Impedance converter and ultra-wideband power amplifier using same
By employing HBT technology and multilayer metal wire coupling impedance transformers in ultra-wideband communication, the bandwidth limitations of traditional impedance matching components and transmission line transformers are solved, enabling the design of high-power output and high-efficiency power amplifiers and simplifying circuit design.
Patent Information
- Application Number
- CN202511571535.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-30
- Publication Date
- 2026-01-13
AI Technical Summary
Existing technologies cannot achieve a balance between high power output and high power-added efficiency in ultra-wideband communications. Traditional impedance matching components and transmission line converters have problems such as bandwidth limitations and large insertion losses, which lead to a decline in the performance of power amplifiers over a wide frequency range.
An ultra-wideband power amplifier is designed using HBT technology combined with a multilayer metal wire coupled impedance transformer. Wideband impedance transformation is achieved through a mutually coupled transmission line structure, providing input and load lines for the power amplifier and simplifying the matching circuit design.
It achieves high power output and high power-added efficiency in the 0.5GHz-6GHz frequency band, simplifies the matching circuit design of power amplifiers, and improves signal transmission efficiency and load matching stability.
Smart Images
Figure CN121333265A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of broadband power amplifiers, and particularly relates to an impedance transformer and an ultra-wideband power amplifier using the same. Background Technology
[0002] In ultra-wideband communication and radio frequency systems, power amplifiers, as core components, need to achieve high power output (>1W) and high power-added efficiency (PAE>30%) over a wide frequency range (e.g., 0.5GHz-6GHz). Impedance matching networks are a key factor determining the performance of power amplifiers: only when the input impedance of the power amplifier is precisely matched with the signal source impedance, and the load line is precisely matched with the load (or subsequent circuit) impedance, can signal transmission efficiency be maximized, reflection loss be avoided, and high power and high efficiency output be guaranteed.
[0003] However, existing technologies have the following significant drawbacks: 1. Bandwidth limitations of traditional impedance matching components: Matching networks constructed using lumped-parameter components (such as discrete capacitors and inductors) are limited by the parasitic parameters of the components themselves (such as parasitic capacitance and inductance), resulting in an extremely narrow effective operating bandwidth (typically covering only a few hundred megahertz), which cannot meet the ultra-wideband requirement of "0.5GHz-6GHz". Furthermore, when such components are integrated into the HBT process, the parasitic parameters are large and the losses are high, which causes the gain and efficiency of the power amplifier to decrease drastically with frequency.
[0004] 2. Performance limitations of conventional transmission line impedance converters: Existing impedance transformers based on coaxial transmission lines have two major drawbacks: they are large in size and can only be used on PCBs; and they have a limited frequency range, meaning that such impedance transformers can only be used below 1 GHz. 3. The conventional transformer impedance converter has a large insertion loss and a narrow bandwidth due to the influence of parasitic parameters; 4. Design complexity and integration challenges of broadband power amplifiers: To achieve broadband performance, existing broadband power amplifiers have to adopt multi-stage, complex matching networks. This not only significantly increases circuit size and design cost, but also introduces additional insertion loss due to the cascading of multiple networks, further reducing power-added efficiency. At the same time, under HBT technology, the transmission loss of high-frequency signals (such as 6GHz) is aggravated after the integration of traditional matching structures with the active region of HBT transistors, making it difficult to achieve a balance between "ultra-wideband coverage, high power output, and high-efficiency operation" at the same time.
[0005] In summary, existing technologies cannot meet the demand for "HBT-based, wide-band, high-power, and high-efficiency amplification" in scenarios such as ultra-wideband communication, and there is an urgent need for a new type of low-cost, high-performance ultra-wideband power amplifier. Summary of the Invention
[0006] The purpose of this invention is to address the aforementioned technical problems by providing an impedance converter and an ultra-wideband power amplifier that utilizes it.
[0007] In view of this, the present invention provides a broadband impedance converter, comprising: a low-impedance port, a mutually coupled transmission line structure, a high-impedance port, and an HBT process substrate. HBT process substrate, serving as the supporting foundation for the overall structure of the impedance converter; The mutually coupled transmission line structure is based on HBT technology and is formed by multi-layer metal wiring, with the layers electrically connected through metal vias. The mutually coupled transmission lines are achieved through tight coupling between different metal layers. The high-impedance end is connected to the input / output end of the power amplifier, while the low-impedance end provides the amplifier with a low-impedance input impedance / load line.
[0008] An ultra-wideband power amplifier employing an impedance transformer includes: The RF input port RFin connects to the input matching network. The input matching network includes an input impedance transformer, a high-pass matching junction L1 / R1, and a coupling capacitor C1, which are connected in sequence to the RF input port RFin. The HBT power amplifier transistor Q1 is driven by a circuit with its base connected to the input matching network and its collector connected to the interstage matching network. The interstage matching network includes inductor L2, coupling capacitor C2, capacitor C3, inductor L4, inductor L5, resistor R3, and capacitor C4. One end of coupling capacitor C2 is connected to the collector of Q1, and the other end is split into two paths: one path is grounded through capacitor C3, and the other path is connected to one end of coupling capacitor C4 through inductor L4. Inductor L5 and resistor R3 are connected in series, with one end connected to the node between inductor L4 and coupling capacitor C4, and the other end grounded. The output stage HBT power amplifier transistor Q2 has its other end connected to the base of coupling capacitor C4, the emitter of Q2 grounded, and the collector of Q2 connected to the output matching network. Output matching network: includes inductor L3, coupling capacitor C5 and output impedance transformer. One end of coupling capacitor C5 is connected to the collector of Q2, and the other end is connected to the output impedance transformer and then connected to the RF output port RFout.
[0009] Preferably, it further includes: The bias control unit outputs two bias voltages. One is connected to the base of Q1 in the driver stage amplifier circuit via resistor R2, and the other is connected to the base of Q2 in the output stage amplifier circuit via resistor R4.
[0010] Preferably, it further includes: The dual power supply and filtering unit includes a first power supply Vcc1 and a second power supply Vcc2. Vcc1 is connected to the collector of Q1 in the driver stage amplifier circuit via a matching inductor L2, and decoupling capacitors C6 and C7 are connected in parallel between Vcc1 and ground. Vcc2 is connected to the collector of Q2 in the output stage amplifier circuit via a matching inductor L3, and decoupling capacitors C8 and C9 are connected in parallel between Vcc2 and ground.
[0011] Preferably, the bias control unit controls the static operating point of Q1 / Q2.
[0012] Preferably, the bias control unit includes a reference voltage source and a temperature compensation circuit.
[0013] The beneficial effects of this invention are: This invention employs HBT technology, combined with coupling between multiple layers of metal wires, to achieve broadband impedance transformation, providing the required input impedance and load lines for the power amplifier; at the same time, it utilizes the high-frequency characteristics of HBT technology to realize an ultra-wideband power amplifier; the broadband impedance transformer can greatly simplify the matching circuit design of the power amplifier, while ensuring the load matching stability and signal transmission efficiency of the power amplifier in a wide frequency range. Attached Figure Description
[0014] Figure 1 This is a schematic diagram of the 1:4 impedance converter of the present invention; Figure 2 This is a schematic diagram of the 1:9 impedance converter of the present invention; Figure 3 This is a schematic diagram of the ultra-wideband power amplifier circuit of the present invention. Detailed Implementation
[0015] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.
[0016] It should be noted that all directional and positional terms used in this invention, such as "up," "down," "left," "right," "front," "back," "vertical," "horizontal," "inner," "outer," "top," "lower," "lateral," "longitudinal," and "center," are only used to explain the relative positional relationships and connections between components in a specific state (as shown in the accompanying drawings). They are merely for the convenience of describing the invention and do not require the invention to be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on the invention. Furthermore, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated.
[0017] In the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.
[0018] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
[0019] An impedance transformer includes: a low-impedance port, a mutually coupled transmission line structure, a high-impedance port, and an HBT process substrate, wherein the impedance values of the low-impedance port and the high-impedance port are 1:4 or 1:9. HBT process substrate, serving as the supporting foundation for the overall structure of the impedance converter; The mutually coupled transmission line structure is set on the surface of the HBT process substrate and is formed by multilayer metal wiring, with the layers electrically connected by metal vias; Among them, the mutually coupled transmission line structure includes coupled transmission lines with specific impedances. Through specific connection methods, impedance transformation can be achieved. It is used to connect to the load end of the ultra-wideband power amplifier to provide a preset load line for the power amplifier, or it is used at the input end to provide a suitable low impedance for the input end of the power amplifier to achieve wideband matching. like Figure 1As shown, by adjusting the coupling length, line width, and spacing of the transmission lines, the impedance transformer achieves a 1:4 impedance transformation ratio, with an operating bandwidth covering 700MHz-6GHz; simultaneously, as Figure 2 As shown, connecting two sets of impedance transformers can achieve a 1:9 impedance transformation. These impedance transformers are used to connect to the load terminal of an ultra-wideband power amplifier, providing a preset load line for the power amplifier. This eliminates the need for additional output matching circuitry between the impedance transformer and the power amplifier, simplifying the power amplifier's matching circuit design. Simultaneously, the corresponding impedance transformer can also be placed at the input terminal to provide low impedance to the power amplifier's input, simplifying the input matching circuit design.
[0020] This invention employs HBT technology, combined with coupling between multiple layers of metal wires, to achieve broadband impedance transformation, providing the required input impedance and load lines for the power amplifier; at the same time, it utilizes the high-frequency characteristics of HBT technology to realize an ultra-wideband power amplifier; the broadband impedance transformer can greatly simplify the matching circuit design of the power amplifier, while ensuring the load matching stability and signal transmission efficiency of the power amplifier in a wide frequency range.
[0021] like Figure 3 As shown, as a preferred example of this application, the ultra-wideband power amplifier includes: The RF input port RFin connects to the input matching network. The input matching network includes an input impedance transformer, a high-pass matching junction L1 / R1, and a coupling capacitor C1, which are connected in sequence to the RF input port RFin. The HBT power amplifier transistor Q1 is driven by a circuit with its base connected to the input matching network and its collector connected to the interstage matching network. The interstage matching network includes inductor L2, coupling capacitor C2, capacitor C3, inductor L4, inductor L5, resistor R3, and capacitor C4. One end of coupling capacitor C2 is connected to the collector of Q1, and the other end is split into two paths: one path is grounded through capacitor C3, and the other path is connected to one end of coupling capacitor C4 through inductor L4. Inductor L5 and resistor R3 are connected in series, with one end connected to the node between inductor L4 and coupling capacitor C4, and the other end grounded. The output stage HBT power amplifier transistor Q2 has its other end connected to the base of coupling capacitor C4, the emitter of Q2 grounded, and the collector of Q2 connected to the output matching network. Output matching network: includes inductor L3, coupling capacitor C5 and output impedance transformer. One end of coupling capacitor C5 is connected to the collector of Q2, and the other end is connected to the output impedance transformer and then connected to the RF output port RFout.
[0022] In this application, the input impedance transformer completes the 50-ohm to low impedance transformation, providing low impedance to the input of the amplifier and simplifying the matching circuit; the multi-component (capacitor, inductor, resistor) inter-stage matching network works together to achieve wide-band impedance transition and low-loss signal transmission between the driver stage and the output stage; the output stage amplifier circuit works with the output impedance transformer to achieve high-power signal amplification and 50Ω load matching; inductors L2 / L3 and capacitor C5 participate in matching, while also serving as power supply and DC blocking functions, eliminating the need for an additional wideband bias, thus reducing cost and increasing efficiency; ultimately enabling the ultra-wideband power amplifier to achieve an output saturation power >1W and a power-added efficiency (PAE) >30% in the 0.5GHz-6GHz frequency band.
[0023] As a preferred example of this application, it also includes: The bias control unit outputs two bias voltages. One voltage is connected to the base of Q1 in the driver stage amplifier circuit via resistor R2, and the other voltage is connected to the base of Q2 in the output stage amplifier circuit via resistor R4. The bias control unit outputs two independent bias voltages to provide stable base bias for the drive stage (Q1 base) and the output stage (Q2 base), ensuring that the HBT power transistor operates at the preset static operating point and effectively improving the linearity and operating stability of the power amplifier.
[0024] As a preferred example of this application, it also includes: The dual power supply and filtering unit includes a first power supply Vcc1 and a second power supply Vcc2. Vcc1 is connected to the collector of Q1 in the driver stage amplifier circuit via a matching inductor L2, and decoupling capacitors C6 and C7 are connected in parallel between Vcc1 and ground. Vcc2 is connected to the collector of Q2 in the output stage amplifier circuit via a matching inductor L3, and decoupling capacitors C8 and C9 are connected in parallel between Vcc2 and ground. No additional wideband biasT is required, which can reduce costs and increase efficiency.
[0025] The embodiments of this application have been described above with reference to the accompanying drawings. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. This application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.
Claims
1. An impedance transformer, characterized in that... This includes: low-impedance ports, mutually coupled transmission line structures, high-impedance ports, and HBT process substrates. The mutually coupled transmission line structure is based on HBT technology and is formed by multi-layer metal wiring, with the layers electrically connected through metal vias. The mutually coupled transmission line structures form a two-port network, which is used to transform high impedance to low impedance.
2. An ultra-wideband power amplifier, employing the impedance transformer described in claim 1, characterized in that: include: RF signal input port RFin; The input matching network includes the input impedance transformer U1, high-pass matching junction L1, R1, and C1; The driver stage amplifier circuit includes a common-emitter power amplifier transistor Q1, with the input matching network connected to the base of Q1 and the collector of Q1 connected to the interstage matching network. The interstage matching network includes inductor L3, capacitor C2, capacitor C3, inductor L4, inductor L5, resistor R3, and capacitor C4; one end of coupling capacitor C2 is connected to the collector of Q1, and the other end is split into two paths, one path is grounded through capacitor C3, and the other path is connected to one end of coupling capacitor C4 through inductor L4; inductor L5 and resistor R3 are connected in series, one end is connected to the node between inductor L4 and coupling capacitor C4, and the other end is grounded; The output stage amplifier circuit includes a common-emitter power amplifier transistor Q2, with the other end of the coupling capacitor C4 connected to the base of Q2, and the collector of Q2 connected to the output matching network. Output matching network: includes capacitor C5, inductor L3 and output impedance transformer U2. One end of coupling capacitor C5 is connected to the collector of Q2, and the other end is connected to the output impedance transformer and then connected to the RF output port RFout.
3. The ultra-wideband power amplifier according to claim 2, characterized in that: The bias control unit outputs two bias voltages. One is connected to the base of Q1 in the driver stage amplifier circuit via resistor R2, and the other is connected to the base of Q2 in the output stage amplifier circuit via resistor R4.
4. The ultra-wideband power amplifier according to claim 3, characterized in that: Also includes: Dual power supply and filtering unit, including first power supply Vcc1 and second power supply Vcc2; Vcc1 is connected to the collector of Q1 in the driver stage amplifier circuit via inductor L2, and decoupling capacitors C6 and C7 are connected in parallel between Vcc1 and ground; Vcc2 is connected to the collector of Q2 in the output stage amplifier circuit via inductor L3, and decoupling capacitors C8 and C9 are connected in parallel between Vcc2 and ground. Inductors L2 / L3 participate in broadband matching, and their values are relatively small, which can be achieved using bonding wires, eliminating the need for additional broadband bias circuitry, thus reducing design complexity and increasing efficiency.
5. The ultra-wideband power amplifier according to claim 4, characterized in that: The bias control unit contains a reference voltage source and a temperature compensation circuit.