Wideband polarization diversity wearable receiving antenna system for capsule endoscope system and capsule endoscope system comprising broadband polarization diversity wearable receiving antenna system

Abstract

The invention discloses a broadband polarization diversity wearable receiving antenna system for a capsule endoscope system and the capsule endoscope system comprising the broadband polarization diversity wearable receiving antenna system, and the wearable receiving antenna system comprises a flexible wearable carrier and a multi-antenna combination array integrated in the flexible wearable carrier; the multi-antenna combination array is composed of at least two independent antenna units. The antenna units have different preset resonant frequencies, and the resonant frequencies take a common reference frequency f0 as a center and are progressively shifted according to a preset step frequency value f to jointly form a synthetic receiving frequency band of which the coverage is wider than the bandwidth of a single antenna; meanwhile, the polarization directions of the antenna units are different from each other, and the antenna units sequentially rotate by a certain angle on the horizontal plane to jointly form a polarization diversity receiving array. On the premise of not depending on an active tuning circuit, the system can passively adapt to body type differences of different users, and effectively capture incoming waves in any polarization direction, so that the stability and success rate of image data receiving are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to a wideband polarization diversity wearable receiving antenna system for a capsule endoscope system and a capsule endoscope system comprising the same, belonging to the technical field of wireless antennas. BACKGROUND

[0002] A capsule endoscope system generally consists of two parts: an in-vivo capsule and an out-of-vivo receiving device. The capsule moves inside the digestive tract and takes pictures, sending data to the outside through a built-in miniature transmitting antenna. The wearable receiving antenna (usually integrated into a belt, vest, waistcoat or abdominal belt) outside the body is responsible for capturing these weak radio frequency signals and transmitting them to the recorder.

[0003] The wearable receiving antenna design in the prior art faces two major challenges:

[0004] 1) Frequency detuning caused by human body load: The wearable antenna works in close proximity or adjacent to human tissue. The human body, as a high dielectric constant and lossy medium, will load on the antenna, causing its actual resonant frequency to deviate from the design frequency. More importantly, this frequency shift is not fixed, it depends on the wearer's body shape (such as fat and thin), the specific wearing position of the antenna on the body (such as the abdomen, waist), and the tightness of the wearing. For standardized production of receiving antennas, the optimal receiving frequency point will change dynamically for different users or different wearing states of the same user. If the transmission frequency of the in-vivo capsule is fixed, signal attenuation due to frequency mismatch will occur, seriously affecting the receiving sensitivity and transmission distance.

[0005] 2) Polarization mismatch caused by the capsule's variable posture: The capsule freely rolls in the digestive tract with the peristalsis of the digestive tract, and the polarization direction of its built-in transmitting antenna changes randomly. The traditional out-of-vivo receiving antenna is usually a single linear polarization. When the polarization directions of the transmitting and receiving antennas are orthogonal, serious polarization loss will occur, which can theoretically reach infinity (no signal can be received), and in actual communication it will show signal deep fading and unstable link. Although there are schemes that use dual-polarized antennas or spatial diversity antennas, their performance improvement is limited when dealing with the completely random three-dimensional posture changes of the capsule.

[0006] To cope with frequency mismatch, some studies attempt to design antennas with wide impedance bandwidth, or adopt frequency reconfigurable technology. However, the former is difficult to achieve a super wideband covering individual differences in a limited volume; the latter needs to introduce complex tuning circuits (such as varactor diodes), increasing system power consumption, cost and uncertainty, which is not suitable for medical devices that need to work stably for a long time. To cope with polarization mismatch, the capsule adopts a circularly polarized antenna, which is a solution, but the circularly polarized antenna is easy to deteriorate its axial ratio performance in the complex medium environment in the capsule, and its design complexity is extremely high in the small built-in installation space of the capsule and the complex surrounding metal environment. Another solution is to deploy multiple spatially separated antennas, but the polarization is not systematically designed, and the efficiency improvement is not significant.

[0007] Therefore, there is an urgent need for a high-reliability wearable receiving antenna system that can adaptively compensate for wearing differences and efficiently cope with random polarization changes of the capsule. SUMMARY

[0008] In order to overcome the shortcomings of the prior art, the present application provides a wearable receiving antenna system for a capsule endoscope system, which passively adapts to the body size differences of different users and effectively captures incoming waves of any polarization direction without relying on active tuning circuits, by frequency pre-offset design and polarization diversity layout of multiple antenna units, thereby fundamentally improving the stability and success rate of image data reception.

[0009] To solve the above technical problems, the technical scheme adopted by the present application is as follows:

[0010] A wideband polarization diversity wearable receiving antenna system for a capsule endoscope system, comprising: a flexible wearable carrier and a multiple antenna combined array integrated in the flexible wearable carrier;

[0011] The multiple antenna combined array is composed of at least two independent antenna units; each antenna unit has a different pre-set resonant frequency, which is centered on a common reference frequency f0 and offset by a predetermined step frequency value f ∆ increasingly, to form a combined receiving frequency band wider than the bandwidth of a single antenna; at the same time, the polarization directions of each antenna unit are different from each other, and are rotated by a certain angle (preferably 30-60°) in the horizontal plane, to form a polarization diversity receiving array.

[0012] The above wideband polarization diversity wearable receiving antenna system for a capsule endoscope system, through the cooperation of "preset frequency diversity" and "polarization diversity", forms a passive intelligent array design, which can passively adapt to the body size differences of different users and effectively capture incoming waves of any polarization direction without relying on active tuning circuits, thereby fundamentally improving the stability and success rate of image data reception.

[0013] The flexible wearable carrier is a waistband, an abdominal band, a vest or a vest of cloth base material.

[0014] In order to further improve the adaptability and stability, the arrangement of the antenna units in the flexible wearable carrier is one of side-by-side, matrix or staggered cross.

[0015] In order to improve the stability and success rate of image data reception, the polarization directions of the antenna units are orthogonal polarization or inclined polarization, forming a polarization diversity array to adapt to the polarization mismatch caused by the random rolling of the capsule in the digestive tract. The aforementioned orthogonal polarization means that the polarization directions of different antenna units are perpendicular to each other, and the inclined polarization means that the polarization directions of different antenna units are neither the same nor perpendicular.

[0016] The resonance frequencies of the antenna units are matched and tuned according to the preset frequency offset based on the center reference frequency f0, forming a receiving window covering a wider frequency band, to compensate for the frequency offset effect caused by the different distances between the antenna and the human body (the physical distance between the extracorporeal receiving antenna and the skin surface of the human body) and the contact parts (the contact parts between the antenna and the human body) of the wearer of different body types, so as to ensure that in any wearing state, one or more antenna units are in the best receiving state, thereby significantly improving the stability and communication distance of the wireless image transmission link.

[0017] The resonance frequencies of the antenna units are symmetrically or asymmetrically spread around the center frequency f0 of the system.

[0018] In order to meet the daily needs, preferably, the number of antenna units is four, the reference frequency is f0, and the preset resonance frequencies of the four antenna units are f0, f0+f ∆1 , f0+f ∆2 , f0+f ∆3 , respectively. The four antenna units are tuned to f0, f0+f ∆1 , f0+f ∆2 , f0+f ∆3 , respectively. This is equivalent to artificially creating a "static wide frequency band" extending from f0 to f0+f ∆3 . Regardless of the body size of the user causing the frequency shift of a single antenna (e.g. moving to low frequency or high frequency), since the original frequency points of the four antennas are already dispersed, there is always one or more antenna whose current effective resonance frequency point can cover or approach the actual transmission frequency of the capsule, thereby ensuring that there is always a high-performance receiving channel. This design cleverly takes advantage of the fact that individual differences affect each antenna differently. The preferred center frequency f0 is 434MHz, the preferred preset frequency offset f ∆1 is -30MHz, and the preferred preset frequency offset f ∆2The preferred preset frequency offset is +30MHz. ∆3 It is +60MHz.

[0019] Each antenna element can use the same physical structure (such as a microstrip patch antenna), but by subtly adjusting the size of the antenna radiating element or tuning and matching discrete components, they can be made to have different preset resonant frequencies.

[0020] This application employs a polarization diversity layout. When the four antenna elements are embedded in the belt, their polarization directions are orthogonal, tilted, or other polarization forms. Preferably, the polarization directions of the four antenna elements are set to rotate 45° sequentially, i.e., the first antenna is 0° (vertical polarization), the second antenna is 45°, the third antenna is 90° (horizontal polarization), and the fourth antenna is -45°, forming a polarization diversity array with four sampling points within a 360° range. Regardless of the capsule's tumbling posture, the polarization direction of its transmitted signal is always close to the polarization direction of one or more receiving antennas, thereby maximizing received power and minimizing polarization loss.

[0021] The antenna elements mentioned above are microstrip patch antennas, planar inverted-F antennas, or loop antennas.

[0022] The aforementioned broadband polarization diversity wearable receiving antenna system for capsule endoscope systems further includes a multi-port selection circuit or a multi-port combining circuit and a radio frequency (RF) receiving unit. The input terminals of the multi-port selection circuit or multi-port combining circuit are respectively connected to the output terminals of each antenna unit, used to select the channel with the best signal quality or to combine signals from multiple channels. The output terminals of the multi-port selection circuit or multi-port combining circuit are connected to the RF receiving unit. The RF receiving unit receives the wireless RF signals transmitted from the capsule endoscope through the multi-port selection circuit or combining circuit connected to each antenna.

[0023] The signals received by each of the aforementioned antenna elements are fed into a multi-port selection circuit or a multi-port combining circuit. This circuit can select the optimal signal output in real time based on the signal strength index (RSSI) and / or signal-to-noise ratio (SNR); or it can use algorithms such as maximum ratio combining to combine multiple signals. For each received signal, the signal is weighted according to the square root of its signal-to-noise ratio (SNR), and then the weighted signals are superimposed in phase to obtain the maximum output signal-to-noise ratio after combining, thereby obtaining diversity gain and further improving signal quality.

[0024] If channel selection is based on signal strength index (RSSI), a reasonable upper limit threshold should be preset (preferably -30 dBm) to avoid signal saturation distortion. If the RSSI of all channels exceeds this upper limit, all channels are considered to be in a saturated state. In this case, any channel can be selected for output, or the channel with the highest signal-to-noise ratio (SNR) can be selected first. The higher the signal-to-noise ratio (SNR), the better the signal quality. Therefore, the channel with the highest SNR is usually selected as the optimal signal. To balance signal strength and quality, a comprehensive decision strategy can be adopted: first, screen the channels with RSSI within a reasonable range (such as -80 dBm to -30 dBm), and then select the output channel with the highest SNR from them.

[0025] A capsule endoscope system includes: the aforementioned wearable receiving antenna system and a capsule endoscope with a built-in transmitting antenna.

[0026] The aforementioned broadband polarization diversity wearable receiving antenna system for capsule endoscopy systems employs a multi-antenna integrated design, integrating several standard antenna elements in a specific layout (side-by-side, matrix, or staggered crossover) within a fabric belt. Each antenna element is alternately polarized using orthogonal polarization, tilted polarization, or other polarization methods, forming a polarization diversity array to accommodate polarization mismatches caused by the random tumbling of the capsule within the digestive tract. Simultaneously, the resonant frequency of each antenna element is referenced to the center reference frequency f0, offset by a preset frequency deviation ∆. 1、 ∆ 2、 ∆3 Incremental Matching Tuning (Taking four antennas as an example, the four antennas are matched and tuned at preset frequency offsets: f0, f0±f ∆1 , f0+f ∆2 , f0+f ∆3 This forms a wider frequency band receiving window to compensate for the frequency offset effect caused by different distances and contact points between the antenna and the body for wearers of different body sizes. This ensures that in any wearing state, the system always has one or more antenna units in the best receiving state, thereby significantly improving the stability and communication distance of the wireless image transmission link.

[0027]

[0028] This invention solves the technical problems of unstable signal reception and degraded link performance caused by differences in wearer body size and variable capsule posture in existing wearable receiving antennas, and has wideband adaptability and polarization diversity function.

[0029] Currently, the Body Mass Index (BMI = weight (kg) / height (m)) is generally used as a metric. 2The study categorized different body types into three types: lean (BMI < 18.5), standard (BMI = 18.5 ~ 23.9), and obese (BMI ≥ 28.0).

[0030] Any techniques not mentioned in this invention are based on existing technologies.

[0031] Compared with the prior art, the present invention has the following significant advantages:

[0032] 1) Excellent body shape adaptability: Through the "preset frequency diversity" array, the system can passively adapt to users of different body shapes, from children to adults and from thin to obese, without any sensing or feedback control. This solves the problem of personalized adaptation of wearable medical devices and ensures the consistency and high reliability of the product.

[0033] 2) High-efficiency polarization matching: Through a systematic interval polarization layout, high-probability matching of arbitrary linearly polarized waves in three-dimensional space is achieved with minimal hardware complexity (four units), effectively combating deep signal fading caused by capsule tumbling, and link stability far exceeds that of single-polarized or dual-polarized antennas.

[0034] 3) Enhanced communication robustness: The dual combination of frequency and polarization diversity mechanism gives the system extremely strong robustness in complex and ever-changing human channel environments. Even when the performance of a single antenna degrades due to detuning or polarization mismatch, other antennas can still maintain good communication, significantly improving the integrity rate of image data transmission and communication distance.

[0035] 4) Simple and reliable structure: The entire system does not require active tuning devices (such as varactor diodes) or mechanical rotation mechanisms. All functions are realized through the static design of the antenna unit. It has low power consumption, controllable cost, and good durability, making it very suitable for medical monitoring scenarios that require long-term continuous operation. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the system composition of the present invention, showing a belt and portable recorder that integrates multiple antenna arrays.

[0037] Figure 2 shows exemplary layout diagrams of antenna elements within the belt: Figure 2(a) side by side, Figure 2(b) 2×2 matrix arrangement, and Figure 2(c) staggered cross arrangement.

[0038] Figure 3 The diagram shows the polarization directions of the four antenna elements (0°, 45°, 90°, -45°).

[0039] Figure 4 A schematic diagram of the preset resonant frequency distribution of the four antenna elements (404MHz, 434MHz, 464MHz, 494MHz).

[0040] Figure 5 shows the frequency offset of a traditional single antenna and the antenna of the present invention on different body shapes: Figure 5(a) shows the frequency offset of a traditional single antenna worn on different body shapes; Figure 5(b) shows the frequency offset of the four-antenna array of the present invention on different body shapes.

[0041] In the figure, 10 is a wearable antenna belt, 20 is a portable recorder, 30 is a capsule endoscope, 40 is a miniature multi-port selector module, 11 is antenna unit ANT1, 12 is antenna unit ANT2, 13 is antenna unit ANT3, and 14 is antenna unit ANT4. Detailed Implementation

[0042] To better understand the present invention, the following embodiments further illustrate the content of the present invention, but the content of the present invention is not limited to the following embodiments.

[0043] Example 1

[0044] like Figure 1 As shown, the wearable receiving antenna system of this embodiment mainly consists of two parts: a wearable antenna belt (10) and a portable recorder (20). In this example, a portable recorder of model ICDR-100C is used. The antenna belt (10) is made of soft and breathable elastic fabric. The upper part of the antenna belt (10) is inlaid with a multi-antenna combination array and a miniature multi-port selector module (40) (single-pole multi-throw electronic switch). The multi-antenna combination array includes four rectangular microstrip patch antenna elements with the same structure.

[0045] As shown in Figure 2, Figure 2(a) shows four identical rectangular microstrip patch antenna elements: ANT1 (11), ANT2 (12), ANT3 (13), and ANT4 (14) arranged side-by-side in the area of ​​the waistband corresponding to the abdomen of the human body. Figure 2(b) shows four identical rectangular microstrip patch antenna elements: ANT1 (11), ANT2 (12), ANT3 (13), and ANT4 (14) arranged in a 2×2 matrix in the area of ​​the waistband corresponding to the abdomen of the human body. Figure 2(c) shows four identical rectangular microstrip patch antenna elements: ANT1 (11), ANT2 (12), ANT3 (13), and ANT4 (14) arranged in an alternating manner in the area of ​​the waistband corresponding to the abdomen of the human body. Each antenna element is independently fed via a microcoaxial cable.

[0046] refer to Figure 3During installation, precise orientation calibration ensures that the linear polarization directions of the four antenna elements ANT1(11), ANT2(12), ANT3(13), and ANT4(14) are at angles of 0°, 45°, 90°, and -45° relative to the vertical direction, respectively. This layout is achieved through physical rotation without altering the antenna design itself. Figures (a)-(c) in Figure 2 are rotated using the aforementioned method to create three implementation methods.

[0047] refer to Figure 4 By finely adjusting the length of each microstrip patch (the patch length mainly determines the resonant frequency), the resonant frequencies of the four antenna elements ANT1(11), ANT2(12), ANT3(13), and ANT4(14) were designed to be 404MHz, 434MHz, 464MHz, and 494MHz, respectively. The bandwidth of each antenna at -10dB return loss is approximately 30MHz. Therefore, the combined effective receiving bandwidth of the four antennas covers a wide range from approximately 389MHz to 509MHz. In Figure 2, the three implementation methods shown in Figures (a)-(c) all have the aforementioned effects.

[0048] The outputs of four antenna units ANT1 (11), ANT2 (12), ANT3 (13), and ANT4 (14) are connected to the input of a miniature multiport selector module (40) located on the side of the belt via cables inside the belt. The output of the miniature multiport selector module (40) is connected to the radio frequency receiving unit in the recorder (20). The miniature multiport selector module (40) monitors the strength of the four signals in real time and automatically switches to the output of the strongest signal to the recorder (20). To ensure that the signal is strong enough but does not cause saturation distortion due to excessive strength, the module presets an upper limit threshold for RSSI (e.g., -30 dBm). If the RSSI of all channels exceeds this upper limit, it is considered that all channels are in a saturated state. At this time, the module can randomly select any channel, or further select the output with the highest SNR based on the SNR index of each channel. In practical applications, a strategy of "limiting amplitude first, then selecting the best" can also be adopted: first, select the channels with RSSI within the effective dynamic range (e.g., -80 dBm to -30 dBm), and then select the one with the highest SNR as the optimal signal output to balance signal strength and quality. The recorder (20) is responsible for demodulating and storing the image data sent back by the capsule.

[0049] To verify the effect, simulation analysis was performed, and the results are shown in Figure 5. A traditional single antenna (resonating at 434MHz) and a four-antenna array (structure as shown in Figure 5) from this embodiment are compared. Figure 3As shown in Figure 5(a), simulations were performed on the surface of human tissue models of different sizes (with significant differences in thickness). The results show that for a single antenna (Figure 5(a), its optimal receiving frequency shifts by up to ±30MHz with changes in the thickness of the human model, and it becomes completely detuned in some models. However, in this embodiment, the four-antenna array always has one or more antennas with resonant frequencies around 434MHz in different models, and the system as a whole maintains excellent receiving performance (return loss <-10dB), verifying its strong adaptability to different body sizes.

[0050] The above-mentioned innovative combination of "preset frequency diversity" and "systematic polarization diversity" provides a highly reliable, adjustment-free wearable receiving antenna solution for capsule endoscopy systems. It cleverly utilizes the redundancy of the array to combat the two main channel degradation factors caused by human uncertainty and capsule randomness, and addresses the challenges of application environment uncertainty with a deterministic structural design, which has significant clinical application value.

[0051] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A broadband polarization diversity wearable receiving antenna system for capsule endoscopy systems, characterized in that, This includes: flexible wearable carriers and multi-antenna arrays integrated within flexible wearable carriers; A multi-antenna array consists of at least two independent antenna elements; each antenna element has a different preset resonant frequency, which are centered around a common reference frequency f0 and incremented by a predetermined step frequency value f. ∆ The increasing offsets together form a wide-coverage synthetic receiving frequency band; at the same time, the polarization directions of each antenna element are different from each other, and they rotate at a certain angle in sequence on the horizontal plane to form a polarization diversity receiving array.

2. The broadband polarization diversity wearable receiving antenna system for a capsule endoscope system according to claim 1, characterized in that, The flexible wearable carrier is a belt, waistband, vest, or vest made of cloth; each antenna element is a microstrip patch antenna, a planar inverted-F antenna, or a loop antenna.

3. The broadband polarization diversity wearable receiving antenna system for a capsule endoscope system according to claim 1 or 2, characterized in that, The antenna elements can be arranged in one of the following ways within the flexible wearable carrier: side-by-side, matrix, or staggered.

4. The broadband polarization diversity wearable receiving antenna system for a capsule endoscope system according to claim 1 or 2, characterized in that, Each antenna element is orthogonally polarized or tilted polarized, forming a polarization diversity array.

5. The broadband polarization diversity wearable receiving antenna system for a capsule endoscope system according to claim 1 or 2, characterized in that, The resonant frequency of each antenna element is based on the center reference frequency f0 and is matched and tuned by increasing the preset frequency offset to form a receiving window covering a wide frequency band. This compensates for the frequency offset effect caused by different distances and contact points between the antenna and the human body for wearers of different body types. This ensures that in any wearing state, one or more antenna elements of the system are always in the best receiving state, thereby significantly improving the stability of the wireless image transmission link and the communication distance.

6. The broadband polarization diversity wearable receiving antenna system for a capsule endoscope system according to claim 1 or 2, characterized in that, The antenna has four elements, with a reference frequency of f0. The preset resonant frequencies of the four antenna elements are f0, f0+f, and f0+f, respectively. ∆1 , f0+f ∆2 , f0+f ∆3 Where f0 is 434MHz, f ∆1 -30MHz, f ∆2 +30MHz, f ∆3 It is +60MHz.

7. The broadband polarization diversity wearable receiving antenna system for a capsule endoscope system according to claim 6, characterized in that, The four antenna elements are, in order, the first antenna, the second antenna, the third antenna, and the fourth antenna; the polarization directions of the four antenna elements are set to rotate by 45° in sequence, that is, the first antenna is 0°, the second antenna is 45°, the third antenna is 90°, and the fourth antenna is -45°, forming a polarization diversity array with four sampling points within a 360° range.

8. The broadband polarization diversity wearable receiving antenna system for a capsule endoscope system according to claim 1 or 2, characterized in that, It also includes a multi-port selection circuit or a multi-port combining circuit and an RF receiving unit; the input terminals of the multi-port selection circuit or the multi-port combining circuit are respectively connected to the output terminals of each antenna unit, and are used to select the channel with the best signal quality or to combine signals from multiple channels. The output terminal of the multi-port selection circuit or the multi-port combining circuit is connected to the RF receiving unit.

9. The broadband polarization diversity wearable receiving antenna system for a capsule endoscope system according to claim 8, characterized in that, The signals received by each antenna element are fed into a multi-port selection circuit or a multi-port combining circuit. This circuit selects the optimal signal output in real time based on the signal strength and / or signal-to-noise ratio. If the channel selection is based on the signal strength, an upper limit threshold is preset to avoid signal saturation distortion. If the signal strength of all channels exceeds the upper limit, all channels are considered to be in a saturated state. At this time, any channel can be selected for output, or the channel with the highest signal-to-noise ratio can be selected. Alternatively, a maximum ratio combining algorithm can be used to synthesize multiple signals. For each received signal, the signal-to-noise ratio is weighted according to the square root of its signal-to-noise ratio, and then the weighted signals are superimposed in phase to obtain the maximum output signal-to-noise ratio after combining, thereby obtaining diversity gain and further improving signal quality.

10. A capsule endoscope system, characterized in that, include: The wearable receiving antenna system according to any one of claims 1 to 9, and the capsule endoscope with a built-in transmitting antenna.

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