High-directivity radio frequency power amplifier power coupler

Abstract

The high-directivity radio frequency power amplifier power coupler comprises a microstrip line and a dielectric substrate, and the dielectric substrate comprises a top layer dielectric substrate, a middle layer dielectric substrate and a bottom layer dielectric substrate which are sequentially arranged from top to bottom. The microstrip line comprises an output microstrip line, a coupling microstrip line, a load end output end microstrip line and a coupling signal output end microstrip line, the output microstrip line is located on the top dielectric substrate, the coupling microstrip line is buried in the middle dielectric substrate, the load end output end microstrip line and the coupling signal output end microstrip line are both buried in the middle dielectric substrate, and the coupling signal output end microstrip line is located on the coupling microstrip line. And the load end output end microstrip line and the coupling signal output end microstrip line are respectively connected with two ends of the coupling microstrip line. By adopting the coupler with the structure in the application, the directivity of the power coupler can be effectively improved, the propagation of a signal in an unexpected direction is reduced, the signal interference and the power loss are reduced, and the performance and the efficiency of a whole radio frequency power amplifier system are improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of high directivity radio frequency power amplifier power coupler, and specifically relates to the field of radio frequency technology. BACKGROUND

[0002] With the rapid development of communication technology, radio frequency power amplifiers are increasingly widely used in wireless communication systems. As a key component in radio frequency power amplifiers, the performance of power couplers has a crucial impact on the signal transmission quality and efficiency of the entire system. Under the requirements of high data rate, low error rate and high reliability in modern communication systems, higher requirements are placed on the directivity of power couplers.

[0003] Currently, in some radio frequency power amplifier application scenarios, such as 5G communication base stations and satellite communications, low directivity power couplers can cause signal scattering in unintended directions during transmission, reducing the strength of useful signals and increasing interference with other channels. At the same time, the increase in power loss can exacerbate the heating problem of the device, affecting the service life and performance stability of the device. Especially for DPD performance stability. Common radio frequency power amplifier power coupler designs are mostly based on traditional coupling structures. For example, the existing microstrip line coupler achieves power coupling by designing a microstrip line of a specific shape and size on a dielectric substrate. Its basic principle is to use the electromagnetic field interaction between microstrip lines to distribute input power to output ports in a certain proportion. However, this traditional microstrip line coupler does not fully consider suppressing the propagation of electromagnetic fields in unintended directions in its structural design, resulting in limited directivity. In addition, a power coupler based on waveguide structure introduced in Chinese patent CN104737364A achieves power distribution by setting coupling holes or coupling slots in the metal waveguide. However, in actual application, due to factors such as waveguide machining precision and installation error, it is difficult to achieve high directivity power coupling, and the size of this structure is relatively large, which is not conducive to the integration of small-sized devices.

[0004] For the above-mentioned prior art, although they are mature power coupler design methods, they have deficiencies in achieving high directivity. For example, the electromagnetic field distribution of the microstrip line coupler is limited by its simple planar structure, making it difficult to effectively control the propagation direction of the signal; for example, although the waveguide structure coupler has advantages in power handling capability, it has limitations in high directivity requirements due to its own structure and manufacturing process limitations. SUMMARY

[0005] In order to overcome the shortcomings and deficiencies existing in the prior art, the utility model discloses a high directivity radio frequency power amplifier power coupler, adopt the coupler of structure in this application can effectively improve the directivity of power coupler, reduce the propagation of signal in the non - desired direction, reduce signal interference and power loss, simultaneously, the compactness and miniaturization of the coupler structure make it can better adapt to the integrated demand of modern communication equipment, improve the performance and efficiency of whole radio frequency power amplifier system.

[0006] The utility model discloses a high directivity radio frequency power amplifier power coupler, including microstrip line and dielectric substrate, the dielectric substrate from top to bottom includes the top layer dielectric substrate, middle layer dielectric substrate and bottom layer dielectric substrate that set gradually, the microstrip line includes output microstrip line, coupling microstrip line, load end output end microstrip line and coupling signal output end microstrip line, the output microstrip line is located the top end surface of top layer dielectric substrate, the coupling microstrip line is buried in middle layer dielectric substrate, load end output end microstrip line and coupling signal output end microstrip line all are buried in middle layer dielectric substrate, and load end output end microstrip line and coupling signal output end microstrip line are connected respectively with both ends of coupling microstrip line.

[0007] Further, the middle layer dielectric substrate is also provided with a sub-microstrip line for increasing the directivity of the coupler.

[0008] Further, the coupler is also provided with a coupling output port and a load connection port, the load connection port is connected with the load end output end microstrip line, and the coupling output port is connected with the coupling signal output end microstrip line.

[0009] Further, the dielectric constant of the top layer dielectric substrate is 3.54, and the thickness of the top layer dielectric substrate is 150 μm.

[0010] Further, the dielectric constant of the middle layer dielectric substrate is 3.73, and the thickness of the middle layer dielectric substrate is 168 μm.

[0011] Further, the dielectric constant of the bottom layer dielectric substrate is 3.54, and the thickness of the bottom layer dielectric substrate is 150 μm.

[0012] Further, the top layer dielectric substrate, the middle layer dielectric substrate and the bottom layer dielectric substrate are compression molded, and are tightly combined without air gap.

[0013] The utility model discloses a coupler can effectively improve the directivity of power coupler, reduce the propagation of signal in the non - desired direction, reduce signal interference and power loss, and the compactness and miniaturization of the coupler structure make it can better adapt to the integrated demand of modern communication equipment, improve the performance and efficiency of the whole radio frequency power amplifier system. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 It is the perspective drawing of the utility model;

[0015] Figure 2 It is the exploded schematic view of the utility model;

[0016] Figure 3 It is the structural schematic view of the microstrip line of the utility model;

[0017] Figure 4 It is the simulation test drawing of the intensity and directivity of the microstrip line coupling degree of the utility model.

[0018] The figure mark is: 11-output microstrip line, 12-coupling microstrip line, 13-load end output end microstrip line, 14-coupling signal output end microstrip line, 15-sub microstrip line, 16-coupling output port, 17-load port, 21-top layer dielectric substrate, 22-middle layer dielectric substrate, 23-bottom layer dielectric substrate. DETAILED DESCRIPTION

[0019] In order to facilitate the understanding of those skilled in the art, the following will be combined with the embodiment and the attached Figures 1-4 Further description of the utility model, the content mentioned in the embodiment is not the limitation of the utility model.

[0020] It should be noted that when an element is referred to as "fixed to" or "provided on" another element, it can be directly on another element or indirectly on the other element.

[0021] When an element is referred to as "connected to" another element, it can be directly connected to another element or indirectly connected to the other element.

[0022] It should be understood that the terms "length", "width", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0023] In addition, the terms "first", "second", etc. are used only for descriptive purposes and are not to be construed as indicating or implying relative importance or an indicated number of technical features. Thus, the features defined with "first", "second" can explicitly or implicitly include one or more of the features.

[0024] In the description of the present application, the meaning of "multiple" is two or more, unless otherwise explicitly and specifically limited.

[0025] See Figures 1-4 A high directivity radio frequency power amplifier power coupler comprises a microstrip line and a dielectric substrate, the dielectric substrate comprises a top layer dielectric substrate 21, a middle layer dielectric substrate 22 and a bottom layer dielectric substrate 23 arranged in sequence from top to bottom, the microstrip line comprises an output microstrip line 11, a coupling microstrip line 12, a load end output microstrip line 13 and a coupling signal output microstrip line 14, the output microstrip line 11 is located on the upper end surface of the top layer dielectric substrate 21, the coupling microstrip line 12 is embedded in the middle layer dielectric substrate 22, the load end output microstrip line 13 and the coupling signal output microstrip line 14 are both embedded in the middle layer dielectric substrate 22, and the load end output microstrip line 13 and the coupling signal output microstrip line 14 are respectively connected with both ends of the coupling microstrip line 12; the middle layer dielectric substrate 22 is further provided with a sub-microstrip line 15 for increasing the directivity of the coupler, the coupler is further provided with a coupling output port 16 and a load connection port 17, the load connection port 17 is connected with the load end output microstrip line 13, and the coupling output port 16 is connected with the coupling signal output microstrip line 14.

[0026] The coupler with the above structure in the embodiment can effectively improve the directivity of the power coupler, reduce the propagation of signals in the non-desired direction, and reduce signal interference and power loss; at the same time, the compactness and miniaturization of the structure of the coupler make it better adapt to the integration demand of modern communication equipment, and improve the performance and efficiency of the whole radio frequency power amplifier system.

[0027] The coupling network of the coupler with the laminated structure has the significant advantage of low insertion loss to the main signal, and the laminated structure of the coupler makes the network of the coupler have the advantage of low standing wave; the embedded design based on the microstrip line also makes the coupling network can fully utilize the PCB space, making the design full of flexibility and low cost; with the increase of frequency, the size of the design based on the microstrip line will decrease, and the present scheme has the potential to be integrated and packaged into an independent device product. The present scheme can be flexibly designed according to the requirements of desired coupling degree, directivity and anti-interference, and only the basic unit parameters need to be modified. The coupling microstrip line 12 is the core component of the present application, which is distributed on the middle layer dielectric substrate 22.

[0028] In this embodiment, the dielectric constant of the top layer dielectric substrate 21 is 3.54, the thickness of the top layer dielectric substrate 21 is 150 μm; the dielectric constant of the middle layer dielectric substrate 22 is 3.73, the thickness of the middle layer dielectric substrate 22 is 168 μm; the dielectric constant of the bottom layer dielectric substrate 23 is 3.54, the thickness of the bottom layer dielectric substrate 23 is 150 μm; the top layer dielectric substrate 21, the middle layer dielectric substrate 22 and the bottom layer dielectric substrate 23 are compression molded, and are tightly combined without air gap between the layers.

[0029] In this embodiment, the dielectric constant and thickness of the top layer dielectric substrate 21, the middle layer dielectric substrate 22 and the bottom layer dielectric substrate 23 are reasonably selected to optimize the electromagnetic field distribution between different layers. In the design of the microstrip line, a bending shape and line width variation are adopted to form an electromagnetic field guiding structure. Specifically, the dielectric constant of the top layer dielectric substrate 21 and the bottom layer dielectric substrate 23 is relatively low, and is mainly used for isolation and protection of the internal structure. The dielectric constant of the middle layer dielectric substrate 22 is relatively high, and is a key area for realizing power coupling. The microstrip line structure is designed on the middle layer dielectric substrate 22. When preparing the dielectric substrate, multiple dielectric substrate materials are prepared, and the designed microstrip line pattern is printed on the corresponding dielectric layer through high-precision printed circuit board (PCB) manufacturing process. Then, the multiple dielectric substrates are laminated to ensure that they are tightly combined without air gap between the layers, so as to ensure stable propagation of the electromagnetic field. After lamination, precise cutting and drilling operations are performed to ensure the stability and reliability of the power coupler.

[0030] In some embodiments, the parameter design of the microstrip line can be determined according to the index requirements of the desired coupling degree and directionality. It is assumed that the coupling intermodulation frequencies are 3rd, 4th and 5th order respectively, and the desired fundamental signal frequency f0=2.110-2.180 GHz.

[0031] As shown in Figure 3 The coupler adopts a 3-level basic unit. In order to obtain intermodulation frequencies of 3rd, 4th and 5th order at the coupling output port 16, the following steps can be performed:

[0032] According to the impedance of the output microstrip line 11 of the amplifier, the coupling degree and the order and direction of the intermodulation of the coupling, the characteristic impedance of the coupling microstrip line 12 is determined according to the dielectric constant of the dielectric substrate; the vertical distance from the power amplifier output microstrip line 11 is determined according to the coupling degree and the directionality. High directionality, tight coupling, anti-interference advantages, high isolation, low standing wave advantages can be achieved.

[0033] The above embodiment is a preferred implementation scheme of the present application, in addition to this, the present application can be implemented in other ways, and any obvious replacement without departing from the concept of the present application is within the protection scope of the present application.

Claims

1. A power coupler for a highly directional radio frequency power amplifier, characterized in that: The device includes microstrip lines and a dielectric substrate. The dielectric substrate comprises, from top to bottom, a top dielectric substrate, a middle dielectric substrate, and a bottom dielectric substrate. The microstrip lines include an output microstrip line, a coupling microstrip line, a load-end output microstrip line, and a coupling signal output microstrip line. The output microstrip line is located on the upper surface of the top dielectric substrate. The coupling microstrip line is embedded in the middle dielectric substrate. Both the load-end output microstrip line and the coupling signal output microstrip line are embedded in the middle dielectric substrate, and the load-end output microstrip line and the coupling signal output microstrip line are respectively connected to the two ends of the coupling microstrip line.

2. The high-directivity RF power amplifier power coupler according to claim 1, characterized in that: The intermediate dielectric substrate also contains a sub-microstrip line to increase the directionality of the coupler.

3. The high-directivity RF power amplifier power coupler according to claim 1, characterized in that: The coupler also has a coupling output port and a load connection port. The load connection port is connected to the microstrip line of the load output terminal, and the coupling output port is connected to the microstrip line of the coupling signal output terminal.

4. The high-directivity RF power amplifier power coupler according to claim 1, characterized in that: The dielectric constant of the top dielectric substrate is 3.54, and the thickness of the top dielectric substrate is 150 μm.

5. A high-directivity RF power amplifier power coupler according to claim 1, characterized in that: The dielectric constant of the intermediate dielectric substrate is 3.73, and the thickness of the intermediate dielectric substrate is 168 μm.

6. The high-directivity RF power amplifier power coupler according to claim 1, characterized in that: The dielectric constant of the bottom dielectric substrate is 3.54, and the thickness of the bottom dielectric substrate is 150 μm.

7. A high-directivity RF power amplifier power coupler according to claim 1, characterized in that: The top dielectric substrate, middle dielectric substrate and bottom dielectric substrate are pressed together, and the layers are tightly bonded together without air gaps.

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