TWI897765B - Antenna device - Google Patents

Abstract

An antenna device, operates at a center frequency. The antenna device includes a substrate and a conductive layer. The substrate has a first plane. The conductive layer is disposed on the first plane of the substrate. The conductive layer has a printed pattern, and the printed pattern includes a radiating element and a matching element. The radiating element has a plurality of meandering portions arranged along a first direction. Two adjacent meandering portions are substantially parallel with each other and electrically coupled to each other. The matching element has a plurality of protruding portions arranged along the first direction. Two adjacent protruding portions are substantially parallel with each other and electrically isolated from each other. Each protruding portion of the matching element is sandwiched between two adjacent meandering portions of the radiating element along a second direction, and the second direction is not parallel with the first direction.

Description

Antenna device

This disclosure relates to an antenna device, and more particularly to an antenna device in the form of a printed antenna suitable for vehicle anti-theft applications.

With the booming development of emerging energy sources and electric engines, various vehicles have become widely used in daily life. To meet safety requirements, vehicles are often equipped with anti-theft devices. These devices include wireless transceivers to receive remote control signals from the driver or detect the movements of suspicious individuals.

Conventional vehicle anti-theft devices typically use a transceiver operating at a frequency of 315 MHz. Furthermore, the transceiver typically employs a helical antenna with a center frequency of 315 MHz.

However, the coiled antennas used in vehicle anti-theft systems have several drawbacks that reduce their effectiveness and lifespan. For example, prolonged vibrations during driving can easily cause the coiled antenna to break, particularly in diesel-powered trucks. Furthermore, the coiled antenna must be assembled and soldered to the circuit board during the manufacturing process, adding to the manufacturing complexity. Furthermore, coiled antennas are typically made of an elastic material, which can easily stretch or deform, leading to dimensional variations.

To address this situation, the vehicle anti-theft industry urgently needs improved antenna devices that can replace conventional spiral antennas with printed antennas and meet user-required center frequency specifications.

According to one embodiment of the present disclosure, an antenna device operating at a center frequency is provided. The antenna device includes a substrate and a conductive layer. The substrate has a first plane. The conductive layer is disposed on the first plane of the substrate. The conductive layer has a printed pattern, which includes a radiating element and a matching element. The radiating element has a plurality of meandering portions arranged along a first direction. Adjacent meandering portions are substantially parallel and electrically coupled to each other. The matching element has a plurality of protruding portions arranged along the first direction. Adjacent protruding portions are substantially parallel and electrically separated from each other. Each protruding portion of the matching element is sandwiched between two adjacent meandering portions of the radiating element along a second direction, which is non-parallel to the first direction.

Other aspects and advantages of the present disclosure will be apparent from a review of the following drawings, detailed description, and claims.

1000: Antenna device

2000: Electronic devices

50:Substrate

51: First Plane

80:Conductive layer

81: Printing pattern

100R: Radiation Zone

100: Radiation Component

200: Matching components

300: Touchdown Zone

110~160:Zigzag Department

210~230: Protrusion

X: First direction

Y: Second direction

W1: Width

L1: Length

P1~P4: Reference positions

111, 131, 141: First paragraph

112, 132, 142: Second paragraph

113: Third paragraph

210e1: First End

210e2: Second End

e_in: signal input terminal

C1, C2, C3: Equivalent capacitance

S11: Forward reflection coefficient

Figure 1A is a schematic diagram of an antenna device according to an embodiment of the present disclosure.

Figure 1B is a top view of the antenna device in Figure 1A.

Figure 2A is a top view of the printed pattern of the antenna device.

Figure 2B is a top view of one of the curved sections of the radiating element.

Figure 2C is a top view of one of the protrusions of the matching component.

Figure 2D shows a top view of the relative arrangement of the protrusion, two adjacent meanders, and the ground contact area.

Figure 3 is a schematic diagram showing how matching components form multiple equivalent capacitors in an antenna device.

Figures 4A and 4B show the frequency response of the antenna device.

The technical terms used in this specification are based on customary terminology in the art. If this specification provides explanations or definitions for certain terms, the interpretation of such terms shall be subject to the explanations or definitions in this specification. Each embodiment disclosed herein has one or more technical features. Where feasible, a person skilled in the art may selectively implement some or all of the technical features of any embodiment, or selectively combine some or all of the technical features of these embodiments.

Figure 1A is a schematic diagram of an antenna device 1000 according to an embodiment of the present disclosure. As shown in Figure 1A, antenna device 1000 is integrated into an electronic device 2000; electronic device 2000 is, for example, a wireless communication transceiver that can be used for vehicle anti-theft purposes. Electronic device 2000 includes a printed circuit board (PCB), which includes a substrate 50 and a conductive layer 80. Conductive layer 80 is disposed on a first plane 51 of substrate 50. Antenna device 1000 of the present disclosure is formed by a portion of substrate 50 and a portion of conductive layer 80. Antenna device 1000 is in the form of a printed antenna, with conductive layer 80 having a predetermined printed pattern 81.

Figure 1B is a top view of the antenna device 1000 in Figure 1A. As shown in Figure 1B, the antenna device 1000 has a radiation region 100R. The radiation region 100R has a width W1 in a first direction X and a length L1 in a second direction Y. The first direction X is substantially perpendicular to the second direction Y. In this embodiment, the width W1 is smaller than the length L1; for example, the width W1 is 10.5 mm, and the length L1 is 33 mm.

Printed pattern 81 is disposed corresponding to radiation region 100R. Printed pattern 81 includes at least a radiation element 100, a matching element 200, and a grounding region 300. Radiation element 100 and matching element 200 are located within radiation region 100R, and grounding region 300 is disposed along and adjacent to the boundary of radiation region 100R. Antenna device 1000 can transmit/receive radio frequency signals by radiating electromagnetic waves via radiation element 100. Radiation element 100 is, for example, a continuous pattern of multiple zigzags. In this embodiment, radiation element 100 extends from reference position P1 in the upper left corner in a direction opposite to second direction Y to reference position P2. Then, at reference position P2, the radiating element 100 makes a 90-degree turn and extends along the first direction X. Furthermore, it makes another 90-degree turn and extends along the second direction Y. Similarly, the radiating element 100 makes another 90-degree turn and extends along the first direction X, and then makes another 90-degree turn and extends in the opposite direction of the second direction Y. The above process is then repeated until the radiating element 100 extends to reference position P3 and then extends along the second direction Y to reference position P4.

The matching element 200 extends along the second direction Y. The matching element 200 is electrically separated from the radiating element 100. Furthermore, the matching element 200 is sandwiched between two adjacent zigzag patterns of the radiating element 100. The grounding region 300 surrounds the radiating element 100 along the first direction X and the second direction Y. Furthermore, the grounding region 300 is electrically coupled to the matching element 200 in the first direction X. Operationally, the matching element 200 forms multiple equivalent capacitances between the radiating element 100 and the grounding region 300. The antenna device 1000 operates at a predetermined center frequency based on these equivalent capacitances. The arrangement of the radiating element 100, the matching element 200, and the grounding region 300 in the printed pattern 81 is described in more detail below with reference to Figures 2A-2C.

Please first refer to Figure 2A, which is a top view of the printed pattern 81 of the antenna device 1000. The radiating element 100 of the printed pattern 81 has a plurality of meandering portions arranged along a first direction X, for example, six meandering portions 110-160. Adjacent meandering portions 110-160 are substantially parallel to each other and electrically coupled to each other. For example, meandering portion 110 is adjacent to meandering portion 120; meandering portion 110 is substantially parallel to and electrically coupled to meandering portion 120. Similarly, adjacent meandering portions 120 and 130 are substantially parallel to and electrically coupled to each other. Similarly, adjacent meandering portions 150 and 160 are substantially parallel to and electrically coupled to each other.

The matching element 200 has a plurality of protrusions, for example, three protrusions 210-230, arranged along a first direction X. Adjacent protrusions 210-230 are substantially parallel to each other and electrically separated from each other. For example, adjacent protrusions 210 and 220 are substantially parallel to each other and electrically separated from each other; adjacent protrusions 220 and 230 are substantially parallel to each other and electrically separated from each other. Furthermore, one of the protrusions 210-230 of the matching element 200 is sandwiched between two adjacent ones of the meandering portions 110-160 of the radiating element 100 along a second direction Y. For example, the protrusion 210 is sandwiched between the adjacent zigzag portions 130 and 140 along the second direction Y; the protrusion 220 is sandwiched between the adjacent zigzag portions 140 and 150 along the second direction Y; and the protrusion 230 is sandwiched between the adjacent zigzag portions 150 and 160 along the second direction Y.

Conversely, one or more of the zigzag portions 110-160 of the radiating element 100 are sandwiched along the second direction Y between adjacent protrusions 210-230 of the matching element 200. For example, the zigzag portion 140 is sandwiched along the second direction Y between adjacent protrusions 210 and 220; and the zigzag portion 150 is sandwiched along the second direction Y between adjacent protrusions 220 and 230.

Next, please refer to Figure 2B, which is a top view of one of the meandering portions of radiating element 100. Figure 2B takes meandering portion 110 as an example. Meandering portion 110 includes a first segment 111, a second segment 112, and a third segment 113. Each of first segment 111, second segment 112, and third segment 113 is in the shape of a straight strip. The length of first segment 111 is substantially equal to the length of second segment 112 (or, in another example, the length of first segment 111 is slightly greater than the length of second segment 112).

The first segment 111 extends in the second direction Y. The second segment 112 also extends in the second direction Y and is substantially parallel to the first segment 111. The third segment 113 extends in the first direction X and is electrically coupled to the first segment 111 and the second segment 112. Based on this arrangement, the first segment 111, the second segment 112, and the third segment 113 form a spiral pattern. Furthermore, the second segment 112 of the zigzag portion 110 is electrically coupled to the adjacent zigzag portion 120 (zigzag portion 120 is not shown in FIG. 2B ).

Next, please refer to Figure 2C, which is a top view of one of the protrusions of the matching element 200. Figure 2C uses protrusion 210 as an example. Protrusion 210 is in a straight strip shape and has a first end 210e1 and a second end 210e2. Second end 210e2 is disposed opposite first end 210e1 along the second direction Y.

Next, please refer to Figure 2D, which is a top view illustrating the relative arrangement of the protrusion 210, two adjacent meandering portions 130 and 140, and the grounding region 300. The protrusion 210 extends along the second direction Y between the two adjacent meandering portions 130 and 140 at its second end 210e2. The length of the protrusion 210 is shorter than the length of both the first section 131 and the second section 132 of the meandering portion 130. Similarly, the length of the protrusion 210 is shorter than the length of both the first section 141 and the second section 142 of the meandering portion 140.

Furthermore, the protrusion 210 is substantially parallel to and electrically separated from the second section 132 of the zigzag portion 130. Similarly, the protrusion 210 is substantially parallel to and electrically separated from the first section 141 of the zigzag portion 140. Furthermore, the grounding region 300 is electrically coupled to the first end 210e1 of the protrusion 210 in the first direction X.

As previously described, in operation, the matching element 200 can form multiple equivalent capacitors between the radiating element 100 and the grounding region 300. For example, the protrusion 210 of the matching element 200 forms an equivalent capacitor that is equivalently coupled between the two adjacent meandering portions 130 and 140 of the radiating element 100 and the grounding region 300. The details of how the matching element 200 forms multiple equivalent capacitors will be further explained below with reference to FIG. 3.

Figure 3 is a schematic diagram illustrating how the matching element 200 forms multiple equivalent capacitors in the antenna device 1000. As shown in Figure 3, the signal input terminal e_in of the antenna device 1000 is electrically coupled to the radiating element 100. The matching element 200 is positioned between the radiating element 100 and the grounding region 300. The protrusion 210 of the matching element 200 forms an equivalent capacitor C1, which is equivalently coupled between the radiating element 100 and the grounding region 300. Similarly, the other two protrusions 220 and 230 of the matching element 200 form equivalent capacitors C2 and C3, respectively, which are equivalently coupled between the radiating element 100 and the grounding region 300.

Antenna device 1000 operates at a predetermined center frequency based on the capacitive effects of equivalent capacitors C1, C2, and C3. In this embodiment, the center frequency is, for example, 315 MHz, which is suitable for the operating frequency of conventional vehicle anti-theft devices. Alternatively, in other examples, the relative positioning of matching element 200 and radiating element 100 can be adjusted, thereby adjusting equivalent capacitors C1, C2, and C3, thereby changing the center frequency of antenna device 1000.

Figures 4A and 4B illustrate the frequency response of antenna device 1000. First, refer to Figure 4A, which shows the frequency response of antenna device 1000 using its forward reflection coefficient S11 at different frequencies. The design of printed pattern 81 of antenna device 1000, based on the relative placement of protrusions 210, 220, and 230 of matching element 200 and radiating element 100, creates predetermined equivalent capacitances C1, C2, and C3 between radiating element 100 and grounding region 300, ensuring that the frequency response of antenna device 1000 meets user specifications. The embodiment of Figure 4A shows that at a frequency of 315 MHz, the forward reflection coefficient S11 of the antenna device 1000 has a trough (i.e., reaches a minimum value). This indicates that the center frequency of the antenna device 1000 is substantially equal to 315 MHz, which meets the specifications of the vehicle anti-theft device required by the user.

Next, referring to FIG. 4B , the relative placement of the protrusions 210, 220, and 230 of the matching element 200 and the radiating element 100 can be changed, thereby adjusting the equivalent capacitances C1, C2, and C3 between the radiating element 100 and the grounding region 300, thereby changing the center frequency of the antenna device 1000. The embodiment of FIG. 4B shows that at a frequency of 433 MHz, the forward reflection coefficient S11 of the antenna device 1000 reaches a local relative minimum, indicating that the center frequency of the antenna device 1000 has been changed to 433 MHz.

In summary, the antenna device 1000 disclosed herein forms at least one equivalent capacitor by placing a matching element 200 between the radiating element 100 and the grounding region 300 of the printed pattern 81. This equivalent capacitor's capacitive effect allows the center frequency of the antenna device 1000 to be adjusted to meet user requirements. Compared to conventional spiral antennas used in vehicle anti-theft devices, the antenna device 1000 disclosed herein is significantly smaller in size. Furthermore, the antenna device 1000 disclosed herein can be manufactured using a simple printed antenna format, significantly reducing manufacturing costs.

Although the present disclosure has been described in detail above with reference to preferred embodiments and examples, it should be understood that these examples are intended to be illustrative rather than restrictive. It is anticipated that those skilled in the art will be able to devise numerous modifications and combinations that fall within the spirit of the present disclosure and the scope of the appended patent applications.

81: Printing pattern

100: Radiation Component

200: Matching components

300: Touchdown Zone

110~160:Zigzag Department

210~230: Protrusion

X: First direction

Y: Second direction

Claims (10)

An antenna device operating at a center frequency comprises: a substrate having a first plane; and a conductive layer disposed on the first plane of the substrate, the conductive layer having a printed pattern, the printed pattern comprising: a radiating element having a plurality of meandering portions arranged along a first direction, wherein adjacent ones of the meandering portions are substantially parallel and electrically coupled to each other, each meandering portion comprising: a first segment extending in a second direction; a second segment substantially parallel to the first segment; and a third segment extending in the first direction and electrically coupled to the first and second segments, wherein each of the first, second, and third segments is in the shape of a straight strip, and the first, second, and third segments form a spiral shape; and A matching element having a plurality of protrusions arranged along the first direction, with adjacent protrusions being substantially parallel and electrically separated from each other. Each protrusion of the matching element is sandwiched between adjacent ones of the meandering portions of the radiating element along a second direction, the second direction being non-parallel to the first direction. The antenna device of claim 1, wherein the second direction is substantially perpendicular to the first direction. The antenna device of claim 1, wherein one or more of the meandering portions of the radiating element are sandwiched between two adjacent protruding portions of the matching element along the second direction. The antenna device of claim 1, wherein each of the protruding portions of the matching element is substantially parallel and electrically separated from the first section and the second section of each of the meandering portions of the radiating element. The antenna device of claim 1, wherein the length of the first section of each meander portion of the radiating element is substantially equal to the length of the second section, and the length of the first section of each meander portion is greater than the length of each protrusion of the matching element. The antenna device of claim 1, wherein each protrusion of the matching element is in the shape of a straight strip, and each protrusion has: a first end; and a second end disposed opposite the first end in the second direction. The antenna device of claim 6, wherein each of the protrusions of the matching element extends along the second direction with the second end between two adjacent ones of the meandering portions of the radiating element. The antenna device of claim 6, wherein the printed pattern further includes: A grounding region surrounding the radiating element along the first direction and the second direction and electrically coupled to the first end of each protrusion of the matching element in the first direction. The antenna device of claim 8, wherein each of the protrusions of the matching element forms an equivalent capacitor between the radiating element and the ground region. The antenna device of claim 9 operates at the center frequency based on the equivalent capacitances formed by the protrusions of the matching element.