CN115802583A

CN115802583A - Double-frequency conversion circuit structure

Info

Publication number: CN115802583A
Application number: CN202111060756.1A
Authority: CN
Inventors: 谢子皓; 王至诘
Original assignee: Realtek Semiconductor Corp
Current assignee: Realtek Semiconductor Corp
Priority date: 2021-09-10
Filing date: 2021-09-10
Publication date: 2023-03-14

Abstract

The application discloses a double-frequency conversion circuit structure, which comprises a first transmission line, a second transmission line and a conductive layer. The first transmission line has a first input terminal, a first output terminal and a second output terminal. The second transmission line has a second input end, a third output end and a fourth output end. The second input terminal is coupled to the first output terminal, and the third input terminal is coupled to the second output terminal. The conductive layer is stacked with the first transmission line and the second transmission line. The conducting layer comprises a first hollow pattern. The first hollow pattern and the second transmission line are overlapped on the top view.

Description

Double-frequency conversion circuit structure

Technical Field

The present application relates to a wireless communication circuit structure, and more particularly, to a dual-band conversion circuit structure.

Background

In a wireless communication system, due to the fact that the linearity of the power output stage is not ideal enough, higher harmonics are formed at the output end more or less and cause interference to other frequency bands. Therefore, it is a concern in the art to suppress the higher harmonics of the system within the specification to improve the performance of the system and meet the regulations.

Disclosure of Invention

The application discloses a double-frequency conversion circuit structure, which comprises a first transmission line, a second transmission line and a conductive layer. The first transmission line has a first input terminal, a first output terminal, and a second output terminal. The second transmission line has a second input terminal, a third output terminal and a fourth output terminal. The second input terminal is coupled to the first output terminal, and the third input terminal is coupled to the second output terminal. The conductive layer is stacked with the first transmission line and the second transmission line. The conducting layer comprises a first hollow pattern. The first hollow pattern and the second transmission line are overlapped on the top view.

The application discloses a dual-frequency conversion circuit structure, which comprises a first conductive layer and a second conductive layer. The second conductive layer comprises a first hollow pattern. The second conductive layer is stacked with the first conductive layer and separated by a dielectric material. The first conductive layer includes a balun circuit, a filter circuit, and a coplanar stripline. The filter circuit includes a transmission line. The transmission line comprises a second hollow pattern. The first hollow pattern is overlapped with the transmission line on the top view, and is not overlapped with the second hollow pattern on the top view. The filter circuit is coupled between the balun circuit and the coplanar stripline.

The double-frequency conversion circuit structure utilizes the hollow patterns on the transmission line and the grounding conductive layer to provide higher insertion loss for the high-frequency signal part. Compared with the prior art, the dual-frequency conversion circuit structure does not use additional components, materials and wiring area, and can improve the suppression capability for higher harmonics.

Drawings

Various embodiments of the present application can be best understood when read in conjunction with the following description and the accompanying drawings. It should be noted that, in accordance with standard practice in the art, the various features of the drawings are not drawn to scale. In fact, the dimensions of some of the features may be exaggerated or minimized intentionally for clarity of illustration.

Fig. 1 is a schematic diagram of a dual-band conversion circuit according to some embodiments of the present disclosure.

Fig. 2 is a schematic diagram of a first conductive layer in a dual-band switching circuit structure according to some embodiments of the present disclosure.

Fig. 3 is a diagram illustrating a second conductive layer in a dual-band switching circuit structure according to some embodiments of the present disclosure.

Fig. 4 is a detailed schematic diagram of a portion of a dual-band converting circuit structure according to some embodiments of the present application.

Description of the symbols:

10: double-frequency conversion circuit structure

100 conductive layer

200 conductive layer

120 transmission line

140 transmission line

160 transmission line

161 first strip line

162 first strip line

T1 hollow pattern

T2 hollow pattern

T3 hollow pattern

T4 hollow pattern

U1 hollow pattern

U2 hollow pattern

U3 hollow pattern

U4 hollow pattern

C1: gap

C2 gap

C3 gap

C4 gap

O1: opening

O2-open mouth

O3-opening

O4 opening

N1: input terminal

N2 is the output end

N3 is the output end

N4 input terminal

N5 input terminal

N6 output terminal

N7 is the output end

N8 input terminal

N9 input terminal

SG1 first stage

SG2 second stage

SG3 third stage

SG4 fourth stage

Detailed Description

The embodiment of the application improves a double-frequency conversion circuit in double-frequency wireless communication so as to increase the harmonic suppression capability of the double-frequency conversion circuit and further reduce higher harmonics of the whole system. Fig. 1 is a schematic diagram of an embodiment of a dual-band conversion circuit 10 according to the present application. The dual-band switching circuit structure 10 is used for receiving an input signal and generating a switching signal to a power output stage (not shown). The power output stage gains the converted signal into an output signal according to the gain value and outputs the output signal. In some embodiments, dual-band conversion circuit architecture 10 is employed in a transmitter for dual-band wireless communications, such as a transmitter conforming to the IEEE 802.11a/b/g/n/ac specification.

The dual-band switching circuit structure 10 is disposed on a dual-layer printed circuit board, which includes a conductive layer 100 and a conductive layer 200 stacked on each other and separated by a dielectric material. The conductive layer 100 is disposed on the top of the double-layer pcb, and includes a dual-frequency microstrip line (microstrip) for receiving an input signal and performing signal processing, and outputs the processed signal through a coplanar strip line (coplanar strip) 160. The conductive layer 200 is used as a reference ground layer and is disposed on the bottom of the double-layer printed circuit board. As shown in fig. 1, the dual-band microstrip line includes a balun circuit (balun circuit) 120 (hereinafter referred to as a transmission line 120) and a filter circuit 140 (hereinafter referred to as a transmission line 140). In a further embodiment, the filter circuit 140 is a low pass filter. The coplanar stripline 160 (hereinafter referred to as a transmission line 160) includes a first stripline 161 and a first stripline 162.

The input end N1 of the transmission line 120 is used for receiving the input signal; the output end N2 and the output end N3 of the transmission line 120 are respectively connected to the input end N4 and the input end N5 of the transmission line 140; the output terminal N6 and the output terminal N7 of the transmission line 140 are respectively connected to the input terminal N8 of the first strip line 161 and the input terminal N9 of the second strip line 162. As shown in the top view of fig. 1, the transmission line 120 and the transmission line 140 are disposed in the range of the conductive layer 200 and overlap with each other, the left end of the transmission line 160 overlaps the conductive layer 200 and extends out of the range of the conductive layer 200 to the right, specifically, the first strip line 161 and the first strip line 162 extend along a direction away from the transmission line 140.

Fig. 2 and 3 are schematic diagrams of the

conductive layers

100 and 200 respectively, so as to facilitate understanding of the relative arrangement of the components in the

conductive layers

100 and 200.

Referring to fig. 2, the transmission line 140 includes hollow patterns T1, T2, T3 and T4. As shown in fig. 3, the conductive layer 200 includes a whole metal having hollow patterns U1, U2, U3 and U4, and as shown in fig. 1, the hollow patterns U1 to U4 are partially overlapped with the transmission line 140, but none of the hollow patterns U1 to U4 is overlapped with the hollow patterns T1 to T4 of the transmission line 140.

Please refer to fig. 4. FIG. 4 is a schematic diagram illustrating the transmission line 140 and the hollow patterns U1-U4. The transmission line 140 includes a first segment SG1, a second segment SG2, a third segment SG3, and a fourth segment SG4. The first section SG1 is connected between the input end N4 and the second section SG 2; the second section SG21 is connected between the first section SG1 and the output end N6; the third section SG3 is connected between the input end N5 and the fourth section SG 4; the fourth segment SG4 is connected between the third segment SG3 and the output terminal N7. In a top view, the first section SG1, the third section SG3, the first strip line 161 and the second strip line 162 are disposed in parallel, the second section SG2 and the fourth section SG4 are disposed in parallel, the first section SG1 and the second section SG2 are disposed perpendicularly, and the third section SG3 and the fourth section SG4 are disposed perpendicularly.

The hollow pattern T1 is arranged in the first section SG 1; the hollow pattern T2 is arranged in the second section SG 2; the hollow pattern T3 is arranged in the third section SG 3; the hollow pattern T4 is disposed in the fourth segment SG4.

In a top view, the hollow patterns T1 to T4 in the transmission line 140 are not closed hollow patterns, and are T-shaped hollow patterns with a gap. The notch C1 of the hollowed-out pattern T1 faces the direction far away from the third section SG 3; the gap C2 of the hollow pattern T2 faces away from the transmission line 160; the notch C3 of the hollowed-out pattern T3 faces the direction far away from the first section SG 1; the notch C4 of the hollow pattern T4 faces away from the transmission line 160. The first section SG1, the hollow pattern T1, the second section SG2 and the hollow pattern T2 are respectively arranged symmetrically to the third section SG3, the hollow pattern T3, the fourth section SG4 and the hollow pattern T4. In some embodiments, the sizes of the hollow patterns T1 and T3 are the same, and the sizes of the hollow patterns T2 and T4 are the same. In some embodiments, the size of the hollow pattern T1 is different from that of the hollow pattern T2. In other embodiments, the directions of the gaps C1-C4 of the hollow patterns T1-T4 can be different from those shown in FIG. 2.

In a top view, the hollow pattern U1 overlaps the first section SG1, the hollow pattern U2 overlaps the first section SG2, the hollow pattern U3 overlaps the first section SG3, and the hollow pattern U4 overlaps the first section SG4. The hollow patterns U1-U4 are closed hollow patterns and are U-shaped hollow patterns with an opening. The first section SG1 penetrates through an opening O1 of the hollow pattern U1, and the opening O1 faces to the input end N4; the second section SG2 penetrates through an opening O2 of the hollow pattern U2, and the opening O2 faces to an output end N6; the third section SG3 penetrates through an opening O3 of the hollow pattern U3, and the opening O3 faces to the input end N5; the fourth segment SG4 passes through the opening O4 of the hollow pattern U4, and the opening O4 faces the output terminal N7. In some embodiments, the hollow pattern U1 and the hollow pattern U3 have the same size, and the hollow pattern U2 and the hollow pattern U4 have the same size. In some embodiments, the size of the hollow pattern U1 is different from that of the hollow pattern U2.

In some embodiments, the dual-band switching circuit structure 10 is used to suppress higher harmonics in the output signal. In other words, the dual frequency conversion circuit structure 10 serves to increase the insertion loss at the high frequency portion. For example, when the dual-band transforming circuit structure 10 is used for transmitting 2.4GHz and/or 5.5GHz signals, the higher harmonics of the signals can be between 10 GHz and 18GHz (e.g., 16.5GHz, which is a triple frequency of the 5.5GHz signal), and the dual-band transforming circuit structure 10 utilizes the hollow design of the transmission line 140 and the conductive layer 200 to increase the stopband bandwidth of 10 GHz to 18 GHz. In some embodiments, the dual-band switching circuit structure 10 provides an insertion loss of about 30dB or more for signals in the frequency band of 10-18 GHz.

In some embodiments, the transmission line 140 and the hollow patterns U1 to U4 are used as a low pass filter, and the frequency response thereof can be obtained according to an elliptic equation, a Butterworth (Butterworth) filter formula or a Chebyshev (Chebyshev) filter formula. The hollow pattern T1, the hollow pattern U1, the hollow pattern T2 and the hollow pattern U2 are sequentially connected in series into one path along the first section SG1 and the second section SG2, and the hollow pattern T3, the hollow pattern U3, the hollow pattern T4 and the hollow pattern U4 are sequentially connected in series into the other path along the third section SG3 and the fourth section SG4. The two paths of signals are connected in parallel to form a two-path low-pass filter, wherein each of the hollow patterns U1-U4 and the hollow patterns T1-T4 is regarded as a band-stop filter, and each band-stop filter provides a transmission zero point for the low-pass filter. The band-stop filters are connected in series to form the low-pass filter.

The stopband bandwidths of the band elimination filters are related to the sizes and the positions of the hollow patterns U1-U4 and the hollow patterns T1-T4. In some embodiments, the smaller the size (e.g., the area of the hollow area) of the hollow patterns U1 to U4, the higher the frequency of the transmission zero point. In some embodiments, the smaller the size of the hollow patterns T1 to T4, the higher the frequency of the corresponding transmission zero.

In other embodiments, the transmission line 140 does not include the hollow patterns T1 and T3.

In other embodiments, the transmission line 140 does not include the cut-out patterns T2 and T4.

In other embodiments, the conductive layer 200 does not include the hollow pattern U1 and the hollow pattern U3.

In other embodiments, the conductive layer 200 does not include the hollow patterns U2 and U4.

In some embodiments, the first section SG1 has at least two T-shaped non-closed hollow patterns with different sizes, and the third section SG3 has at least two T-shaped non-closed hollow patterns with different sizes. In some embodiments, the second section SG2 has at least two T-shaped open-out patterns with different sizes, and the fourth section SG4 has at least two T-shaped open-out patterns with different sizes. In a further embodiment, the sizes of all the T-shaped hollow patterns on the first section SG1 and the second section SG2 are different from each other, and the sizes of all the T-shaped hollow patterns on the third section SG3 and the fourth section SG4 are different from each other.

In some embodiments, the conductive layer 200 further includes two U-shaped hollow patterns with the same size different from the hollow patterns U1 and U2 and respectively overlapped with the first segment SG1 and the third segment SG3. In some embodiments, the conductive layer 200 further includes two identical U-shaped hollow patterns different from the hollow patterns U3 and U4 and respectively overlaps the second segment SG2 and the fourth segment SG4. In a further embodiment, all the U-shaped hollow patterns overlapping with the first section SG1 and the second section SG2 are different from each other in size, and all the U-shaped hollow patterns overlapping with the third section SG3 and the fourth section SG4 are different from each other in size.

The foregoing description has set forth briefly the features of certain embodiments of the present application so that those skilled in the art may more fully understand the various embodiments of the present application. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should understand that they can still make various changes, substitutions and alterations herein without departing from the spirit and scope of the present disclosure.

Claims

1. A dual-band switching circuit structure, comprising:

a first transmission line having a first input terminal, a first output terminal and a second output terminal; and

a second transmission line having a second input terminal coupled to the first output terminal, a third input terminal coupled to the second output terminal, a third output terminal and a fourth output terminal, an

A conductive layer, stacked with the first transmission line and the second transmission line, comprising:

a first hollow pattern, wherein the first hollow pattern and the second transmission line are overlapped on a top view.

2. The dual-band switching circuit structure of claim 1, wherein the second transmission line comprises a second hollow pattern, wherein the second hollow pattern and the first hollow pattern do not overlap in the top view.

3. The dual-band switching circuit structure of claim 2, wherein the conductive layer further comprises a third hollow pattern, wherein the third hollow pattern overlaps the second transmission line in the top view and is separated from the first hollow pattern, and wherein the first hollow pattern and the third hollow pattern are U-shaped.

4. The dual-band switching circuit structure of claim 3, wherein the second transmission line further comprises a fourth hollow pattern, wherein the first hollow pattern, the second hollow pattern, the third hollow pattern and the fourth hollow pattern do not overlap in the top view.

5. The dual-band switching circuit structure of claim 4, wherein the second and fourth hollow patterns are T-shaped patterns and are not closed hollow patterns.

6. A dual-band switching circuit structure, comprising:

a first conductive layer; and

a second conductive layer including a first hollow pattern, wherein the second conductive layer and the first conductive layer are stacked and separated by a dielectric material,

wherein the first conductive layer comprises:

a balun circuit;

a filter circuit, comprising a transmission line, wherein the transmission line comprises a second hollow pattern, wherein the first hollow pattern is overlapped with the transmission line on a plan view and is not overlapped with the second hollow pattern on the plan view; and

a coplanar strip line, wherein the filter circuit is coupled between the balun circuit and the coplanar strip line.

7. The dual-band transforming circuit structure according to claim 6, wherein the second conductive layer further comprises a third hollow pattern and the transmission line further comprises a fourth hollow pattern, wherein the third hollow pattern overlaps the transmission line in the top view, and the first hollow pattern, the second hollow pattern, the third hollow pattern and the fourth hollow pattern do not overlap each other in the top view.

8. The dual-band transforming circuit structure of claim 7, wherein the transmission line has a first segment, a second segment, a third segment and a fourth segment, wherein the first segment is parallel to the third segment, the second segment is parallel to the fourth segment, and the first segment is perpendicular to the second segment,

wherein the first hollow pattern and the first section are overlapped on the top view, and the second hollow pattern is arranged in the first section.

9. The dual band switching circuit structure of claim 8, wherein said first cutout pattern is a U-shaped pattern having an opening.

10. The dual-band switching circuit structure of claim 6, wherein said second cutout pattern is a T-shaped pattern.