A multi-channel Doherty power amplifier and its bandwidth extension method

Abstract

A multi-channel Doherty power amplifier and its bandwidth extension method are disclosed. The power amplifier includes a power divider, an input multiplexer, a main amplification branch, an auxiliary amplification branch, a power combiner, and an impedance matching unit. By constructing multiple frequency complementary branches and introducing an impedance compression network, the power amplifier can continuously cover a wider frequency band, thereby extending the bandwidth. This solves the problem of the requirement for broadband operating mode or multi-frequency reconfiguration mode of energy transmission array in microwave energy transmission systems. The main branch covers the required entire operating bandwidth, and (n-1) auxiliary branches form a frequency complementary relationship to jointly cover the entire operating bandwidth. Each branch uses the impedance compression network to extend its own bandwidth. The main branch and each auxiliary branch completely and continuously cover the operating bandwidth, thereby significantly extending the bandwidth of the Doherty power amplifier.

Description

Technical Field

[0001] This invention relates to a multi-channel Doherty power amplifier and a bandwidth extension method, belonging to the field of radio frequency and microwave technology. Background Technology

[0002] Radio frequency (RF) power amplifiers are crucial components of the transmitter in wireless systems such as microwave power transmission and microwave communication, directly impacting the overall performance of the transmitter. On one hand, to adapt to dynamic changes in transmission distance, power amplifiers are required to maintain high conversion efficiency over a wide power dynamic range. On the other hand, to meet the application requirements of broadband energy and information transmission or frequency division multiplexing of energy or information transmission under multi-target conditions, power amplifiers are required to have a large bandwidth. Traditional Doherty power amplifiers can meet the first requirement, providing high efficiency within a certain power back-off range. Especially with a multi-channel Doherty architecture, an even larger dynamic range can be achieved. However, in the Doherty power amplifier architecture, the impedance adjustment network at the output of the auxiliary amplifier branch has narrowband characteristics, often limiting the Doherty power amplifier to a narrowband amplifier. Furthermore, when facing greater operating bandwidth requirements, the input compensation line bandwidth in each branch is also insufficient, making it difficult to meet system requirements. Summary of the Invention

[0003] The technical problem solved by this invention is to address the bandwidth limitation problem of traditional Doherty power amplifiers in the current technology, and to propose a multi-channel Doherty power amplifier and a bandwidth extension method.

[0004] The present invention solves the above-mentioned technical problem through the following technical solution:

[0005] A multi-channel Doherty power amplifier includes a power divider, an input multiplexer, a main amplification branch, an auxiliary amplification branch, a power combiner, and an impedance matching unit, wherein:

[0006] The power divider receives broadband low-power microwave signal input and distributes it to the main amplifier branch and the input multiplexer.

[0007] The main amplification branch receives low-power microwave signals and amplifies them, then outputs broadband high-power microwave signals to the power combiner.

[0008] The input multiplexer receives broadband low-power microwave signals and distributes the signals into n-1 channels to each auxiliary amplifier branch.

[0009] The auxiliary amplification branch receives the dispersed low-power microwave signal and amplifies it, then outputs n-1 high-power microwave signals with complementary frequencies to the output multiplexer.

[0010] The output multiplexer receives n-1 channels of complementary high-power microwave signals and performs frequency domain synthesis to output a broadband high-power microwave signal to the power combiner.

[0011] The power combiner receives broadband high-power microwave signals, synthesizes them, and then processes them through an impedance matching unit for broadband matching before outputting a microwave power signal that meets the load requirements to the external load.

[0012] The number of auxiliary amplification branches is (n-1), where:

[0013] The power divider's input terminal is connected to the input signal, and its output terminals are connected to the main amplification branch and the input multiplexer's input terminal, respectively. The input multiplexer's output terminal is connected to the input terminals of the first auxiliary amplification branch, the second auxiliary amplification branch, and so on up to the (n-1)th auxiliary amplification branch. The output terminals of the first auxiliary amplification branch, the second auxiliary amplification branch, and so on up to the (n-1)th auxiliary amplification branch are all connected to the input terminal of the output multiplexer. The output terminal of the output multiplexer and the output terminal of the main amplification branch are connected to the power combiner. The output terminal of the power combiner is connected to the impedance matching unit.

[0014] The main amplification branch includes a main input impedance compression network, a main input compensation line, a main input matching, a main amplifier, a main output impedance compression network, and a main output impedance adjustment network.

[0015] The main input impedance compression network is used to widen the bandwidth of the input compensation line and send the broadband signal to the main input compensation line; the main input compensation line receives the broadband signal and performs broadband phase compensation processing; the main input matching receives the compensated signal and performs impedance matching on the input terminal of the main power amplifier in terms of signal level; the main amplifier receives the input signal and amplifies it; the main output impedance compression network reduces the impedance variation range of the output impedance adjustment network within the broadband; the main output impedance adjustment network receives the microwave power signal output by the main output impedance compression network, adjusts the output impedance, and sends the resulting broadband high-power microwave signal to the power combiner.

[0016] Each of the first auxiliary amplification branch to the (n-1)th auxiliary amplification branch includes an input impedance compression network, an input compensation line, an input matching line, an amplifier, an output impedance compression network, and an output impedance adjustment network. The input impedance compression network widens the bandwidth of the input compensation line and sends the broadband signal to it. The input compensation line receives the broadband signal and performs broadband phase compensation processing. The auxiliary input matching line receives the compensated signal and performs impedance matching on the input of the auxiliary power amplifier at the signal level. The auxiliary amplifier receives the input signal and amplifies its power. The auxiliary output impedance compression network reduces the impedance variation range of the output impedance adjustment network within the broadband range. The output impedance adjustment network receives the microwave power signal output from the output impedance compression network, adjusts its output impedance, and then sends the resulting broadband high-power microwave signal to the output multiplexer.

[0017] When the power amplifier is operating, the first auxiliary amplification branch, the second auxiliary amplification branch, and up to the (n-1)th auxiliary amplification branch are simultaneously activated; the operating frequency of the main amplification branch is [f1, f2]. n Within a narrow frequency range, the first auxiliary amplification branch operates within the narrow frequency range of [f1, f2], the second auxiliary amplification branch operates within the narrow frequency range of [f2, f3], and the (n-1)th auxiliary amplification branch operates within the narrow frequency range of [f...]. n-1 ,f n Within a narrow frequency band, where f1 < f2 < f3 < ... < f n .

[0018] When the main branch power amplifier is working, the first auxiliary amplifier branch, the second auxiliary amplifier branch, and up to the (n-1)th auxiliary amplifier branch are turned on simultaneously; the power level difference between the main branch power amplifier and the auxiliary branch power amplifier is used to ensure the dynamic range of the multi-channel Doherty amplifier.

[0019] The power divider, power combiner, and impedance matching unit all employ a transmission line design with broadband characteristics.

[0020] The number of auxiliary amplification branches (n-1) and the design parameters of the impedance compression network are determined based on the operating bandwidth requirements of the power amplifier and the bandwidth expansion capability of the impedance compression network.

[0021] The input multiplexer and output multiplexer are designed according to the frequency characteristics of each auxiliary amplification branch to achieve frequency complementarity and continuously cover the required operating bandwidth.

[0022] A method for bandwidth extension of a multi-channel Doherty power amplifier, based on a multi-channel Doherty power amplifier, includes:

[0023] A power divider is used to receive broadband low-power microwave signals and distribute them to the main amplifier branch and the input multiplexer, respectively.

[0024] The main amplification branch receives low-power microwave signals and amplifies them, then outputs broadband high-power microwave signals to the power combiner.

[0025] The input multiplexer receives broadband low-power microwave signals and distributes the signals into (n-1) paths to each auxiliary amplifier branch.

[0026] In each auxiliary amplification branch, the dispersed low-power microwave signal is received and amplified, and n-1 high-power microwave signals with complementary frequencies are output to the output multiplexer.

[0027] In the output multiplexer, n-1 complementary high-power microwave signals are received and frequency-domain synthesized to output a broadband high-power microwave signal to the power combiner.

[0028] After receiving broadband high-power microwave signals using a power combiner and combining them, the signal is then subjected to broadband impedance matching by an impedance matching unit before outputting a microwave power signal that meets the load requirements to an external load.

[0029] The advantages of this invention compared to the prior art are:

[0030] (1) This invention provides a multi-channel Doherty power amplifier and a bandwidth extension method. First, it utilizes frequency complementarity to extend the operating bandwidth of the Doherty power amplifier. The main branch and the first auxiliary branch partially cover the lower end of the operating bandwidth, while the main branch and the (n-1)th auxiliary branch partially cover the higher end. The middle bandwidth is covered by the main branch and other auxiliary branches. Further, it utilizes an impedance compression network to extend the bandwidth of the passive network of each branch, and the main branch and each auxiliary branch completely and continuously cover the operating bandwidth. This invention can extend the bandwidth of existing Doherty power amplifiers from narrowband to several octaves.

[0031] (2) The present invention can be compatible with the working mode of multi-frequency power amplifier within a large bandwidth by adjusting the impedance compression network of each auxiliary branch. It has made substantial progress in the widening effect of the Doherty power amplifier working bandwidth compared with the existing background technology. Attached Figure Description

[0032] Figure 1 A block diagram of a broadband multi-channel Doherty power amplifier provided for the invention;

[0033] Figure 2 A schematic diagram of the bandwidth extension of a multi-channel Doherty power amplifier provided for the invention;

[0034] Figure 3 A schematic diagram illustrating the frequency complementarity characteristics of the auxiliary branches of a multi-channel Doherty power amplifier provided for the invention.

[0035] Figure 4 Block diagram of a broadband four-channel Doherty power amplifier provided for the invention;

[0036] Figure 5 A broadband characteristic diagram of a broadband four-channel Doherty power amplifier provided for the invention; Detailed Implementation

[0037] A multi-channel Doherty power amplifier and its bandwidth extension method are disclosed. The power amplifier includes a power divider, an input multiplexer, a main amplification branch, an auxiliary amplification branch, a power combiner, and an impedance matching unit. By constructing multiple frequency complementary branches and introducing an impedance compression network, the power amplifier can continuously cover a wider frequency band, thereby extending the bandwidth. This solves the problem of the requirement for broadband operating mode or multi-frequency reconfiguration mode of energy transmission array in microwave energy transmission systems. The main branch covers the required entire operating bandwidth, and (n-1) auxiliary branches form a frequency complementary relationship to jointly cover the entire operating bandwidth. Each branch uses the impedance compression network to extend its own bandwidth. The main branch and each auxiliary branch completely and continuously cover the operating bandwidth, thereby significantly extending the bandwidth of the Doherty power amplifier.

[0038] In a multi-channel Doherty power amplifier:

[0039] The power divider receives broadband low-power microwave signal input and distributes it to the main amplifier branch and the input multiplexer.

[0040] The main amplification branch receives low-power microwave signals and amplifies them, then outputs broadband high-power microwave signals to the power combiner.

[0041] The input multiplexer receives a broadband low-power microwave signal and distributes the signal evenly as (n-1) channels to the input terminals of each auxiliary amplifier branch;

[0042] The auxiliary amplifier branch receives the distributed low-power microwave signal and amplifies it, then outputs (n-1) high-power microwave signals with complementary frequencies to the output multiplexer.

[0043] The output multiplexer receives (n-1) high-power microwave signals with complementary frequencies and performs frequency domain synthesis to output a broadband high-power microwave signal to the power combiner.

[0044] The power combiner receives broadband high-power microwave signals, synthesizes them, performs broadband impedance matching through an impedance matching unit, and then outputs a microwave power signal that meets the load requirements to the external load.

[0045] The main amplification branch includes a main input impedance compression network, a main input compensation line, a main input matching line, a main amplifier, a main output impedance compression network, and a main output impedance adjustment network.

[0046] The auxiliary amplification branches include an input impedance compression network, an input compensation line, an input matching line, an amplifier, an output impedance compression network, and an output impedance adjustment network. There are n-1 auxiliary amplification branches, among which:

[0047] The power divider's input terminal is connected to the input signal, and its output terminals are connected to the main amplification branch and the input multiplexer's input terminal, respectively. The input multiplexer's output terminal is connected to the input terminals of the first auxiliary amplification branch, the second auxiliary amplification branch, and so on up to the (n-1)th auxiliary amplification branch. The output terminals of the first auxiliary amplification branch, the second auxiliary amplification branch, and so on up to the (n-1)th auxiliary amplification branch are all connected to the input terminal of the output multiplexer. The output terminal of the output multiplexer and the output terminal of the main amplification branch are connected to the power combiner. The output terminal of the power combiner is connected to the impedance matching unit.

[0048] In the main amplification branch, the main input impedance compression network is used to widen the bandwidth of the main input compensation line and send the broadband signal to the main input compensation line; the main input compensation line receives the broadband signal and performs broadband phase compensation processing on it to meet the synchronization requirements of each signal; the main input matching receives the compensated signal and performs impedance matching on the input terminal of the main power amplifier in terms of signal level to meet the high-efficiency input requirements of the signal; the main amplifier receives the input signal and amplifies it; the main output impedance compression network reduces the impedance variation range of the output impedance adjustment network within the broadband, meeting the bandwidth widening requirements of the impedance adjustment network; the main output impedance adjustment network receives the microwave power signal output by the main output impedance compression network, adjusts the output impedance to meet the high-efficiency output requirements of the microwave power signal, and sends the resulting broadband high-power microwave signal to the power combiner.

[0049] In the first auxiliary amplification branch to the (n-1)th auxiliary amplification branch, the input impedance compression network is used to widen the bandwidth of the input compensation line and send the broadband signal to the input compensation line; the input compensation line receives the broadband signal and performs broadband phase compensation processing to meet the synchronization requirements of each signal; the auxiliary input matching receives the compensated signal and performs impedance matching on the input terminal of the auxiliary power amplifier in terms of signal level to meet the requirements of efficient signal input; the auxiliary amplifier receives the input signal and amplifies it; the auxiliary output impedance compression network reduces the impedance variation range of the output impedance adjustment network in the broadband to meet the bandwidth widening requirements of the impedance adjustment network; the output impedance adjustment network receives the microwave power signal output by the output impedance compression network, adjusts the output impedance to meet the requirements of efficient microwave power signal output, and sends the resulting broadband high-power microwave signal to the output multiplexer.

[0050] When the power amplifier is operating, the first auxiliary amplification branch, the second auxiliary amplification branch, and up to the (n-1)th auxiliary amplification branch are simultaneously activated; the operating frequency of the main amplification branch is [f1, f2]. n Within a narrow frequency range, the first auxiliary amplification branch operates within the narrow frequency range of [f1, f2], the second auxiliary amplification branch operates within the narrow frequency range of [f2, f3], and the (n-1)th auxiliary amplification branch operates within the narrow frequency range of [f...]. n-1 ,f n Within a narrow frequency band, where f1 < f2 < f3 < ... < f n .

[0051] A method for bandwidth extension of a multi-channel Doherty power amplifier using a multi-channel Doherty power amplifier is described below:

[0052] A power divider is used to receive broadband low-power microwave signals and distribute them to the main amplifier branch and the input multiplexer, respectively.

[0053] The main amplification branch receives low-power microwave signals and amplifies them, then outputs broadband high-power microwave signals to the power combiner.

[0054] The input multiplexer receives broadband low-power microwave signals and distributes the signals into n-1 channels to each auxiliary amplifier branch.

[0055] In each auxiliary amplification branch, the dispersed low-power microwave signal is received and amplified, and n-1 high-power microwave signals with complementary frequencies are output to the output multiplexer.

[0056] In the output multiplexer, n-1 complementary high-power microwave signals are received and frequency-domain synthesized to output a broadband high-power microwave signal to the power combiner.

[0057] After receiving broadband high-power microwave signals using a power combiner and combining the signals, broadband impedance matching is performed through an impedance matching unit, and a microwave power signal that meets the load requirements is output to the external load.

[0058] The following description, in conjunction with the accompanying drawings and preferred embodiments, provides further details:

[0059] In the current embodiment, such as Figure 2 The diagram shown is a schematic of a multi-channel Doherty power amplifier bandwidth extension circuit. Specific technical solutions include:

[0060] The system comprises a power divider, an input multiplexer, a main amplification branch, a first auxiliary amplification branch, a second auxiliary amplification branch, up to the (n-1)th auxiliary amplification branch, an output multiplexer, a power combiner, and an impedance matching unit. The power divider's input terminal is connected to the input signal, and its output terminals are connected to the main amplification branch and the input multiplexer, respectively. The output terminal of the input multiplexer is connected to the input terminals of the first auxiliary amplification branch, the second auxiliary amplification branch, up to the (n-1)th auxiliary amplification branch, respectively. The input terminals of the first auxiliary amplification branch, the second auxiliary amplification branch, up to the (n-1)th auxiliary amplification branch are all connected to the output multiplexer. The output terminal of the output multiplexer and the output terminal of the main amplification branch are connected to the power combiner. The output terminal of the power combiner is then connected to the impedance matching unit. The main amplification branch, following the signal transmission path, sequentially includes: an input impedance compression network, a main input compensation line, a main input matching line, a main amplifier, a main output impedance compression network, and a main output impedance adjustment network. The first auxiliary amplification branch, following the signal transmission path, sequentially includes: a first auxiliary... The input impedance compression network, the first auxiliary input compensation line, the first auxiliary input matching, the first auxiliary amplifier, the first auxiliary output impedance compression network, and the first auxiliary output impedance adjustment network are all present. The second auxiliary amplification branch, following the signal transmission path, sequentially includes: the second auxiliary input impedance compression network, the second auxiliary input compensation line, the second auxiliary input matching, the second auxiliary amplifier, the second auxiliary output impedance compression network, and the second auxiliary output impedance adjustment network. Similarly, the (n-1)th auxiliary amplification branch, following the signal transmission path, sequentially includes: the (n-1)th auxiliary input impedance compression network, the (n-1)th auxiliary input compensation line, the (n-1)th auxiliary input matching, the (n-1)th auxiliary amplifier, the (n-1)th auxiliary output impedance compression network, and the (n-1)th auxiliary output impedance adjustment network.

[0061] The main branch and multiple auxiliary branches continuously cover the entire operating bandwidth. The main branch and auxiliary branches work together to achieve a large dynamic range, ensuring the microwave power amplifier's characteristics of large dynamic range, large bandwidth, and high efficiency.

[0062] When the amplifier is working, the first auxiliary amplification branch, the second auxiliary amplification branch, and up to the (n-1)th auxiliary amplification branch are simultaneously activated; the operating frequency of the main amplification branch is [f1, f2]. n Within a narrow frequency range, the first auxiliary amplification branch operates within the narrow frequency range of [f1, f2], the second auxiliary amplification branch operates within the narrow frequency range of [f2, f3], and similarly, the (n-1)th auxiliary amplification branch operates within the narrow frequency range of [f...]. n-1 ,f n Within a narrow frequency band, where f1 < f2 < f3 < ... < f n .

[0063] When the amplifier is operating, the main amplification branch and the first to (n-1)th auxiliary amplification branches further utilize impedance compression networks to broaden the bandwidth; the main amplification branch inserts an impedance compression network before the input compensation line and the output impedance adjustment network, so that its operating frequency range reaches [f1, f2]. n The first auxiliary amplification branch inserts an impedance compression network before the input compensation line and the output impedance adjustment network to achieve an operating frequency range of [f1, f2]. The second auxiliary amplification branch inserts an impedance compression network before the input compensation line and the output impedance adjustment network to achieve an operating frequency range of [f2, f3]. Similarly, the (n-1)th auxiliary amplification branch achieves an operating frequency range of [f1, f2]. n-1 ,f n ], where f1 < f2 < f3 < ... < f n .

[0064] When this amplifier is working, the main amplification branch, the first auxiliary amplification branch, the second auxiliary amplification branch, and up to the (n-1)th auxiliary amplification branch are all turned on simultaneously. The dynamic range of the multi-channel Doherty amplifier is guaranteed by utilizing the power level difference between the main branch power amplifier and the auxiliary branch power amplifier. If the power level of the auxiliary branch power amplifier is set to one-quarter of the power level of the main branch power amplifier, the dynamic range of the multi-channel Doherty amplifier can reach 6dB, that is, it still maintains high efficiency when the power drops back by 6dB.

[0065] The power divider is designed and manufactured using a transmission line with broadband characteristics, the power combiner is designed and manufactured using a transmission line with broadband characteristics, and the impedance matching unit is designed and manufactured using a transmission line with broadband characteristics.

[0066] The method for widening the bandwidth of multi-channel Doherty power amplifiers is specifically designed as follows:

[0067] (1) Based on the system's operating bandwidth requirements and the bandwidth expansion capability of the impedance compression network, determine the number of auxiliary branches to form a broadband multi-channel Doherty power amplifier scheme.

[0068] (2) Based on the requirement of continuous bandwidth coverage, allocate working bandwidth to each auxiliary branch and design an impedance compression network to broaden the bandwidth of each auxiliary branch;

[0069] (3) Design input multiplexers and output multiplexers according to the frequency characteristics of each auxiliary branch to form complementary frequency characteristics, so that the Doherty power amplifier can continuously cover the required operating bandwidth.

[0070] The bandwidth widening method for the multi-channel Doherty power amplifier is based on a multi-channel Doherty architecture, but the multiple auxiliary branches are not used to increase the dynamic range; rather, they are used to widen the bandwidth through frequency complementarity. Figure 3As shown. When the amplifier is working, the first, second, and up to the (n-1)th auxiliary amplification branches are simultaneously activated, and the operating frequency of the main amplification branch is [f1, f2]. n Within a narrow frequency range, the first auxiliary amplification branch operates within the narrow frequency range of [f1, f2], the second auxiliary amplification branch operates within the narrow frequency range of [f2, f3], and similarly, the (n-1)th auxiliary amplification branch operates within the narrow frequency range of [f...]. n-1 ,f n Within a narrow frequency band, where f1 < f2 < f3 < ... < f n The main amplification branch and the first to (n-1)th auxiliary amplification branches further utilize impedance compression networks to broaden the bandwidth. The main amplification branch inserts an impedance compression network before the input compensation line and the output impedance adjustment network, enabling its operating frequency range to reach [f1, f2]. n The first auxiliary amplification branch inserts an impedance compression network before the input compensation line and the output impedance adjustment network to achieve an operating frequency range of [f1, f2]. The second auxiliary amplification branch inserts an impedance compression network before the input compensation line and the output impedance adjustment network to achieve an operating frequency range of [f2, f3]. Similarly, the (n-1)th auxiliary amplification branch achieves an operating frequency range of [f1, f2]. n-1 ,f n ], where f1 < f2 < f3 < ... < f n .

[0071] The block diagram of the broadband multi-channel Doherty power amplifier is as follows: Figure 1 As shown, the input signal is a broadband low-power microwave signal, and the output signal is a broadband high-power microwave signal.

[0072] Broadband low-power microwave signals are distributed to the main branch and input multiplexer (2) of the Doherty power amplifier via a power divider (1). In the main branch, the low-power signal passes through the main input impedance compression network (3), main input compensation line (4), main input matching (5), main amplifier (6), main output impedance compression network (7), and main output impedance adjustment network (8) to form a broadband high-power microwave signal. In the auxiliary branch, the input multiplexer divides the broadband low-power microwave signal into (n-1) low-power microwave signals with complementary working bandwidths. The total working bandwidth completely covers the bandwidth required by the system. In each auxiliary branch, the low-power signal passes through the main input impedance compression network (3), main input compensation line (4), main input matching (5), main amplifier (6), main output impedance compression network (7), and main output impedance adjustment network (8) to form multiple high-power microwave signals with complementary frequencies. The signals from these auxiliary branches are fed into the output multiplexer (9) for frequency domain synthesis to form a broadband high-power microwave signal. The broadband high-power microwave signal output from the output multiplexer (9) and the broadband high-power microwave signal output from the main branch are fed into the power combiner (10), and then through the impedance matching unit (11), a broadband, high-dynamic microwave power signal can be output to the load. The multi-channel Doherty power amplifier maintains its inherent high dynamic characteristics.

[0073] The total operating bandwidth [f1, f] required for main branch coverage n (n-1) auxiliary branches respectively cover [f1,f2], [f2,f3], ..., [f n-1 ,f n The bandwidth of f1 < f2 < f3 < ... < f n This utilizes the main branch and all auxiliary branches to completely and continuously cover the operating bandwidth, thereby significantly widening the bandwidth of the Doherty power amplifier.

[0074] Specific examples illustrate:

[0075] To verify the method of this patent, a 2-12GHz broadband four-channel Doherty power amplifier was designed and developed based on the above method, such as... Figure 4 As shown, the broadband characteristics are as follows: Figure 5 As shown, it includes one main power amplifier branch and two auxiliary branches. The main branch has a bandwidth of 2-12GHz; the first auxiliary branch has a bandwidth of 2-4GHz, the second auxiliary branch has a bandwidth of 4-8GHz, and the third auxiliary branch has a bandwidth of 8-12GHz. The entire four-channel Doherty power amplifier achieves a bandwidth of six octaves, thus achieving the goal of bandwidth widening.

[0076] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

[0077] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A multi-channel Doherty power amplifier, characterized in that: It includes a power divider, input multiplexer, main amplification branch, auxiliary amplification branch, power combiner, impedance matching unit, and output multiplexer, wherein: The power divider receives broadband low-power microwave signal input and distributes it to the main amplifier branch and the input multiplexer. The main amplification branch receives low-power microwave signals and amplifies them, then outputs broadband high-power microwave signals to the power combiner. The input multiplexer receives broadband low-power microwave signals and distributes the signals into n-1 channels to each auxiliary amplifier branch. The auxiliary amplification branch receives the dispersed low-power microwave signal and amplifies it, then outputs n-1 high-power microwave signals with complementary frequencies to the output multiplexer. The output multiplexer receives n-1 channels of complementary high-power microwave signals and performs frequency domain synthesis to output a broadband high-power microwave signal to the power combiner. The power combiner receives broadband high-power microwave signals, combines them, and then processes them through an impedance matching unit for broadband matching before outputting a microwave power signal that meets the load requirements to an external load. The main amplification branch includes a main input impedance compression network, a main input compensation line, a main input matching line, a main amplifier, a main output impedance compression network, and a main output impedance adjustment network. The main input impedance compression network is used to widen the bandwidth of the main input compensation line and send the broadband signal to the main input compensation line; the main input compensation line receives the broadband signal and performs broadband phase compensation processing; the main input matching receives the compensated signal and performs impedance matching on the main amplifier at the signal level; the main amplifier receives the input signal and amplifies it; the main output impedance compression network reduces the impedance variation range of the output impedance adjustment network within the broadband; the main output impedance adjustment network receives the microwave power signal output by the main output impedance compression network, adjusts the output impedance, and sends the resulting broadband high-power microwave signal to the power combiner; Each of the first auxiliary amplification branch to the (n-1)th auxiliary amplification branch includes an input impedance compression network, an input compensation line, an input matching line, an auxiliary amplifier, an output impedance compression network, and an output impedance adjustment network. The input impedance compression network widens the bandwidth of the input compensation line and sends the broadband signal to it. The input compensation line receives the broadband signal and performs broadband phase compensation processing on it. The input matching line receives the compensated signal and performs impedance matching on the input terminal of the auxiliary amplifier at the signal level. The auxiliary amplifier receives the input signal and amplifies its power. The output impedance compression network narrows the impedance variation range of the output impedance adjustment network within the broadband range. The output impedance adjustment network receives the microwave power signal output from the output impedance compression network, adjusts its output impedance, and then sends the resulting broadband high-power microwave signal to the output multiplexer. When a multi-channel Doherty power amplifier is operating, the first auxiliary amplification branch, the second auxiliary amplification branch, and up to the (n-1)th auxiliary amplification branch are simultaneously activated; the operating frequency of the main amplification branch is... Within a narrow frequency range, the operating frequency range of the first auxiliary amplification branch is: Within the narrow frequency band, the operating frequency of the second auxiliary amplifier branch is Within a narrow frequency range, the operating frequency range of the (n-1)th auxiliary amplification branch is... On the narrow frequency range, among which ; The dynamic range of the multi-channel Doherty amplifier is ensured by utilizing the power level difference between the main amplifier branch and the auxiliary amplifier branch.

2. A multi-channel Doherty power amplifier according to claim 1, characterized in that: The number of auxiliary amplification branches is (n-1), where: The power divider's input terminal is connected to the input signal, and its output terminals are connected to the main amplification branch and the input multiplexer's input terminal, respectively. The input multiplexer's output terminal is connected to the input terminals of the first auxiliary amplification branch, the second auxiliary amplification branch, and so on up to the (n-1)th auxiliary amplification branch. The output terminals of the first auxiliary amplification branch, the second auxiliary amplification branch, and so on up to the (n-1)th auxiliary amplification branch are all connected to the input terminal of the output multiplexer. The output terminal of the output multiplexer and the output terminal of the main amplification branch are connected to the power combiner. The output terminal of the power combiner is connected to the impedance matching unit.

3. A multi-channel Doherty power amplifier according to claim 1, characterized in that: The power divider, power combiner, and impedance matching unit all employ a transmission line design with broadband characteristics.

4. A multi-channel Doherty power amplifier according to claim 1, characterized in that: The number of auxiliary amplification branches (n-1) and the design parameters of the impedance compression network are determined based on the operating bandwidth requirements of the power amplifier and the bandwidth expansion capability of the impedance compression network.

5. A multi-channel Doherty power amplifier according to claim 1, characterized in that: The input multiplexer and output multiplexer are designed according to the frequency characteristics of each auxiliary amplification branch to achieve frequency complementarity and continuously cover the required operating bandwidth.

6. A method for bandwidth extension of a multi-channel Doherty power amplifier as described in claim 1, characterized in that... include: A power divider is used to receive broadband low-power microwave signals and distribute them to the main amplifier branch and the input multiplexer, respectively. The main amplification branch receives low-power microwave signals and amplifies them, then outputs broadband high-power microwave signals to the power combiner. The input multiplexer receives broadband low-power microwave signals and distributes the signals into (n-1) paths to each auxiliary amplifier branch. In each auxiliary amplification branch, the dispersed low-power microwave signal is received and amplified, and n-1 high-power microwave signals with complementary frequencies are output to the output multiplexer. In the output multiplexer, n-1 complementary high-power microwave signals are received and frequency-domain synthesized to output a broadband high-power microwave signal to the power combiner. After receiving broadband high-power microwave signals using a power combiner and combining the signals, broadband impedance matching is performed by an impedance matching unit, and then a microwave power signal that meets the load requirements is output to the external load. The main amplification branch includes a main input impedance compression network, a main input compensation line, a main input matching, a main amplifier, a main output impedance compression network, and a main output impedance adjustment network. The main input impedance compression network is used to widen the bandwidth of the main input compensation line and send the broadband signal to the main input compensation line; the main input compensation line receives the broadband signal and performs broadband phase compensation processing; the main input matching receives the compensated signal and performs impedance matching on the main amplifier at the signal level; the main amplifier receives the input signal and amplifies it; the main output impedance compression network reduces the impedance variation range of the output impedance adjustment network within the broadband; the main output impedance adjustment network receives the microwave power signal output by the main output impedance compression network, adjusts the output impedance, and sends the resulting broadband high-power microwave signal to the power combiner; Each of the first auxiliary amplification branch to the (n-1)th auxiliary amplification branch includes an input impedance compression network, an input compensation line, an input matching line, an auxiliary amplifier, an output impedance compression network, and an output impedance adjustment network. The input impedance compression network widens the bandwidth of the input compensation line and sends the broadband signal to it. The input compensation line receives the broadband signal and performs broadband phase compensation processing on it. The input matching line receives the compensated signal and performs impedance matching on the input terminal of the auxiliary amplifier at the signal level. The auxiliary amplifier receives the input signal and amplifies its power. The output impedance compression network narrows the impedance variation range of the output impedance adjustment network within the broadband range. The output impedance adjustment network receives the microwave power signal output from the output impedance compression network, adjusts its output impedance, and then sends the resulting broadband high-power microwave signal to the output multiplexer. When a multi-channel Doherty power amplifier is operating, the first auxiliary amplification branch, the second auxiliary amplification branch, and up to the (n-1)th auxiliary amplification branch are simultaneously activated; the operating frequency of the main amplification branch is... Within a narrow frequency range, the operating frequency range of the first auxiliary amplification branch is: Within the narrow frequency band, the operating frequency of the second auxiliary amplifier branch is Within a narrow frequency range, the operating frequency range of the (n-1)th auxiliary amplification branch is... On the narrow frequency range, among which ; The dynamic range of the multi-channel Doherty amplifier is ensured by utilizing the power level difference between the main amplifier branch and the auxiliary amplifier branch.

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