RF circuit using zigzag wiring instead of resistors

Abstract

The present invention provides a radio frequency circuit in which a font-shaped routing replaces a resistor, which is used to replace the resistor, and the resistor has a first equivalent impedance at the radio frequency frequency. The radio frequency circuit in which the font-shaped routing replaces the resistor comprises a routing layer and a ground layer, wherein the routing layer comprises a first pad, a second pad and a font-shaped routing unit. The second pad corresponds to the first pad. The font-shaped routing unit is connected between the first pad and the second pad and has a line width, and the line width is less than the line width of 50 ohms. The ground layer is arranged below the routing layer and is separated from the routing layer by a height. The font-shaped routing unit has a second equivalent impedance at the radio frequency frequency, and the second equivalent impedance is determined according to the line width, height and radio frequency frequency, and the second equivalent impedance is the same as or similar to the first equivalent impedance. Thereby, the font-shaped routing can replace the physical resistor without affecting the high-frequency impedance matching.

Description

Technical Field

[0001] The invention relates to a radio frequency circuit, in particular to a radio frequency circuit with a font-shaped wiring replacing a resistor. Background Art

[0002] As electronic products become smaller and smaller, and different radio frequency (RF) technologies are used, and many different RF components exist in the same system and interfere with each other, multiple sets of matching circuits need to be reserved in the RF circuit to solve the interference and mismatching problems. If the reserved circuit is not used, a physical resistor is still needed to connect the circuit. Figure 1 A three-dimensional schematic diagram of a conventional radio frequency circuit 100 with a resistor is shown, which includes a first pad 200, a second pad 300 and a resistor 400. The resistor 400 is connected between the first pad 200 and the second pad 300. For a product, the physical resistor 400 is an additional cost.

[0003] If the physical resistor 400 is removed to save costs, in order to maintain the original impedance matching and RF signal performance, the general existing practice requires re-adjusting the matching circuits before and after. This situation is particularly serious in the high-frequency band of WIFI 5G, and all RF tests need to be re-measured, thereby increasing manufacturing costs and time. It can be seen that there is currently a lack of a RF circuit in the market that can avoid re-adjusting the matching circuit and re-measuring the RF test, reduce manufacturing costs and shorten time, and replace the resistor with a Font routing. Therefore, relevant practitioners are looking for a solution. Summary of the invention

[0004] Therefore, the purpose of the present invention is to provide a radio frequency circuit that uses a V-shaped trace to replace resistors. The V-shaped trace is used to connect two pads (i.e., footprint) and a corresponding ground layer to create a high-frequency inductance characteristic similar to that of a physical resistor, thereby improving the high-frequency impedance effect of general existing traces and solving the impedance mismatch problem in the prior art.

[0005] According to one embodiment of the structural form of the present invention, a radio frequency circuit in which a zigzag routing replaces a resistor is provided, which is used to replace a resistor, and the resistor has a first equivalent impedance at a radio frequency frequency. The radio frequency circuit in which the zigzag routing replaces the resistor includes a routing layer and a grounding layer, wherein the routing layer includes a first pad, a second pad and a zigzag routing unit. The second pad corresponds to the first pad. The zigzag routing unit is connected between the first pad and the second pad and has a line width, and the line width is less than the line width of 50 ohms. The grounding layer is arranged below the routing layer and is separated from the routing layer by a height. The zigzag routing unit has a second equivalent impedance at a radio frequency frequency, and the second equivalent impedance is determined according to the line width, height and radio frequency frequency, and the second equivalent impedance is the same or similar to the first equivalent impedance. The radio frequency circuit in which the zigzag routing replaces the resistor also includes another grounding layer, which is arranged between the routing layer and the grounding layer, and the other grounding layer has a perforation, and the perforation corresponds to the zigzag routing unit of the routing layer. The routing layer and the grounding layer are both arranged on a printed circuit board.

[0006] Thus, the radio frequency circuit of the present invention that replaces the resistor with the font routing uses the solder pad of the original circuit and combines the font routing unit and the ground layer to make its high frequency impedance characteristics equivalent to those of the physical resistor. Therefore, the physical resistor can be directly replaced without affecting the impedance matching. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 A three-dimensional schematic diagram of a conventional radio frequency circuit with a resistor is shown;

[0008] Figure 2 A schematic diagram showing a radio frequency circuit in which a resistor is replaced by a zigzag wiring according to a first embodiment of the present invention;

[0009] Figure 3 Show Figure 2 A cross-sectional view of a radio frequency circuit along section line 3-3 in which a resistor is replaced by a zigzag trace;

[0010] Figure 4 A schematic diagram showing a radio frequency circuit in which a resistor is replaced by a zigzag wiring according to a second embodiment of the present invention;

[0011] Figure 5 A schematic diagram showing a radio frequency circuit in which a resistor is replaced by a zigzag wiring according to a third embodiment of the present invention;

[0012] Figure 6 A schematic diagram showing a radio frequency circuit in which a resistor is replaced by a zigzag wiring according to a fourth embodiment of the present invention;

[0013] Figure 7 A schematic diagram showing a radio frequency circuit in which a resistor is replaced by a zigzag wiring according to a fifth embodiment of the present invention;

[0014] Figure 8 A schematic diagram showing a radio frequency circuit with a zigzag wiring replacing a resistor according to a sixth embodiment of the present invention; and

[0015] Fig. 9 A schematic diagram showing a radio frequency circuit with a zigzag wiring replacing a resistor according to a seventh embodiment of the present invention.

[0016] Description of reference numerals:

[0017] 100: RF circuits with resistors

[0018] 100a, 100b, 100c, 100d, 100e, 100f, 100g: RF circuits with zigzag traces replacing resistors

[0019] 200: First pad

[0020] 300: Second welding pad

[0021] 400: Resistance

[0022] 500a,500b,500c,500d,500e,500f,500g: font routing unit

[0023] 510a, 510b, 510e: first transmission line

[0024] 520a, 520b, 520e: Second transmission line

[0025] 530a, 530b, 530e: The third transmission line

[0026] 540b: Fourth transmission line

[0027] 550b: The fifth transmission line

[0028] 600a, 600b, 600c, 600d, 600e, 600f, 600g: Perforation

[0029] D: Spacing

[0030] H: Height

[0031] Layer1: routing layer

[0032] Layer2, Layer3: Ground layer

[0033] R: Region

[0034] TW: Line width

[0035] θ1: first angle

[0036] θ2: Second angle DETAILED DESCRIPTION

[0037] Please refer to Figure 1 , Figure 2 and Figure 3 ,in Figure 2 A schematic diagram showing a radio frequency circuit 100a in which a resistor is replaced by a zigzag wiring according to a first embodiment of the present invention; and Figure 3 Show Figure 2 The cross-sectional view of the radio frequency circuit 100a with a zigzag wiring replacing a resistor along the section line 3-3. The radio frequency circuit 100a with a zigzag wiring replacing a resistor is used to replace Figure 1 The resistor 400 has a first equivalent impedance at a radio frequency. The radio frequency circuit 100a with a zigzag wiring replacing a resistor comprises a wiring layer Layer1 and a ground layer Layer3.

[0038] The routing layer Layer1 includes a first pad 200, a second pad 300 and a font routing unit 500a. The second pad 300 corresponds to the first pad 200. The font routing unit 500a is connected between the first pad 200 and the second pad 300 and has a line width TW, which is less than a 50 ohm line width. The ground layer Layer3 is disposed below the routing layer Layer1 and is separated from the routing layer Layer1 by a height H. The font routing unit 500a has a second equivalent impedance at the radio frequency frequency, and the second equivalent impedance is determined according to the line width TW, the height H and the radio frequency frequency, and the second equivalent impedance is the same or similar to the first equivalent impedance. In this way, the radio frequency circuit 100a of the present invention, in which the font routing replaces the resistor, uses the pad of the original circuit, and combines the font routing unit 500a and the ground layer Layer3, so that its high-frequency impedance characteristics are equivalent to those of the physical resistor 400, so that the physical resistor 400 can be directly replaced without affecting the impedance matching. In addition, the present invention removes the physical resistor 400 and replaces it with the font wiring unit 500a, and the equivalent impedance characteristic of the font wiring unit 500a can avoid the re-adjustment of the matching circuit and the re-measurement of the RF test, thereby significantly reducing the manufacturing cost and shortening the time.

[0039] Specifically, the resistor 400 is a 0 ohm resistor. The radio frequency is less than or equal to 10 GHz, which can cover all wireless communication systems using frequencies below 10 GHz. In the routing layer Layer1, the first pad 200 and the second pad 300 are both pads (PADs) of a surface mount device (SMD). The first pad 200 and the second pad 300 are separated by a spacing D, and a region R is formed between the first pad 200 and the second pad 300. The size of the region R conforms to one of the standard sizes 0201, 0402, and 0603 of the SMD. Among them, the standard size 0201 has a first length and a first width, and the first length and the first width are 0.6 mm and 0.3 mm respectively; the standard size 0402 has a second length and a second width, and the second length and the second width are 1.0 mm and 0.5 mm respectively; the standard size 0603 has a third length and a third width, and the third length and the third width are 1.6 mm and 0.8 mm respectively.

[0040] exist Figure 2 In the embodiment of the invention, the shape of the Z-shaped routing unit 500a is Z-shaped (i.e., zigzag) and includes a first transmission line 510a, a second transmission line 520a, and a third transmission line 530a. The first transmission line 510a is connected to the first pad 200, and the second transmission line 520a is connected to the first transmission line 510a. The third transmission line 530a is connected between the second transmission line 520a and the second pad 300. The first transmission line 510a, the second transmission line 520a, and the third transmission line 530a are all located between the first pad 200 and the second pad 300, and there is a first angle θ1 between the first transmission line 510a and the second transmission line 520a, and there is a second angle θ2 between the second transmission line 520a and the third transmission line 530a, and the first angle θ1 is equal to the second angle θ2. Furthermore, the font wiring unit 500a has a line length, which is equal to the total length of the first transmission line 510a, the second transmission line 520a and the third transmission line 530a. In one embodiment, the first angle θ1 can be 90 degrees, the line length can be equal to 16 mil, and the line width TW can be equal to 2 mil, but the present invention is not limited thereto.

[0041] The radio frequency circuit 100a in which the resistor is replaced by a font-shaped trace further includes a ground layer Layer2, and the ground layer Layer2 is disposed between the trace layer Layer1 and the ground layer Layer3. The ground layer Layer2 has a through hole 600a, and the through hole 600a corresponds to the font-shaped trace unit 500a of the trace layer Layer1. The through hole 600a can increase the inductance of the font-shaped trace unit 500a at the radio frequency frequency, thereby making the second equivalent impedance of the font-shaped trace unit 500a the same or similar to the first equivalent impedance of the resistor 400 of 0 ohm. The ground layer Layer2 and the ground layer Layer3 are both grounded and are both disposed below the trace layer Layer1. The trace layer Layer1 and the ground layers Layer2 and Layer3 are all disposed on a printed circuit board (PCB), and the printed circuit board can be one of a glass fiber substrate (FR4 PCB) and a ceramic substrate (Ceramic PCB). In one embodiment, the height H between the routing layer Layer 1 and the ground layer Layer 3 may be equal to 0.6 to 3.5 times the line width of 50 ohms. Preferably, the height H is equal to 1.4 times the line width of 50 ohms. In another embodiment, the height H may be greater than or equal to 2 mil and less than or equal to 15 mil, but the present invention is not limited thereto.

[0042] For example, Table 1 shows the impedance of the RF circuit 100a with a zigzag wiring replacing resistors, a 0 ohm resistor and a 50 ohm line width under different RF frequency conditions (1 GHz, 2.44 GHz and 5.85 GHz) on the Smith Chart. Table 2 shows the error of the imaginary impedance of the RF circuit 100a with a zigzag wiring replacing resistors and a 50 ohm line width compared to a 0 ohm resistor under different RF frequency conditions. It can be seen from Table 1 and Table 2 that the first equivalent impedance of the resistor 400 (0 ohm resistor) at 5.85 GHz is 48.52-j4.59, and the second equivalent impedance of the font routing unit 500a at 5.85 GHz is 48.41-j5.29; in other words, when the RF frequency is 5.85 GHz (WIFI 5G), the error of the imaginary impedance of the RF circuit 100a of the font routing replacing the resistor of the present invention compared with the 0 ohm resistor is only 0.7 ohms (5.29 ohms minus 4.59 ohms), and the error of the existing 50 ohm line width (that is, the existing pads are connected with a 50 ohm line width) compared with the imaginary impedance of the 0 ohm resistor is 3.72 ohms (8.31 ohms minus 4.59 ohms), so the present invention improves the error of 3.02 ohms (3.72 ohms minus 0.7 ohms).

[0043] Table 1

[0044]

[0045]

[0046] Table 2

[0047]

[0048] Please refer to Figure 2 , Figure 3 and Figure 4 ,in Figure 4 A schematic diagram of a radio frequency circuit 100b in which a resistor is replaced by a zigzag routing according to a second embodiment of the present invention is shown. The radio frequency circuit 100b in which a resistor is replaced by a zigzag routing comprises a routing layer Layer 1 and ground layers Layer 2 and Layer 3. The routing layer Layer 1 comprises a first pad 200, a second pad 300 and a zigzag routing unit 500b. The zigzag routing unit 500b is in a Z-shape and comprises a first transmission line 510b, a second transmission line 520b, a third transmission line 530b, a fourth transmission line 540b and a fifth transmission line 550b. The first transmission line 510b is connected to the first pad 200, and the fifth transmission line 550b is connected to the second pad 300. The first transmission line 510b, the second transmission line 520b, the third transmission line 530b, the fourth transmission line 540b and the fifth transmission line 550b are connected to each other in sequence. In addition, the ground layer Layer2 has a through hole 600b, and the through hole 600b corresponds to the middle portion of the font wiring unit 500b of the wiring layer Layer1.

[0049] Please refer to Figure 2 , Figure 3 and Figure 5 ,in Figure 5 The schematic diagram of the RF circuit 100c with the zigzag wiring replacing the resistor according to the third embodiment of the present invention is shown. The RF circuit 100c with the zigzag wiring replacing the resistor comprises a wiring layer Layer 1 and ground layers Layer 2 and Layer 3. The wiring layer Layer 1 comprises a first pad 200, a second pad 300 and a zigzag wiring unit 500c. The zigzag wiring unit 500c is in a Z-shape and is connected to the ground layer 200. Figure 2 The shape of the Font wiring unit 500a is similar to that of the Font wiring unit 500a, and the only difference is that the sharp corner becomes an arc corner. In addition, the ground layer Layer2 has a through hole 600c, and the through hole 600c is connected to Figure 2 The through hole 600a is the same as that of the embodiment, so it will not be described in detail.

[0050] Please refer to Figure 2 , Figure 3 , Figure 4 and Figure 6 ,in Figure 6The schematic diagram of the radio frequency circuit 100d with the zigzag wiring replacing the resistor according to the fourth embodiment of the present invention is shown. The radio frequency circuit 100d with the zigzag wiring replacing the resistor comprises a wiring layer Layer 1 and ground layers Layer 2 and Layer 3. The wiring layer Layer 1 comprises a first pad 200, a second pad 300 and a zigzag wiring unit 500d. The zigzag wiring unit 500d is in a Z-shape and is connected to the ground layer 200. Figure 4 The shape of the Font wiring unit 500b is similar to that of the Font wiring unit 500b, and the only difference is that the sharp corner becomes an arc corner. In addition, the ground layer Layer2 has a through hole 600d, and the through hole 600d is connected to Figure 4 The perforation 600b is the same as that of the embodiment, so it will not be described in detail.

[0051] Please refer to Figure 2 , Figure 3 and Figure 7 ,in Figure 7 A schematic diagram of a radio frequency circuit 100e in which a resistor is replaced by a zigzag routing according to a fifth embodiment of the present invention is shown. The radio frequency circuit 100e in which a resistor is replaced by a zigzag routing comprises a routing layer Layer 1 and ground layers Layer 2 and Layer 3. The routing layer Layer 1 comprises a first pad 200, a second pad 300 and a zigzag routing unit 500e. The zigzag routing unit 500e is in an inverted U shape (i.e., a U shape) and comprises a first transmission line 510e, a second transmission line 520e and a third transmission line 530e. The first transmission line 510e is connected between the first pad 200 and the second transmission line 520e, and the third transmission line 530e is connected between the second pad 300 and the second transmission line 520e. In addition, the ground layer Layer 2 has a through hole 600e, and the through hole 600e corresponds to the zigzag routing unit 500e of the routing layer Layer 1, the upper portion of the first pad 200 and the upper portion of the second pad 300.

[0052] Please refer to Figure 2 , Figure 3 , Figure 7 and Figure 8 ,in Figure 8 The schematic diagram of the radio frequency circuit 100f with a zigzag wiring replacing a resistor according to the sixth embodiment of the present invention is shown. The radio frequency circuit 100f with a zigzag wiring replacing a resistor comprises a wiring layer Layer 1 and ground layers Layer 2 and Layer 3. The wiring layer Layer 1 comprises a first pad 200, a second pad 300 and a zigzag wiring unit 500f. The zigzag wiring unit 500f is in an inverted U shape and is connected to the ground layer 200. Figure 7 The shape of the Font wiring unit 500e is similar to that of the Font wiring unit 500e, the only difference is that the sharp corner becomes a curved corner. In addition, the ground layer Layer2 has a through hole 600f, and the through hole 600f is connected to Figure 7 The perforations of 600e are the same and therefore will not be described again.

[0053] Please refer to Figure 2 , Figure 3 and Fig. 9 ,in Fig. 9 The schematic diagram of the radio frequency circuit 100g with the zigzag wiring replacing the resistor according to the seventh embodiment of the present invention is shown. The radio frequency circuit 100g with the zigzag wiring replacing the resistor comprises a wiring layer Layer 1 and ground layers Layer 2 and Layer 3. The wiring layer Layer 1 comprises a first pad 200, a second pad 300 and a zigzag wiring unit 500g. The zigzag wiring unit 500g is in an S-shape, that is, the wiring is a curve. In addition, the ground layer Layer 2 has a through hole 600g, and the through hole 600g is connected to the ground layer 2. Figure 2 The through hole 600a is the same as that of the embodiment, so it will not be described in detail.

[0054] The technical effects of the aforementioned perforations 600b, 600c, 600d, 600e, 600f, and 600g are similar to those of Figure 2 The technical effect of the through hole 600a is the same, that is, the inductance of each font wiring unit 500b, 500c, 500d, 500e, 500f, 500g at the radio frequency can be improved, so that the second equivalent impedance of each font wiring unit 500b, 500c, 500d, 500e, 500f, 500g is the same or similar to the first equivalent impedance of the 0 ohm resistor 400.

[0055] Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention. Any person skilled in the art can make various changes and modifications without departing from the concept and scope of the present invention. Therefore, the scope of protection of the present invention shall be based on the definition of the claims.

Claims

1. A radio frequency circuit in which a resistor is replaced by a zigzag wiring, wherein the resistor has a first equivalent impedance at a radio frequency, characterized in that The RF circuit in which the resistor is replaced by the zigzag trace includes: A routing layer, including: a first welding pad; a second bonding pad, corresponding to the first bonding pad; and A straight-line wiring unit connected between the first pad and the second pad and having a line width that is smaller than a 50-ohm line width; and A ground layer, disposed below the wiring layer and spaced apart from the wiring layer by a height; The font wiring unit has a second equivalent impedance at the radio frequency, the second equivalent impedance is determined according to the line width, the height and the radio frequency, and the second equivalent impedance is the same as or similar to the first equivalent impedance; The RF circuit in which the resistor is replaced by the font-shaped trace also includes: Another grounding layer is disposed between the wiring layer and the grounding layer, and the other grounding layer has a through hole, and the through hole corresponds to the font wiring unit of the wiring layer; Wherein, the wiring layer and the grounding layer are both arranged on a printed circuit board.

2. The radio frequency circuit with a zigzag wiring replacing a resistor as claimed in claim 1, characterized in that The height is greater than or equal to 2 mil and less than or equal to 15 mil.

3. The radio frequency circuit with a zigzag wiring replacing a resistor as claimed in claim 1, characterized in that The height is equal to 0.6 to 3.5 times the 50-ohm line width.

4. The radio frequency circuit with a zigzag wiring replacing a resistor as claimed in claim 1, characterized in that The first pad is spaced apart from the second pad by a distance, and the first pad and the second pad form an area, the size of the area conforms to one of a standard size 0201, a standard size 0402, and a standard size 0603 of a surface mount component; The standard size 0201 has a first length and a first width, and the first length and the first width are 0.6 mm and 0.3 mm respectively; The standard size 0402 has a second length and a second width, and the second length and the second width are 1.0 mm and 0.5 mm respectively; The standard size 0603 has a third length and a third width, and the third length and the third width are 1.6 mm and 0.8 mm respectively.

5. The radio frequency circuit with a zigzag wiring replacing a resistor as claimed in claim 1, characterized in that The font routing unit also has a line length equal to 16 mils, and a line width equal to 2 mils.

6. The radio frequency circuit with a zigzag wiring replacing a resistor as claimed in claim 1, characterized in that The resistor is a 0 ohm resistor, and the radio frequency is less than or equal to 10 GHz.

7. The radio frequency circuit with a zigzag wiring replacing a resistor as claimed in claim 1, characterized in that The shape of the shaped wiring unit is one of a Z shape, an S shape and an inverted U shape.

8. The radio frequency circuit with a zigzag wiring replacing a resistor as claimed in claim 7, characterized in that The Z-shaped wiring unit is in the shape of the letter Z and includes: a first transmission line connected to the first pad; a second transmission line connected to the first transmission line; and a third transmission line connected between the second transmission line and the second pad; The first transmission line, the second transmission line and the third transmission line are all located between the first pad and the second pad, there is a first angle between the first transmission line and the second transmission line, there is a second angle between the second transmission line and the third transmission line, and the first angle is equal to the second angle.

9. The radio frequency circuit with a zigzag wiring replacing a resistor as claimed in claim 1, characterized in that The printed circuit board is one of a glass fiber substrate and a ceramic substrate.

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