TW202322469A - Antenna device including a resonant structure for improving performance - Google Patents

Abstract

An antenna device includes a first coil, a second coil and a resonant circuit. The first coil includes a first terminal and a second terminal electrically connected to a processing circuit, where the first terminal is used to receive a first signal, and the second terminal is used to transmit a second signal. A first current flows on the first coil in a first direction. The second coil includes a first terminal and a second terminal. A second current flows on the second coil in a second direction. The resonant circuit is electrically connected between the first terminal and the second terminal of the second coil, and corresponding to a resonant frequency. The first coil is insulated from the second coil. In a coupling range of the first coil and the second coil, the directions of the first current and the second current are opposite to one another.

Description

Antenna device including resonant structure to improve performance

The present invention relates to an antenna device, especially an antenna device including a resonant structure to improve performance.

In the field of antenna-related engineering, the loop antenna (loop antenna) is a common type of antenna. Loop antennas may include coil structures for transmitting and receiving wireless signals. In various scenarios, the application of the loop antenna can be seen. For example, in a near field communication (near field communication, NFC) device, the loop antenna can be set to send and receive signals.

Although the above-mentioned loop antennas are available, there are still difficult problems in practice. When a loop antenna is used, the field strength of the antenna is often attenuated near the central position, resulting in poor performance of signal transmission and reception. In addition, if the shape of the loop antenna has a concave part due to hardware limitations, the antenna field strength is often insufficient in the concave part, and it is difficult to lose the sending and receiving signal. In addition, if the loop antenna is covered by a shield such as the back cover of the mobile phone, a protective case, etc., it will also cause poor performance in sending and receiving signals. At present, there is still a lack of suitable solutions in the art to deal with the above-mentioned problems.

The embodiment provides an antenna device including a first coil, a second coil and a resonant circuit. The first coil is used for receiving a first signal, wirelessly transmitting a first wireless signal according to the first signal, wirelessly receiving a second wireless signal, and transmitting a second signal according to the second wireless signal. The first coil includes a first end and a second end, wherein the first end is electrically connected to a processing circuit for receiving the first signal, and the second end is electrically connected to the processing circuit for transmit the second signal. A first current flows on the first coil in a first direction. The second coil includes a first end and a second end. A second current flows on the second coil in a second direction. The resonant circuit is electrically connected between the first end and the second end of the second coil, wherein the resonant circuit corresponds to a resonant frequency. The first coil is insulated from the second coil, and in a coupling range between the first coil and the second coil, the directions of the first current and the second current are opposite to each other.

In order to deal with the above-mentioned problems and improve the field strength of the antenna so as to improve the performance of sending and receiving signals, the embodiments may provide the following antenna devices.

FIG. 1 is a schematic diagram of an antenna device 100 electrically connected to a processing circuit 155 in an embodiment. FIG. 2 is a schematic diagram of another viewing angle in which the antenna device 100 in FIG. 1 is electrically connected to the processing circuit 155 . Figure 1 can be a top view, Figure 2 can be a perspective view, Figure 1 and Figure 2 are for illustration, and the details of the hardware and the ratio of the dimensions of each part are not limited to those shown in Figure 1 and Figure 2 .

As shown in FIG. 1 and FIG. 2 , the antenna device 100 may include a first coil 110 , a second coil 120 and a resonant circuit 130 . The first coil 110 can be used to receive the first signal S1, wirelessly transmit the first wireless signal SR1 according to the first signal S1, wirelessly receive the second wireless signal SR2, and transmit the second signal S2 according to the second wireless signal SR2.

The first coil 110 may include a first end 110A and a second end 110B, electrically connected to the processing circuit 155 . The first terminal 110A can be used to receive the first signal S1 from the processing circuit 155 , and the second terminal 110B can be used to transmit the second signal S2 to the processing circuit 155 . The first current I1 can flow on the first coil 110 in a first direction D1. The second coil 120 may include a first end 120A and a second end 120B. The second current I2 can flow in the second coil 120 in the second direction D2. The resonant circuit 130 can be electrically connected between the first end 120A and the second end 120B of the second coil 120 , wherein the resonant circuit 130 can correspond to the resonant frequency described later.

The second coil 120 and the resonant circuit 130 can form a resonant structure, and this resonant structure can generate a current I1 opposite to the first current I1 in the coupling range R of the first coil 110 and the second coil 120 by coupling with the first coil 110. The second current I2. This resonant structure can increase the coupling amount and coupling range, and improve the antenna pattern of the antenna formed by the first coil 110, thereby improving the performance of sending and receiving signals (for example, transmitting the first wireless signal SR1 and receiving the second wireless signal SR2) . The coupling range R may be a portion where the first coil 110 and the second coil 120 approach and/or overlap.

The first coil 110 is insulated from the second coil 120, because in the coupling range R of the first coil 110 and the second coil 120, the first current I1 and the second current I2 are opposite, so the first direction D1 and the second direction D2 are all clockwise or all are counterclockwise. As shown in Figures 1 and 2, a three-dimensional space may be defined using an X-axis, a Y-axis, and a Z-axis, wherein any two of the X-axis, Y-axis, and Z-axis are orthogonal to each other. The first coil 110 and the second coil 120 may correspond to the plane formed by the X axis and the Y axis, and the second coil 120 may be located above the first coil 110 along the Z axis.

According to an embodiment, as shown in FIG. 1 and FIG. 2 , the projection direction of the first coil 110 along the Z axis may correspond to the first area A1, and the shape of the first area A1 has a concave portion. The projection direction of the second coil 120 along the Z axis may correspond to the second area A2, and the projection direction of the second area A2 along the Z axis may correspond to the concave portion. In other words, the second coil 120 may be placed above the concave portion in the shape of the first area A1 formed by the first coil 110 . The second coil 120 can be wirelessly coupled with the first coil 110 , and the second coil 120 can accordingly improve the antenna field strength of the first coil 110 in the concave portion, thereby improving the performance of sending and receiving signals. According to an embodiment, as shown in FIG. 1 , the first coil 110 may partially overlap the second coil 120 , and the overlapping area of the first coil 110 and the second coil 120 may correspond to the coupling range R.

FIG. 3 is a schematic diagram of an antenna device 300 electrically connected to the processing circuit 155 in another embodiment. The antenna device 300 may be similar to the antenna device 100 in FIG. 1 and FIG. 2 , and the similarities will not be repeated. However, as shown in FIG. 3 , the first coil 100 of the antenna device 300 may not overlap the second coil 120 . As shown in FIG. 3, since the second coil 120 and the resonant circuit 130 can form a resonant structure, in the coupling region R, the difference between the first current I1 on the first coil 100 and the second current I2 on the second coil 120 directions are reversed. The resonant structure can increase the coupling amount and coupling range, and make the first direction D1 of the first current I1 and the second direction D2 of the second current I2 be in the same direction, for example, both are clockwise or both are counterclockwise. The number of turns of each of the first coil 110 and the second coil 120 may be greater than or equal to 1, and the current direction mentioned here is the current direction on one turn of the coil in a top view.

FIG. 4 is a schematic diagram of an antenna device 400 electrically connected to the processing circuit 155 in another embodiment. The antenna device 400 can be similar to the antenna device 100 in FIG. 1 and the antenna device 300 in FIG. 3 , and the similarities will not be repeated. However, according to an embodiment, as shown in FIG. 4 , the first coil 110 may correspond to the first area A1 in the projection direction along the Z axis, and the second coil 120 may correspond to the second area A2 in the projection direction along the Z axis. , and the second area A2 may be located within the first area A1. In other words, the second coil 120 can be placed within the first area A1 surrounded by the first coil 110 to increase the field strength of the antenna near the center of the first area A1 , thereby improving the performance of wireless transceiving signals.

As shown in FIG. 4 , in the coupling region R, the first current I1 on the first coil 110 can be opposite to the second current I2 on the second coil 120 . For example, if one of the first direction D1 and the second direction D1 is clockwise, the other can be counterclockwise.

For example, if the first coil 110 is the antenna of a wireless card reader, by setting the resonance structure formed by the second coil 120 and the resonant circuit 130, it is possible to effectively improve the ability of the card reader to detect mobile devices (such as mobile phones) near the central position. ) of the efficacy.

FIG. 5 is a schematic diagram of an antenna device 500 in another embodiment. Fig. 5 is a side view, and the antenna device 500 may be similar to the antenna device 100 in Fig. 1, including the first coil 110, the second coil 120 and the resonant circuit 130, and the similarities will not be repeated. As shown in FIG. 5 , the second coil 120 may include a first part 121 , a second part 122 and a third part 123 . The first part 121 may be parallel to the first coil 110 along the Y-axis direction. The second part 120 may be parallel to the first coil 110 along the Y-axis direction. The third part 123 can be electrically connected between the first part 121 and the second part 122 . As shown in Figure 5, the first shield 510 can be located between the first coil 110 and the first part 121 of the second coil 120, and the second shield 520 can be located between the first part 121 of the second coil 120 and the second coil 120. Section 122 between.

For example, the first cover 510 can be a back cover of a mobile phone, and the second cover 520 can be a protective shell or an ornament of a mobile phone. By bending the second coil 120 so that the second portion 122 of the second coil 120 is not shielded by the second shield 520 , it is helpful to improve the performance of transmitting the first wireless signal SR1 and receiving the second wireless signal SR2 . According to an embodiment, the above-mentioned first coil 110 and second coil 120 may be formed on a flexible printed circuit board (Flexible Printed Circuit, FPC), so as to be adjusted to a suitable shape and bent.

，其中f為共振頻率，L為共振電路130之電感的電感值，C為共振電路130之電容的電容值，且共振頻率f可對應於第一無線訊號SR1及第二無線訊號SR2之頻率。 According to an embodiment, the above-mentioned resonant circuit 130 may include at least one capacitor. For example, the resonant circuit 130 may include a capacitor and an inductor connected in series to form a series LC resonant circuit. For another example, the resonant circuit 130 may include capacitors and inductors connected in parallel to form a parallel LC resonant circuit. As an example, the resonant frequency can be expressed as f =

, where f is the resonant frequency, L is the inductance of the resonant circuit 130, C is the capacitance of the resonant circuit 130, and the resonant frequency f may correspond to the frequency of the first wireless signal SR1 and the second wireless signal SR2.

To sum up, by disposing the resonant loop structure formed by the second coil 120 and the resonant circuit 130, the antenna pattern of the first coil 110 can be improved, and the radiated energy can be increased where the radiated energy of the antenna is weak. The resonant ring structure formed by the second coil 120 and the resonant circuit 130 can be a passive structure. By inducing the electromagnetic field of the first coil 110 in a parasitic manner, the field shape of the antenna can be improved without additionally requiring additional attention to the second coil 120 and the resonant circuit 130. power supply. The antenna devices 100, 300, 400, and 500 provided by the embodiments have recesses in the area covered by the antenna coils, and when the antennas are affected by shelters, they can improve the performance of wireless sending and receiving signals, thus helping to solve the problems in this field. The above descriptions are only preferred embodiments of the present invention, and all equivalent changes and modifications made according to the scope of the patent application of the present invention shall fall within the scope of the present invention.

100,300,400,500: Antenna device 110: the first coil 120: second coil 120A, 110A: first end 120B, 110B: the second end 121: Part 1 122: Part Two 123: Part Three 130: Resonant circuit 155: Processing circuit 510: The first cover 520: Second cover A1: The first area A2: Second area D1: the first direction D2: Second direction I1: first current I2: second current R: coupling range S1: The first signal S2: Second signal SR1: The first wireless signal SR2: Second wireless signal X, Y, Z: axes

FIG. 1 is a schematic diagram of an antenna device electrically connected to a processing circuit in an embodiment. Fig. 2 is a schematic diagram of another viewing angle showing the electrical connection of the antenna device in Fig. 1 to the processing circuit. FIG. 3 is a schematic diagram of an antenna device electrically connected to a processing circuit in another embodiment. FIG. 4 is a schematic diagram of an antenna device electrically connected to a processing circuit in another embodiment. Fig. 5 is a schematic diagram of an antenna device in another embodiment.

100: Antenna device

110: the first coil

120: second coil

120A, 110A: first end

120B, 110B: the second end

130: Resonant circuit

155: Processing circuit

A1: The first area

A2: Second area

D1: the first direction

D2: Second direction

I1: first current

I2: second current

R: coupling range

S1: The first signal

S2: Second signal

SR1: The first wireless signal

SR2: Second wireless signal

X, Y, Z: axes

Claims (10)

An antenna device comprising: A first coil for receiving a first signal, wirelessly transmitting a first wireless signal according to the first signal, wirelessly receiving a second wireless signal, and transmitting a second signal according to the second wireless signal, the first The coil includes a first end electrically connected to a processing circuit for receiving the first signal, and a second end electrically connected to the processing circuit for transmitting the second signal, wherein a first current is supplied by a a first direction flows on the first coil; a second coil comprising a first end and a second end, wherein a second current flows in the second coil in a second direction; and a resonant circuit electrically connected between the first end and the second end of the second coil, wherein the resonant circuit corresponds to a resonant frequency; Wherein the first coil is insulated from the second coil, and in a coupling range between the first coil and the second coil, the directions of the first current and the second current are opposite to each other. The antenna device as described in claim 1, wherein the first coil corresponds to a first area in a projection direction, the shape of the first area has a concave portion, and the second coil corresponds to a second coil in the projection direction. area, and the second area corresponds to the concave portion in the projection direction. The antenna device according to claim 2, wherein the first coil partially overlaps the second coil, and an overlapping area of the first coil and the second coil corresponds to the coupling range. The antenna device as claimed in claim 2, wherein the first coil does not overlap the second coil. The antenna device as claimed in claim 3 or 4, wherein the first direction is the same as the second direction. The antenna device according to claim 1, wherein the first coil corresponds to a first area in a projection direction, the second coil corresponds to a second area in the projection direction, and the second area is located in the first within the area. The antenna device as claimed in claim 6, wherein the first direction is opposite to the second direction. The antenna device as claimed in claim 1, wherein the second coil comprises: a first portion parallel to the first coil; a second portion parallel to the first coil; and a third part electrically connected between the first part and the second part; A first shield is located between the first coil and the first portion of the second coil, and a second shield is located between the first portion and the second portion of the second coil. The antenna device as claimed in claim 1, wherein the second coil is formed on a flexible printed circuit board. The antenna device as claimed in claim 1, wherein the resonant circuit includes at least one capacitor.

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