached diagram.) Figure 3d As shown, the correlation coefficient matrix appears to be an identity matrix with very small off-diagonal terms. This means that the electric fields from different transmitters to receivers are almost independent, demonstrating that the rich scattering generator 200 fabricated in this invention can accurately simulate the characteristics of rich scattering channels, providing ideal conditions for FAMA interference avoidance. Importantly, the method of generating the environment does not affect the conclusions of this invention. In fact, the inventors found that the results of the experimental setup are closer to the expectations in Rayleigh fading environments. Therefore, this method is effective and provides robust verification for subsequent experimental setups.

[0109] Furthermore, waveguide-fed transmitters can be used to simulate the propagation characteristics of rich scattering in real-world environments. Please refer to [link / reference needed]. Figure 4a and Figure 4b ,in, Figure 4a A schematic diagram showing the experimental setup for the FAMA system; Figure 4b This is a schematic diagram of the abundant scattering generator 200 as the transmitting end and the multiple access signal search antenna used in the measurement. Figure 4a and Figure 4b As shown, in the experiment, the elementary fluid antenna 100 (multiple access signal search antenna) served as the receiver Rx, and the transmitters Tx1, Tx2, and Tx3, composed of rich scattering generators 200, were used at a communication distance of d = 0.5 meters. The rich scattering generator 200 represents a specific case of independent scattering of the three transmitted signals. Ten independent transmission cases were tested in the experiment. At the receiver Rx, the SINR was measured using a VNA (vector network analyzer 300), while the time-varying position matrix of the elementary fluid antenna 100 (multiple access signal search antenna) was input into a laptop computer 400, covering all 120 different locations. The laptop computer 400 also controlled the VNA (vector network analyzer 300) to synchronously record channel data. It should be noted that... Figure 4b The red cable in the diagram is the DC power supply cable for the FPGA controller 131. The distance between the transmitters Tx1, Tx2, and Tx3 and the receiver Rx is 0.5 meters.

[0110] The verified metafluidic antenna 100 (multiple access signal search antenna) employs a unique architecture design that supports position switching. It consists of 8 × 15 = 120 antenna elements 110, i.e., 120 switchable positions. Each antenna element 110 can be independently controlled, switching to different operating states, thereby achieving dynamic reconfiguration of the antenna radiation position (or the resulting aperture). This is achieved through PIN diodes 1111 integrated in each antenna element 110 and controlled by an integrated control board 130. The control board 130 is connected to each PIN diode 1111 via bias vias, providing the necessary DC current to the PIN diodes 1111 to switch between "ON" and "OFF" states. Figure 4c and Figure 4d The front and rear views of a meta-fluid antenna 100 (multi-access signal search antenna) according to an embodiment of the present invention are shown respectively. The rear view also shows brief details of the integrated control board 130. Figure 4c and Figure 4d As shown, the original fluid antenna 100 (multiple access signal search antenna) provided by this invention has two ports, one connected to a 50Ω load and the other connected to an RF link. The front of the original fluid antenna 100 (multiple access signal search antenna) consists of 8 rows and 15 columns, totaling 120 antenna elements 110. Each antenna element 110 is controlled by four PIN diodes 1111, which can switch between "radiating" and "non-radiating" states. The control board 130 is seamlessly integrated with the antenna section through a bias via. By reprogramming the FPGA, the radiation position of the original fluid antenna 100 (multiple access signal search antenna) can be changed, achieving dynamic control of the antenna radiation pattern.

[0111] The metafluid antenna 100 (multiple access signal search antenna) operates at a center frequency of 26.5 GHz and has a bandwidth of 1 GHz. Ten independent experiments (Case 1 to Case 10) simulating a three-user FAMA system were conducted using 30 waveguide feed generators, with the metafluid antenna 100 (multiple access signal search antenna) serving as the receiver (Rx). In the experiments, the metafluid antenna 100 (multiple access signal search antenna) was connected to one of the four ports of a vector network analyzer 300 (VNA) as the receiving antenna, while the transmitting group consisted of three random electric field transmitting antennas (i.e., three-user waveguide-fed transmitters), which were connected to the remaining three transmitters (Tx1, Tx2, and Tx3). This setup allowed for the measurement of the received signal-to-noise ratio (SINR, i.e., signal-to-interference plus noise ratio) at different activation positions of the metafluid antenna 100 receiver, thus revealing the interference immunity of the FAMA system using the newly designed fluid antenna system (multiple access signal search antenna). Specifically, any of the transmitters Tx1, Tx2, or Tx3 can be considered the target user. However, if Tx1 is the target user, then Tx2 and Tx3 will become interference signals at the receiver Rx of the metafluid antenna 100 (multiple access signal search antenna). In the experiment, we considered all possible combinations to ensure that there was no bias towards any particular transmitter.

[0112] Please continue to refer to this. Figures 5a to 5d , Figures 5a to 5d Experimental results demonstrating achievable SINR performance for FAMA using the Metafluid Antenna 100 (Multiple Access Signal Search Antenna) in a specific channel scenario (Generator Case 9) are presented. The results include SINR data for the Metafluid Antenna 100 (Multiple Access Signal Search Antenna, Rx) in the 26 GHz to 27 GHz frequency range. Figures 5a to 5c The diagram also marks the activation locations where FAMA maximizes SINR at any frequency. Figure 5a A schematic diagram of SINR measured at different frequencies in a scenario where transmitter Tx1 is the target user and transmitters Tx2 and Tx3 are interference sources. Figure 5b This diagram illustrates the SINR measurements at different frequencies when transmitter Tx2 is the target user and transmitters Tx1 and Tx3 are interference sources.

[0113] Figure 5c A schematic diagram of SINR measured at different frequencies when transmitter Tx3 is the target user and transmitters Tx1 and Tx2 are interference sources. Figure 5d A schematic diagram of the complete experimental setup for connecting the elemental fluid antenna 100 (multiple access signal search antenna) and the transmitter group provided by this invention to the vector network analyzer 300 for measurement.

[0114] like Figures 5a to 5cAs shown, at each frequency point, the SINR values ​​received by the receiver Rx (multiple access signal search antenna) at all 120 possible active positions are displayed, where, Figure 5a In the scenario shown, at a frequency of 26.8 GHz, the SINR of the elementary fluid antenna 100 (multiple access signal search antenna) at position (5,6) (i.e., antenna element 110 in the 5th row and 6th column) is marked as the maximum value, reaching 31.27 dB; Figure 5b In the scenario shown, at a frequency of 26.1 GHz, the SINR of the elementary fluid antenna 100 (multiple access signal search antenna) at position (6,4) (i.e., antenna element 110 in the 6th row and 4th column) is marked as the maximum value, reaching 24.71 dB; Figure 5c In the scenario shown, at frequencies close to 26 GHz, the SINR of the metafluid antenna 100 (multiple access signal search antenna) at position (5,9) (i.e., antenna element 110 in row 5, column 9) is marked as the maximum, reaching 24.79 dB. The experimental results clearly demonstrate that at any frequency, the metafluid antenna 100 (multiple access signal search antenna) can achieve a wide range of SINR values ​​by changing the activation position. This verifies the feasibility of implementing the FAMA concept through a positionally flexible FAS (multiple access signal search antenna), and also proves the practicality of the proposed metafluid antenna 100 (multiple access signal search antenna). Clearly, in all three scenarios, the metafluid antenna 100 (multiple access signal search antenna) as the receiver Rx achieves a high SINR (>24 dB), indicating that interference signals are effectively avoided. Note that the SINR measurement of the FAS (multiple access signal search antenna) can be achieved by sequentially activating each antenna element 110. Thanks to a switching speed of up to 20 MHz, the SINR measurement of the FAS can be easily completed.

[0115] although Figures 5a to 5c The results are encouraging, but they are limited to the environment of Case 9. To gain a more comprehensive understanding of the performance of FAMA implemented using the metafluid antenna 100 (multiple access signal search antenna) provided by this invention, in Figures 6a to 6c The diagram illustrates SINR measurement data at 26.5 GHz for the original fluid antenna 100 (multiple access signal search antenna) provided by this invention under all propagation conditions (Examples 1 to 10), wherein... Figure 6a A schematic diagram illustrating the observable SINR range of the fluidic antenna 100 (multiple access signal search antenna) provided in one embodiment of the present invention, with the transmitter Tx1 as the target user, in all cases (cases 1 to 10), as shown below. Figure 6a As shown, when the target user is the transmitter Tx1, the average SINR of the original fluid antenna 100 (multiple access signal search antenna) provided by the present invention is marked as 20.21dB in all cases (case 1 to case 10). Figure 6b A schematic diagram illustrating the observable SINR range of the fluidic antenna 100 (multiple access signal search antenna) provided in one embodiment of the present invention, with the transmitter Tx1 as the target user, in all cases (cases 1 to 10), as shown below. Figure 6b As shown, when the target user is the transmitter Tx2, the average SINR achievable by the metafluid antenna 100 (multiple access signal search antenna) is 15.45 dB. Figure 6c The diagram illustrates the observable SINR range of the fluidic antenna 100 (multiple access signal search antenna) provided in one embodiment of the present invention, with the transmitter Tx3 as the target user, in all cases (cases 1 to 10), and the actual SINR at all antenna element 110 locations in the scenario of case 2. Figure 6c As shown, when the target user is the transmitter Tx3, the average SINR achievable by the fluid-electro-optical antenna 100 (multiple access signal search antenna) is 23.78 dB. In the scenario of Case 2, the fluid-electro-optical antenna 100 (multiple access signal search antenna) achieves the maximum SINR of 13.41 dB at the location of the 104th antenna element 110. Furthermore, for comparison, SINR measurement data are provided when the fluid-electro-optical antenna 100 (multiple access signal search antenna) provided by this invention is replaced with a conventional fixed-position antenna. The specific SINR performance comparison results are as follows... Figure 6d As shown, this is a schematic diagram comparing the maximum SINR achievable by the fluid antenna 100 (multiple access signal search antenna) provided in one embodiment of the present invention with the SINR received by a conventional fixed-position antenna.

[0116] It should be noted that, for the sake of clarity, Figures 6a to 6d Only results at 26.5 GHz are shown, but the general discussion in this paper also applies to other operating frequencies of the Metafluid Antenna 100 (Multiple Access Signal Search Antenna). Figures 6a to 6cAs shown, the SINR measurement data of the metafluid antenna 100 (multiple access signal search antenna) provided by this invention at a frequency of 26.5 GHz under all propagation conditions (Case 1 to Case 10) are presented in three sets of bar charts. Each set represents the experimental results when a certain transmitter is the target user. Each bar chart contains 10 bars, representing the SINR range of the metafluid antenna 100 (multiple access signal search antenna) provided by this invention in 10 independent experiments (Case 1 to Case 10). For any experiment, the results show a large range of high and low SINR, indicating that the metafluid antenna 100 (multiple access signal search antenna) experiences different degrees of interference as the activation position changes, which is a necessary characteristic for the normal operation of FAMA. Obviously, in all the experiments considered, the metafluid antenna 100 (multiple access signal search antenna) can achieve good SINR performance by simply changing the activation position. The worst-case scenario is in Case 7 where the transmitter Tx2 is the target user, in which case the SINR of the fluidic antenna 100 (multiple access signal search antenna) provided by this invention is 9.43 dB; while the best-case scenario is in Case 2 where the transmitter Tx1 is the target user, in which case the SINR of the fluidic antenna 100 (multiple access signal search antenna) provided by this invention reaches 38.10 dB. For the fluidic antenna 100 (multiple access signal search antenna) provided by this invention, only the maximum SINR value is shown, representing the performance of FAMA. Conventional antennas use high-gain fixed-position horn antennas. All 10 sets of experiments were considered. Figure 6d As shown, compared to conventional antennas, the FAMA performance using the metafluid antenna 100 (multiple access signal search antenna) provided by this invention is significantly improved, and conventional antennas failed to achieve any meaningful SINR in all experiments, indicating that they were severely affected by interference. Note that the proof of concept in this paper does not focus on conventional antenna metrics (such as radiation pattern and S-parameters), but rather aims to confirm the ability of the metafluid antenna 100 (multiple access signal search antenna) provided by this invention to effectively avoid interference in artificial Rayleigh fading environments. Experimental results show that the metafluid antenna 100 (multiple access signal search antenna) provided by this invention achieves a minimum SINR of 13.41 dB at 26.5 GHz, verifying the successful implementation of FAS (multiple access signal search antenna) and the effectiveness of the FAMA concept. The choice of a horn antenna in this invention is intentional and serves as an optimistic benchmark because it performs better in terms of interference management and SINR control. Encouragingly, the metafluid antenna 100 (multiple access signal search antenna) provided by this invention significantly outperforms this optimistic benchmark in communication performance. This comparative experiment further verifies the capability of the original fluid antenna 100 (antenna multiple access signal search antenna) provided by the present invention in rich scattering environments.

[0117] It is important to clarify that although this invention uses a PIN diode 1111 for antenna position reconfiguration, the fluid antenna 100 (multiple access signal search antenna) provided by this invention does not belong to the traditional category of reconfigurable antennas. Traditional reconfigurable antennas are typically limited to changing radiation characteristics (e.g., operating frequency, efficiency), and have never been designed to reconfigure the position of the antenna aperture. This is because traditional antenna experts, focusing on purely functional antenna design, did not see the advantages of changing the antenna aperture position. However, wireless communication is concerned not only with the antenna's radiation efficiency, but also with the unique importance of the specific location of signal reception. Especially in wireless communication, a key characteristic is that the signal received at any location attenuates randomly (manifesting as Rayleigh fading under rich scattering conditions), meaning that communication performance varies with the antenna position. This characteristic gave rise to the emerging concept of FAS (fluid antenna system), which has had a significant impact on the field of wireless communication and inspired inventors to design, for the first time, an antenna capable of utilizing spatial domain signal variations by reconfiguring its aperture position. The main contribution of this invention lies in proposing a metafluid antenna 100 architecture (multiple access signal search antenna), which, by controlling a PIN diode 1111, can dynamically change the position of its radiating aperture within a specified two-dimensional (2D) region. This adaptability utilizes the spatial diversity characteristics in Rayleigh fading environments, thereby enabling the use of channel variations to enhance signal reception and mitigate interference. Furthermore, this invention is the first to experimentally verify FAMA (Frequency and Spatial Diversity Antenna) using a novel reconfigurable antenna (i.e., a multiple access signal search antenna), a contribution that is unprecedented in the prior art.

[0118] Unlike MIMO, where spatial diversity is determined by the number of radio frequency links at the mobile end, FAS, even with a fixed number of radio frequency links, liberates entirely new degrees of freedom through spatial domain location signal reconstruction. For multi-user communication on the same physical channel, FAS identifies the classic fading phenomenon—signal amplitude varies at different locations due to the combination of multipath propagation paths—and utilizes this phenomenon to avoid interference at the receiver by adjusting antenna positions. This fundamentally changes the way interference is mitigated in wireless networks. Traditional methods achieve this through complex signal processing (called precoding) at the base station, requiring Channel State Information (CSI) from all users. The FAS method (called FAMA), however, eliminates the need for CSI estimation and feedback, as well as complex precoding optimization, directly addressing interference at the receiver. Therefore, FAMA has enormous potential to improve the scalability of multi-user wireless communication. Although theoretical research on the superior performance of FAMA has emerged in recent years, demonstrating a more comprehensive evaluation when considering various performance metrics, experimental results have been lacking, and there is currently no successfully designed FAS prototype to verify the effectiveness of FAMA. Therefore, this invention is the first to propose a FAS antenna (i.e., multiple access signal search antenna) design that achieves position reconfigurability, and experimental tests were conducted on FAMA, which is original and of great significance.

[0119] Finally, it's worth mentioning that CSI estimation for FAS has been discussed in relevant literature, and machine learning techniques have proven to have many applications in various FAS communication problems. Future work will focus on extending the experimental environment to real-world propagation scenarios. While the current experimental setup effectively simulates Rayleigh fading conditions using an artificially enriched scattering generator200, testing in a real-world environment will provide stronger evidence for the capabilities of FAS and the robustness of FAMA in practical scenarios.

[0120] In summary, while the emerging concept of FAS (Fluorescent Antenna System) for mitigating interference through antenna position reconfiguration is exciting, and numerous theoretical works have reported its superior performance in wireless communication, experimental verification remains lacking, and the effectiveness of FAS remains largely speculative. To fill this gap, this invention makes two key contributions. First, utilizing programmable waveguide feeding, this invention designs and manufactures a software-controlled metafluid antenna 100 (Multiple Access Signal Search Antenna), which can reconfigure its radiation position on a given surface as needed, achieving position-flexible FAS functionality for the first time. Figuratively speaking, the metafluid antenna 100 (Multiple Access Signal Search Antenna) proposed in this invention is like a movable radiating element, riding on the radio waves of the natural space domain, navigating and activating at spatial points where communication conditions become ideal. This is a unique characteristic of FAS, eliminating the need for expensive signal processing at the transmitter in advanced precoding schemes in 5G, which is a major obstacle in the prior art. The second major contribution of this invention is providing experimental verification for the use of FAS in multi-user communication (referred to as FAMA in the communications field). Specifically, this invention fabricates numerous waveguide feed generators with arbitrarily placed slots to simulate real radio propagation environments with rich scattering. Using a prototype antenna (multiple access signal search antenna) as the receiver, the concept of FAMA was tested in a three-user scenario (one target transmitter and two interfering transmitters). Experimental verification shows that implementing FAMA using the metafluid antenna 100 (multiple access signal search antenna) provided by this invention is feasible, with an average received SINR exceeding 15 dB under all considerations. Overall, the results of this invention provide strong experimental evidence that FAMA is practically achievable and achieves promising performance, paving the way for scalable multiple access technologies. Last but not least, the experimental results demonstrate the superiority of the metafluid antenna 100 (multiple access signal search antenna) provided by this invention over conventional fixed-position antennas, further emphasizing the importance of FAS.

[0121] It should be noted that all simulations in this invention were performed using CSTMicrowave Studio 2024. The metafluid antenna 100 (multiple access signal search antenna) uses a PIN diode 1111 (model MADP-000907-14020) and is modeled as an equivalent series circuit. In the "OFF" state (activating the radiating slot), the PIN diode 1111 has characteristics of C = 0.025pF and L = 30pH. In the "ON" state (blocking other slots), the PIN diode 1111 has characteristics of R = 7.8Ω and L = 30pH. The electric field correlation coefficient and SINR were calculated using Matlab 2023. The metafluid antenna 100 (multiple access signal search antenna) and the rich scattering generator 200 are manufactured using printed circuit board (PCB) technology. The metafluid antenna 100 integrates an AVP50G FPGA core board, whose 120 I / O ports are controlled via Verilog HDL programming. The switching frequency of the output signal can reach up to 1MHz, while the switching frequency of the PIN diode 1111 can reach up to 20MHz. SINR measurements were performed using a Keysight N5227A network analyzer, with measurement control performed by a laptop computer 400 running Matlab control code.

[0122] Based on the same inventive concept, this invention also provides an electronic device, which includes the multiple access signal search antenna provided by this invention. Since the electronic device provided by this invention includes the multiple access signal search antenna for wireless communication systems provided by this invention, it possesses at least all the beneficial effects of the multiple access signal search antenna for wireless communication systems provided by this invention. Specific details can be found in the relevant descriptions above; therefore, the beneficial effects of the electronic device provided by this invention will not be elaborated upon here. It should be noted that the electronic device includes, but is not limited to, video products such as televisions, video recorders, and digital cameras; communication products such as mobile phones, communication switching equipment, and communication transmission equipment; and learning aids such as translators, learning machines, and electronic dictionaries, etc., without listing all examples. Those skilled in the art should understand that this invention does not limit the scope of the electronic device.

[0123] In summary, the multiple access signal search antenna and electronic device for wireless communication systems provided by the present invention have the following beneficial effects;

[0124] (1) Dynamic adjustment capability: This invention employs multiple access signal search antenna technology, which can dynamically adjust the radiation position and mode, flexibly receive and reflect signals from different paths, effectively increase the strength of the received signal, reduce interference, adapt to changing signal environments, and thus achieve higher signal quality. This dynamic adjustment capability makes it more adaptable than fixed-position antennas, especially in complex and multi-user scenarios, where it can better utilize interference to enhance transmission performance.

[0125] (2) Compact structure and easy integration: The multi-access signal search antenna provided by the present invention has a small size design, which can be easily integrated into the existing platform while maintaining compatibility with the current installation method. This allows it to be upgraded to 5G or IoT systems without making significant changes to the existing infrastructure.

[0126] (3) High-frequency band support: The multiple access signal search antenna provided by this invention can operate in the 26GHz to 27GHz frequency band, filling the gap in coverage of traditional low-frequency antennas in the high-frequency band. High-frequency support is particularly important for 5G and future IoT applications because it can meet higher data transmission requirements.

[0127] (4) Multifunctional Applications: The multiple access signal search antenna provided by this invention is not only suitable for conventional communication, but can also be arrayed to form MU-MIMO and MIMO architectures to meet the multi-user needs of WiFi 6 and 5G communication, improving system capacity and communication efficiency. In 5G / 6G networks with high-speed and low-latency requirements, the multiple access signal search antenna provided by this invention can effectively improve communication quality and ensure user experience. In the millimeter-wave band, the multiple access signal search antenna provided by this invention can effectively address multipath attenuation and interference problems in high-frequency propagation, and is suitable for satellite communication, IoT, and high-speed wireless transmission. In high-density interference scenarios (such as urban environments and large event venues), the multiple access signal search antenna provided by this invention can automatically adjust the radiation position, thereby optimizing signal reception quality.

[0128] The above advantages make the multiple access signal search antenna provided by this invention significantly competitive with traditional antennas in terms of high-frequency coverage, gain enhancement, dynamic adaptability and miniaturization, making it very suitable for future 5G and IoT application scenarios.

[0129] It should be noted that the above description is merely a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention in any way. Any changes or modifications made by those skilled in the art based on the above disclosure are within the protection scope of the present invention. Obviously, those skilled in the art can make various modifications and variations to the present invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the present invention and its equivalents, the present invention also intends to include these modifications and variations.

Claims

1. A multiple access signal search antenna for a wireless communication system, characterized in that, It includes multiple antenna elements, each of which can switch between a radiating state and a non-radiating state under the control of its control element; The radiation position of the multiple access signal search antenna is determined by the antenna element in the radiation state, so that by controlling the radiation or non-radiation state of each antenna element, the radiation position of the multiple access signal search antenna can be adjusted to improve the signal reception quality.

2. The multiple access signal search antenna according to claim 1, characterized in that, It also includes a control board electrically connected to each of the control elements to control the on / off state of the control elements.

3. The multiple access signal search antenna according to claim 2, characterized in that, The control board is configured to dynamically control the antenna element with the highest signal-to-interference-plus-noise ratio to switch to the radiation state based on the real-time signal-to-interference-plus-noise ratio.

4. The multiple access signal search antenna according to claim 2 or 3, characterized in that, The control element of each antenna element includes at least one PIN diode, and for each antenna element, the antenna element is dynamically switched to a radiating state or a non-radiating state by controlling the switching state of the PIN diode in the antenna element.

5. The multiple access signal search antenna according to claim 4, characterized in that, The control board is electrically connected to each of the PIN diodes via a bias via.

6. The multiple access signal search antenna according to claim 4, characterized in that, It also includes a DC bias circuit configured to provide DC current to the PIN diode.

7. The multiple access signal search antenna according to claim 1, characterized in that, The multiple antenna elements are arranged in a two-dimensional array on the same plane.

8. The multiple access signal search antenna according to claim 7, characterized in that, Any two adjacent antenna elements located in the same column are configured not to be in a radiating state at the same time.

9. The multiple access signal search antenna according to claim 1, characterized in that, It also includes a millimeter-wave feed waveguide that provides power to the plurality of antenna elements. The millimeter-wave feed waveguide has a plurality of slots, and the plurality of slots are configured one-to-one with the plurality of antenna elements.

10. An electronic device, characterized in that, Includes the multiple access signal search antenna according to any one of claims 1 to 9.

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