frequency divider

Abstract

A frequency divider is disposed on a circuit board and includes a first coupling unit, a second coupling unit, a third coupling unit, a long loop unit, a short loop unit, and at least one ground plane. The first coupling unit and the second coupling unit couple the long loop unit, the first coupling unit and the third coupling unit couple the short loop unit, each of the first coupling unit, the second coupling unit, the third coupling unit, the long loop unit, and the short loop unit includes at least one signal via and is located on at least two conductive layers, and the at least one ground plane is located on another conductive layer of the circuit board. Thus, layout area can be saved. The present disclosure also relates to a circuit element.

Description

Technical Field

[0001] This disclosure relates to a frequency divider and circuit element, and more particularly to a frequency divider and circuit element disposed on a circuit board. Background Technology

[0002] Driven by humanity's pursuit of a more convenient life, diverse wireless communication systems and radio frequency (RF) technologies have been developed, such as 5G millimeter-wave antenna modules (AiP, Antenna in Package). Chip manufacturers, module packaging companies, and system integrators all consider this a crucial battleground in the 5G industry. However, 5G millimeter-wave antenna modules typically require a very small size; therefore, some RF circuit components that occupy significant volume or area in existing technologies (such as dividers / multiplexers) are not suitable for 5G millimeter-wave antenna modules.

[0003] In view of this, how to reduce the size, cost and design complexity of circuit components such as frequency dividers in wireless communication modules, while meeting the radio frequency characteristics requirements of wireless communication systems, and further making the products more competitive in the market, has become a topic of concern in the market. Summary of the Invention

[0004] This disclosure provides a frequency divider disposed on a circuit board, which couples a long ring unit through a first coupling unit and a second coupling unit, and couples a short ring unit through a first coupling unit and a third coupling unit. Each of the first coupling unit, the second coupling unit, the third coupling unit, the long ring unit, and the short ring unit includes at least one signal via and is located in at least two conductive layers, thereby saving area and volume and reducing design complexity.

[0005] According to one embodiment of this disclosure, a frequency divider is provided, disposed on a circuit board. The circuit board sequentially includes a first conductive layer, a second conductive layer, and a third conductive layer. The frequency divider includes a first coupling unit, a second coupling unit, a third coupling unit, a long ring unit, a short ring unit, and at least one ground plane. The first coupling unit is connected to a first feed point, the second coupling unit is connected to a second feed point, and the third coupling unit is connected to a third feed point. The first and second coupling units couple to the long ring unit, and the first and third coupling units couple to the short ring unit. Each of the first, second, and third coupling units, the long ring unit, and the short ring unit includes at least one signal via and is located on the first and third conductive layers. The at least one ground plane is located on the second conductive layer and serves as a reference ground for the first, second, third, long, and short ring units. Attached Figure Description

[0006] Figure 1A perspective schematic diagram of a frequency divider according to an embodiment of the present disclosure is shown;

[0007] Figure 2 Draw Figure 1 Exploded view of the conductive layer of the frequency divider;

[0008] Figure 3 Draw Figure 1 Exploded view of the signal lines of the intermediate frequency divider;

[0009] Figure 4 Draw Figure 1 Top view of the signal lines of the intermediate frequency divider;

[0010] Figure 5 Draw Figure 1 S-parameter diagram of the intermediate frequency divider; and

[0011] Figure 6 Draw Figure 1 A schematic diagram of the surface current density of a frequency divider.

[0012] The reference numerals in the attached figures are explained as follows:

[0013] 100: Frequency divider

[0014] 101: First conductive layer

[0015] 101g, 102g, 103g, 104g, 105g: Grounding plane

[0016] 102: Second conductive layer

[0017] 103: Third conductive layer

[0018] 104: Fourth conductive layer

[0019] 105: Fifth conductive layer

[0020] 108: Circuit Board

[0021] 109, 139, 159: Grounding vias

[0022] 110: First feed line

[0023] 119: First Feed Point

[0024] 120: First coupling unit

[0025] 123, 124, 133, 134, 136, 137, 153, 154, 156, 157, 166, 167, 176, 177, 186, 187: line segments

[0026] 125, 135, 138, 155, 158, 168, 188: Signal vias

[0027] 130: Long ring unit

[0028] 131: First coupling part

[0029] 132: Second coupling section

[0030] 150: Short ring unit

[0031] 151: Third Coupling Section

[0032] 152: Fourth Coupling Section

[0033] 160: Second coupling unit

[0034] 170: Second feed line

[0035] 179: Second Feed Point

[0036] 180: Third coupling unit

[0037] 190: Third feed line

[0038] 199: Third Feed Point

[0039] g23: Spacing

[0040] h1: Thickness

[0041] w2, w3, y1: Width

[0042] x: First direction

[0043] x1: Length

[0044] y: Second direction

[0045] z: Third-party direction Detailed Implementation

[0046] Figure 1 A perspective view of a frequency divider 100 according to an embodiment of the present disclosure is shown. Figure 2 Draw Figure 1 Exploded view of the conductive layer of the intermediate frequency divider 100. Figure 3 Draw Figure 1 Exploded view of the signal lines of the intermediate frequency divider 100. Figure 4 Draw Figure 1 A top view of the signal lines of the frequency divider 100. To clearly show the structure of the frequency divider 100, the accompanying diagrams in this disclosure are illustrated in a Cartesian coordinate system with a first direction x, a second direction y, and a third direction z. Figure 1 Illustration omitted Figure 2 The grounding via 109 is shown, and the signal lines located on the inner conductive layer of the circuit board 108 are drawn with solid lines. Please refer to... Figures 1 to 4According to one embodiment of this disclosure, the circuit element is specifically a frequency divider 100. The frequency divider 100 is disposed on a circuit board 108 and includes a first coupling unit 120, a second coupling unit 160, a third coupling unit 180, a long ring unit 130, a short ring unit 150, and at least one ground plane (e.g., at least ground plane 102g). The circuit board 108 specifically includes a fourth conductive layer 104, a first conductive layer 101, a second conductive layer 102, a third conductive layer 103, and a fifth conductive layer 105 in sequence. In addition, the circuit element in other embodiments of this disclosure may be a frequency divider with three or more terminals or a circuit element containing frequency division characteristics. The shape and size of the circuit board are not limited to the figures in this disclosure. The circuit board may be a printed circuit board, a flexible circuit board, or a circuit substrate made of other dielectric materials, and is not limited thereto.

[0047] The first coupling unit 120 is connected to the first feed point 119 (e.g., ...). Figure 3 As shown), the second coupling unit 160 is connected to the second feed point 179, and the third coupling unit 180 is connected to the third feed point 199. The first coupling unit 120 and the second coupling unit 160 are coupled to the long ring unit 130, and the first coupling unit 120 and the third coupling unit 180 are coupled to the short ring unit 150. That is, the signal is fed in from the first feed point 119 (common port), and reaches the second feed point 179 (low pass port) and the third feed point 199 (high pass port) through the loop paths of the long ring unit 130 and the short ring unit 150, respectively.

[0048] The first coupling unit 120 includes a signal via 125 and is located in the first conductive layer 101 and the third conductive layer 103. Specifically, the first coupling unit 120 is formed by sequentially connecting a line segment 123 in the first conductive layer 101, the signal via 125, and a line segment 124 in the third conductive layer 103. The second coupling unit 160 includes a signal via 168 and is located in the first conductive layer 101 and the third conductive layer 103. Specifically, the second coupling unit 160 is formed by sequentially connecting a line segment 166 in the first conductive layer 101, the signal via 168, and a line segment 167 in the third conductive layer 103. The third coupling unit 180 includes a signal via 188 and is located in the first conductive layer 101 and the third conductive layer 103. Specifically, the third coupling unit 180 is formed by sequentially connecting a line segment 186 in the first conductive layer 101, the signal via 188, and a line segment 187 in the third conductive layer 103. The long ring unit 130 includes signal vias 135 and 138 and is located in the first conductive layer 101 and the third conductive layer 103. The short ring unit 150 includes signal vias 155 and 158 and is located in the first conductive layer 101 and the third conductive layer 103. Furthermore, the line segments of the frequency divider according to this disclosure can be straight lines, arcs, or curves. In addition, the "connection" described in this disclosure refers to a physical connection between two components, which can be a direct or indirect connection, while the "coupled" described in this disclosure refers to two components that are separated from each other and have no physical connection, and the electric field energy generated by the current through one component excites the electric field energy of the other component.

[0049] Grounding planes 101g, 102g, 103g, 104g, and 105g are located on the first conductive layer 101, the second conductive layer 102, the third conductive layer 103, the fourth conductive layer 104, and the fifth conductive layer 105, respectively, and are interconnected through multiple grounding vias 109 to maintain system grounding. At least one of each of the grounding planes 101g, 102g, 103g, 104g, and 105g is present, with at least grounding planes 102g, 104g, and 105g serving as reference grounds for the first coupling unit 120, the second coupling unit 160, the third coupling unit 180, the long ring unit 130, and the short ring unit 150. Therefore, the frequency divider 100 is a low-profile frequency divider design that does not require the use of the waveguide structure commonly used in existing technologies. This saves layout area and volume, and also eliminates the need to design two independent frequency band antennas at the antenna end, thereby reducing antenna complexity and space occupation. Therefore, it is suitable for antenna modules such as 5G millimeter wave.

[0050] In detail, the long annular unit 130 includes a first coupling portion 131, which is specifically formed by sequentially connecting a line segment 133 located in the first conductive layer 101, a signal via 135, and a line segment 134 located in the third conductive layer 103. The short annular unit 150 includes a third coupling portion 151, which is specifically formed by sequentially connecting a line segment 153 located in the first conductive layer 101, a signal via 155, and a line segment 154 located in the third conductive layer 103. The first coupling portion 131 and the third coupling portion 151 are located on both sides of the first coupling unit 120 (i.e., on the positive and negative directions of the second direction y of the first coupling unit 120, respectively). At least a portion of the first coupling unit 120, at least a portion of the first coupling portion 131, and at least a portion of the third coupling portion 151 are parallel to each other, i.e., at least a portion of the first coupling unit 120 and at least a portion of the first coupling portion 131 maintain the same distance, and at least a portion of the first coupling unit 120 and at least a portion of the third coupling portion 151 maintain the same distance. Specifically, a portion of line segment 123 of the first coupling unit 120, a portion of line segment 133 of the first coupling part 131, and a portion of line segment 153 of the third coupling part 151 are parallel to each other; signal vias 125, 135, and 155 are parallel to each other; and a portion of line segment 124 of the first coupling unit 120, a portion of line segment 134 of the first coupling part 131, and a portion of line segment 154 of the third coupling part 151 are parallel to each other. Thus, the first coupling unit 120 co-couples the long ring unit 130 and the short ring unit 150. This helps the dual-sided vertical ring structure frequency divider 100 to simultaneously meet the requirements of signal feed coupling and reduced layout area.

[0051] Furthermore, the long annular unit 130 includes a second coupling portion 132, specifically formed by sequentially connecting a line segment 136 located in the first conductive layer 101, a signal via 138, and a line segment 137 located in the third conductive layer 103. The short annular unit 150 includes a fourth coupling portion 152, specifically formed by sequentially connecting a line segment 156 located in the first conductive layer 101, a signal via 158, and a line segment 157 located in the third conductive layer 103. The second coupling unit 160 is farther away from the first coupling unit 120 than the second coupling portion 132, and the third coupling unit 180 is farther away from the first coupling unit 120 than the fourth coupling portion 152, such as... Figure 4As shown, the second coupling unit 160 and the third coupling unit 180 are located outside the second coupling portion 132 and the fourth coupling portion 152, respectively, to improve the isolation between the high-pass and low-pass terminals. At least a portion of the second coupling unit 160 and at least a portion of the second coupling portion 132 are parallel to each other. Specifically, a portion of line segment 166, signal via 168, and a portion of line segment 167 of the second coupling unit 160 are parallel to a portion of line segment 136, signal via 138, and a portion of line segment 137 of the second coupling portion 132, respectively, thereby coupling the second coupling unit 160 to the long ring unit 130. At least a portion of the third coupling unit 180 and at least a portion of the fourth coupling portion 152 are parallel to each other. Specifically, a portion of line segment 186, signal via 188, and a portion of line segment 187 of the third coupling unit 180 are parallel to a portion of line segment 156, signal via 158, and a portion of line segment 157 of the fourth coupling portion 152, respectively, thereby coupling the third coupling unit 180 to the short ring unit 150. This helps the dual-sided vertical ring structure frequency divider 100 to simultaneously meet the requirements of signal isolation and reduced layout area. Furthermore, in the frequency divider according to this disclosure, the line segments outside the coupling portion of each ring unit can be located in a conductive layer different from the coupling portion.

[0052] The ratio of the path length of the short ring unit 150 in the first conductive layer 101 to the path length of the first coupling unit 120 in the first conductive layer 101 can be between 2.2 and 12. Similarly, the ratio of the path length of the short ring unit 150 in the third conductive layer 103 to the path length of the first coupling unit 120 in the third conductive layer 103 can also be between 2.2 and 12. All path lengths mentioned in this disclosure refer to their center path lengths. Furthermore, these ratios can all be between 2.5 and 6. This allows for a balance between signal coupling and layout design flexibility. In this embodiment, the path length of the long ring unit 130 in the first conductive layer 101 and the third conductive layer 103 is 2660 μm (micrometer). The ratio of the path length of the short ring unit 150 in the first conductive layer 101 (1827 μm) to the path length of the first coupling unit 120 in the first conductive layer 101 (602 μm) is 3.03. The ratio of the path length of the short ring unit 150 in the third conductive layer 103 (1827 μm) to the path length of the first coupling unit 120 in the third conductive layer 103 (602 μm) is also 3.03.

[0053] Specifically, the frequency divider 100 further includes ground vias 139 and 159. The ground via 139 connects the line segments (not separately labeled) of the long annular unit 130 in the first conductive layer 101 and the third conductive layer 103, and the ground plane 102g. The ground via 159 connects the line segments (not separately labeled) of the short annular unit 150 in the first conductive layer 101 and the third conductive layer 103, and the ground plane 102g. Thus, when the signal wavelength matches the loop path length of each of the long annular unit 130 and the short annular unit 150, a resonance frequency corresponding to the wavelength will be generated, and the ground vias 139 and 159 connected to the loop path can generate a low-frequency mode at the adjacent position of the resonance frequency, achieving a dual-mode effect and expanding the operating bandwidth.

[0054] The total number of signal vias 135 and 138 included in the long annular unit 130 is two, and the total number of signal vias 155 and 158 included in the short annular unit 150 is two. Each of the long annular unit 130 and the short annular unit 150 is in a vertical figure-eight shape (or "day" shape), and the ground via 139 is the center of the vertical figure-eight shape of the long annular unit 130, and the ground via 159 is the center of the vertical figure-eight shape of the short annular unit 150. On each of the first conductive layer 101 and the third conductive layer 103, the path lengths from the ground via 139 connected to the long annular unit 130 to the signal vias 135 and 138 included in the long annular unit 130 are equal, that is, the path length from the ground via 139 to the signal via 135 is equal to the path length from the ground via 139 to the signal via 138. The path lengths from the ground via 159 connected to the short annular unit 150 to the signal vias 155 and 158 included in the short annular unit 150 are equal, that is, the path length from the ground via 159 to the signal via 155 is equal to the path length from the ground via 159 to the signal via 158. Thus, the ground vias 139 and 159 at the center of the vertical figure-eight loop path can generate a low-frequency mode at the adjacent position of the resonance frequency, and at the same time contribute to achieving an expanded operating bandwidth and reducing the layout area.

[0055] The frequency divider 100 may further include a first feed line 110, a second feed line 170, segments 176 and 177, and a third feed line 190, all located on the second conductive layer 102 of the circuit board 108, which is sandwiched between the first conductive layer 101 and the third conductive layer 103. A first feed point 119 connects the first feed line 110 to the signal via 125 of the first coupling unit 120; a second feed point 179 connects the second feed line 170 to the signal via 168 of the second coupling unit 160; and a third feed point 199 connects the third feed line 190 to the signal via 188 of the third coupling unit 180, forming three sets of tuning fork-like structures including striplines and feed arm-type coupling units. This satisfies the signal coupling requirements of the vertically oriented frequency divider 100. Furthermore, each of the first feed line 110, the second feed line 170, segments 176 and 177, the third feed line 190, the first coupling unit 120, the second coupling unit 160, the third coupling unit 180, the long ring unit 130, and the short ring unit 150 is specifically a stripline. It should be understood that some transmission lines in the frequency divider according to this disclosure may be microstrip lines, and are not limited to this embodiment. Furthermore, each of the first feed line 110, the second feed line 170, and the third feed line 190 has a 50-ohm impedance and a width of 62µm. Segment 176 has a width of 150µm and a length of 300µm, and segment 177 has a width of 32µm and a length of 287µm. The second feed line 170, segments 176 and 177, the second feed point 179, and the signal via 168 are connected in sequence. The widths of segments 176 and 177 are different from those of the second feed line 170, forming an impedance matching unit. In the frequency divider according to this disclosure, the impedance matching unit can be a wire, pattern, or chip component on a circuit board.

[0056] The frequency divider 100 is specifically mirror-symmetrical to the second conductive layer 102. This reduces the design complexity of the dual-mode frequency divider 100. Furthermore, as in this embodiment… Figure 4As shown, the width w2 of line segment 123 of the first coupling unit 120, the width of line segment 166 of the second coupling unit 160, and the width of line segment 186 of the third coupling unit 180 are all 40um. The width w3 of the wire of the long ring unit 130 and the width of the wire of the short ring unit 150 are both 62um. The spacing g23 between the line segments of each parallel and adjacent coupling unit and the line segments of each ring unit is between 31.2um and 42um. The length x1 of the coupling resonant structure of the frequency divider 100 is 2162.6um and the width y1 is 1023um. The thickness h1 of the circuit board 108 is 400um. Therefore, the frequency divider 100 has sufficiently small length and width dimensions to be suitable for 5G millimeter wave products.

[0057] Figure 5 Draw Figure 1 The S-parameter diagram of the intermediate frequency divider 100 shows that the first measurement terminal (common terminal), the second measurement terminal (low-pass terminal), and the third measurement terminal (high-pass terminal) used to measure the S-parameters in the diagram can be respectively located at the edges of the first feed line 110, the second feed line 170, and the third feed line 190 on the circuit board 108. Please refer to... Figure 5 The frequency divider 100 has a low-pass 3dB band defined by parameter S21 from 26.02GHz to 29.65GHz, and a high-pass 3dB band defined by parameter S31 from 37.00GHz to 40.36GHz. Within the low-pass 3dB band and the high-pass 3dB band, each of parameters S22 and S33 has two extreme values, and their corresponding frequencies are defined as resonant frequencies. That is, the low-pass 3dB band and the high-pass 3dB band each generate two resonant frequencies, exhibiting a dual-mode operation. Specifically, S2... The S21 parameter's indicator point m1 is 26.50GHz, -2.21dB; the S21 parameter's indicator point m2 is 28.00GHz, -2.08dB; the S21 parameter's indicator point m3 is 29.50GHz, -2.66dB; the S31 parameter's indicator point m4 is 37.00GHz, -2.91dB; the S31 parameter's indicator point m5 is 38.50GHz, -1.92dB; and the S31 parameter's indicator point m6 is 40.00GHz, -2.47dB. Furthermore, the frequency divider 100 has a low-frequency band rejection of approximately 30dB based on parameter S31, a high-frequency band rejection of more than 25dB based on parameter S21, and a low-pass to high-pass isolation of more than 25dB based on parameter S23. Thus, the bandwidth of the low-pass 3dB band and the high-pass 3dB band is suitable for the frequency bands (n257, n260 and n261) where 5G millimeter wave FR2 is widely used today.

[0058] In other words, the long ring unit 130 corresponds to the low-pass 3dB band, and the short ring unit 150 corresponds to the high-pass 3dB band. Each of the low-pass 3dB and high-pass 3dB bands specifically contains two resonant frequencies. This effectively reduces design complexity and expands the bandwidth of each of the dual operating bands.

[0059] Figure 6 Draw Figure 1 A schematic diagram of the surface current density of the intermediate frequency divider 100, wherein... Figure 6 The varying shades of color along the edges of the intermediate frequency divider 100 are merely illustrative and do not represent the magnitude of the surface current density. Please refer to [reference needed]. Figures 4 to 6 According to this disclosure, the surface current densities of the frequency divider 100 at 28 GHz and 39 GHz are respectively as follows: Figure 6 As shown in (a) and (b), after the signal of the frequency divider 100 is fed in from the common terminal located at the first feed line 110, the low-frequency signal in the low-pass 3dB band near 28GHz will resonate through the loop path of the long loop unit 130 at the corresponding low-pass terminal, while the high-frequency signal in the high-pass 3dB band near 39GHz will resonate through the loop path of the short loop unit 150 at the corresponding high-pass terminal. Furthermore, each band in the low-pass 3dB and high-pass 3dB bands has dual modes due to the generation of adjacent lower-frequency modes, and as shown... Figure 5 The S-parameters of the dual-mode are shown, thus the frequency divider 100 is specifically suitable for today's 5G millimeter-wave products and can expand the operating bandwidth.

[0060] Although the present invention has been disclosed above with reference to embodiments, it is not intended to limit the present invention. Any person skilled in the art can make various modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A frequency divider, characterized in that, Distributed on a circuit board, wherein the circuit board sequentially includes a first conductive layer, a second conductive layer, and a third conductive layer, the frequency divider includes: A first coupling unit is connected to a first feed point; A second coupling unit is connected to a second feed point; A third coupling unit is connected to a third feed point; A long ring-shaped unit, wherein the first coupling unit and the second coupling unit are coupled to the long ring-shaped unit; A short ring unit, wherein the first coupling unit and the third coupling unit couple the short ring unit, and each of the first coupling unit, the second coupling unit, the third coupling unit, the long ring unit, and the short ring unit includes at least one signal via and is located in the first conductive layer and the third conductive layer; and At least one ground plane is located in the second conductive layer, wherein the at least one ground plane is the reference ground for the first coupling unit, the second coupling unit, the third coupling unit, the long ring unit and the short ring unit.

2. The frequency divider as described in claim 1, characterized in that, The long ring unit includes a first coupling portion, and the short ring unit includes a third coupling portion. Each of the first coupling portion and the third coupling portion includes the at least one signal via and is located in the first conductive layer and the third conductive layer. The first coupling portion and the third coupling portion are located on both sides of the first coupling unit, and at least a portion of the first coupling unit, at least a portion of the first coupling portion, and at least a portion of the third coupling portion are parallel to each other.

3. The frequency divider as described in claim 1, characterized in that, The long ring unit includes a second coupling portion, and the short ring unit includes a fourth coupling portion. Each of the second coupling portion and the fourth coupling portion includes the at least one signal via and is located in the first conductive layer and the third conductive layer. The second coupling unit is farther away from the first coupling unit than the second coupling portion, and at least a portion of the second coupling unit and at least a portion of the second coupling portion are parallel to each other. The third coupling unit is farther away from the first coupling unit than the fourth coupling portion, and at least a portion of the third coupling unit and at least a portion of the fourth coupling portion are parallel to each other.

4. The frequency divider as described in claim 1, characterized in that, The ratio of the path length of the short ring unit located in one of the first conductive layer and the third conductive layer to the path length of the first coupling unit located in the conductive layer is between 2.2 and 12.

5. The frequency divider as described in claim 1, characterized in that, The frequency divider is mirror-symmetrical about the second conductive layer.

6. The frequency divider as described in claim 1, characterized in that, It also includes: Two grounding vias, wherein one of the two grounding vias is connected to the long annular unit and the at least one grounding plane, and the other of the two grounding vias is connected to the short annular unit and the at least one grounding plane.

7. The frequency divider as described in claim 6, characterized in that, The long ring unit corresponds to a low-pass 3dB frequency band, and the short ring unit corresponds to a high-pass 3dB frequency band. Each of the low-pass 3dB frequency band and the high-pass 3dB frequency band contains two resonant frequencies.

8. The frequency divider as described in claim 6, characterized in that, The long ring unit and the short ring unit each contain two signal vias, and each of the long ring unit and the short ring unit is figure-eight shaped. In one of the first conductive layer and the third conductive layer, the path lengths from the grounding via connected to the long annular unit to the two signal vias contained therein are equal, and the path lengths from the grounding via connected to the short annular unit to the two signal vias contained therein are equal.

9. The frequency divider as described in claim 1, characterized in that, It also includes: A first feed line, wherein the first feed point is connected between the first feed line and the at least one signal via of the first coupling unit; and A second feed line, wherein the second feed point is connected between the second feed line and the at least one signal via of the second coupling unit; and A third feed line, wherein the third feed point is connected between the third feed line and the at least one signal via of the third coupling unit; The first feed line, the second feed line, and the third feed line are all located in the second conductive layer.

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