Conformal antenna system for double-lens capsule type endoscope and double-lens capsule type endoscope comprising conformal antenna system

Abstract

The invention discloses a conformal antenna system for a double-lens capsule type endoscope and the double-lens capsule type endoscope comprising the conformal antenna system. The conformal antenna system for the double-lens capsule type endoscope comprises two lenses arranged at the two ends in a shell and lens supports corresponding to the two lenses respectively, and further comprises a conductive radiator, and the lens supports are made of non-metal materials. And the conductive radiator is integrated on the surface or inside the lens bracket of one or two lenses and forms a conformal structure with the lens bracket. According to the invention, the antenna and the lens bracket are designed in an integrated and conformal manner, so that the problem that the installation space of the capsule type endoscope is deficient is fundamentally solved, and metal interference in the capsule type endoscope is effectively isolated, thereby realizing high radiation efficiency and stable remote wireless communication.

Description

Technical Field

[0001] This invention relates to a conformal antenna for a dual-lens capsule endoscope and a dual-lens capsule endoscope containing the antenna, belonging to the field of antenna design technology for dual-lens capsule endoscopes. Background Technology

[0002] Wireless capsule endoscopy is an important tool for diagnosing gastrointestinal diseases. To obtain a more comprehensive view, dual-lens or even multi-lens capsule endoscopes have become a development trend. For example, existing technology discloses a dual-lens capsule endoscope that includes a standard lens. However, the dual-lens design drastically compresses the internal space of the capsule with two lens modules, image sensors, more circuit boards, and batteries, leaving very limited space for antenna installation.

[0003] Currently, the antennas of capsule endoscopes are typically designed as independent modules, installed on the inner wall of the capsule shell or near the circuit board. For example, some patents disclose directional antennas with specific structures, or antennas made of flexible materials that can be deployed around the circuit board. These designs are feasible in single-lens capsules with relatively ample space, but face significant challenges in dual-lens capsules: first, it is difficult to find sufficient clearance for the antenna; second, the antenna is forced to be close to or between large metal components such as circuit boards and batteries, which severely interfere with the antenna's near-field radiation, leading to impedance mismatch, reduced efficiency, and pattern distortion, ultimately resulting in unstable wireless transmission signals and shortened communication distance.

[0004] Furthermore, existing designs have another significant drawback in resolving the conflict between antenna size and wavelength: to reduce the resonant frequency of an antenna (such as a helical or loop antenna) to the target frequency band within extremely limited space, compensation is typically only performed at the circuit level, such as by connecting large wire-wound inductors in parallel or series at the RF port. However, this purely circuit-matching method inherently comes at the cost of sacrificing antenna radiation performance: the large inductor itself introduces additional ohmic losses, and its lumped-parameter characteristics disrupt the optimal energy radiation state of the antenna as a distributed-parameter system, leading to a significant decrease in the antenna's radiation efficiency and gain.

[0005] Therefore, under the extreme spatial constraints of dual-lens capsule endoscopes, the core challenge is finding an installation location and form for the antenna that can be both far from internal electromagnetic interference and achieve effective impedance matching through the structure itself, without introducing additional lossy components. Summary of the Invention

[0006] This invention aims to overcome the shortcomings of the prior art and provide a conformal antenna for a dual-lens capsule endoscope and a dual-lens capsule endoscope containing the antenna. The antenna and lens support structure are integrated into a conformal design, which fundamentally solves the problem of insufficient installation space. Furthermore, the optimized layout effectively isolates internal metal interference, thereby achieving high radiation efficiency and stable long-distance wireless communication.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0008] A conformal antenna system for a dual-lens capsule endoscope includes two lenses disposed at both ends inside a housing and lens supports corresponding to the two lenses respectively. It also includes a conductive radiator conformally to the lens supports. The lens supports are made of a non-metallic dielectric material with a dielectric constant greater than 3.5. The conductive radiator is configured on the surface or inside one or both lens supports according to antenna design theory, thereby forming a conformal antenna unit that works using the dielectric loading principle together with the lens supports.

[0009] The above-mentioned conformal structure design makes the antenna an integral part of the lens's non-metallic base support structure.

[0010] The lens brackets described above are used to mount the corresponding lenses.

[0011] To balance the advantages of radiation efficiency and lightweight design, the lens holder is made of plastic.

[0012] The aforementioned lens bracket serves as the dielectric loading substrate for the conductive radiator. By utilizing the dielectric constant of its (lens bracket) material, it actively reduces the physical resonant frequency of the antenna (conductive radiator), thereby matching the antenna to the target operating frequency band. This structure enables the antenna to exhibit matched impedance characteristics within the operating frequency band, thus eliminating the need for external impedance matching by using large-value wire-wound inductors in parallel / series at the RF port.

[0013] The antenna of this invention uses a dielectric loading method to adjust the resonant frequency. Specifically, it utilizes the dielectric properties of the lens bracket material to complete the dielectric loading, which can effectively reduce the inherent resonant frequency of the antenna to the target operating frequency band. Compared with the traditional matching scheme of "connecting a large inductance wire-wound inductor in parallel at the RF port", this scheme does not require additional inductor components, which simplifies the antenna structure layout and reduces signal loss and volume redundancy introduced by the inductor.

[0014] The present application proposes a scheme that conformally designs the conductive radiator with the lens non-metallic support frame and utilizes the high dielectric constant of the support frame to achieve antenna matching. This scheme differs substantially from existing schemes that conform the antenna with the housing or use an independent dielectric substrate, and the effect is significant.

[0015] As one preferred embodiment, the relative permittivity of the material used for the lens mount is greater than or equal to 6. More preferably, the relative permittivity of the material used for the lens mount is between 6 and 9, and the loss tangent is less than 0.01. More preferably, the loss tangent is less than 0.005. For example, it can be a ceramic-filled polymer or a special engineering plastic with high dielectric properties (such as modified polyphenylene ether, specific types of liquid crystal polymers LCP, etc.). More preferably: PREPERM® PP7600-8030 RS (manufacturer: Avient, formerly Polyventon, USA, relative permittivity 6.0 (10GHz), loss tangent 0.002 (10GHz), barium titanate ceramic-filled modified PPO), PREPERM® PP7600-8050 (manufacturer: Avient, USA, relative permittivity 8.0 (10GHz), loss tangent 0.003 (10GHz), barium titanate ceramic-filled modified PPO).

[0016] The lens mount in this application is made of engineering plastic with a specific high dielectric constant. By precisely designing and selecting the dielectric constant of the lens mount, and utilizing the dielectric loading effect, the resonant frequency of the antenna can be effectively reduced without increasing the physical length of the antenna conductor, thus achieving precise matching with the operating frequency. This design, through the interaction between electromagnetic fields and materials, replaces the traditional passive matching method of adding high-loss inductors to the port, achieving low-loss and high-efficiency matching of the antenna structure itself.

[0017] The conductive radiator of this application may adopt a radiating structure of helical antenna, loop antenna, loop-helical antenna, monopole antenna or inverted F-type antenna.

[0018] Conductive radiators can be metallic conductive wires or conductive microstrip lines, etc.

[0019] During fabrication, the conductive radiator can be combined with the lens bracket through winding, pasting, embedding, direct printing, or LDS laser engraving. In other words, the conductive radiator can be firmly bonded to the non-metallic base support structure through direct bonding, wrapping, film pasting, hot-pressing embedding, direct printing, or LDS laser engraving.

[0020] This invention's antenna system aims to cover key industrial, scientific, and medical (ISM) application frequency bands. Its core target operating frequency bands include, but are not limited to: 433 MHz ± 5 MHz (e.g., 430–438 MHz, widely used in medical telemetry), 868 MHz ± 10 MHz (e.g., 863–870 MHz, European ISM band), and 915 MHz ± 13 MHz (e.g., 902–928 MHz, North American ISM band). The antenna design can be optimized for any one or more of these specific frequency bands. Under the extreme space constraints of existing dual-lens capsule endoscopes, traditional miniature antennas (such as planar inverted-F antennas or small helical antennas placed near the circuit board) struggle to effectively cover the aforementioned ISM frequency bands. The main bottleneck lies in:

[0021] 1) Conflict between physical and electrical dimensions: To achieve resonance in the low-frequency band (e.g., 433MHz), the antenna requires a physical length of approximately λ / 4 (about 17cm), which is impossible within a capsule (typically <3cm in length). Traditional solutions are forced to use lumped inductors with extremely high inductance for matching. Such inductors have extremely low Q values ​​and huge losses in the target frequency band, resulting in antenna radiation efficiency typically below 10%, narrow effective bandwidth, and inability to achieve stable coverage.

[0022] 2) Deterioration of the near-field environment: The antenna is placed close to metal / high dielectric constant components such as batteries and image sensors, and its near-field energy is absorbed and disturbed in large quantities, resulting in resonant frequency shift and impedance mismatch, which further narrows the available bandwidth.

[0023] This application fundamentally resolves the aforementioned contradictions through the following collaborative design, achieving efficient and stable coverage of the target ISM band:

[0024] 1) Structural Innovation: Dielectric Loading and Conformal Design: The conductive radiator is conformally integrated with a lens holder that has a high dielectric constant (εᵣ ≥ 3.5). The wavelength shortening effect of electromagnetic waves in the dielectric (λ = λ0 / √εᵣ) allows the antenna to maintain the required electrical dimensions while reducing its physical size by a factor of √εᵣ, thereby "pulling" the inherent resonant frequency to the target low-frequency ISM band (such as 433MHz).

[0025] 2) Material Innovation: Low-loss dielectric substrate: Engineering plastics (such as LCP and modified PPO) with a loss tangent of <0.01, preferably <0.005) are strictly selected. The low-loss characteristic ensures that radio frequency energy is effectively radiated rather than converted into heat dissipation during dielectric loading, which is the key to achieving high radiation efficiency (more than 15% improvement in the examples).

[0026] 3) Matching Innovation: Intrinsic Impedance Matching: The aforementioned dielectric loading effect itself constitutes part of the antenna distributed parameter matching network. By precisely coordinating the design of the support's dielectric constant, geometry, and conductor configuration, the antenna's input impedance at the target frequency can be directly close to 50Ω, thereby eliminating the need for the high-loss, large-value winding inductor required in traditional solutions, and in principle avoiding the additional ohmic losses introduced by it.

[0027] To further improve the antenna's radiation efficiency and extend the communication distance, this application designs the lens bracket as a multi-level stepped structure extending along the optical axis. The lens is installed at the top center of the lens bracket, and the conductive radiators are arranged in a predetermined manner along the periphery of the sides of each step in the multi-level stepped structure, so as to extend the effective electrical length of the antenna and optimize its radiation pattern.

[0028] To further save space, the sides of each step are provided with annular slots arranged along the perimeter. Each annular slot contains a circumferentially arranged conductive radiator. After completing one revolution within its corresponding annular slot, one end of each conductive radiator extends to the capsule endoscope's circuit board and connects to the matching port of the RF transceiver chip. The RF transceiver chip within the capsule endoscope is located on the circuit board, which is common knowledge, and this application does not offer any special improvements in this regard; therefore, it will not be elaborated upon further.

[0029] As one preferred implementation, the lens support has a three-tiered structure, consisting of a first tier, a second tier, and a third tier from bottom to top. The lens is mounted at the center of the top of the third tier. The first tier has a first-level annular groove along its periphery on its side, the second tier has a second-level annular groove along its periphery on its side, and the third tier has a third-level annular groove along its periphery on its side. The first tier annular groove contains a first annular conductive radiator arranged circumferentially, the second tier annular groove contains a second annular conductive radiator arranged circumferentially, and the third tier annular groove contains a third annular conductive radiator arranged circumferentially. One end of each of the first, second, and third annular conductive radiators extends to the capsule endoscope circuit board and connects to the matching port of the RF transceiver chip.

[0030] A dual-lens capsule endoscope includes a housing, with a first lens module and a second lens module located at both ends inside the housing. The first lens module and / or the second lens module integrates a conformal antenna as described above.

[0031] There is also a circuit board, battery, etc. between the first lens module and the second lens module. This application has not made any special improvements to this part, so it will not be described in detail.

[0032] The lenses used in the first and second lens modules include standard lenses and telephoto lenses.

[0033] The first lens module includes a first lens and a lens bracket for supporting the first lens. The second lens module includes a second lens and a lens bracket for supporting the second lens. When each lens module also includes a conformally conformally formed conductive radiator, it also includes the corresponding conductive radiator.

[0034] To meet daily needs, a conformal antenna as described above can be integrated into one of the lens modules.

[0035] To further reduce the impact on antenna performance, the plane containing the conductive radiator of the conformal antenna is approximately parallel to the plane containing the capsule endoscope circuit board and battery.

[0036] The aforementioned conformal antenna is integrated into the non-metallic lens bracket of one or two lens modules. With this arrangement, the conductive radiator of the antenna can be positioned in the end region of the capsule, with its main radiating plane forming an angle or even perpendicular to the plane of the main internal metal components (circuit board, battery), minimizing the absorption and obstruction of the antenna radiation field by the metal objects.

[0037] The aforementioned conformal antenna for dual-lens capsule endoscopes features a conductive radiator that conforms to the non-metallic support frame of the imaging lens at one end of the capsule endoscope, integrating the conductive radiator onto the surface or interior of the support frame. This design deeply integrates the antenna with the optomechanical structure, providing an ideal placement away from internal metal interference sources within the extremely confined space of the dual-lens capsule. It effectively solves the problems of insufficient antenna installation space and susceptibility to interference from metal components leading to performance degradation in existing technologies. It significantly reduces electromagnetic shielding effects and eddy current losses, and fundamentally addresses the issue of insufficient electrical dimensions at the physical structural material level, avoiding the introduction of lossy components. This significantly improves the antenna's radiation efficiency, the stability of wireless transmission signals, and the communication range.

[0038] The above describes a miniaturized conformal antenna suitable for dual-lens capsule endoscopes. Of course, the conformal antenna of this application is also applicable to single-lens capsule endoscopes.

[0039] In existing technologies, antennas such as CN209285451U and CN204927490U require a large amount of installation space. However, this application does not require a separate or independent installation location, conforms to the lens bracket, does not occupy additional functional space, and achieves "zero-space" integration.

[0040] In existing technologies, antennas located near or between large metal components (batteries, PCBs) suffer severe performance interference. For example, the antenna in patent CN109301454B is designed as a one-piece patch attached to the outer wall of the capsule shell. This antenna is very close to the circuit boards and batteries inside the patch area, resulting in metal interference and reduced antenna radiation performance. Similarly, the antenna in patent CN223583217U, a loop antenna wound inside the capsule, is also very close to surrounding circuit boards and batteries, leading to metal interference and reduced antenna radiation performance. In contrast, the antenna in this application is located at the end of the capsule and conforms to the lens's plastic support base, thus avoiding metal interference sources inside the capsule.

[0041] In existing technologies, the near-field environment is harsh, and radiation efficiency is easily suppressed. For example, in patent CN223583217U, although a structure for fixing the coil antenna is designed inside the capsule, the antenna is still affected by the circuit board above and below the antenna and around the coil, which reduces the antenna radiation efficiency. In contrast, this application optimizes the radiation environment through the design of a conformal antenna structure, which is conducive to the outward radiation of energy and results in higher efficiency.

[0042] In existing technologies, antennas are mostly independent components, increasing assembly steps and tolerance risks. For example, the antenna in patent CN109301454B would be very difficult to assemble and install, and the stability and reliability of the installation cannot be effectively guaranteed. In contrast, this application integrates the antenna with the lens bracket, resulting in a compact structure, simplified assembly, improved structural integration, and space savings.

[0043] In the prior art, traditional single-lens capsule endoscopes, which have relatively ample space, are only suitable for use with single-lens capsule endoscopes, as described in patents CN209285451U, CN204927490U, and CN 119362026A. They are not suitable for dual-lens capsule endoscopes. This application, however, is applicable not only to single-lens capsule endoscopes but also, and more importantly, to dual-lens capsule endoscopes where space is extremely limited.

[0044] Any techniques not mentioned in this invention are based on existing technologies.

[0045] Compared with existing technologies, this patent has the following significant advantages:

[0046] 1) Extreme space utilization: The antenna and lens non-metallic base support frame are designed to conformally, achieving "zero extra space occupation" of the antenna in the dual-lens capsule, solving the fundamental problem of where the antenna can be installed.

[0047] 2) Superior anti-interference performance: The antenna is positioned at the end of the capsule, away from the densely packed circuit boards and batteries in the center, achieving physical isolation from the main sources of interference. Simultaneously, the non-metallic plastic support serves as a carrier, avoiding the impact of additional metal structures on antenna performance.

[0048] 3) Improved radiation performance: The optimized layout allows the antenna radiator to radiate energy more freely to the outside of the capsule, reducing energy leakage into the capsule, thereby improving the overall radiation efficiency and gain of the antenna.

[0049] 4) Enhanced transmission reliability: The aforementioned spatial and anti-interference advantages directly translate into a better wireless link budget, ensuring that image data can be transmitted at a higher rate and in a more stable manner in complex in-body environments, thus extending the effective communication distance.

[0050] 5) High structural integration: The antenna, as a functional layer of the lens module, simplifies the overall assembly process of the capsule and improves the consistency and reliability of production.

[0051] 6) Achieving low-loss intrinsic matching: By selecting a substrate material with a high dielectric constant, the antenna resonant frequency is actively reduced using the dielectric loading effect, fundamentally solving the problem of insufficient electrical size in miniaturized antennas. This avoids the additional ohmic losses caused by introducing large-size wire-wound inductors into the matching network, thus maximizing the intrinsic radiation gain and efficiency of the antenna while ensuring good impedance matching (excellent S11 performance), achieving simultaneous optimization of matching performance and radiation performance.

[0052] This invention achieves the following comprehensive beneficial effects through the above technical solution: First, the conformal integrated design directly resolves the spatial contradiction of having nowhere to install the antenna; second, positioning the antenna on the non-metallic support at the end of the capsule avoids coupling with the main metal interference source from a physical layout perspective; most importantly, by selecting a support material with a specific dielectric constant and optimizing the structure, dielectric loading matching of the antenna itself is achieved, fundamentally eliminating the need for traditional lossy matching inductors, thus preserving and improving the intrinsic radiation performance of the antenna while solving the matching problem. Ultimately, these effects work synergistically to ensure stable and efficient remote wireless image transmission within the extremely compact dual-lens capsule endoscope. Attached Figure Description

[0053] Figure 1 This is a schematic diagram of the integrated layout of the conformal antenna of the present invention on a dual-lens capsule endoscope.

[0054] Figure 2 for Figure 1 Cross-sectional view.

[0055] Figure 3This is a schematic diagram of the conformal design of the conductive radiator and the lens bracket of the present invention.

[0056] Figure 4 This is a schematic diagram of the conformal antenna layout of the present invention.

[0057] In the figure, 10-Conformal antenna conductive radiator; 11-First ring conductive radiator; 12-Second ring conductive radiator; 13-Third ring conductive radiator; 20-First lens non-metallic base support frame; 21-First-level ring slot; 22-Second-level ring slot; 23-Third-level ring slot; 31-First lens; 32-Second lens; 40-Housing shell; 51-First PCB circuit board; 521-Second PCB circuit board; 522-Fourth PCB circuit board; 53-Third PCB circuit board; 60-Lithium battery; Detailed Implementation

[0058] 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.

[0059] The directional terms such as “center,” “longitudinal,” “lateral,” “length,” “width,” “thickness,” “upper,” “lower,” “front,” “back,” “left,” “right,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” “outer,” “clockwise,” and “counterclockwise” in this application are based on the orientation or positional relationship shown in the accompanying drawings and are used only for the convenience of describing this application. They are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting this application.

[0060] Example 1

[0061] like Figures 1 to 4As shown, this embodiment provides a conformal antenna for a dual-lens capsule endoscope. The capsule endoscope includes a biocompatible capsule shell (40), with a first lens (31) at one end and a second lens (32) at the other end. The first lens (31) and the second lens (32) are respectively mounted on corresponding lens supports 20. Between the two lens supports 20, a first PCB circuit board (51), a third PCB circuit board (53), a lithium battery (60), a second PCB circuit board (521), and a fourth PCB circuit board (522) are arranged in sequence. The first PCB circuit board (51) is mainly equipped with a wireless radio frequency chip and discrete components; the third PCB circuit board (53) is mainly equipped with an MCU main control chip and discrete components; the second PCB circuit board (521) is mainly equipped with a CMOS sensor chip, an LED light group, a first lens (31), a lens bracket 20 and discrete components; the fourth PCB circuit board (522) is mainly equipped with a CMOS sensor chip, an LED light group, a second lens (32), a lens bracket 20 and discrete components; the first PCB circuit board (51) and the third PCB circuit board (53) are connected by a flexible flat cable; the second PCB circuit board (521) and the third PCB circuit board (53) are connected by a flexible flat cable; the fourth PCB circuit board (522) and the third PCB circuit board (53) are connected by a flexible flat cable; the first PCB circuit board (51) is connected to the tail conductor reserved in the conformal antenna conductive radiator (10). The first lens (31) and its corresponding lens holder (20) form a first lens module, and the second lens (32) and its corresponding lens holder (20) form a second lens module. In this example, the conductive radiator is fabricated on the lens holder (20) of the first lens (31) of the capsule endoscope. The lens holder (20) is made of non-metallic material and is formed by hot pressing with a high-precision mold.

[0062] Example 2

[0063] Based on Example 1, the following improvements were made: the lens holder (20) is made of plastic material with a relative permittivity (εr) preferably in the range of 3.5 to 10, and has a low loss tangent (tanδ < 0.01, preferably less than 0.005). In this example, the lens holder (20) is made of Avient PREPERM® PP7600-8030RS material, with a relative permittivity of 6.0 (10GHz) and a loss tangent of 0.002 (10GHz).

[0064] Example 3

[0065] Based on Embodiment 2, the following improvements were made: The lens support 20 adopts a three-stage stepped structure, consisting of a first-stage step, a second-stage step, and a third-stage step. The side of the first-stage step is provided with a first-stage annular groove (21) arranged along the periphery; the side of the second-stage step is provided with a second-stage annular groove (22) arranged along the periphery; and the side of the third-stage step is provided with a third-stage annular groove (23) arranged along the periphery. The first-stage annular groove (21) contains a first annular conductive radiator (11) arranged circumferentially; the second-stage annular groove (22) contains a second annular conductive radiator (12) arranged circumferentially; and the third-stage annular groove (23) contains a third annular conductive radiator (13) arranged circumferentially. The first annular conductive radiator (11), the second annular conductive radiator (12), and the third annular conductive radiator (13) together form a complete antenna conforming to the non-metallic lens support, suitable for dual-lens capsule endoscopes. In this example, a ring antenna radiation structure is used, but it can also be configured as a spiral, annular spiral, F-type, or other structural forms as needed.

[0066] Example 4

[0067] Based on Example 3, the following improvements were made: In this example, the conductive radiator is an ultra-thin foil with a thickness of 10 μm, and a protective layer is formed by gold plating (Au) on the surface. The conductive radiator is attached and wound in the first-level annular slot (21), the second-level annular slot (22), and the third-level annular slot (23) to form the first annular conductive radiator (11), the second annular conductive radiator (12), and the third annular conductive radiator (13), respectively, forming the conformal antenna conductive radiator (10). After the first annular conductive radiator (11), the second annular conductive radiator (12), and the third annular conductive radiator (13) are wound around once, their tail ends extend downward and are connected to the matching port on the RF transceiver chip on the first PCB circuit board (51). The conjugate impedance matching with the antenna is achieved through the discrete device matching network on the first PCB circuit board (51), thereby optimizing the S11 return loss parameter of the antenna so that the return loss performance of the conformal antenna conductive radiator (10) reaches the best level for practical application.

[0068] In each case, the antenna is cleverly "hidden" within the lens's mechanical structure. For example... Figure 1 As shown, the antenna conductive radiator (10) is located at the end of the capsule, and its main radiation plane is approximately parallel to the capsule's optical axis (i.e., the direction of the capsule's optical lens). This arrangement allows the antenna radiation field to avoid obstruction and absorption by internal metal components to the greatest extent possible, and the energy is radiated more effectively to the outside of the capsule.

[0069] Verification was conducted through electromagnetic simulation and experiments.

[0070] 1) When the conformal antenna conductive radiator (10) is conformally mounted on a lens support with a high dielectric constant, the resonant frequency of the antenna will "shift left" towards lower frequencies due to the wavelength shortening effect of electromagnetic waves in the medium. By precisely controlling the dielectric constant of the material and the geometric parameters of the antenna structure, the resonant point of the antenna can be accurately "pulled" to the target operating frequency of 433MHz, achieving a return loss better than -15dB or even -20dB (S11). Compared with the traditional compensation scheme of connecting a large inductor (e.g., 22nH or more) in parallel at the 50-ohm matching port, this material co-design method can improve the measured radiation efficiency of the antenna by more than 15%, because it avoids the significant loss caused by lumped inductor elements.

[0071] 2) Under the same 433MHz operating frequency band and human tissue environment, the conformal antenna in this embodiment, compared to traditional antennas placed in the middle of the capsule close to the PCB circuit board or battery, achieves a radiation efficiency improvement of over 40%, and its radiation direction is more oriented towards the outside of the capsule. This directly indicates stronger external signal reception and a more stable transmission link. Verification through electromagnetic simulation combined with model testing shows that at a 433MHz operating frequency, the main lobe of the antenna's radiation pattern points outwards from the capsule, with a peak gain exceeding -15 dBi. Compared to traditional center-mounted antennas (whose gain is typically in the range of -25 dBi to -20 dBi, and whose radiation pattern is distorted due to metal obstruction), the actual gain improvement exceeds 5-10 dB, directly meaning that at the same transmit power, the signal strength received externally can be enhanced by 1-2 times or more. Communication distance is affected by transmit power, antenna gain, receiver sensitivity, and environment. Considering a typical setting of approximately 1 milliwatt (approximately 0 dBm) transmit power inside the capsule, and referring to the standard transmission distance range of a 433MHz module in open areas... Based on link budget analysis and anechoic chamber testing simulating human tissue environment, the effective communication distance of this conformal antenna solution is significantly improved: Traditional center-channel antenna: In a test environment filled with simulated digestive fluid, its stable transmission distance is typically no more than 1 meter due to low gain and poor directivity. This conformal antenna: Thanks to high gain and an optimized outward radiation pattern, a stable data transmission distance of over 1.5 meters can be achieved under the same test environment. In a typical location on the human abdomen, it ensures reliable signal reception by the external receiver. Signal stability is evaluated through the fluctuation range of Received Signal Strength Indication (RSSI) and the bit error rate. On a test platform dynamically simulating intestinal peristalsis, continuous video data transmission tests were conducted for over 1 hour: RSSI stability: The capsule using this antenna showed an external RSSI value fluctuation range of less than ±5 dB, while the RSSI fluctuation of the traditional center-channel antenna often exceeded ±10 dB, indicating that this solution is less affected by changes in the capsule's posture within the body. Bit Error Rate: At an image data transmission rate of 2 Mbps, the average bit error rate (BER) of this antenna scheme is less than 1×10⁻ 5 This meets the reliability requirements for wireless high-definition image transmission. In contrast, traditional antennas have a significantly higher bit error rate at the same data rate and may experience image stuttering due to packet loss.

[0072] Example 5

[0073] The difference from Example 4 is that the lens bracket (20) is made of LCPL204G30 from Toray Lumica of Japan, with a relative permittivity of 4.2 (1MHz) and a loss tangent of 0.004 (10GHz). The rest of the structure, the form of the conductive radiator, the antenna layout and the connection method are consistent with Example 4.

[0074] Verification was conducted through electromagnetic simulation and experiments.

[0075] 1) When using this LCP material as the antenna dielectric loading substrate, although its relative permittivity is slightly lower than that of the material in Example 4, it can still effectively utilize the dielectric loading effect to "pull" the antenna's resonant frequency towards lower frequencies. By adjusting the antenna structure parameters and appropriately increasing the length of the conformal antenna's conductive radiator, the antenna resonant point can still be precisely tuned to the target operating frequency of 433MHz, achieving a return loss better than -15dB (S11). At the same time, thanks to the extremely low loss tangent of the LCP material, the antenna's radiation efficiency at the resonant point remains at a high level. Compared to the traditional scheme of paralleling a large inductor at the RF port for matching, the measured radiation efficiency is improved by more than 14%.

[0076] 2) In the 433MHz band, tests conducted in a simulated human tissue environment showed that the main lobe of the antenna in this embodiment pointed outwards from the capsule, with a peak gain exceeding -17 dBi. Compared to a traditional center-mounted antenna, the gain is improved by approximately 3–8 dB, and the effective communication distance can reach over 1.2 meters. Regarding signal transmission stability, in a dynamically simulated intestinal environment, the RSSI fluctuation range was controlled within ±5 dB, and the bit error rate was less than 1 × 10⁻⁻⁻⁶. 5 This meets the reliability requirements for high-definition image transmission.

[0077] Example 6

[0078] The difference from Example 4 is that the lens bracket (20) is made of PREPERM® PP7600-8050, manufactured by Avient, USA, with a relative permittivity of 8.0 (10GHz) and a loss tangent of 0.003 (10GHz). The rest of the structure, conductive radiator form, antenna layout and connection method are consistent with Example 4.

[0079] Verification was conducted through electromagnetic simulation and experiments.

[0080] 1) When using this high dielectric constant (εᵣ=8.0) material as the dielectric substrate, the wavelength shortening effect is more significant, and the resonant frequency of the antenna under the same physical dimensions shifts further to lower frequencies. By appropriately shortening the physical length of the ring conductor or adjusting the stepped structure parameters, the antenna resonant point can still be precisely tuned to 433MHz, achieving S11 performance better than -16dB. The synergistic effect of the material's high dielectric constant and low loss characteristics allows the antenna to maintain good impedance matching while improving radiation efficiency by approximately 12% or more compared to traditional inductive matching schemes.

[0081] 2) In the 433MHz operating frequency band, the peak gain of the antenna in this embodiment reaches -18.5 dBi in a simulated human tissue environment, and the main lobe of the radiation pattern clearly points outward from the capsule. Compared with a traditional center-mounted antenna, the gain improvement exceeds 2-6 dB. At the same transmit power, the measured effective communication distance exceeds 1.2 meters. In dynamic intestinal simulation tests, RSSI fluctuation is less than ±4 dB, and the bit error rate is stable at 1×10⁻⁻⁻⁶. 6 The following demonstrates superior signal transmission stability and anti-interference capability.

[0082] Comparative Example 1

[0083] The difference from Example 4 is that the lens bracket (20) is replaced with polypropylene (PP) with a strength of 2.3 (test frequency 1MHz) and a loss tangent of approximately 0.0005 (test frequency 10GHz). The remaining structure, conductive radiator form, antenna layout, and connection method are consistent with Example 4.

[0084] Verification was conducted through electromagnetic simulation and experiments.

[0085] 1) Due to the low dielectric constant of polypropylene (εᵣ<3.5), the dielectric loading effect is weak, and the shortening of electromagnetic wave wavelength is not significant. Under the same antenna structure, the resonant frequency of the antenna is significantly higher than the target frequency of 433MHz, and it is impossible to "pull" it to the target frequency band through structural adjustments. Even attempts to lower the frequency by increasing the length of the conductor are not feasible due to the space limitations of the capsule.

[0086] 2) In tests conducted in the 433MHz band, the antenna exhibited poor S11 performance (return loss better than -6dB with extremely narrow bandwidth) and severe impedance mismatch. The measured radiation efficiency was below 5%, the gain was only around -28 dBi, and the radiation pattern was significantly distorted due to interference from internal metal components. The effective communication distance was less than 0.5 meters, and the signal fluctuation was large (RSSI fluctuation exceeded ±15 dB), with a high bit error rate, failing to meet the stability requirements for image transmission.

[0087] The above description is merely a preferred embodiment of this patent and is not intended to limit the scope of protection of this patent. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this patent shall be included within the scope of protection of this patent.

Claims

1. A conformal antenna system for a dual-lens capsule endoscope, comprising two lenses disposed at both ends within a housing and lens holders corresponding to the two lenses respectively, characterized in that: It also includes a conductive radiator conformally to the lens bracket, which is made of a non-metallic dielectric material with a dielectric constant greater than 3.

5. The conductive radiator is configured on the surface or inside one or two of the lens brackets, thereby forming a conformal antenna unit that works using the dielectric loading principle together with the lens bracket.

2. The conformal antenna system for a dual-lens capsule endoscope as described in claim 1, characterized in that: The lens holder is made of plastic.

3. The conformal antenna system for a dual-lens capsule endoscope as described in claim 1 or 2, characterized in that: The lens bracket serves as the dielectric loading substrate for the conductive radiator. By utilizing the dielectric constant of its material, it actively reduces the physical resonant frequency of the conductive radiator, thereby matching the conductive radiator to the target operating frequency band. This structure enables the conductive radiator to exhibit matched impedance characteristics within the operating frequency band, thus eliminating the need for external impedance matching by using large-value wire-wound inductors in parallel or series at the RF port.

4. The conformal antenna system for a dual-lens capsule endoscope as described in claim 1 or 2, characterized in that: The relative permittivity of the material used for the lens bracket is between 6 and 9, and the loss tangent is less than 0.

01.

5. The conformal antenna system for a dual-lens capsule endoscope as described in claim 1 or 2, characterized in that: The conductive radiator adopts a radiating structure of helical antenna, loop antenna, loop-helical antenna, monopole antenna or inverted F-type antenna; the conductive radiator is combined with the lens bracket by winding, pasting, embedding, direct printing or LDS laser engraving.

6. The conformal antenna system for a dual-lens capsule endoscope as described in claim 1 or 2, characterized in that: The lens bracket is a multi-level stepped dielectric structure extending along the optical axis. The lens is mounted at the top center of the lens bracket, and conductive radiators are arranged around the periphery of the sides of each step to extend the effective electrical length of the antenna and optimize its radiation pattern.

7. The conformal antenna system for a dual-lens capsule endoscope as described in claim 6, characterized in that: The sides of each step are provided with annular grooves arranged around the perimeter. Each annular groove contains a conductive radiator arranged circumferentially. After each conductive radiator has been arranged around the corresponding annular groove, one end of it extends to the capsule endoscope circuit board and is connected to the matching port of the radio frequency transceiver chip.

8. The conformal antenna system for a dual-lens capsule endoscope as described in claim 6, characterized in that: The lens support has a three-tiered structure, consisting of a first tier, a second tier, and a third tier from bottom to top. The lens is mounted at the center of the top of the third tier. The first tier has a first-level annular groove along its perimeter on its side, the second tier has a second-level annular groove along its perimeter on its side, and the third tier has a third-level annular groove along its perimeter on its side. The first tier has a first annular conductive radiator arranged circumferentially in its first annular groove, the second tier has a second annular conductive radiator arranged circumferentially in its second annular groove, and the third tier has a third annular conductive radiator arranged circumferentially in its third annular groove. One end of each of the first, second, and third annular conductive radiators extends to the capsule endoscope circuit board and connects to the matching port of the RF transceiver chip.

9. A dual-lens capsule endoscope, characterized in that, The device includes a housing, with a first lens module and a second lens module disposed at both ends inside the housing, wherein the first lens module and / or the second lens module integrates a conformal antenna as described in any one of claims 1 to 10.

10. The dual-lens capsule endoscope as described in claim 9, characterized in that: The plane containing the conductive radiator of the conformal antenna is parallel to the plane containing the capsule endoscope circuit board and battery.

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