Impedance matching circuit based on transformer and communication equipment
Through the transformer-based impedance matching circuit, a dual transformer unit is used to connect to specific windings, combined with capacitors and NPN transistors, the problems of insufficient bandwidth and excessive size in 5G communication are solved, and efficient signal transmission and equipment miniaturization are achieved.
Patent Information
- Application Number
- CN202422365144.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-27
- Publication Date
- 2025-07-29
- Estimated Expiration
- 2034-09-27
AI Technical Summary
In 5G communication, existing transformers have problems such as insufficient bandwidth, excessive size, high loss, high risk of electromagnetic interference and high manufacturing difficulties, and it is difficult to meet the needs of broadband and miniaturization at the same time.
Transformer-based impedance matching circuits, including mutually coupled dual transformer units and specific winding connection methods, combined with capacitors and NPN-type transistors, optimize circuit performance to achieve broadband characteristics and miniaturization.
It realizes efficient impedance matching and flat frequency response in the N77 and N79 frequency bands, reduces insertion loss, improves signal transmission quality and system reliability, and supports the miniaturization of 5G communication equipment.
Smart Images
Figure CN223168309U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of impedance matching circuits, in particular to an impedance matching circuit based on a transformer and communication equipment using the circuit. Background Art
[0002] With the rapid development of 5G communication technology, the N77 (3.3-4.2 GHz) and N79 (4.4-5.0 GHz) frequency bands are increasingly being used in communication systems. This places higher demands on transformer performance, particularly in terms of bandwidth and miniaturization. However, existing transformer designs face numerous challenges in meeting these requirements.
[0003] In terms of bandwidth, traditional transformer designs struggle to maintain stable performance across the wide frequency range of 3.3-5.0 GHz. This results in suboptimal impedance matching at certain frequencies, impacting power transmission efficiency. Maintaining a flat frequency response across such a wide frequency band is also a significant challenge, potentially leading to signal distortion and compromising communication quality.
[0004] Miniaturization is another prominent issue. Existing technologies often require separate transformers for the N77 and N79 frequency bands, significantly increasing the overall circuit area. Large transformers make tight integration with other circuits difficult, limiting the miniaturization of power amplifier modules. Furthermore, miniaturization also presents heat dissipation challenges, increasing power density per unit area and making thermal management more difficult.
[0005] The issue of losses at high frequencies cannot be ignored. As the frequency increases, the skin effect and proximity effect become more pronounced, increasing insertion loss and reducing the overall efficiency of the transformer. This not only affects signal transmission quality but also increases system power consumption.
[0006] There's a clear contradiction between bandwidth and size. Broadband designs often require more complex structures, which inevitably leads to larger sizes. Simply reducing the size, on the other hand, can sacrifice bandwidth, making it difficult to simultaneously meet the demands of both bandwidth and miniaturization.
[0007] Furthermore, the compact layout also increases the risk of electromagnetic interference between the transformer and other circuits, which may negatively impact the performance of the entire system.
[0008] In terms of manufacturing and cost, the design of high-performance, small-size transformers increases manufacturing difficulty and can significantly increase production costs. Complex designs also face yield challenges, which affects the possibility of large-scale production. Utility Model Content
[0009] The purpose of the utility model is to provide an impedance matching circuit based on a transformer to solve the problems of insufficient bandwidth, excessive size and the like existing in the prior art.
[0010] To achieve the above object, the present utility model provides an impedance matching circuit based on a transformer, which includes a first transformer unit and a second transformer unit. The first transformer unit includes a first winding and a second winding, and the second transformer unit includes a third winding and a fourth winding. Among them, the first end of the first winding is connected to the first end of the third winding, the first end of the second winding is connected to the first end of the fourth winding, and the second end of the second winding is connected to the second end of the third winding.
[0011] Further, the circuit further includes a first capacitor and a second capacitor. The first end of the first capacitor is connected to the first end of the second winding and the first end of the fourth winding, and the first end of the second capacitor is connected to the first end of the first winding and the first end of the third winding.
[0012] Specifically, the circuit further includes a third capacitor and a fourth capacitor. The first end of the third capacitor is connected to the second end of the first winding, and its second end is connected to the second end of the fourth winding. The first end of the fourth capacitor is connected to the second end of the second winding and the second end of the third winding, and its second end is grounded.
[0013] In addition, the circuit further includes a first transistor and a second transistor. The collector of the first transistor is connected to the second end of the first winding, and the collector of the second transistor is connected to the second end of the fourth winding.
[0014] Further, the circuit further includes a third transistor and a fourth transistor. The base of the third transistor is connected to the second end of the first capacitor, and the base of the fourth transistor is connected to the second end of the second capacitor.
[0015] Specifically, the first transistor, the second transistor, the third transistor, and the fourth transistor are all NPN-type transistors, and their emitters are all grounded.
[0016] Further, the operating frequency band of the circuit covers the N77 frequency band and the N79 frequency band.
[0017] The present utility model also provides a 5G communication device, which includes the above-mentioned impedance matching circuit based on a transformer. Specifically, the 5G communication device can be a 5G base station or a 5G mobile terminal.
[0018] The impedance matching circuit based on a transformer provided by the present utility model achieves broadband characteristics through the design of mutually coupled dual-transformer units and the winding connection method cooperating therewith, and can cover both N77 and N79 frequency bands simultaneously. This design reduces the size of the transformer to a certain extent, improves the integration degree, and at the same time ensures good impedance matching and flat frequency response, and preferably solves the problems of insufficient bandwidth and excessive size existing in the prior art.
[0019] The impedance matching circuit provided by the present utility model optimizes the circuit performance by configuring capacitors and transistors. Through the differential configuration and grounding design of NPN transistors, the linearity and common-mode rejection ability of the circuit are improved. At the same time, this design also improves the bandwidth characteristics and temperature stability of the circuit, and improves the reliability of the overall system. In addition, the impedance matching circuit of the present utility model can be applied to 5G base stations and mobile terminals, has a wide range of application prospects, and provides good support for the performance improvement and miniaturization development of 5G communication devices. Brief Description of the Drawings
[0020] Figure 1 It is a schematic diagram of the structure of a power amplifier transformer in a 5G communication system in the prior art;
[0021] Figure 2 It is a schematic diagram of the structure of an impedance matching circuit based on a transformer in an embodiment of the present utility model. Detailed Embodiment
[0022] The technical solution of the present utility model will be elaborated in detail below in conjunction with the drawings and specific embodiments. It should be noted that the described embodiments are only used to explain the technical principle of the present utility model, rather than to limit its protection scope. Those skilled in the art should understand that various transformations, modifications or equivalent replacements can be made to these embodiments without departing from the spirit and scope of the present utility model. These transformations, modifications or equivalent replacements should all be regarded as falling within the protection scope defined by the claims of the present utility model.
[0023] Before describing the specific embodiments of the present utility model, first refer to Figure 1 to illustrate the transformer structure in the prior art. As Figure 1As shown, the power amplifier transformers in the existing 5G communication systems usually adopt a double-winding structure. This structure includes two transformer units TF1 and TF2, and each transformer unit contains two coupled windings. Although this structure is common, it faces many problems when meeting the broadband requirements of 5G communication systems. Specifically, in the traditional design, in order to support the N77 and N79 frequency bands of 5G, power amplifiers usually need to be designed separately. This approach leads to an increase in cost or a larger area required for the module. In addition, the matching frequency bandwidth of traditional transformers (winders) is limited and a larger area is required to achieve it. Especially for the requirement of simultaneously covering the N77 and N79 frequency bands, the existing transformer components often cannot provide sufficient frequency bandwidth.
[0024] This design method has several problems: the overall circuit area increases and it is difficult to meet the miniaturization requirement; the cost is relatively high because independent power amplifiers need to be designed for different frequency bands; the matching frequency bandwidth of the transformer is insufficient, especially when simultaneously covering a wide frequency band such as N77 and N79; there may be a problem of performance degradation in the transition region between frequency bands and it is difficult to achieve smooth broadband coverage; there are problems such as large impedance matching difficulty and high insertion loss. Especially in the wide frequency range of 3.3 - 5.0 GHz, it is difficult for the existing technology to maintain stable performance and flat frequency response. These problems limit the performance improvement and miniaturization development of 5G communication devices.
[0025] In contrast, the impedance matching circuit proposed by the present utility model overcomes the above disadvantages, and the specific implementation is described as follows.
[0026] As Figure 2 shown, the present utility model provides a transformer-based impedance matching circuit, which is particularly applicable to the N77 and N79 frequency bands. The impedance matching circuit includes a first transformer unit TF1 and a second transformer unit TF2. The first transformer unit TF1 includes a first winding and a second winding, and the second transformer unit TF2 includes a third winding and a fourth winding.
[0027] In this embodiment, the first end of the first winding is connected to the first end of the third winding, the first end of the second winding is connected to the first end of the fourth winding, and the second end of the second winding is connected to the second end of the third winding. This coupling connection method helps to achieve broadband characteristics and impedance matching.
[0028] The impedance matching circuit further includes a plurality of capacitors for achieving impedance matching and optimizing frequency response. Specifically, the impedance matching circuit includes a first capacitor C1, a second capacitor C2, a third capacitor C3, and a fourth capacitor C4. The first end of the first capacitor C1 is connected to the first end of the second winding and the first end of the fourth winding. The first end of the second capacitor C2 is connected to the first end of the first winding and the first end of the third winding. The third capacitor C3 is connected between the collector of the transistor Q1P and the ground. The fourth capacitor C4 is connected between the second end of the second winding and the second end of the third winding and the ground.
[0029] In a specific embodiment, the capacitance values of the first capacitor C1 and the second capacitor C2 are in the range of 1 - 10 pF, and the capacitance values of the third capacitor C3 and the fourth capacitor C4 are in the range of 0.5 - 5 pF. The selection of these capacitance values helps to achieve good impedance matching and flat frequency response within the N77 and N79 frequency bands.
[0030] The impedance matching circuit further includes a plurality of transistors for achieving power amplification and signal processing. Specifically, the impedance matching circuit includes a first transistor Q1P, a second transistor Q1N, a third transistor Q2P, and a fourth transistor Q2N. The collector of the first transistor Q1P is connected to the second end of the first winding, and the collector of the second transistor Q1N is connected to the second end of the fourth winding. The base of the third transistor Q2P is connected to the second end of the first capacitor C1, and the base of the fourth transistor Q2N is connected to the second end of the second capacitor C2.
[0031] In a specific embodiment, the first transistor Q1P, the second transistor Q1N, the third transistor Q2P, and the fourth transistor Q2N are all NPN - type transistors, and their emitters are all grounded. This configuration is beneficial to the common - mode rejection ratio and linearity of the circuit, while improving the temperature stability and facilitating maintaining stable amplification performance within a wide frequency band.
[0032] Wherein:
[0033] The impedance matching circuit achieves broadband operation through structural design. Its working principle is as follows:
[0034] 1. Pre - stage amplification: The input signal first passes through the pre - stage differential amplifier composed of the transistors Q1P and Q1N. This stage amplifies the input signal and increases the signal strength.
[0035] 2. Transformer coupling: The amplified signal enters transformer units TF1 and TF2. These two transformer units are connected in a specific way to form a composite transformer structure. The first winding is connected to the first end of the third winding, the second winding is connected to the first end of the fourth winding, and the second end of the second winding is connected to the second end of the third winding. This connection method can maintain good impedance matching within a wider frequency band.
[0036] 3. Capacitance optimization: Capacitors C1, C2, C3, and C4 play important roles in the circuit. C3 and C4 are mainly used for low-frequency compensation, connected between the collector of the pre-stage differential amplifier transistor Q1P and ground, and between the midpoint of the transformer and ground. C1 and C2 are used for high-frequency matching, respectively connected between the output of the transformer and the bases of the post-stage differential amplifier transistors Q2P and Q2N. The coordinated use of these capacitors further optimizes the frequency response, ensuring good performance throughout the frequency band.
[0037] 4. Post-stage amplification: The signal after transformer coupling and capacitance optimization finally reaches the post-stage differential amplifier composed of transistors Q2P and Q2N. This stage further amplifies the signal, increases the output power, and ensures that the signal can be better transmitted to the load.
[0038] 5. Wideband operation: Through the collaborative work of the above-mentioned stages, the transformer can maintain high efficiency and low loss simultaneously within the N77 frequency band (3.3 - 4.2 GHz) and the N79 frequency band (4.4 - 5.0 GHz). The composite transformer structure provides wideband impedance matching ability, and the designed capacitance network ensures a flat frequency response throughout the frequency band.
[0039] This design not only realizes wideband operation but also achieves the goal of miniaturization through an optimized structural layout. The compact design of the entire circuit makes it suitable for space-constrained 5G communication devices such as base stations and mobile terminals.
[0040] In practical applications, the impedance matching circuit can be implemented using multi-layer PCB technology to further reduce the overall size of the transformer. This miniaturized design makes the impedance matching circuit particularly suitable for space-constrained application scenarios such as 5G base stations and mobile terminals.
[0041] In an embodiment of the present utility model, a 5G communication device is provided, which includes the impedance matching circuit as described in the foregoing embodiment. This 5G communication device can be a 5G base station or a 5G mobile terminal.
[0042] The impedance matching circuit provided by the present utility model has the following beneficial effects: By adopting a specific dual-transformer unit design and a special winding connection method, broadband characteristics are achieved, which can cover both N77 and N79 frequency bands simultaneously, and the spectrum utilization efficiency is preferably improved. This design greatly reduces the size of the impedance matching circuit, improves the integration level, and solves the problems of insufficient bandwidth and excessive size existing in the prior art. The introduction of multiple capacitors optimizes the impedance matching and frequency response, reduces the insertion loss, and improves the signal transmission quality. The differential configuration and grounding design of the NPN-type transistor improve the linearity and common-mode rejection ability of the circuit, improve the temperature stability, and enhance the reliability and efficiency of the overall system. This design is not only applicable to 5G base stations, but also can be applied to mobile terminals, having a good application prospect, and providing important support for the performance improvement and miniaturization development of 5G communication devices.
[0043] The present utility model has been described in detail through the above specific embodiments. However, it should be understood that the above content is only illustrative and not used to limit the scope of the present utility model. Those of ordinary skill in the art can make various modifications and variations to the present utility model according to the specific application scenarios and actual requirements without departing from the spirit and scope of the present utility model, and these modifications and variations are all within the protection scope of the present utility model.
Claims
1. A transformer-based impedance matching circuit, characterized in that, Comprising: A first transformer unit, comprising a first winding and a second winding; A second transformer unit, comprising a third winding and a fourth winding; Wherein, a first end of the first winding is connected to a first end of the third winding, A first end of the second winding is connected to a first end of the fourth winding, A second end of the second winding is connected to a second end of the third winding.
2. The circuit according to claim 1, characterized in that Further comprising: A first capacitor, a first end of which is connected to a first end of the second winding and a first end of the fourth winding; A second capacitor, a first end of which is connected to a first end of the first winding and a first end of the third winding.
3. The circuit according to claim 2, wherein Further comprising: A third capacitor, a first end of which is connected to a second end of the first winding and a second end of which is connected to a second end of the fourth winding; A fourth capacitor, a first end of which is connected to a second end of the second winding and a second end of the third winding, and a second end of which is grounded.
4. The circuit according to claim 2, wherein Further comprising: A first transistor, a collector of which is connected to a second end of the first winding; A second transistor, a collector of which is connected to a second end of the fourth winding.
5. The circuit according to claim 4, characterized in that Further comprising: A third transistor, a base of which is connected to a second end of the first capacitor; A fourth transistor, a base of which is connected to a second end of the second capacitor.
6. The circuit according to claim 5, characterized in that, The first transistor, the second transistor, the third transistor and the fourth transistor are all NPN-type transistors, and emitters of them are all grounded.
7. The circuit according to claim 1, wherein The operating frequency band of the transformer-based impedance matching circuit covers N77 band and N79 band.
8. A 5G communication device, characterized in that, Comprising the circuit according to any one of claims 1 to 7.
9. The 5G communication device according to claim 8, wherein The 5G communication device is a 5G base station or a 5G mobile terminal.