High-efficiency radio frequency power amplifier for IMT international mobile communication

Abstract

The invention belongs to the field of wireless communication power amplifiers, and particularly relates to a radio frequency power amplifier for IMT international mobile communication. The radio frequency power amplifier in the design is a board-level radio frequency power amplifier. The radio frequency power amplifier in the design can cover an n104 frequency band (6.425-7.125 GHz) in international mobile communication (IMT); the circuit has the advantages of being simple in structure and small in size while meeting good index requirements. The power amplifier has a wide application prospect in the field of wireless communication power amplifiers, and further development of related wireless communication technologies can be promoted.

Description

Technical Field

[0001] The present invention belongs to the field of wireless communication power amplifiers, and in particular relates to a radio frequency power amplifier for IMT international mobile communications. Background Art

[0002] The 6GHz band is the only high-quality resource with large bandwidth in the mid-frequency band. It has the advantages of wide coverage and large capacity, and is the best potential spectrum resource for the future development of mobile communications.

[0003] As a crucial component of various wireless transmitters, RF power amplifiers (RFPAs) play a key role in wireless communication systems. For IMT international mobile communication systems, especially in the 6 GHz frequency band, RF power amplifiers are subject to even more stringent requirements. On the one hand, they must have higher output power to ensure effective signal transmission over a wider area; on the other hand, they must maintain high efficiency and reduce energy consumption. For mobile communication devices, in particular, efficient power amplifiers help extend device battery life. However, existing RF power amplifiers often struggle to fully meet the requirements in terms of power output and drain efficiency when faced with complex application scenarios in the 6 GHz frequency band, leaving room for further optimization and improvement. Summary of the Invention

[0004] Purpose of the invention: In response to the above problems, the present invention proposes a radio frequency power amplifier for the 6GHz (n104) frequency band of IMT international mobile communications. Its circuit size is small, with a length of 44mm and a width of only 16mm. This radio frequency power amplifier is based on an inverse Class F power amplifier design to solve the problem of low power amplifier output efficiency in this frequency band. This radio frequency power amplifier can be used in wireless transmitter systems in this frequency band. It can output sufficient power in this frequency band while ensuring high efficiency and gain. The maximum output power is greater than 37dBm (5W), the drain efficiency is greater than 50%, and the gain is stable within the frequency band, which can meet the requirements of high output power and high efficiency.

[0005] In order to solve the above problems, the present invention adopts the following technical solutions:

[0006] A radio frequency power amplifier circuit includes an input matching network, an output matching network, a DC bias circuit, and a stabilization circuit. It is characterized by:

[0007] The input matching network includes a series microstrip transmission line, an input DC blocking capacitor and three cross-connected microstrip lines; the output matching network includes three cross-connected harmonic suppression networks, an output impedance tuning line and an output DC blocking capacitor; the DC bias includes a gate DC bias and a drain DC bias; and the stabilization circuit includes two series resistors.

[0008] The first end of the series microstrip line in the input matching circuit is used to access the radio frequency signal, and the second end is connected to the first end of the input DC blocking capacitor; the second end of the input DC blocking capacitor is connected to the first end of the first resistor of the stabilization circuit; the second end of the first resistor of the stabilization circuit is connected to three cross-shaped connecting microstrip lines; the second end of the third cross-shaped microstrip line among the three cross-shaped connecting microstrip lines is connected to the first end of the second resistor of the stabilization circuit; and the third end of the third cross-shaped microstrip line among the three cross-shaped connecting microstrip lines is connected to the transistor gate.

[0009] The first cross-shaped microstrip line in the three cross-shaped harmonic suppression networks in the output matching circuit is connected to the first end of the output impedance tuning line; the first terminal of the output impedance tuning line is connected to the drain of the transistor; the third terminal of the first cross-shaped microstrip line in the three cross-shaped harmonic suppression networks is connected to the first end of the second cross-shaped connection in the harmonic suppression network; the third terminal of the second cross-shaped microstrip line in the three cross-shaped harmonic suppression networks is connected to the first end of the third cross-shaped connection in the harmonic suppression network; and the third terminal of the third cross-shaped microstrip line in the three cross-shaped harmonic suppression networks is connected to the output DC blocking capacitor.

[0010] The gate DC bias is composed of two transmission lines with an electrical length of λ / 4 and two grounded capacitors; the second end of the second resistor of the stabilization circuit is connected to the first end of the first microstrip line of the gate DC bias; the second end of the first microstrip line of the gate DC bias is connected to the first end of the first grounded capacitor; the second end of the first grounded capacitor is grounded; the first end of the second microstrip line of the gate DC bias is connected to the first end of the first grounded capacitor; the second end of the second microstrip line of the gate DC bias is connected to the first end of the second grounded capacitor; the second end of the second grounded capacitor is grounded; the second end of the second microstrip line of the gate DC bias is connected to the power supply V GS The drain DC bias is composed of two transmission lines with an electrical length of λ / 4 and two grounded capacitors; the first end of the first microstrip line of the drain DC bias is connected to the second end of the third cross-connected microstrip line in the three cross-connected harmonic suppression networks; the second end of the first microstrip line of the drain DC bias is connected to the first end of the third grounded capacitor; the first end of the second microstrip line of the drain DC bias is connected to the first end of the third grounded capacitor; the second end of the third grounded capacitor is grounded; the second end of the second microstrip line of the gate-drain DC bias is connected to the fourth grounded capacitor; the second end of the second microstrip line of the gate-drain DC bias is connected to the power supply V DS .

[0011] The advantages of the present invention are:

[0012] 1. The present invention provides a high-efficiency radio frequency power amplifier for IMT international mobile communications. The radio frequency power amplifier can cover the n104 frequency band (6.425-7.125 GHz) in IMT international mobile communications and has a certain excess bandwidth, ensuring stability and feasibility in actual use.

[0013] 2. The present invention is a high-efficiency radio frequency power amplifier for IMT international mobile communications. The maximum output power of the radio frequency power amplifier can reach 37dBm (5W), which can meet the effective transmission of signals in long-distance communications and expand the communication range.

[0014] 3. The present invention is a high-efficiency radio frequency power amplifier for IMT international mobile communications. The radio frequency power amplifier has a saturated drain efficiency greater than 50% and has a high energy conversion efficiency.

[0015] 4. The present invention is a high-efficiency radio frequency power amplifier for IMT international mobile communications. Its circuit size is small, with a length of 44 mm and a width of only 16 mm, which saves circuit board area and reduces costs. At the same time, the smaller size makes it easier to integrate into communication systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of a high-efficiency radio frequency power amplifier circuit for IMT international mobile communications according to the present invention.

[0017] Figure 2 This is a drain efficiency curve diagram of a high-efficiency radio frequency power amplifier for IMT international mobile communications according to the present invention.

[0018] Figure 3 This is an output-input power curve diagram of a high-efficiency radio frequency power amplifier for IMT international mobile communications according to the present invention. DETAILED DESCRIPTION

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of the application are for the purpose of describing specific embodiments only. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the accompanying drawings are intended to cover non-exclusive inclusions. The terms "first" and "second" in the specification and claims of this application and the accompanying drawings are used to distinguish different objects, not to describe a specific order.

[0020] The present invention is a high-efficiency radio frequency power amplifier for IMT international mobile communications. The present invention will be described in more detail below with reference to the accompanying drawings and technical solutions. The circuit schematic diagram of the high-efficiency radio frequency power amplifier for IMT international mobile communications is shown in FIG. Figure 1 shown.

[0021] Class F and inverse class F RF power amplifiers have output matching networks with harmonic impedance control. By adjusting the harmonic components of the transistor drain voltage and current, the current and voltage waveforms are reshaped, and the overlapping parts of the voltage and current waveforms are reduced or even eliminated to achieve high-efficiency operation. The inverse class F achieves voltage and current misalignment by constructing a drain voltage containing only even harmonics and a drain current containing only odd harmonics, thereby achieving high-efficiency operation. In actual design, only the third harmonic is generally controlled. According to the inverse class F impedance conditions, the second harmonic should be open-circuited and the third harmonic should be short-circuited. For this design, it is required that the second harmonic of 6.425-7.125GHz is open-circuited and the third harmonic is short-circuited. In specific implementation, the three cross-connected harmonic suppression networks in the output matching circuit can achieve the second harmonic of 6.425-7.125GHz open-circuited and the third harmonic short-circuited.

[0022] Figure 1 In the figure, T1, T2, T3, T4, T5 and T6 represent the six segments of microstrip lines of the output matching circuit. In actual design, T2 and T4 are divided into two segments, forming a cross connection with T1, T3 and T5. T2 is divided into T 21 、T 22 , T 21 、T 22 The electrical length is the same as the characteristic impedance; T4 is divided into T 41 、T 42 , T 41 、T 42 The electrical length is the same as the characteristic impedance. The characteristic impedances of the six microstrip lines corresponding to the microstrip lines are Z 01 , Z 02 , Z 03 , Z 04 , Z 05 , Z 06 The electrical lengths of the six microstrip lines are θ 01 ,θ 02 ,θ 03 ,θ 04 ,θ 05 ,θ 06 . The six microstrip lines have θ 02 ,θ 06 The electrical length relative to the fundamental frequency is 50°, θ 03The electrical length relative to the fundamental frequency is 30°, and the electrical length relative to the third harmonic frequency is 90°. The harmonic suppression network composed of the six microstrip lines can short-circuit the third harmonic within the frequency band.

[0023] In the actual design, the transistor used was a Cree CGHV1F006S 6W GaN HEMT transistor. The transistor drain voltage was set to 40V and the gate voltage to -2.9V. The capacitors used were Murata GRM15 and GRM18 series capacitors. The circuit was implemented using microstrip lines. The RF power amplifier was implemented using Rogers 4350B material, with a relative dielectric constant of 3.66 and a thickness of 0.508mm. The bottom metal ground layer is the grounding layer.

[0024] The input-output power curve of the high-efficiency radio frequency power amplifier for IMT international mobile communications is as follows: Figure 2 As shown. It can be seen that when the input power is 29dBm, the output power in the range of 6.425-7.125GHz can reach 37dBm. The RF power amplifier drain efficiency-output power curve is shown in Figure 3 It can be seen that when the output power is 37dBm, the drain efficiency (DE) within 6.425-7.125GHz is greater than 50%.

Claims

1. A radio frequency power amplifier for IMT international mobile communications, comprising an input matching network, an output matching network, a DC bias circuit, and a stabilization circuit, characterized in that: The input matching network includes a series microstrip transmission line, an input DC blocking capacitor and an input matching circuit; the output matching network includes a harmonic suppression network, an output impedance tuning line and an output DC blocking capacitor; the transistor drain is connected in series with an inverse F-class harmonic suppression network, and the inverse F-class harmonic suppression circuit is respectively connected to the drain DC bias and the output tuning line.

2. The radio frequency power amplifier for IMT international mobile communications according to claim 1, wherein: The input matching circuit is composed of three cross-shaped microstrip lines, the third cross-shaped microstrip line is connected to the second resistor of the stabilization circuit and the gate DC bias, and the input end of the input matching circuit is the first resistor of the stabilization circuit.

3. The radio frequency power amplifier for IMT international mobile communications according to claim 1, wherein: The harmonic suppression network in the output matching circuit is composed of three cross-connected harmonic suppression networks, the third cross-connected network in the harmonic suppression network is connected to the drain DC bias, and the network input end is a tuning line.

4. The radio frequency power amplifier for IMT international mobile communications according to claim 1, wherein: The dielectric layer of the radio frequency power amplifier has a size of 44 mm×16 mm×0.508 mm, and is made of Rogers 4350B material with a dielectric constant of 3.66 and a loss tangent value of 0.0037.

5. The radio frequency power amplifier for IMT international mobile communications according to claim 1, wherein: Its frequency range covers the entire n104 band, from 6.425-7.125GHz, and has a certain amount of excess bandwidth, ensuring adaptability, stability and feasibility in actual use.

6. The radio frequency power amplifier for IMT international mobile communications according to claim 1, wherein: When the input power is 29dBm, the output power in the range of 6.425-7.125GHz can reach 37dBm. When the output power is 37dBm, the drain efficiency (DE) in the range of 6.425-7.125GHz is greater than 50%.

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