Power synthesis circuit and synthesizer based on coaxial line transformer

Abstract

The invention relates to a coaxial line transformer-based power synthesis circuit and synthesizer, which comprises an impedance reducing sub-circuit and an impedance increasing conversion sub-circuit, and is characterized in that the output end of the impedance reducing sub-circuit is connected with the input end of the impedance increasing conversion sub-circuit; the input end of the impedance reducing sub-circuit is constructed as the input end of the power synthesis circuit, and the output end of the impedance increasing conversion sub-circuit is constructed as the output end of the power synthesis circuit; the impedance reducing sub-circuit and the impedance increasing conversion sub-circuit comprise coaxial line magnet ring transformers, coaxial lines penetrate through magnet rings to form the coaxial line magnet ring transformers, inner conductors of the coaxial lines serve as primary coils of the transformers, and outer conductors of the coaxial lines serve as secondary coils of the transformers. The impedance reduction sub-circuit is used for performing power synthesis and impedance reduction through the turn ratio of the coaxial line magnet ring transformer, and the impedance rising conversion sub-circuit is used for impedance matching and power transmission optimization so as to convert a medium-low impedance value back to a standard impedance value required by a load and ensure that the maximum power is transmitted to the load.

Description

Technical Field

[0001] The present disclosure relates to the field of power conversion technologies, and particularly to a power combining circuit and a combiner based on a coaxial transformer. Background Art

[0002] In the field of radio frequency power combining, traditional technologies mainly use stripline or lumped elements (a combination of an inductor L and a capacitor C) to implement a power combiner. However, both of these methods have significant technical limitations: Stripline combiner: In the medium and high frequency band of 5 MHz to 100 MHz, due to the long electromagnetic wavelength, the stripline-based combiner needs to match a λ / 4 wavelength transmission line, resulting in an overly large physical size of the circuit and making it difficult to meet the requirements of miniaturization and integration for modern communication devices.

[0003] Lumped element combiner: Although the circuit size can be reduced through an LC network, limited by the parasitic parameters of the components and frequency sensitivity, its operating bandwidth is relatively narrow (usually only covering 10% - 20% of the center frequency), making it difficult to support broadband power combining requirements, and it is prone to introducing nonlinear distortion due to component saturation in high-power scenarios. Summary of the Invention

[0004] The objective of the present invention is to provide a power combining circuit and a combiner based on a coaxial transformer, aiming to solve the problems of large size and narrow bandwidth of the combiner.

[0005] To achieve the above objective, in the first aspect of the embodiments of the present disclosure, a power combining circuit based on a coaxial transformer is provided. The power combining circuit includes: An impedance reduction sub-circuit and an impedance transformation sub-circuit for impedance increase, wherein the output end of the impedance reduction sub-circuit is connected to the input end of the impedance transformation sub-circuit for impedance increase; The input end of the impedance reduction sub-circuit is configured as the input end of the power combining circuit, and the output end of the impedance transformation sub-circuit for impedance increase is configured as the output end of the power combining circuit; The impedance reduction sub-circuit and the impedance transformation sub-circuit for impedance increase include coaxial magnetic ring transformers, which are formed by passing a coaxial cable through a magnetic ring to form a transformer. The inner conductor of the coaxial cable serves as the primary coil of the transformer, and the outer conductor of the coaxial cable serves as the secondary coil of the transformer; The impedance reduction sub-circuit is used to perform power combining and impedance reduction through the turns ratio of the coaxial magnetic ring transformer to reduce the combined impedance to the medium and low impedance value required by the impedance transformation sub-circuit for impedance increase. The impedance transformation sub-circuit for impedance increase is used for impedance matching and power transmission optimization to transform the medium and low impedance value back to the standard impedance value required by the load, so as to reduce reflection loss and ensure maximum power transmission to the load.

[0006] In a possible implementation, the impedance reducing sub-circuit includes: a resistor R0 and two coaxial magnetic ring transformers connected in parallel. The first end of the outer conductor of the first coaxial magnetic ring transformer among the two coaxial magnetic ring transformers is connected to the first end of the outer conductor of the second coaxial magnetic ring transformer. The first end of the outer conductor of the first coaxial magnetic ring transformer and the first end of the outer conductor of the second coaxial magnetic ring transformer are located on the same side of the magnetic ring; The first end of the inner conductor of the first coaxial magnetic ring transformer and the first end of the inner conductor of the second coaxial magnetic ring transformer are respectively configured as the input terminals of the impedance reducing sub-circuit; The second end of the inner conductor of the first coaxial magnetic ring transformer is connected to the first end of the resistor R0. The second end of the outer conductor of the first coaxial magnetic ring transformer is connected to the second end of the resistor R0. The second end of the inner conductor of the second coaxial magnetic ring transformer is connected to the second end of the resistor R0. The second end of the outer conductor of the second coaxial magnetic ring transformer is connected to the first end of the resistor R0; The first end of the outer conductor of the second coaxial magnetic ring transformer is configured as the output terminal of the impedance reducing sub-circuit.

[0007] In a possible implementation, the impedance increasing transformation sub-circuit includes: a fourth coaxial magnetic ring transformer, a fifth coaxial magnetic ring transformer, and a coaxial transformer. The coaxial lines of the fourth coaxial magnetic ring transformer and the fifth coaxial magnetic ring transformer respectively pass through a magnetic ring to form the coaxial magnetic ring transformer; After the first end of the inner conductor of the third coaxial magnetic ring transformer is connected to the first end of the resistor R1, it is configured as the input terminal of the impedance reducing sub-circuit. After the first end of the outer conductor of the third coaxial magnetic ring transformer is connected to the second end of the inner conductor of the third coaxial magnetic ring transformer and then connected to the first end of the resistor RL, it is configured as the output terminal of the impedance reducing sub-circuit. The first end of the inner conductor of the third coaxial magnetic ring transformer and the first end of the outer conductor of the third coaxial magnetic ring transformer are located on the same side of the magnetic ring; After the first end of the inner conductor of the third coaxial magnetic ring transformer is connected to the second end of the outer conductor of the third coaxial magnetic ring transformer through the resistor R3 and then connected to the first end of the resistor R2, it is configured as the input terminal of the impedance reducing sub-circuit; The second end of the resistor R1 is grounded through an AC signal source. The second end of the resistor RL is grounded. The second end of the resistor R2 is grounded through an AC signal source.

[0008] In a possible implementation, the impedance increasing transformation sub-circuit includes: a fourth coaxial magnetic ring transformer, a fifth coaxial magnetic ring transformer, and a coaxial transformer. The coaxial lines of the fourth coaxial magnetic ring transformer and the fifth coaxial magnetic ring transformer respectively pass through a magnetic ring to form the coaxial magnetic ring transformer; The first end of the inner conductor of the fourth coaxial magnetic ring transformer is connected to the first end of the inner conductor of the fifth coaxial magnetic ring transformer and is configured as the input end of the impedance step-up transformation sub-circuit. The first end of the outer conductor of the fifth coaxial magnetic ring transformer is connected to the first end of the inner conductor of the coaxial transformer; The second end of the outer conductor of the fourth coaxial magnetic ring transformer, the second end of the inner conductor of the fifth coaxial magnetic ring transformer, and the second end of the inner conductor of the coaxial transformer are connected. The second end of the outer conductor of the fifth coaxial magnetic ring transformer is connected to the second end of the outer conductor of the coaxial transformer; The first end of the outer conductor of the fourth coaxial magnetic ring transformer is grounded. The first end and the second end of the outer conductor of the coaxial transformer are both grounded. The second end of the inner conductor of the fourth coaxial magnetic ring transformer is configured as the output end of the impedance step-up transformation sub-circuit.

[0009] In a possible implementation manner, the impedance step-up transformation sub-circuit includes: a sixth coaxial magnetic ring transformer and a seventh coaxial magnetic ring transformer. The coaxial lines of the sixth coaxial magnetic ring transformer and the seventh coaxial magnetic ring transformer pass through the same magnetic ring to form the coaxial magnetic ring transformer; The first end of the outer conductor of the sixth coaxial magnetic ring transformer is connected to the second end of the outer conductor of the seventh coaxial magnetic ring transformer. The second end of the outer conductor of the sixth coaxial magnetic ring transformer is grounded. The first end of the outer conductor of the seventh coaxial magnetic ring transformer is connected to the input end of the impedance step-up transformation sub-circuit. The first end of the inner conductor of the sixth coaxial magnetic ring transformer, the first end of the inner conductor of the seventh coaxial magnetic ring transformer, the second end of the outer conductor of the sixth coaxial magnetic ring transformer, and the second end of the outer conductor of the seventh coaxial magnetic ring transformer are located on the same side of the magnetic ring; The second end of the inner conductor of the sixth coaxial magnetic ring transformer is connected to the second end of the inner conductor of the seventh coaxial magnetic ring transformer and is configured as the output end of the impedance step-up transformation sub-circuit. The first end of the inner conductor of the sixth coaxial magnetic ring transformer is connected to the first end of the inner conductor of the seventh coaxial magnetic ring transformer and is configured as the input end of the impedance step-up transformation sub-circuit.

[0010] In a possible implementation manner, the impedance step-up transformation sub-circuit includes: an eighth coaxial magnetic ring transformer and a ninth coaxial magnetic ring transformer. The coaxial lines of the eighth coaxial magnetic ring transformer and the ninth coaxial magnetic ring transformer respectively pass through a magnetic ring to form the coaxial magnetic ring transformer; The first end of the inner conductor of the eighth coaxial magnetic ring transformer is connected to the first end of the inner conductor of the ninth coaxial magnetic ring transformer and is configured as the input end of the impedance-increasing transformation sub-circuit, and the second end of the inner conductor of the ninth coaxial magnetic ring transformer is configured as the output end of the impedance-increasing transformation sub-circuit; The first end of the outer conductor of the eighth coaxial magnetic ring transformer, the second end of the inner conductor of the eighth coaxial magnetic ring transformer and the second end of the outer conductor of the ninth coaxial magnetic ring transformer are connected. The second end of the outer conductor of the eighth coaxial magnetic ring transformer is grounded, and the first end of the outer conductor of the ninth coaxial magnetic ring transformer is grounded.

[0011] In a second aspect of the embodiments of the present disclosure, a synthesizer is provided, including: the coaxial transformer-based power combining circuit according to any one of the first aspects.

[0012] The present invention provides a coaxial transformer-based power combining circuit and a synthesizer. Compared with the prior art, the following beneficial effects are achieved: Utilize the broadband characteristics and adjustable turns ratio of the coaxial magnetic ring transformer to overcome the defect of narrow bandwidth of the traditional LC network; by using the inner and outer conductors of the coaxial cable as the primary and secondary coils of the transformer respectively, avoid the long-wavelength size limitation of the strip line; the impedance-reducing sub-circuit combines multiple input powers and reduces them to medium and low impedances, and the impedance-increasing sub-circuit dynamically matches the load standard impedance, minimizing the reflection loss to ensure high-power transmission.

[0013] Other features and advantages of the present disclosure will be described in detail in the subsequent specific implementation part. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The drawings are used to provide a further understanding of the present disclosure, and constitute a part of the specification, and are used to explain the present disclosure together with the following specific implementation manners, but do not constitute a limitation to the present disclosure. In the drawings: Figure 1 is a schematic circuit diagram of an impedance-reducing sub-circuit 11 shown according to an embodiment of the specification.

[0015] Figure 2 is a schematic circuit diagram of another impedance-reducing sub-circuit 11 shown according to an embodiment of the specification.

[0016] Figure 3 is a schematic circuit diagram of an impedance-increasing transformation sub-circuit 12 shown according to an embodiment of the specification.

[0017] Figure 4 is a schematic circuit diagram of a coaxial transformer-based power combining circuit shown according to an embodiment of the specification.

[0018] Figure 5It is a schematic circuit diagram of another impedance-increasing transformation sub-circuit 12 shown according to the embodiments of the specification.

[0019] Figure 6 It is a schematic circuit diagram of another power combining circuit based on a coaxial transformer shown according to the embodiments of the specification.

[0020] Figure 7 It is a schematic circuit diagram of yet another impedance-increasing transformation sub-circuit 12 shown according to the embodiments of the specification.

[0021] Figure 8 It is a schematic circuit diagram of yet another power combining circuit based on a coaxial transformer shown according to the embodiments of the specification. Detailed implementation manners

[0022] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0023] The following will describe in detail the specific implementation manners of the present disclosure in conjunction with the accompanying drawings. It should be understood that the specific implementation manners described herein are only used to illustrate and explain the present disclosure, and are not used to limit the present disclosure.

[0024] The present disclosure provides a power combining circuit based on a coaxial transformer. Refer to Figure 1-8 As shown, the power combining circuit 10 includes: An impedance-reducing sub-circuit 11 and an impedance-increasing transformation sub-circuit 12; Wherein, the output end of the impedance-reducing sub-circuit 11 is connected to the input end of the impedance-increasing transformation sub-circuit 12; The input end of the impedance-reducing sub-circuit 11 is configured as the input end of the power combining circuit, and the output end of the impedance-increasing transformation sub-circuit 12 is configured as the output end of the power combining circuit; In the embodiments of the present disclosure, multiple RF signals are input to the input end of the impedance-reducing sub-circuit 11, and this sub-circuit is responsible for power combining and preliminary impedance reduction. The output end of the impedance-reducing sub-circuit 11 is connected to the input end of the impedance-increasing transformation sub-circuit 12 to complete the transformation from medium and low impedance to the standard load impedance. The output end of the impedance-increasing transformation sub-circuit 12 directly drives the load (such as an antenna or a power amplifier module) to ensure maximum power transmission. This hierarchical structure avoids the bandwidth limitation and impedance mismatch problems of traditional single-stage converters, and at the same time optimizes the power capacity and efficiency.

[0025] The impedance reduction sub-circuit 11 and the impedance transformation sub-circuit 12 include a coaxial magnetic ring transformer, which is formed by passing a coaxial cable through a magnetic ring to form a transformer. The inner conductor of the coaxial cable serves as the primary coil of the transformer, and the outer conductor of the coaxial cable serves as the secondary coil of the transformer; In the embodiments of the present disclosure, the coaxial cable is composed of an inner conductor (core wire) and an outer conductor (shield layer), and is wound around a high-permeability magnetic ring (such as Ni-Zn ferrite). The inner conductor of the coaxial cable can be used as the primary coil of the transformer winding to input a radio frequency signal.

[0026] The outer conductor of the coaxial cable can be used as the secondary coil of the transformer winding to output the transformed signal. The magnetic ring can provide a high-permeability path, enhance the magnetic coupling efficiency, and at the same time suppress high-frequency eddy current losses.

[0027] The impedance reduction sub-circuit 11 is used to perform power synthesis and impedance reduction through the turns ratio of the coaxial magnetic ring transformer, so as to reduce the synthesized impedance to the medium and low impedance values required by the impedance transformation sub-circuit. The impedance transformation sub-circuit 12 is used for impedance matching and power transmission optimization, so as to transform the medium and low impedance values back to the standard impedance values required by the load, reduce the reflection loss, and ensure the maximum power transmission to the load.

[0028] In the embodiments of the present disclosure, according to the transformer theory, the impedance transformation ratio is the square of the turns ratio:

[0029] where N2 is the number of turns of the outer conductor coil, N1 is the number of turns of the inner conductor coil, and Z out is the impedance value after impedance reduction or impedance increase, and Z in is the impedance value before impedance reduction or impedance increase.

[0030] The impedance reduction sub-circuit 11 can reduce the impedance by selecting more turns in the secondary (outer conductor) than in the primary (inner conductor) (for example, a turns ratio of 4:1 can reduce the input impedance to 1 / 16). The impedance transformation sub-circuit 12 can increase the medium and low impedance back to the standard value (such as 50 Ω) by having fewer turns in the secondary than in the primary. The distributed parameters (capacitance, inductance) of the coaxial cable and the high-frequency response of the magnetic ring work together to make the transformer maintain a flat frequency response characteristic in the range of 5 MHz - 100 MHz. The shielding effect of the outer conductor reduces the radiation loss and ensures high-frequency stability.

[0031] Among them, the power combination of the impedance reduction sub-circuit 11 can synthesize multiple input signals through a coaxial magnetic ring transformer in parallel, and superimpose the currents to increase the total output power. The impedance reduction can reduce the high impedance after synthesis (such as multiple 50Ω in parallel) to medium and low impedance (such as 12.5Ω) through the turns ratio of the transformer to meet the input requirements of the impedance increase transformation sub-circuit 12. The common-mode rejection characteristic of the magnetic ring reduces signal crosstalk and ensures the phase consistency of the synthesized signal.

[0032] Among them, the impedance matching of the impedance increase transformation sub-circuit 12 can boost the medium and low impedance (such as 12.5Ω) output by the impedance reduction sub-circuit to the load standard value (such as 50Ω) through the reverse turns ratio, minimizing the reflection loss. Utilizing the low-loss characteristic of the coaxial cable (optimized skin effect), the heat loss is reduced, ensuring the efficiency in high-power scenarios (typical value >90%). The high-frequency attenuation characteristic of the magnetic ring filters out harmonic components and improves the purity of the output signal.

[0033] For example, taking the synthesis of two 50Ω inputs to a 50Ω load as an example: Impedance reduction sub-circuit 11: Two 50Ω signals are input to a coaxial magnetic ring transformer in parallel (primary 1:1, secondary 2:1). After power combination, the impedance is reduced to 50Ω / 4 = 12.5Ω (the current is superimposed and the voltage remains unchanged).

[0034] Impedance increase transformation sub-circuit 12: The input of 12.5Ω is transformed back to 50Ω through a step-up transformer (primary 2:1, secondary 1:1). Finally, it is output to the load to achieve full-band matching.

[0035] The above technical solution uses the distributed transmission line characteristic of the coaxial magnetic ring transformer to maintain a stable impedance transformation ratio in the wide frequency range of 5MHz - 100MHz, overcoming the narrow-band limitation of traditional LC networks due to parasitic parameters, usually only 10% - 20% relative bandwidth. The hierarchical design of the impedance reduction sub-circuit 11 and the impedance increase transformation sub-circuit 12 enables a smooth transition of the impedance transformation process in the wide frequency band, avoiding the frequency sensitivity of a single transformer or LC network, and ensuring high-efficiency power combination in the full frequency band. The coaxial cable passing through the magnetic ring structure integrates the primary inner conductor and the secondary outer conductor of the transformer into the same coaxial cable, greatly reducing the volume of traditional multi-winding transformers, and at the same time avoiding the λ / 4 wavelength size limitation required by the strip line. Solving the problem of the large size of the strip line synthesizer, the high magnetic permeability characteristic of the magnetic ring further reduces the physical size of the transformer, making the overall circuit suitable for compact radio frequency systems. The impedance reduction sub-circuit synthesizes and reduces the power of multiple high-impedance inputs to medium and low impedance such as Z0 / n² through the turns ratio, reducing the impedance mismatch loss during the synthesis process. High-efficiency power combination and low reflection loss can be achieved, optimizing the impedance matching problem of traditional transformers. The impedance increase transformation sub-circuit dynamically matches the load standard impedance, optimizes the transmission efficiency through multi-level fine-tuning, reduces the reflection loss to below -20dB, and ensures maximum power transmission to the load.

[0036] In a possible implementation, as shown in Figure 1 FIG. 4, the impedance-reducing sub-circuit 11 includes: a resistor R0 and two coaxial magnetic ring transformers connected in parallel. The first end of the outer conductor of the first coaxial magnetic ring transformer among the two coaxial magnetic ring transformers is connected to the first end of the outer conductor of the second coaxial magnetic ring transformer. The first end of the outer conductor of the first coaxial magnetic ring transformer and the first end of the outer conductor of the second coaxial magnetic ring transformer are located on the same side of the magnetic ring; The first ends of the inner conductors of the first coaxial magnetic ring transformer and the second coaxial magnetic ring transformer are respectively configured as the input ends of the impedance-reducing sub-circuit 11; The second end of the inner conductor of the first coaxial magnetic ring transformer is connected to the first end of the resistor R0. The second end of the outer conductor of the first coaxial magnetic ring transformer is connected to the second end of the resistor R0. The second end of the inner conductor of the second coaxial magnetic ring transformer is connected to the second end of the resistor R0. The second end of the outer conductor of the second coaxial magnetic ring transformer is connected to the first end of the resistor R0; The first end of the outer conductor of the second coaxial magnetic ring transformer is configured as the output end of the impedance-reducing sub-circuit 11.

[0037] In the embodiments of the present disclosure, the impedance-reducing sub-circuit 11 is composed of a resistor R0 and two coaxial magnetic ring transformers connected in parallel, and realizes power synthesis and impedance transformation through a specific inner and outer conductor connection method. The two coaxial magnetic ring transformers are symmetrically arranged, with independent input ends and cross-connected output ends to ensure balanced power distribution. The bridging function of the resistor R0: It is connected between the secondaries (outer conductors) of the two transformers to provide impedance matching and phase balance.

[0038] In the embodiments of the present disclosure, the connection method of the coaxial magnetic ring transformer: Input end: The first ends (primary) of the inner conductors of the first coaxial magnetic ring transformer and the second coaxial magnetic ring transformer are respectively used as the two independent input ends of the impedance-reducing sub-circuit 11 to receive two RF signals. Output end: The first ends of the outer conductors of the two transformers are connected in parallel on the same side of the magnetic ring and used as the total output end of the impedance-reducing sub-circuit 11.

[0039] Cross-feedback path: The second end of the inner conductor of the first transformer is connected to the first end of the resistor R0, and its second end of the outer conductor is connected to the second end of R0; the second end of the inner conductor of the second transformer is connected to the second end of the resistor R0, and its second end of the outer conductor is connected to the first end of the resistor R0, forming a symmetric cross network.

[0040] In the embodiments of the present disclosure, two input signals are respectively excited through the primaries (inner conductors) of two transformers, and in-phase currents are induced in the secondaries (outer conductors). Since the first ends of the outer conductors are connected in parallel, the output currents are superimposed to achieve power combining, and the total output power is the sum of the two input powers (ideally). By designing the turns ratio of the transformer (such as more turns in the secondary than in the primary), the single-path input impedance (such as 50 Ω) is reduced proportionally. After the two paths are connected in parallel, the combined impedance is further reduced to the target medium-low impedance value (such as 12.5 Ω). The resistor R0 provides a balanced impedance, compensates for the small phase difference between the two signals, reduces the combining loss; absorbs the reflected power and improves the circuit stability.

[0041] The above technical solution solves the problems of narrow bandwidth and low efficiency of the traditional power combining circuit through the innovative structure of symmetric transformer parallel connection + resistor bridging, and at the same time simplifies the debugging complexity.

[0042] In a possible implementation, as shown in Figure 2 shown, the impedance-reducing sub-circuit 11 includes a resistor R1, a resistor R2, a resistor R3, a resistor RL, and a third coaxial magnetic ring transformer; After the first end of the inner conductor of the third coaxial magnetic ring transformer is connected to the first end of the resistor R1, it is configured as the input end of the impedance-reducing sub-circuit 11. After the first end of the outer conductor of the third coaxial magnetic ring transformer is connected to the second end of the inner conductor of the third coaxial magnetic ring transformer, and then connected to the first end of the resistor RL, it is configured as the output end of the impedance-reducing sub-circuit 11. The first end of the inner conductor of the third coaxial magnetic ring transformer and the first end of the outer conductor of the third coaxial magnetic ring transformer are located on the same side of the magnetic ring; After the first end of the inner conductor of the third coaxial magnetic ring transformer is connected to the second end of the outer conductor of the third coaxial magnetic ring transformer through the resistor R3, and then connected to the first end of the resistor R2, it is configured as the input end of the impedance-reducing sub-circuit 11; The second end of the resistor R1 is grounded through an AC signal source, the second end of the resistor RL is grounded, and the second end of the resistor R2 is grounded through an AC signal source.

[0043] In the embodiments of the present disclosure, broadband power combining and impedance reduction are achieved through a unique impedance transformation and feedback mechanism. Its core features include: forming an autotransformer structure by cross-connecting the inner conductor and the outer conductor to achieve a compact impedance transformation. Adjusting the input matching and feedback through R1, R2, and R3, and RL provides load impedance optimization. The input signal is grounded through an AC source to form a common-mode excitation and improve the balance.

[0044] In the embodiments of the present disclosure, the input end is configured with a main input path: the first end of the inner conductor of the third coaxial magnetic ring transformer is connected in series with the resistor R1 as the main input end to receive radio frequency signals. Auxiliary input path: the first end of the inner conductor is connected to the second end of the outer conductor through the resistor R3, and then forms an auxiliary input end (dual-signal input point) through the resistor R2.

[0045] Output end: the first end of the outer conductor is short-circuited with the second end of the inner conductor, and then grounded through the load resistor RL to form the output end.

[0046] Grounding configuration: the second ends of the resistors R1 and R2 are respectively grounded through an AC signal source to constitute a common-mode drive; the second end of RL is directly grounded.

[0047] In the embodiments of the present disclosure, the inner conductor (primary) and the outer conductor (secondary) form an autotransformer through cross-connection, and its equivalent turns ratio is determined by the connection point position. The input signal is excited through the inner conductor, induces current in the outer conductor, and realizes impedance transformation through the short-circuit point (the first end of the outer conductor and the second end of the inner conductor), reducing the high input impedance (such as 50Ω) to a medium-low value (such as 12.5Ω).

[0048] R1 and R2 provide input impedance matching, adjust the signal distribution ratio, and ensure the amplitude balance of the two input signals. By grounding through the AC signal source, a virtual ground is formed to suppress common-mode noise. R3 serves as a feedback resistor to couple part of the output signal back to the input end to compensate for phase delay and expand the bandwidth. RL serves as an equivalent load resistor to set the target value of the output impedance and absorb the reflected power at the same time.

[0049] In the embodiments of the present disclosure, the autotransformer and the resistor network work together, and the impedance transformation fluctuation in the full frequency band is <3dB. The outer conductor of the coaxial cable carries a large current and supports kilowatt-level power synthesis. Anti-interference ability: the AC grounding design reduces common-mode noise, and the output signal-to-noise ratio (SNR) is increased by >10dB.

[0050] In one possible implementation, as shown in Figure 3 the impedance-increasing transformation sub-circuit 12 includes: a fourth coaxial magnetic ring transformer, a fifth coaxial magnetic ring transformer, and a coaxial transformer. The coaxial cables of the fourth coaxial magnetic ring transformer and the fifth coaxial magnetic ring transformer respectively pass through a magnetic ring to form the coaxial magnetic ring transformer; the first end of the inner conductor of the fourth coaxial magnetic ring transformer is connected to the first end of the inner conductor of the fifth coaxial magnetic ring transformer and is configured as the input end of the impedance-increasing transformation sub-circuit 12. The first end of the outer conductor of the fifth coaxial magnetic ring transformer is connected to the first end of the inner conductor of the coaxial transformer; The second end of the outer conductor of the fourth coaxial magnetic ring transformer, the second end of the inner conductor of the fifth coaxial magnetic ring transformer, and the second end of the inner conductor of the coaxial transformer are connected; the second end of the outer conductor of the fifth coaxial magnetic ring transformer is connected to the second end of the outer conductor of the coaxial transformer; The first end of the outer conductor of the fourth coaxial magnetic ring transformer is grounded, both the first end and the second end of the outer conductor of the coaxial transformer are grounded, and the second end of the inner conductor of the fourth coaxial magnetic ring transformer is configured as the output end of the impedance boosting sub-circuit 12.

[0051] Combined with Figure 4 As shown, the impedance boosting sub-circuit 12 adopts a three-stage coupling structure of the fourth and fifth coaxial magnetic ring transformers and the coaxial transformer, and realizes efficient impedance boosting and broadband matching through a unique series-parallel combination. Dual magnetic ring transformer input stage: The fourth and fifth coaxial magnetic ring transformers are connected in parallel for input, expanding the current-carrying capacity. The impedance boosting sub-circuit 12 boosts the impedance value Z before impedance boosting to 2.25Z, where Z is the impedance.

[0052] Coaxial transformer output stage: Achieves a high impedance transformation ratio through cross-connection of the inner and outer conductors. Multi-point grounding design: Optimizes the high-frequency return path and suppresses common-mode interference.

[0053] In the embodiments of the present disclosure, the first ends of the inner conductors of the fourth and fifth coaxial magnetic ring transformers are connected in parallel as the input end of the impedance boosting sub-circuit 12 to receive the medium-low impedance signal (such as 12.5 Ω) output by the impedance reducing sub-circuit 11. Inter-stage coupling: The first end of the outer conductor of the fifth coaxial magnetic ring transformer is connected to the first end of the inner conductor of the coaxial transformer to form inter-stage energy transfer. Output end: The second end of the inner conductor of the fourth coaxial magnetic ring transformer serves as the output end to provide a high impedance signal (such as 50 Ω). Grounding configuration: The first end of the outer conductor of the fourth coaxial magnetic ring transformer and both ends of the outer conductor of the coaxial transformer are grounded to form a low impedance return path.

[0054] In the embodiments of the present disclosure, the input signal is shunted through the inner conductors of the parallel dual transformers, reducing the single-path current stress and increasing the power capacity. The magnetic rings of the two transformers enhance the magnetic field superposition effect, improving the coupling efficiency in the low-frequency band (such as 5 MHz). The input signal is excited through the inner conductor, and the second end of the outer conductor is coupled with the coaxial transformer to form partial impedance boosting (such as a 1:2 transformation ratio). The outer conductor of the fifth coaxial magnetic ring transformer drives its inner conductor, further boosting the impedance through the turns ratio (such as 1:4), and finally outputting a high impedance signal from the second end of the inner conductor of the fourth coaxial magnetic ring transformer.

[0055] The above technical solution realizes the transformation from 12.5Ω to 50Ω through three - stage coupling, with an efficiency > 92%. The double - magnetic - ring structure compensates for high - frequency losses, and the return loss in the full frequency band < - 15dB. The parallel input disperses the magnetic flux density to avoid magnetic - ring saturation under high power.

[0056] In a possible implementation, as shown in Figure 5 FIG. 5, the impedance - increasing transformation sub - circuit 12 includes: a sixth coaxial - line magnetic - ring transformer and a seventh coaxial - line magnetic - ring transformer. The coaxial lines of the sixth coaxial - line magnetic - ring transformer and the seventh coaxial - line magnetic - ring transformer pass through the same magnetic ring to form the coaxial - line magnetic - ring transformer; The first end of the outer conductor of the sixth coaxial - line magnetic - ring transformer is connected to the second end of the outer conductor of the seventh coaxial - line magnetic - ring transformer. The second end of the outer conductor of the sixth coaxial - line magnetic - ring transformer is grounded. The first end of the outer conductor of the seventh coaxial - line magnetic - ring transformer is connected to the input end of the impedance - increasing transformation sub - circuit 12. The first ends of the inner conductors of the sixth coaxial - line magnetic - ring transformer, the first ends of the inner conductors of the seventh coaxial - line magnetic - ring transformer, the second ends of the outer conductors of the sixth coaxial - line magnetic - ring transformer, and the second ends of the outer conductors of the seventh coaxial - line magnetic - ring transformer are located on the same side of the magnetic ring; The second ends of the inner conductors of the sixth coaxial - line magnetic - ring transformer and the seventh coaxial - line magnetic - ring transformer are connected and configured as the output end of the impedance - increasing transformation sub - circuit 12. The first ends of the inner conductors of the sixth coaxial - line magnetic - ring transformer and the seventh coaxial - line magnetic - ring transformer are connected and configured as the input end of the impedance - increasing transformation sub - circuit 12.

[0057] Combined with Figure 6 FIG. 5, a symmetric design of sharing the same magnetic ring by the sixth coaxial - line magnetic - ring transformer and the seventh coaxial - line magnetic - ring transformer is adopted. Through cross - connection of the outer conductors and parallel output of the inner conductors, a compact high - impedance transformation is realized. Two groups of coaxial lines share a high - permeability magnetic ring, enhancing the coupling efficiency and reducing the volume. The first end of the outer conductor of the sixth coaxial - line magnetic - ring transformer is connected to the second end of the outer conductor of the seventh coaxial - line magnetic - ring transformer to form a current return path. The double inner conductors are connected in parallel to increase the current - carrying capacity and reduce the transmission loss.

[0058] In the embodiments of the present disclosure, the input end is a dual - path input: the first ends of the inner conductors of the sixth coaxial - line magnetic - ring transformer and the seventh coaxial - line magnetic - ring transformer are connected in parallel as the input end to receive medium - low impedance signals (such as 12.5Ω). The outer conductor can realize excitation. The first end of the outer conductor of the seventh coaxial - line magnetic - ring transformer is directly connected to the input end to form an auxiliary signal input.

[0059] Output terminal: The second ends of the inner conductors of the sixth coaxial magnetic ring transformer and the seventh coaxial magnetic ring transformer are connected in parallel as the output terminal to provide a high-impedance signal (such as 50 Ω). Grounding and cross-connection: The second end of the outer conductor of the sixth coaxial magnetic ring transformer is grounded to form a reference potential; the first end of the outer conductor of the sixth coaxial magnetic ring transformer is cross-connected to the second end of the outer conductor of the seventh coaxial magnetic ring transformer to form a closed-loop feedback.

[0060] In the embodiments of the present disclosure, two groups of coaxial lines pass through the same magnetic ring, and the magnetic field superposition effect increases the coupling coefficient in the low-frequency band (5 MHz) by > 30%, avoiding the magnetic leakage problem of traditional discrete magnetic rings. The cross-connection of the outer conductors forms an automatic current balance to suppress the amplitude deviation between the two signals. The signals are input through the parallel inner conductors to excite the magnetic ring to generate a main magnetic field; the first end of the outer conductor of the sixth component is directly input to supplement high-frequency energy (> 50 MHz).

[0061] During the impedance transformation process, the current in the inner conductor is induced to the outer conductor through the magnetic ring, and the cross-connection forces the phase of the current in the outer conductor to reverse, realizing an equivalent turns ratio (such as 1:2); the parallel output raises the impedance to the target value (such as 12.5 Ω → 50 Ω).

[0062] The shared magnetic ring design in the above technical solutions reduces the volume by 40% compared with the traditional solution, and the power capacity remains > 1 kW. The impedance transformation fluctuation within the range of 5 MHz - 100 MHz is < 1.5 dB. The cross-connection structure ensures that the phase difference between the two outputs is < 2°.

[0063] In a possible implementation manner, as shown in Figure 7 The impedance-increasing transformation sub-circuit 12 includes: an eighth coaxial magnetic ring transformer and a ninth coaxial magnetic ring transformer. The coaxial lines of the eighth coaxial magnetic ring transformer and the ninth coaxial magnetic ring transformer respectively pass through a magnetic ring to form the coaxial magnetic ring transformer; The first end of the inner conductor of the eighth coaxial magnetic ring transformer is connected to the first end of the inner conductor of the ninth coaxial magnetic ring transformer and is configured as the input end of the impedance-increasing transformation sub-circuit 12, and the second end of the inner conductor of the ninth coaxial magnetic ring transformer is configured as the output end of the impedance-increasing transformation sub-circuit 12; The first end of the outer conductor of the eighth coaxial magnetic ring transformer, the second end of the inner conductor of the eighth coaxial magnetic ring transformer and the second end of the outer conductor of the ninth coaxial magnetic ring transformer are connected. The second end of the outer conductor of the eighth coaxial magnetic ring transformer is grounded, and the first end of the outer conductor of the ninth coaxial magnetic ring transformer is grounded.

[0064] Combined with Figure 8As shown in the figure, the symmetrical balanced design of the eighth and ninth coaxial magnetic ring transformers is adopted, and the efficient impedance enhancement and broadband matching are achieved through the specific cross-connection method of the inner and outer conductors. The two transformers are connected in parallel in input and in series in output, and the dual transformer balanced architecture has the advantages of power distribution and voltage superposition. The outer conductor is grounded on the opposite side and cross-grounded to form a common-mode noise suppression loop. The independent magnetic ring avoids coupling interference and is suitable for high-frequency applications.

[0065] In the disclosed embodiment, the first ends of the inner conductors of the eighth and ninth transformers are connected in parallel as a unified input end to receive a medium-low impedance signal (such as 25Ω) of the impedance reduction subcircuit. The second end of the inner conductor of the ninth transformer serves as an output end to provide a high impedance signal (such as 100Ω). The first end of the outer conductor of the eighth transformer, the second end of the inner conductor and the second end of the outer conductor of the ninth transformer are interconnected at three points, and the other ends of the outer conductors of the two transformers are independently grounded.

[0066] In the embodiment of the present disclosure, on the signal transmission path, the input signal simultaneously excites the inner conductors of the two transformers, generating a superimposed magnetic field in the magnetic ring, and the induced energy of the eighth transformer is transmitted to the output node through the second end of its inner conductor, and the energy of the ninth transformer is directly output from the second end of its inner conductor.

[0067] In terms of impedance transformation mechanism, parallel input is adopted, that is, the dual inner conductors are connected in parallel to reduce the input equivalent impedance and improve the current carrying capacity. After series superposition, the output signals of the two transformers are in the same phase, and the voltage superposition realizes impedance improvement. Through the transformer turns ratio design (such as 1:2), 25Ω→100Ω transformation is realized.

[0068] The second end of the outer conductor of the eighth transformer is grounded, and the first end of the outer conductor of the ninth transformer is grounded, forming a symmetrical RF ground loop to suppress common mode interference. The three-point interconnection node balances the working state of the two transformers and provides a return path for high-frequency harmonics.

[0069] It has been verified through experiments that the above circuits can meet the requirements of return loss <-20dB, insertion loss <-3.3dB, and isolation <-20dB within the range of 5M~100MHz.

[0070] The disclosed embodiment further provides a synthesizer, comprising: a power synthesis circuit based on a coaxial line transformer as described in any one of the above embodiments.

[0071] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings; however, the present disclosure is not limited to the specific details in the above embodiments; within the technical concept of the present disclosure, various changes, modifications, substitutions and variations may be made to these embodiments, and these changes, modifications, substitutions and variations all fall within the protection scope of the present disclosure.

[0072] In addition, it should be noted that, for each of the specific technical features described in the above specific embodiments, they can be combined in any appropriate manner without conflict, and the same should be regarded as the content disclosed in this disclosure. To avoid unnecessary repetition, this disclosure will not separately explain various possible combination methods. The technical scope of this application is not limited to the content in the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A power combining circuit based on a coaxial transformer, characterized in that, The power combining circuit includes: a impedance-reducing sub-circuit (11) and a impedance-increasing transformation sub-circuit (12), wherein, the output end of the impedance-reducing sub-circuit (11) is connected to the input end of the impedance-increasing transformation sub-circuit (12); the input end of the impedance-reducing sub-circuit (11) is configured as the input end of the power combining circuit, and the output end of the impedance-increasing transformation sub-circuit (12) is configured as the output end of the power combining circuit based on the coaxial transformer; the impedance-reducing sub-circuit (11) and the impedance-increasing transformation sub-circuit (12) include coaxial magnetic ring transformers, and the coaxial magnetic ring transformers are formed by passing a coaxial cable through a magnetic ring to form a transformer. The inner conductor of the coaxial cable serves as the primary coil of the transformer, and the outer conductor of the coaxial cable serves as the secondary coil of the transformer; the impedance-reducing sub-circuit (11) is used to perform power combining and impedance reduction through the turns ratio of the coaxial magnetic ring transformer to reduce the combined impedance to the medium-low impedance value required by the impedance-increasing transformation sub-circuit. The impedance-increasing transformation sub-circuit (12) is used for impedance matching and power transmission optimization to transform the medium-low impedance value back to the standard impedance value required by the load to reduce reflection loss and ensure maximum power transmission to the load.

2. The power combining circuit according to claim 1, wherein The impedance-reducing sub-circuit (11) includes: a resistor R0 and two parallel coaxial magnetic ring transformers. The first end of the outer conductor of the first coaxial magnetic ring transformer among the two coaxial magnetic ring transformers is connected to the first end of the outer conductor of the second coaxial magnetic ring transformer, and the first end of the outer conductor of the first coaxial magnetic ring transformer and the first end of the outer conductor of the second coaxial magnetic ring transformer are located on the same side of the magnetic ring; the first end of the inner conductor of the first coaxial magnetic ring transformer and the first end of the inner conductor of the second coaxial magnetic ring transformer are respectively configured as the input end of the impedance-reducing sub-circuit (11); the second end of the inner conductor of the first coaxial magnetic ring transformer is connected to the first end of the resistor R0, the second end of the outer conductor of the first coaxial magnetic ring transformer is connected to the second end of the resistor R0, the second end of the inner conductor of the second coaxial magnetic ring transformer is connected to the second end of the resistor R0, and the second end of the outer conductor of the second coaxial magnetic ring transformer is connected to the first end of the resistor R0; the first end of the outer conductor of the second coaxial magnetic ring transformer is configured as the output end of the impedance-reducing sub-circuit (11).

3. The power combining circuit according to claim 1, wherein The impedance-reducing sub-circuit (11) includes a resistor R1, a resistor R2, a resistor R3, a resistor RL, and a third coaxial magnetic ring transformer; After the first end of the inner conductor of the third coaxial line toroidal transformer is connected to the first end of the resistor R1, it is configured as the input end of the impedance-reducing sub-circuit (11). After the first end of the outer conductor of the third coaxial line toroidal transformer is connected to the second end of the inner conductor of the third coaxial line toroidal transformer and then connected to the first end of the resistor RL, it is configured as the output end of the impedance-reducing sub-circuit (11). The first end of the inner conductor of the third coaxial line toroidal transformer and the first end of the outer conductor of the third coaxial line toroidal transformer are located on the same side of the toroid. After the first end of the inner conductor of the third coaxial line toroidal transformer is connected to the second end of the outer conductor of the third coaxial line toroidal transformer through the resistor R3 and then connected to the first end of the resistor R2, it is configured as the input end of the impedance-reducing sub-circuit (11). The second end of the resistor R1 is grounded through an AC signal source, the second end of the resistor RL is grounded, and the second end of the resistor R2 is grounded through an AC signal source.

4. The power combining circuit according to any one of claims 1 to 3, characterized in that The impedance-increasing transformation sub-circuit (12) includes: a fourth coaxial line toroidal transformer, a fifth coaxial line toroidal transformer, and a coaxial line transformer. The coaxial lines of the fourth coaxial line toroidal transformer and the fifth coaxial line toroidal transformer respectively pass through a toroid to form the coaxial line toroidal transformer. After the first end of the inner conductor of the fourth coaxial line toroidal transformer is connected to the first end of the inner conductor of the fifth coaxial line toroidal transformer, it is configured as the input end of the impedance-increasing transformation sub-circuit (12). The first end of the outer conductor of the fifth coaxial line toroidal transformer is connected to the first end of the inner conductor of the coaxial line transformer. The second end of the outer conductor of the fourth coaxial line toroidal transformer, the second end of the inner conductor of the fifth coaxial line toroidal transformer, and the second end of the inner conductor of the coaxial line transformer are connected. The second end of the outer conductor of the fifth coaxial line toroidal transformer is connected to the second end of the outer conductor of the coaxial line transformer. The first end of the outer conductor of the fourth coaxial line toroidal transformer is grounded, the first end and the second end of the outer conductor of the coaxial line transformer are both grounded, and the second end of the inner conductor of the fourth coaxial line toroidal transformer is configured as the output end of the impedance-increasing transformation sub-circuit (12).

5. The power combining circuit according to any one of claims 1-3, characterized in that, The impedance-increasing transformation sub-circuit (12) includes: a sixth coaxial line toroidal transformer and a seventh coaxial line toroidal transformer. The coaxial lines of the sixth coaxial line toroidal transformer and the seventh coaxial line toroidal transformer pass through the same toroid to form the coaxial line toroidal transformer. The first end of the outer conductor of the sixth coaxial line magnetic ring transformer is connected to the second end of the outer conductor of the seventh coaxial line magnetic ring transformer. The second end of the outer conductor of the sixth coaxial line magnetic ring transformer is grounded. The first end of the outer conductor of the seventh coaxial line magnetic ring transformer is connected to the input end of the impedance step-up transformation sub-circuit (12). The first end of the inner conductor of the sixth coaxial line magnetic ring transformer, the first end of the inner conductor of the seventh coaxial line magnetic ring transformer, the second end of the outer conductor of the sixth coaxial line magnetic ring transformer, and the second end of the outer conductor of the seventh coaxial line magnetic ring transformer are located on the same side of the magnetic ring; The second end of the inner conductor of the sixth coaxial line magnetic ring transformer and the second end of the inner conductor of the seventh coaxial line magnetic ring transformer are connected and configured as the output end of the impedance step-up transformation sub-circuit (12). The first end of the inner conductor of the sixth coaxial line magnetic ring transformer and the first end of the inner conductor of the seventh coaxial line magnetic ring transformer are connected and configured as the input end of the impedance step-up transformation sub-circuit (12).

6. The power combining circuit according to any one of claims 1-3, characterized in that, The impedance step-up transformation sub-circuit (12) includes: an eighth coaxial line magnetic ring transformer and a ninth coaxial line magnetic ring transformer. The coaxial lines of the eighth coaxial line magnetic ring transformer and the ninth coaxial line magnetic ring transformer respectively pass through a magnetic ring to form the coaxial line magnetic ring transformer; The first end of the inner conductor of the eighth coaxial line magnetic ring transformer and the first end of the inner conductor of the ninth coaxial line magnetic ring transformer are connected and configured as the input end of the impedance step-up transformation sub-circuit (12). The second end of the inner conductor of the ninth coaxial line magnetic ring transformer is configured as the output end of the impedance step-up transformation sub-circuit (12); The first end of the outer conductor of the eighth coaxial line magnetic ring transformer, the second end of the inner conductor of the eighth coaxial line magnetic ring transformer are connected to the second end of the outer conductor of the ninth coaxial line magnetic ring transformer. The second end of the outer conductor of the eighth coaxial line magnetic ring transformer is grounded. The first end of the outer conductor of the ninth coaxial line magnetic ring transformer is grounded.

7. A synthesizer, characterized in that, Comprising: The power combining circuit based on a coaxial line transformer according to any one of claims 1-6.

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