CN211088504U - Square-ring-shaped capacitive loading implantation type circularly polarized antenna with double-bending resonant ring - Google Patents
Square-ring-shaped capacitive loading implantation type circularly polarized antenna with double-bending resonant ring Download PDFInfo
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- CN211088504U CN211088504U CN201922444197.9U CN201922444197U CN211088504U CN 211088504 U CN211088504 U CN 211088504U CN 201922444197 U CN201922444197 U CN 201922444197U CN 211088504 U CN211088504 U CN 211088504U
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Abstract
The utility model discloses a square ring shape capacitive loading implanted circular polarized antenna who introduces two resonance rings of buckling, outside quad ring utilizes the electromagnetic coupling to imitate the circular polarizer which is formed by the double-bending resonance rings and arranged in an array is more compact in structure, can concentrate stronger electromagnetic energy and excite two degenerate orthogonal modes with equal amplitudes and 90-degree phase difference, thereby realizing circular polarization radiation, forming a rectangular branch with increased gap in the middle of a U-shaped branch, and being capable of adjusting and enhancing the circular polarization purity of the antenna, wherein the volume of the antenna is only 9 × 9 multiplied by 0.635mm 3The antenna has the characteristics of miniaturization, wide band, circular polarization, interference resistance and the like, is suitable for the ISM 2.45GHz frequency band, and meets the working requirements of miniaturization and circular polarization of the antenna after being implanted into a human tissue environment.
Description
Technical Field
The utility model relates to an implanted antenna technical field, concretely relates to square ring shape capacitive loading implanted circular polarized antenna who introduces two resonance ring of buckling is applicable to the wireless bio-medical treatment device of implanted circular polarization of ISM 2.45GHz frequency channel.
Background
The bioelectromagnetism covers a plurality of fields such as biology, medical technology, electromagnetism and the like, is concerned by researchers, and is more and more widely applied to medical diagnosis, treatment and the like. The application of the bioelectromagnetism in a medical system can not only help doctors diagnose and prevent diseases, but also monitor the change of human physiological parameters in real time, thereby providing a great deal of convenience for patients. The implanted antenna is a key link of a remote medical monitoring system, is a carrier for information transmission, and is very important for the design and research of the implanted antenna. The performance of the implanted antenna directly affects the working efficiency and stability of the remote medical monitoring system. The implanted antenna transmits the physiological parameters monitored by the sensor to the in-vitro receiving device, and a doctor analyzes the parameters to complete the diagnosis process. Common wireless medical equipment includes wearing formula, the formula of taking into and implanted, and the wireless medical equipment work of wearing formula is in free space, and is lower to the antenna requirement, and the formula of taking into and the work of implanted wireless medical equipment is in the human body, and the electromagnetic characteristic of wireless medical equipment can be influenced to the strong coupling between wireless medical equipment and the human body, and how to design the implanted antenna that the performance is good, the operation is stable is a problem that needs to solve urgently in the biological electromagnetism field. The circularly polarized antenna can receive and transmit linearly polarized waves in any direction or circularly polarized waves in the same rotating direction, has the advantages of easiness in conformality, strong anti-interference capability, low error rate, multipath interference resistance and the like, is suitable for environments with frequently changed relative positions of an external antenna and an implanted antenna, and the implanted antenna needs to have a wider working frequency band, a smaller design size, a reduced SAR value absorbed by a human body and the like. The method for widening the frequency band of the implanted antenna comprises the following steps: reducing the Q value of the equivalent resonant circuit; a multi-resonance coupling structure is added to replace a simple resonance structure, such as a parasitic patch; designing a plurality of patches on the same plane, increasing resonance points through the coupling of the patches and widening the bandwidth; the antenna adopts a multilayer stacked structure, adopts multilayer patches and multilayer dielectric substrates in the antenna, and feeds power in an electromagnetic coupling or aperture coupling mode; by adopting a fractal technology and adopting fractal antenna elements or arranging the array units according to a fractal rule, the fractal antenna can widen the bandwidth of the antenna and reduce the size of the antenna at the same time. The method for miniaturizing the implanted antenna mainly comprises the following steps: increasing the relative dielectric constant; the meander technology, which is to open a slot or a slit on a radiation patch and guide current to be distributed along the slit, thereby extending the current path on the surface of the antenna and enabling the resonant frequency to shift to the low frequency direction; an antenna loading technology is adopted, wherein a short-circuit probe, a short-circuit sheet or a short-circuit surface is introduced between a radiation patch and a floor to form a quarter-wavelength structure, so that the size of an antenna is reduced; the capacitive inductive loading technology can offset inductive impedance, and the miniaturization and impedance matching of the antenna are realized. The main method for realizing the circular polarization characteristic comprises the following steps: adopting a caliber coupling feed method; setting a short-circuit probe; introducing a perturbation structure on the radiation patch, namely introducing a gap or a loading branch on the radiation patch or the floor; loading a circular polarizer composed of an open resonant ring, and the like. The split ring resonator is a sub-wavelength magnetic resonator, has negative dielectric constant property, can inhibit surface waves, reduce mutual coupling and reduce the size of an antenna, and can generate weaker left-handed material characteristics when an implanted antenna is loaded with the split ring resonator to form an array.
SUMMERY OF THE UTILITY MODEL
The utility model aims at providing an introduce square ring shape capacitive loading implanted circular polarized antenna of two resonance rings of buckling, this antenna have characteristics such as miniaturization, broadband, circular polarization, anti-interference, biocompatibility are good, and convenient and the integration of the wireless biomedical devices of implanted are applicable to ISM 2.45GHz frequency channel, can satisfy the demand of the wireless biomedical devices of implanted to the antenna performance.
The technical scheme of the utility model is that: introduce two square ring capacitive loading implanted circular polarized antenna who buckles the resonant ring, constitute its characterized in that by dielectric substrate 1, the square ring capacitive loading radiating element 2, downside short circuit probe 3, upside short circuit probe 4, coaxial connector 5, the floor 6 that introduce two resonance rings:
a. The square ring capacitive loading radiation unit 2 introduced with the double-bending resonance ring consists of an outer square ring 2-1, an inner square ring 2-2 and a double-bending resonance ring 2-3, the outer square ring 2-1 can excite an additional mode close to the resonance frequency of a main mode by utilizing the electromagnetic coupling effect so as to widen the impedance bandwidth of the antenna, a left interdigital capacitor 2-4, an upper interdigital capacitor 2-5, a right interdigital capacitor 2-6 and a lower interdigital capacitor 2-7 are added between the four radiation edges of the outer square ring 2-1 and the inner square ring 2-2 to generate the capacitive loading characteristic, the size of the implanted antenna is reduced, the miniaturization of the antenna is realized, the double-bending resonance ring 2-3 is loaded in the inner square ring 2-2, and the circular polarizer with the array layout consisting of the double-bending resonance rings 2-3 is more compact in structure, stronger electromagnetic energy can be concentrated, a single bending resonance ring is formed by bending a square ring by half, the inner part of the bending resonance ring is disconnected and two U-shaped branches are symmetrically placed, a gap is formed between the two U-shaped branches, an E-shaped groove is formed in the single bending resonance ring, the rectangular branch is additionally arranged in the gap and is connected with the upper edge of the E-shaped groove, a circular polarizer consisting of double bending resonance rings 2-3 can excite two degenerate orthogonal modes with equal amplitudes and 90-degree phase difference, so that circular polarization radiation is realized, the circular polarization purity of the implanted antenna can be adjusted and enhanced by the added rectangular branch, the double bending resonance rings 2-3 are connected with the inner square ring 2-2 through rectangular conduction bands, and the two single bending resonance rings are symmetrical about the transverse symmetrical axis of the dielectric substrate 1;
b. The lower short-circuit probe 3 and the upper short-circuit probe 4 are arranged at the lower left corner and the upper left corner of an inner square ring 2-2 in the square-ring capacitive loading radiation unit 2 introduced with the double-bent resonant ring, the lower short-circuit probe 3 and the upper short-circuit probe 4 are symmetrical about a transverse axis of the antenna dielectric substrate 1, the lower short-circuit probe 3 and the upper short-circuit probe 4 are increased to form a standing wave structure, and the size of the antenna is further reduced;
c. The coaxial connector 5 is positioned on the right side of an inner square ring 2-2 in the square annular capacitive loading radiation unit 2 introduced with the double-bending resonance ring and positioned on a transverse symmetrical axis of the dielectric substrate 1, an inner core of the coaxial connector 5 is connected with the inner square ring 2-2 in the square annular capacitive loading radiation unit 2 introduced with the double-bending resonance ring, and an outer core of the coaxial connector 5 is connected with the floor 6;
d. The floor 6 is a square complete metal patch structure, and can form a shielding layer to isolate the electronic device of the wireless biomedical device from the implanted circularly polarized antenna, reduce the interference of the antenna on other electronic devices, and improve the electromagnetic compatibility.
the length L of the dielectric substrate 1 is 8 mm-10 mm, and the width W is 8 mm-10 mm.
The distance W between the square ring capacitive loading radiating element 2 with the double-bending resonant ring and the edge of the dielectric substrate 1 10.2 mm-0.3 mm, the square ring capacitive loading radiation unit 2 introduced with the double-bending resonance ring consists of an outer square ring 2-1, an inner square ring 2-2 and a double-bending resonance ring 2-3, and the outer side length of the outer square ring 2-1 is W 38.4 mm-8.6 mm, side length W of the inner side 137.8 mm-8 mm, the outer side length of the inner square ring 2-1 is W 126.2 mm-6.4 mm, side length W of the inner side 114.4 mm-4.6 mm, the distance L between the outer square ring 2-1 and the inner square ring 2-2 20.7 mm-0.9 mm, the left interdigital capacitor 2-4, the upper interdigital capacitor 2-5, the right interdigital capacitor 2-6 and the upper and lower branch length L in the lower interdigital capacitor 2-7 are increased by the outer square ring 2-1 and the inner square ring 2-2 10.6 mm-0.7 mm, width W 20.1 mm-0.2 mm, and the width W of the space between the upper branch knot and the lower branch knot 40.1 mm-0.2 mm, the double-bending resonance ring 2-3 is connected with the inner square ring 2-2 through a rectangular conduction band with width W of the rectangular conduction band 50.2 mm-0.4 mm, length L 30.2 mm-0.4 mm, length L of single bending resonance ring 7Is 1.7mm & 1.8mm, width W 63.8 mm-4 mm, and the ring width W of the single bending resonance ring 70.2 mm-0.4 mm, the width W of the branch connected with the U-shaped branch 100.9 mm-1.1 mm, length L 80.3 mm-0.4 mm, and the left branch length L of the U-shaped branch 50.8 mm-0.9 mm, the length of the right branch 60.9 mm-1.1 mm, upper branch length W 90.9 mm-1.1 mm, and the width W of the U-shaped branch 140.3 mm-0.4 mm, and the length L of the rectangular branch is increased in the middle of the split 41.1 mm-1.3 mm, width W 8Is 0.1 mm-0.3 mm.
The radius R of the lower short-circuit probe 3 and the upper short-circuit probe 4 10.2 mm-0.4 mm, and the distance R between the centers of the lower short-circuit probe 3 and the upper short-circuit probe 4 and the center of the dielectric substrate 1 23.5 mm-3.9 mm, and the included angles a between the lower short-circuit probe 3 and the upper short-circuit probe 4 and the longitudinal symmetry axis of the dielectric substrate 1 1The radius of the lower short-circuit probe 3 and the radius of the upper short-circuit probe 4 are equal to the radius of the inner core of the coaxial connector 5, and the radius is 42-47 degrees.
The distance W between the center of the coaxial connector 5 and the center of the dielectric substrate 1 0Is 2.5 mm-2.9 mm.
the floor 6 is a complete square metal patch, the size of the floor 6 is the same as that of the medium substrate 1, L is 8 mm-10 mm, and W is 8 mm-10 mm in width.
The square-ring capacitive loading implanted circular polarized antenna with the double-bending resonant ring introduced is coated with a layer of ultrathin biocompatible film alumina on the outer surface, has small influence on the reflection coefficient and the antenna gain, is close to the dielectric constant of the dielectric substrate 1, and has the dielectric constant r9.2, loss tangent tan of 0.008 and coating thickness of 0.03mm, and isolates the implanted circular polarization from human tissue of the antenna, thereby preventing the conductive patch of the antenna from directly contacting with the human tissue and reducing the influence of the human tissue on the performance of the implanted circular polarization antenna.
The utility model has the effects that: the utility model discloses a square ring capacitive loading implanted circular polarized antenna who introduces two resonance rings of buckling, the additional mode that resonance frequency is close with the master mode can be aroused out to the outside quad ring utilizing the electromagnetic coupling effect to widen antenna impedance bandwidth the circularly polarizer with array layout formed by double-bent resonance rings is more compact in structure, can concentrate stronger electromagnetic energy, can excite two degenerate orthogonal modes with equal amplitudes and 90-degree phase difference, thereby realizing circularly polarized radiation, forms a rectangular branch with increased gaps in the middle of a U-shaped branch, can adjust and enhance the circularly polarized purity of the implanted antenna, forms a shielding layer for isolating the electronic device of the wireless biomedical device from the implanted circularly polarized antenna, reduces the interference of the antenna on other electronic devices, improves the electromagnetic compatibility, increases a short-circuit probe to form a standing wave structure, further reduces the size of the antenna, and has a planar structure with the volume of only 9 multiplied by 0.635mm 3The antenna has the characteristics of miniaturization, wide band, circular polarization, interference resistance, good biocompatibility and the like, is suitable for the ISM 2.45GHz frequency band, and meets the working requirements of miniaturization and circular polarization of the antenna after being implanted into a human tissue environment.
Drawings
Fig. 1 is a schematic front structural diagram of an embodiment of the present invention.
Fig. 2 is a schematic side view of an embodiment of the present invention.
Fig. 3 is a schematic back structure diagram of an embodiment of the present invention.
Fig. 4 is an illustration of the effect of the embodiment of the present invention on the antenna impedance bandwidth and the axial ratio bandwidth before and after capacitive loading is introduced between the outer square ring and the inner square ring.
FIG. 5 shows an embodiment of the present invention, in which the gap formed between the U-shaped branches increases the length L of the rectangular branches 4Width W of 8The effect on the antenna impedance bandwidth and the axial ratio bandwidth.
Fig. 6 is a schematic view of the depth of the implanted skin layer according to the embodiment of the present invention.
Fig. 7 illustrates the effect of different implantation depths H on the antenna impedance bandwidth and axial ratio bandwidth according to embodiments of the present invention.
Fig. 8 is a simulation and actual measurement impedance bandwidth curve according to an embodiment of the present invention.
Fig. 9 is an E-plane radiation pattern of an embodiment of the present invention at a frequency of 2.45 GHz.
Fig. 10 is an H-plane radiation pattern at a frequency of 2.45GHz in accordance with an embodiment of the present invention.
Detailed Description
The utility model discloses a concrete implementation mode is: as shown in fig. 1, the square-ring capacitive loading implanted circular polarized antenna with the double-bending resonant ring introduced comprises a dielectric substrate 1, a square-ring capacitive loading radiation unit 2 with the double-bending resonant ring introduced, a lower short-circuit probe 3, an upper short-circuit probe 4, a coaxial connector 5 and a floor 6, and is characterized in that: the square ring capacitive loading radiation unit 2 introduced with the double-bending resonance ring consists of an outer square ring 2-1, an inner square ring 2-2 and a double-bending resonance ring 2-3, the outer square ring 2-1 can excite an additional mode close to the resonance frequency of a main mode by utilizing the electromagnetic coupling effect so as to widen the impedance bandwidth of the antenna, a left interdigital capacitor 2-4, an upper interdigital capacitor 2-5, a right interdigital capacitor 2-6 and a lower interdigital capacitor 2-7 are added between the four radiation edges of the outer square ring 2-1 and the inner square ring 2-2 to generate the capacitive loading characteristic, the size of the implanted antenna is reduced, the miniaturization of the antenna is realized, the double-bending resonance ring 2-3 is loaded in the inner square ring 2-2, and the circular polarizer with the array layout consisting of the double-bending resonance rings 2-3 is more compact in structure, stronger electromagnetic energy can be concentrated, a single bending resonance ring is formed by bending a square ring by half, the inner part of the bending resonance ring is disconnected and two U-shaped branches are symmetrically placed, a gap is formed between the two U-shaped branches, an E-shaped groove is formed in the single bending resonance ring, the rectangular branch is additionally arranged in the gap and is connected with the upper edge of the E-shaped groove, a circular polarizer consisting of double bending resonance rings 2-3 can excite two degenerate orthogonal modes with equal amplitudes and 90-degree phase difference, so that circular polarization radiation is realized, the circular polarization purity of the implanted antenna can be adjusted and enhanced by the added rectangular branch, the double bending resonance rings 2-3 are connected with the inner square ring 2-2 through rectangular conduction bands, and the two single bending resonance rings are symmetrical about the transverse symmetrical axis of the dielectric substrate 1; the lower short-circuit probe 3 and the upper short-circuit probe 4 are arranged at the lower left corner and the upper left corner of an inner square ring 2-2 in the square-ring capacitive loading radiation unit 2 introduced with the double-bent resonant ring, the lower short-circuit probe 3 and the upper short-circuit probe 4 are symmetrical about a transverse axis of the antenna dielectric substrate 1, the lower short-circuit probe 3 and the upper short-circuit probe 4 are increased to form a standing wave structure, and the size of the antenna is further reduced; the coaxial connector 5 is positioned on the right side of an inner square ring 2-2 in the square annular capacitive loading radiation unit 2 introduced with the double-bending resonance ring and positioned on a transverse symmetrical axis of the dielectric substrate 1, an inner core of the coaxial connector 5 is connected with the inner square ring 2-2 in the square annular capacitive loading radiation unit 2 introduced with the double-bending resonance ring, and an outer core of the coaxial connector 5 is connected with the floor 6; the floor 6 is a square complete metal patch structure, and can form a shielding layer to isolate the electronic device of the wireless biomedical device from the implanted circularly polarized antenna, reduce the interference of the antenna on other electronic devices, and improve the electromagnetic compatibility.
the length L of the dielectric substrate 1 is 8 mm-10 mm, and the width W is 8 mm-10 mm.
The distance W between the square ring capacitive loading radiating element 2 with the double-bending resonant ring and the edge of the dielectric substrate 1 10.2 mm-0.3 mm, the square ring capacitive loading radiation unit 2 introduced with the double-bending resonance ring consists of an outer square ring 2-1, an inner square ring 2-2 and a double-bending resonance ring 2-3, and the outer side length of the outer square ring 2-1 is W 38.4 mm-8.6 mm, side length W of the inner side 137.8 mm-8 mm, the outer side length of the inner square ring 2-1 is W 126.2 mm-6.4 mm, side length W of the inner side 114.4 mm-4.6 mm, the distance L between the outer square ring 2-1 and the inner square ring 2-2 20.7 mm-0.9 mm, the left interdigital capacitor 2-4, the upper interdigital capacitor 2-5, the right interdigital capacitor 2-6 and the upper and lower branch length L in the lower interdigital capacitor 2-7 are increased by the outer square ring 2-1 and the inner square ring 2-2 10.6 mm-0.7 mm, width W 20.1 mm-0.2 mm, and the width W of the space between the upper branch knot and the lower branch knot 40.1 mm-0.2 mm, the double-bending resonance ring 2-3 is connected with the inner square ring 2-2 through a rectangular conduction band with width W of the rectangular conduction band 50.2 mm-0.4 mm long L30.2 mm-0.4 mm, length L of single bending resonance ring 71.7 mm-1.8 mm, width W 63.8 mm-4 mm, and the ring width W of the single bending resonance ring 70.2 mm-0.4 mm, the width W of the branch connected with the U-shaped branch 100.9 mm-1.1 mm, length L 80.3 mm-0.4 mm, and the left branch length L of the U-shaped branch 50.8 mm-0.9 mm, the length of the right branch 60.9 mm-1.1 mm, upper branch length W 90.9 mm-1.1 mm, and the width W of the U-shaped branch 140.3 mm-0.4 mm, and the length L of the rectangular branch is increased in the middle of the split 41.1 mm-1.3 mm, width W 8Is 0.1 mm-0.3 mm.
The radius R of the lower short-circuit probe 3 and the upper short-circuit probe 4 10.2 mm-0.4 mm, and the distance R between the centers of the lower short-circuit probe 3 and the upper short-circuit probe 4 and the center of the dielectric substrate 1 23.5 mm-3.9 mm, and the included angles a between the lower short-circuit probe 3 and the upper short-circuit probe 4 and the longitudinal symmetry axis of the dielectric substrate 1 1The radius of the lower short-circuit probe 3 and the radius of the upper short-circuit probe 4 are equal to the radius of the inner core of the coaxial connector 5, and the radius is 42-47 degrees.
The distance W between the center of the coaxial connector 5 and the center of the dielectric substrate 1 0Is 2.5 mm-2.9 mm.
the floor 6 is a complete square metal patch, the size of the floor 6 is the same as that of the medium substrate 1, L is 8 mm-10 mm, and W is 8 mm-10 mm in width.
The square-ring capacitive loading implanted circular polarized antenna with the double-bending resonant ring introduced is coated with a layer of ultrathin biocompatible film alumina on the outer surface, has small influence on the reflection coefficient and the antenna gain, is close to the dielectric constant of the dielectric substrate 1, and has the dielectric constant r9.2, loss tangent tan of 0.008 and coating thickness of 0.03mm, and isolates the implanted circular polarization from human tissue of the antenna, thereby preventing the conductive patch of the antenna from directly contacting with the human tissue and reducing the influence of the human tissue on the performance of the implanted circular polarization antenna.
Example (b): the specific manufacturing process is as described in the embodiment. Selecting Rogers RO3210 dielectric substrate with dielectric constant r10.2, loss tangent tan 0.003, thickness H0.635 mm, coaxial joint the length L of the dielectric substrate is 9mm, the width W of the dielectric substrate is 9mm, the outer square ring 2-1 can excite an additional mode close to the resonant frequency of the main mode by utilizing the electromagnetic coupling effect, so that the impedance bandwidth of the antenna is widened, the interdigital capacitor is added between the outer square ring 2-1 and the inner square ring 2-2, the capacitive loading characteristic is generated, the size of the implanted antenna is reduced, the miniaturization of the antenna is realized, and the distance W between the square ring capacitive loading radiation unit 2 of the double-bent resonant ring and the edge of the dielectric substrate 1 is introduced 10.25mm, the square ring capacitive loading radiation unit 2 introduced with the double-bending resonance ring consists of an outer square ring 2-1, an inner square ring 2-2 and a double-bending resonance ring 2-3, and the outer side length of the outer square ring 2-1 is W 38.5mm, inner side length W 137.9mm, the outer side length of the inner square ring 2-1 is W 126.3mm, inner side length W 11is 4.5mm, and the distance L between the outer square ring 2-1 and the inner square ring 2-2 20.8mm, the left interdigital capacitor 2-4, the upper interdigital capacitor 2-5, the right interdigital capacitor 2-6 and the upper and lower branch length L in the lower interdigital capacitor 2-7 are added by the outer square ring 2-1 and the inner square ring 2-2 1Is 0.66mm, width W 20.14mm, and the width W of the space between the upper branch and the lower branch 4Is 0.14 mm. The circular polarizer with the array layout formed by the double-bending resonant rings 2-3 is more compact in structure, can concentrate stronger electromagnetic energy and can excite two degenerate orthogonal modes with equal amplitudes and 90-degree phase difference, so that circular polarization radiation is realized, the double-bending resonant rings 2-3 are connected with the inner square ring 2-2 through the rectangular conduction band, and the width W of the rectangular conduction band is larger 5is 0.3mm and has a length L 30.3mm, length L of single bending resonance ring 7Is 1.75mm and has a width W 63.9mm, ring width W of single bending resonance ring 70.3mm, a branch width W of the branch connected with the U-shaped branch 101.02mm, length L 80.32mm, the left branch length L of the U-shaped branch 50.85mm, the length of the right branch is L 61.05mm, upper branch length W 90.96mm, the width of the U-shaped branch 140.32mm, and the length L of the rectangular branch section is increased in the middle of the gap 4Is 1.2mm, width W 80.2mm, a rectangular branch with increased gap is formed in the middle of the U-shaped branch, and the implanted type can be adjusted and enhanced The circular polarization purity of the antenna. The addition of the short-circuit probe can form a standing wave structure, further reduce the size of the antenna, and the radius R of the lower short-circuit probe 3 and the upper short-circuit probe 4 10.3mm, and the distance R between the centers of the lower short-circuit probe 3 and the upper short-circuit probe 4 and the center of the dielectric substrate 1 23.7mm, and the included angles a between the lower short-circuit probe 3 and the upper short-circuit probe 4 and the longitudinal symmetry axis of the dielectric substrate 1 1The radius of the lower short-circuit probe 3 and the radius of the upper short-circuit probe 4 are equal to the radius of the inner core of the coaxial connector 5 at 45 degrees. The distance W between the center of the coaxial connector 5 and the center of the dielectric substrate 1 0the thickness of the floor 6 is 2.7mm, the floor is a square complete metal patch structure, a shielding layer can be formed, the electronic device of the wireless biomedical device and the implanted circularly polarized antenna are isolated, the interference of the antenna on other electronic devices is reduced, the electromagnetic compatibility is improved, the size of the floor 6 is the same as that of the medium substrate 1, L is 9mm, the width W is 9mm, the outer surface of the square annular capacitive loading implanted circularly polarized antenna introduced with the double-bending resonant ring is plated with a layer of ultrathin biocompatible thin film alumina, the influences on the reflection coefficient and the antenna gain are small, the dielectric constant is close to that of the medium substrate 1, and the dielectric constant is approximate to that of the medium substrate 1 r9.2, loss tangent tan of 0.008 and coating thickness of 0.03mm, and isolates the implanted circular polarization from human tissue of the antenna, thereby preventing the conductive patch of the antenna from directly contacting with the human tissue and reducing the influence of the human tissue on the performance of the implanted circular polarization antenna.
Analyzing the influence on the impedance bandwidth and the axial ratio bandwidth of the antenna before and after capacitive loading is introduced between the outer square ring and the inner square ring is shown in fig. 4, and it can be seen from the figure that the resonant frequency of the antenna is shifted to the low frequency direction by introducing the capacitive loading, the resonance degree is not changed greatly, the influence on the impedance bandwidth and the axial ratio bandwidth is small, the axial ratio performance optimum point is shifted accordingly, the size of the antenna before and after the capacitive loading is increased is reduced by 68%, which shows that the interdigital capacitance is increased between the outer square ring and the inner square ring, the capacitive loading characteristic is generated, the size of the implanted antenna is reduced, and the miniaturization of the antenna is realized.
the method comprises the steps of selecting a gap formed in the middle of a U-shaped branch to increase the length L of the rectangular branch 4Width W of 8Analysis of antenna impedance the effects of Bandwidth and axial ratio Bandwidth are shown in FIG. 5, with L being selected respectively 4＝1.1mm、W8＝0.1mm、L4＝1.2mm、W80.2mm and L 4＝1.3mm、 W8The performance of the antenna is analyzed under three conditions of 0.3mm, and as can be seen from fig. 5, the resonant frequency of the antenna slightly shifts towards the high-frequency direction, the resonant degree increases and then decreases, the lowest value of the axial ratio performance decreases and then increases, and the point with the optimal axial ratio performance shifts, which indicates that the impedance matching and the circular polarization purity of the antenna are improved, because the rectangular branch with increased gap is formed in the middle of the U-shaped branch, and the circular polarization purity of the implanted antenna can be adjusted and enhanced.
the utility model discloses an implanted circular polarized antenna mainly uses the environment for the skin layer, the simulation environment is 100mm × 28 mm's individual layer skin model, arrange the antenna in individual layer skin model center, the implantation depth of antenna is H, it is shown in figure 6 to implant skin layer degree of depth schematic diagram, different implantation depth H is shown in figure 7 to the influence of antenna impedance bandwidth and axial ratio bandwidth, the initial value of implantation depth is 4mm, when implantation depth H changes 2mm, implanted circular polarized antenna impedance bandwidth and axial ratio bandwidth still can cover required ISM 2.4GHz ~ 2.48GHz frequency channel, it has higher stability to explain implanted circular polarized antenna.
The implanted circularly polarized antenna is placed in a solution simulating human skin for testing, wherein the skin solution comprises 36.7% of polyethylene glycol octyl phenyl ether, 5.1% of diethylene glycol monobutyl ether and 58.2% of deionized water. The impedance bandwidth of an implanted circularly polarized antenna is tested by using a network vector analyzer, the circular polarization characteristic of the antenna is tested in an indirect mode of matching an external linearly polarized dipole antenna, the simulation result and the test result of the impedance bandwidth and the axial ratio bandwidth are shown in fig. 8, the simulation impedance bandwidth of the implanted circularly polarized antenna is 2.18 GHz-2.82 GHz, the resonance frequency point in a frequency band is 2.45GHz, the simulation axial ratio bandwidth is 2.29 GHz-2.59 GHz, the actually measured impedance bandwidth is 2.15 GHz-2.78 GHz, the resonance frequency point in the frequency band is 2.43GHz, the actually measured axial ratio bandwidth is 2.26 GHz-2.52 GHz, the impedance bandwidth and the axial ratio bandwidth can cover the required working frequency, the resonance degree is increased to a certain extent, the test result and the simulation result are basically consistent, good resonance can be realized in the frequency band of 2.4 GHz-2.48 GHz, the resonance frequency and the axial ratio coefficient are slightly shifted to the low frequency direction, and the reasons for frequency shift of the implanted circularly polarized antenna are mainly ISM (industrial, The influence of the existence of bubbles on the antenna test and the simulation test environment dielectric constant are different between the simulated human body tissue and the simulated human body tissue.
E-plane and H-plane radiation patterns of the implanted circularly polarized antenna at a frequency point of 2.45GHz are tested, the radiation characteristics of the antenna are checked, and the actually measured patterns are shown in figures 9 and 10. The radiation pattern shows that the antenna has better directivity, the maximum radiation direction of the implanted circularly polarized antenna is along the Z-axis direction, namely towards the outer side of a human body, the main polarization is right-hand circular polarization, the maximum value of the actual gain along the Z-axis direction is-17.5 dBi, the difference between the main polarization and the cross polarization is 29.6dBi, the circularly polarizer mainly formed by the double-bent resonant rings in an array layout has a more compact structure, stronger electromagnetic energy can be concentrated, two degenerate orthogonal modes with equal amplitudes and 90-degree phase difference can be excited, so that the circularly polarized radiation is realized, the implanted circularly polarized antenna has wider axial ratio wave beams in a working frequency band, and the radiation characteristic is better.
In order to meet the safety requirement of the implanted circular polarized antenna after the antenna is implanted into human tissue, the safety of the implanted circular polarized antenna is comprehensively analyzed, the input power of the implanted circular polarized antenna is set to be 1W, the safety range of the human model for absorbing energy is evaluated by utilizing an average SAR value, through simulation calculation, the maximum average SAR value of the implanted circular polarized antenna at 2.45GHz when the human tissue is 1g is 235.8W/kg, the maximum average SAR value of the implanted circular polarized antenna at 10g is 51.3W/kg, in order to meet the safety standards of IEEEC95.1-1999 and IEEEC95.1-2005 on the SAR value, the maximum input power corresponding to the implanted circular polarized antenna is 8.7mW and 46.8mW respectively, and the implanted circular polarized antenna meets the requirement that the electromagnetic radiation under the conditions is safe and harmless to the human tissue.
Claims (4)
1. Introduce square ring shape capacitive loading implantation formula circular polarized antenna of two resonance rings of buckling, by dielectric substrate (1), introduce square ring shape capacitive loading radiating element (2) of two resonance rings of buckling, downside short circuit probe (3), upside short circuit probe (4), coaxial joint (5), floor (6) constitute, its characterized in that:
a. The square ring capacitive loading radiation unit (2) with the double-bending resonance ring introduced consists of an outer square ring (2-1), an inner square ring (2-2) and a double-bending resonance ring (2-3), wherein a left interdigital capacitor (2-4), an upper interdigital capacitor (2-5), a right interdigital capacitor (2-6) and a lower interdigital capacitor (2-7) are added between four radiation edges of the outer square ring (2-1) and the inner square ring (2-2), the double-bending resonance ring (2-3) is loaded in the inner square ring (2-2), the double-bending resonance ring (2-3) forms a circular polarizer structure with an array layout, a single bending resonance ring is formed by bending a square ring by half, the inner part of the bending resonance ring is disconnected and two U-shaped branches are symmetrically placed, a gap is formed between the two U-shaped branches, an E-shaped groove is formed inside the single bending resonance ring, a rectangular branch is added in the middle of the gap and is connected with the upper edge of the E-shaped groove, the double bending resonance ring (2-3) is connected with the inner side square ring (2-2) through a rectangular conduction band, and the two single bending resonance rings are symmetrical about the transverse symmetry axis of the dielectric substrate (1);
b. The lower short-circuit probe (3) and the upper short-circuit probe (4) are arranged at the lower left corner and the upper left corner of an inner square ring (2-2) in a square-ring capacitive loading radiation unit (2) with a double-bent resonance ring introduced, and the lower short-circuit probe (3) and the upper short-circuit probe (4) are symmetrical about the transverse axis of the antenna dielectric substrate (1);
c. The coaxial connector (5) is positioned on the right side of an inner square ring (2-2) in the square-ring-shaped capacitive loading radiation unit (2) for introducing the double-bending resonance ring and positioned on a transverse symmetrical axis of the dielectric substrate (1), an inner core of the coaxial connector (5) is connected with the inner square ring (2-2) in the square-ring-shaped capacitive loading radiation unit (2) for introducing the double-bending resonance ring, and an outer core of the coaxial connector (5) is connected with the floor (6);
d. The floor (6) is of a square complete metal patch structure, forms a shielding layer and isolates the electronic device of the wireless biomedical device from the implanted circularly polarized antenna.
2. the square-ring-shaped capacitive-loading implantable circularly polarized antenna with the double-bent resonant ring introduced according to claim 1, wherein the length L of the dielectric substrate (1) is 8 mm-10 mm, and the width W of the dielectric substrate is 8 mm-10 mm.
3. the square-ring capacitive-loading implanted circularly polarized antenna with the double-bent resonant ring introduced into the claim 1 is characterized in that the floor (6) is a complete square metal patch, the size of the floor (6) is the same as that of the dielectric substrate (1), L is 8 mm-10 mm, and W is 8 mm-10 mm.
4. The square-ring capacitive loading implantable circular polarized antenna with the double-bending resonant ring introduced according to claim 1, wherein the outer surface of the square-ring capacitive loading implantable circular polarized antenna with the double-bending resonant ring is coated with a layer of ultrathin biocompatible thin film alumina, which has small influence on reflection coefficient and antenna gain, and is close to the dielectric constant of the dielectric substrate (1) and has a dielectric constant close to that of the dielectric substrate (1) r9.2, loss tangent tan of 0.008, coating thickness of 0.03mm, and isolation of implanted circular polarization from antenna human tissue.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201922444197.9U CN211088504U (en) | 2019-12-30 | 2019-12-30 | Square-ring-shaped capacitive loading implantation type circularly polarized antenna with double-bending resonant ring |
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| CN201922444197.9U CN211088504U (en) | 2019-12-30 | 2019-12-30 | Square-ring-shaped capacitive loading implantation type circularly polarized antenna with double-bending resonant ring |
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| CN211088504U true CN211088504U (en) | 2020-07-24 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114639963A (en) * | 2022-04-06 | 2022-06-17 | 合肥若森智能科技有限公司 | Multi-band dual-circular-polarization omnidirectional antenna |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114639963A (en) * | 2022-04-06 | 2022-06-17 | 合肥若森智能科技有限公司 | Multi-band dual-circular-polarization omnidirectional antenna |
| CN114639963B (en) * | 2022-04-06 | 2024-03-29 | 合肥若森智能科技有限公司 | Multi-band double circular polarization omnidirectional antenna |
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