KR20230055423A - Self-diplexing antenna and implantable device comprising the same - Google Patents

Abstract

A self-diplexing antenna according to the present embodiment includes: two semicircular radiating patches including open slots of different lengths and spaced apart from each other on the same plane; a ground plane including symmetrical pattern slots; a dielectric layer positioned between the semicircular radiating patches and the ground plane; a connection pin adjacent to an inner circumferential surface of the semicircular radiating patches and connecting each of the semicircular radiating patches to the ground plane. Ports feeds the two semicircular radiating patches at different frequencies. Therefore, it is possible to provide a self-diplexing antenna with small volume and low power consumption.

Description

Self-diplexing antenna and implantable device including the same {SELF-DIPLEXING ANTENNA AND IMPLANTABLE DEVICE COMPRISING THE SAME}

The present technology relates to self-diplexing antennas and implantable devices incorporating the same.

Implantable medical devices (IMDs) have emerged as an important part of biomedical engineering because they can monitor damaged organs. Modern implantable devices are mainly used for applications such as intracranial pressure monitoring, intraoral tongue drive systems, cardiac pacemakers, glucose monitoring and wireless capsule endoscopy. Implantable devices are manufactured to receive and transmit biosignals from damaged, non-irradiated body parts. Implantable devices include various types of electronics (batteries, sensors, printed circuit boards (PCBs) with surface mount devices (SMDs) and micro cameras) and RF components (rectifiers and antennas).

Traditionally, electrochemical energy sources (batteries) and direct current (DC) power through wires have been common sources of power for implantable devices. The operating lifetime and size of an implantable device depended entirely on the battery. Despite the challenges of using batteries, battery use increases the temperature and overall dimensions of implantable devices, and patients may have to undergo unwanted surgery to replace worn-out batteries, resulting in implantable devices with DC wires. Driving the device can cause infection aches and pains in damaged human organs. In order to overcome these disadvantages, wireless power transfer is recently recommended to smoothly and safely drive an implantable device.

Wireless power transfer technology is an approach to charging and powering electronic components for a wide range of applications, including biomedical engineering. Other technologies, such as implantable devices via magnetic resonance, short-range inductive coupling and capacitive coupling, are also used to drive electronic components in implantable devices, such as spinal cord stimulators (SCS), prosthetics and prosthetics. Adopted in WoW. However, these technologies have some problems, such as small transmission distance, large receiver (Rx) coil, and power leakage, and the power transfer efficiency (PTE) of these technologies depends on the size of the transmitter (Tx) and Rx coils and their It depends on the separation and misalignment between them. However, more recently it has been designed to address the misalignment between the multi-coil Tx and Rx coils.

Current wireless power transfer technologies include transmission of electromagnetic (EM) free space radiation, and midfield wireless power transfer technologies for driving implantable devices located deep inside the body are also being studied. Advantages of electromagnetic wave propagation over wireless power transfer technology include a wide range of distances inside human tissue. However, existing field sources such as antennas cannot provide suitable patterns for wireless power transfer technology because they lack phase control.

High-performance implantable antennas play an important role in data transmission. These implantable antennas are often integrated with rectifiers to drive the electronic components of implantable devices. Several studies on implantable antennas for various applications have been reported.

However, since the prior art simultaneously transmits and receives data in all bands, an external multiplexer is required to independently transmit and receive data in all bands through a single antenna. It is obvious that the same antenna cannot operate in dual mode (transmit antenna for data transmission and receive antenna for wireless power supply).

Dual-mode operation requires highly isolated multiplexer circuitry, which increases device volume, and multiplexer circuitry increases the complexity and size of implantable devices. Additionally, additional multiplexer circuitry consumes power, which affects the overall performance (transmission efficiency and battery life) of the implantable device. Also, it is very difficult to manage different power levels in different bands through one antenna.

The present technology is intended to solve the above-described difficulties of the prior art, and provides an implantable device having a small volume and low power consumption and an antenna capable of self-diplexing.

A self-diplexing antenna according to the present embodiment includes two semicircular radiating patches including open slots of different lengths and spaced apart from each other on the same plane; a ground plane comprising symmetrical pattern slots; a dielectric layer positioned between the semicircular radiating patches and the ground plane; and a connecting pin adjacent to an inner circumferential surface of the semicircular radiating patches to connect each of the semicircular radiating patches to the ground plane, and includes ports feeding the two semicircular radiating patches at different frequencies.

According to one aspect of this embodiment, the open slots are formed in an arc shape from which the semicircular radiating patch is removed, and a finger connected to the semicircular radiating patch is formed inside at least one of the open slots.

According to one aspect of this embodiment, the ports are disposed asymmetrically, and are connected to the semicircular radiating patch and the ground plane.

According to one aspect of the present embodiment, the symmetrical pattern slot is a pattern formed by removing the ground plane based on a central axis formed in a longitudinal direction, and is disposed biasedly in one direction of the two semicircular radiating patches.

According to one aspect of this embodiment, the symmetric pattern slots improve the isolation of the semicircular radiating patch.

An implantable device according to the present embodiment includes: a housing; Two semicircular radiating patches each including open slots of different lengths and spaced apart from each other located on the same plane, and a ground plane including a symmetric pattern slot located on a different plane from the semicircular radiating patches a self-diplexing antenna; a rectifier including a rectifier circuit and a matching network including a second L-section including a series inductor, a shunt inductor, and a shorting stub; A sensor that collects biometric information in the body; and a battery charged with the power provided by the rectifier and providing power to the implantable device.

According to one aspect of this embodiment, the housing is any one of a capsule type housing and a flat type housing.

According to one aspect of this embodiment, the implantable device further includes a circuit unit for processing the body biometric information collected by the sensor.

According to one aspect of this embodiment, the rectification circuit unit includes a diode for direct current rectifying the RF energy provided by the antenna, and a capacitor for filtering power provided to a load.

According to the present embodiment, since a self-diplexable antenna is used, a multiplexing circuit is not required, and power consumption of the implantable device can be reduced and the volume of the implantable device can be reduced.

1(a) is a diagram showing a planar layout of a self-diplexing antenna 10, and FIG. 1(b) is a diagram showing a rear layout of a self-duplexing antenna 10, FIG. 1(c) is a diagram showing the side layout of the self-duplexing antenna 10.
2 is a diagram showing an example of simulating an electric field (E-field) distribution in the self-diplexing antenna 10 according to the present embodiment.
3(a) is a schematic layout diagram of the rectifier according to this embodiment, and FIG. 3(b) is a schematic equivalent circuit diagram of the rectifier according to this embodiment.
4(a) is a diagram showing an experimental setup of the rectifier of this embodiment. FIG. 4(b) is a diagram showing the result of a simulation experiment, the experimental result, and the reflection coefficient S11 of the RF-DC conversion efficiency as a function of the input power of the rectifier according to the present embodiment.
5 is an exploded perspective view showing the outline of a deep tissue implantation type implantable device 1 in the body.
6 is an exploded perspective view illustrating a flat type implantable device.

Hereinafter, this embodiment will be described with reference to the accompanying drawings.

self-diplexing antenna

1(a) is a diagram showing a planar layout of a self-diplexing antenna 10, and FIG. 1(b) is a diagram showing a rear layout of a self-duplexing antenna 10, FIG. 1(c) is a diagram showing the side layout of the self-duplexing antenna 10.

Referring to FIG. 1, the self-diplexing antenna 10 according to this embodiment includes open slots 130 and 140 having different lengths, respectively, and two semicircular radiating patches positioned on the same plane and spaced apart from each other. fields 110 and 120, a ground plane 200 including a symmetrical pattern slot 210, a dielectric layer positioned between the semicircular radiation patches 110 and 120 and the ground plane 120, and the semicircular radiation patches A connection pin adjacent to the inner circumferential surface of (110, 120) connecting each of the semicircular radiating patches and the ground plane, and feeding the two semicircular radiating patches (110, 120) at different frequencies, respectively. (feeding) includes ports (port1, port2).

The two radiating patches are closely spaced with an edge-to-edge distance of 0.0038λg1, where λg1 is the guided wavelength in the lower frequency band. Both radiation patches are fed by 50 ohm coaxial cable, and Rogers RO 3010 (tan δ = 0.0022) is used as the substrate (sb) and superstrate (sp) for the two radiation patches. In one embodiment, the substrate and super straight may be a 0.13 mm and high permittivity (er = 10.2) material.

Referring to FIGS. 1(a) to 1(c), the self-diplexing antenna 10 according to the present embodiment has semicircular radiation patches 110 located on the upper surface and located on the inner circumference of the radiation patches. It includes a shorting pin 120 and open arc slots 130 and 140 formed in each of the radiation patches 110.

In one embodiment, the semicircular patches 110 and 120 are disposed asymmetrically from each other, and ports (port1, port2) connected to the substrate and the super straight are positioned, and the ports are asymmetrically excited by a 50 ohm coaxial probe.

In addition, a shorting pin is positioned on the inner circumferential surface of the semicircular patches 110, and the shorting pin is electrically connected to the substrate sb and the super straight sp, and lowers the operating band of the radiating patch. For example, the radiating patch resonated at approximately 5 GHz when there was no shorting pin, but resonated at 2.5 GHz when only shorting pins were formed. Furthermore, the radiating patch had an isolation of about 12.3 dB when there was no shorting pin, but when a shorting pin was formed, an isolation of 14.8 dB was achieved, increasing the isolation by about 2.5 dB. could get

Open slots 130 and 140 are located at the center of each semicircular patch 110 . In one embodiment, the open slots 130 and 140 may be formed by etching a radiating patch, and the open slots 130 and 140 may have an arc shape, and any one or more of the open slots 130 and 140 may be formed in an arc shape. A finger (F) may be formed therein. The open slot and the finger F formed therein may induce an additional capacitance effect to lower the resonant frequency. The effect of the additional capacitance on the resonant frequency of the antenna can be understood based on the slow wave phenomenon.

The series combination of inductance (Lo) and capacitance (Co) is analogous to the equivalent circuit of an antenna analogous to an ideal transmission line. In addition, the equation below shows the relationship between the propagation speed and the reactance (inductance and capacitance) of the antenna. It can be seen that the propagation speed (vp) is inversely proportional to the reactance. The arc-shaped rectangular slot induces a capacitive effect, increasing the capacitance value, so that a lower resonant frequency can be obtained when the propagation speed decreases and the guided wavelength is constant.

(vp: propagation velocity, Lo: total inductance, Co: total capacitance, c: speed of light in vacuum, λg: induced wavelength, f _res : resonance frequency)

Referring to Figure 1 (b), a symmetrical pattern slot 210 is formed on the ground plane. By forming the symmetrical pattern slots 210 in the ground plane 200, the separation between the semicircular radiating patch 110 and the semicircular radiating patch 120 is improved. In one embodiment, the symmetrical pattern slots 210 may be formed by etching the conductor forming the ground plane 200 in a symmetrical shape around the axis A. In addition, the symmetric pattern slots 210 may be positioned biased in either direction of the semicircular radiation patch 110 or the semicircular radiation patch 120 .

The maximum separation obtained when the symmetrical pattern slot 210 was not formed on the ground plane 200 was 16dB, but the separation between the semicircular radiating patch 110 and the semicircular radiating patch 120 by forming the symmetrical pattern slot 210 improved by more than 21 dB. Accordingly, it can be seen from the isolation characteristics that the semicircular patch 110 and the semicircular patch 120 function as self-diplexing antennas by operating with high isolation in different frequency bands.

2 is a diagram showing an example of simulating an electric field (E-field) distribution in the self-diplexing antenna 10 according to the present embodiment. In FIG. 2 (a), when power is supplied through port 1 (port 1), it can be seen that the self-diplexing antenna 10 resonates at a resonance frequency of 915 MHz in the semicircular radiating patch 110. Referring to FIG. 2 (b), when power is supplied through port 2, it can be confirmed that the semicircular radiating patch 120 of the self-diplexing antenna 10 resonates at a resonance frequency of 1470 MHz.

From FIGS. 2 (a) and 2 (b), it can be seen that the self-diplexing antenna 10 has a radiation pattern similar to that of the omni-directional antenna at both 915 MHz and 1470 MHz frequencies, from which radio waves are received from transmitters around the patient. It can be seen that radio waves can be transmitted to a receiver around the patient. Furthermore, it can be seen that power can be received in all directions without being affected by misalignment.

rectifier

3(a) is a schematic layout diagram of the rectifier according to this embodiment, and FIG. 3(b) is a schematic equivalent circuit diagram of the rectifier according to this embodiment. 3(a) and 3(b), a rectifier 20 according to this embodiment includes a matching network 300 and a rectifier circuit 400, and converts energy transmitted to RF into DC energy. convert to The rectifier 20 according to the present embodiment provides power capable of driving or charging an electronic component using the power provided to the implantable device (see FIGS. 1, 2, and 5 and 6). The rectifier circuit according to this embodiment was designed at Keysight ADS.

The rectifier 20 according to this embodiment includes a matching network 300 and a rectifier circuit 400 connected to each other in a cascade. The matching network 300 includes a second-order L-section matching network including a series inductor L1 and a shunt inductor L2, and RF energy is input from the self-diplexing antenna 10 according to the present embodiment. . Matching between the input source and the rectifier circuit is done through a series inductor (L1) and a short-circuited stub. The shunt inductor (L2) is disposed on the direct current (DC) return path.

In one embodiment, the diode may be a diode having low junction capacitance and low sensitive voltage and fast switching characteristics. For example, the diode may be a HSMS-2852. The shunt capacitor (C) operates as an output filter, and the operating frequency can be adjusted by adjusting the capacitance of the capacitor (C).

Optimization of the rectifier according to this embodiment was performed so that maximum power is delivered to the rectifier circuit by minimizing return loss and improving RF-DC conversion efficiency. Each parameter, including the microstrip's trace and lumped element values, was adjusted to deliver maximum power.

4(a) is a diagram showing an experimental setup of the rectifier of this embodiment. Referring to FIG. 4(a), the rectifier according to the present embodiment is disposed in an implantable device connected to an antenna, and the implantable device is disposed deep inside minced pork. Different values of input power were generated through the RF signal generator and the output was analyzed through the DMM. FIG. 4(b) is a diagram showing the result of a simulation experiment, the experimental result, and the reflection coefficient S11 of the RF-DC conversion efficiency as a function of the input power of the rectifier according to the present embodiment. Referring to FIG. 4(b), the rectifier according to this embodiment has sufficient impedance matching over a wide range of input power. It can be seen that the reflection curve is lower than -10dB for input power ranging from -28 to 5dBm. In addition, in order to measure the RF-DC conversion efficiency of the rectifier circuit for input power, the input port of the rectifier was connected to a signal generator and the output was connected to a digital multimeter (DMM). As shown, it is confirmed that the simulation result and the measurement result coincide, and it can be confirmed that the RF-DC conversion efficiency is 50% or more in the input power range of -14 to 5 dBm.

The rectifier according to this embodiment has a 50% efficiency even at a low input power of -14dBm and a peak efficiency of 76.1% at 2dBm. With low input power and high RF-DC conversion efficiency of 50% or more at −14 to 5 dBm, the rectifier according to the present embodiment is sufficient for use in low-power communication devices such as implantable devices.

implantable device

Hereinafter, embodiments of implantable devices 1 and 2 will be described with reference to FIGS. 5 and 6 . 5 is an exploded perspective view showing the outline of a deep tissue implantation type implantable device 1, and FIG. 6 is an exploded perspective view showing a flat type implantable device. Referring to FIG. 5, the tissue-implantable implantable device 1 according to this embodiment includes a self-diplexing antenna 10 according to this embodiment, and a rectifier 20 that receives power from the antenna and converts it into DC power. , wherein the self-diplexing antenna 10 and rectifier 20 are housed within the capsule 32 .

Referring to FIG. 6, the tissue-implantable implantable device 2 according to this embodiment includes a self-diplexing antenna 10 according to this embodiment, and a rectifier 20 receiving power from the antenna and converting it into DC power. It is housed in a flat container 34.

5 and 6, the implantable devices 1 and 2 according to the present embodiment include a battery 40 charged by DC power provided by a rectifier 20 and providing power to internal circuitry. And, the sensor 50 disposed in the body to receive biometric information, and the circuit unit 60 to process the information collected by the sensor 40 may be further included.

As described above, the self-diplexing antenna 10 operates in radio waves of two bands, and has high isolation, enabling diplexing, from which wireless power transmission and biometric information are possible. The advantage of being able to transmit and receive simultaneously is provided.

In addition, the implantable devices 1 and 2 include the rectifier 20 described above. As described above, the rectifier according to the present embodiment has a conversion efficiency of 50% or more even at low input power, and furthermore, since the self-diplexing antenna 10 has a non-directional characteristic as described above, it is implanted in the body. Even if the possible devices and power transmitters are not strictly arranged, good wireless power transmission and reception is possible, providing high convenience.

Although it has been described with reference to the embodiments shown in the drawings to aid understanding of the present invention, this is an embodiment for implementation and is only exemplary, and those having ordinary knowledge in the field can make various modifications and equivalents therefrom. It will be appreciated that other embodiments are possible. Therefore, the true technical scope of protection of the present invention will be defined by the appended claims.

1, 2: implantable device 10: self-diplexing antenna
20: rectifier 32, 34: housing
40: battery 50: sensor
60: circuit part 110, 120: semicircular radiating patch
130, 140: open slot 200: ground plane
210: symmetric pattern slot 300: matching network
400: rectification circuit

Claims (9)

two semicircular radiating patches, each including open slots of different lengths, located on the same plane and spaced apart from each other;
a ground plane comprising symmetrical pattern slots;
a dielectric layer positioned between the semicircular radiating patches and the ground plane;
A connection pin adjacent to an inner circumferential surface of the semicircular radiating patches and connecting each of the semicircular radiating patches to the ground plane;
A self-diplexing antenna including ports for feeding the two semicircular radiating patches at different frequencies, respectively. According to claim 1,
The open slots are formed in an arc shape from which the semicircular radiating patch is removed,
A self-diplexing antenna having a finger connected to the semicircular radiating patch formed inside at least one of the open slots. According to claim 1,
The ports are arranged asymmetrically from each other,
A self-diplexing antenna connected to the semicircular radiating patch and the ground plane. According to claim 1,
The symmetric pattern slot is
A pattern formed by removing the ground plane based on a central axis formed in the longitudinal direction,
A self-diplexing antenna disposed biasedly in one of the two semicircular radiating patches. According to claim 1,
The symmetric pattern slot is
A self diplexing antenna for improving the isolation of the semicircular radiating patch. An implantable device, the implantable device comprising:
housing;
Two semicircular radiating patches each including open slots of different lengths and spaced apart from each other located on the same plane, and a ground plane including a symmetric pattern slot located on a different plane from the semicircular radiating patches a self-diplexing antenna;
a rectifier including a rectifier circuit and a matching network including a second L-section including a series inductor, a shunt inductor, and a shorting stub;
A sensor that collects biometric information in the body;
and a battery charged with the power provided by the rectifier and providing power to the implantable device. According to claim 6,
the housing
An implantable device that is any one of a capsule type housing and a flat type housing. According to claim 6,
The implantable device is
The implantable device further includes a circuit unit that processes the biometric information collected by the sensor. According to claim 6,
The rectifying circuit part
A diode for rectifying the RF energy provided by the antenna into direct current;
An implantable device that includes a capacitor that filters power provided to a load.

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