Multi-way Power Research Articles

Ultracompact multiway ultrasonic power splitters based on phononic crystal with a triangular lattice

We report the ultracompact multiway power splitters based on the phononic crystal with a triangular lattice. Such power splitters can effectively divide ultrasonic energy into multiple channels (n≥2) and output them. The arrow-shaped and star-shaped power splitters were separately discussed in detail based on the finite element method (FEM) as examples. The phononic bandgap in the triangular lattice arrangement and dispersive curves of a single phononic waveguide were analyzed, respectively. Also, the displacement field distribution and transmission efficiency of these outputs were calculated to evaluate the efficiency of the splitters. The results indicate that these splitters possess novel and promising properties, including ultracompact, high-efficiency, and large bandwidth. The perturbations analysis of the power splitter proves that it has good mechanical stability. It is to be expected that these ultracompact splitters will present practical applications in future acoustic wave circuits.

A Compact Broadband Power Combiner for High-Power, Continuous-Wave Applications.

A compact broadband combiner with a high power capacity and a low insertion loss, which is especially useful for solid-state power sources where multi-way power synthesis is needed, was designed and experimentally investigated. The combiner could combine the microwave signals of sixteen terminals into a single one and was based on a radial-line waveguide whose circumferential symmetry benefited the amplitude and phase consistency of the combiner. Simulation and experimental results showed that the prototype device, designed for S-band applications, exhibited a reflection coefficient S1,1 < -20 dB in the range of 2.06-2.93 GHz, which corresponds to a relative bandwidth of approximately 34.6%. At 2.45 GHz, the phase imbalance was ±4.5° and the 16-way transmission coefficient was concentrated around -12.0~-12.3 dB. The insertion loss of the device at ambient and elevated temperatures was simulated and experimentally verified, which is of importance for the design of similar high-power microwave combiners. High-power tests proved that even without enforced wind or liquid cooling, the device can handle continuous power (CW) of at least 3.9 kW, which can be much enhanced by taking regular cooling measures. The combined features of the designed combiner suggest promising applications for power synthesis in high-power, solid-state RF sources.

Wideband Multi-Channel Multi-Way Power Combiner With High Frequency Selectivity

A wideband multi-channel multi-way power combiner with high frequency selectivity circuit using the center-loaded multimode step impedance resonator (SIR) is presented in this paper. The SIR stubs can generate four transmission zeros on the both sides of the passbands, which improves the frequency selectivity of the two channels. The distributed coupling technique is used to connect the two different-frequency channels without any additional matching network. The presented power combiner is designed, fabricated, and measured. The measured center frequency and relative 3-dB bandwidth of the two channels are 1.73/2.71 GHz and 43%/35%, respectively. The measured input return loss are greater than 16.4/20.8 dB, the measured output return loss is greater than 20.4/13.4 dB, and the measured insertion loss are 0.7/1.0 dB. Moreover, the measured different-frequency isolation between the two channels is greater than 26.8 dB, and the measured same -frequency isolation are greater than 23.9/29.1 dB, respectively.

Machine Learning Methods for Feedforward Power Flow Control of Multi-Active-Bridge Converters

Controlling the multiway power flow in a multi-active-bridge (MAB) converter is important for achieving high performance and sophisticated functions. Traditional feedforward methods for MAB converter control rely on precise lumped circuit models. This article presents a machine learning (ML) method for the feedforward power flow control of an MAB converter without a precise circuit model. A feedforward neural network was developed to capture the nonlinear characteristics and predict the phases needed to achieve the targeted power flow. The neural network was trained with a large amount of data, collected with a set of known phase angles. This trained network was used to predict the phases to achieve the targeted power flow. A six-port MAB converter was built and tested to validate the methodology and demonstrate the “machine-learning-in-the-loop” implementation. Transfer learning was proven to be effective in reducing the size of the training data needed to obtain an accurate ML model. ML-based feedforward power flow control can achieve comparable accuracy as traditional model-based methods and can function without a precise lumped circuit element model of the MAB converter.

A 60-GHz 32-Way Hybrid Power Combination Power Amplifier in 55-nm Bulk CMOS

This article presents a high output power <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$V$ </tex-math></inline-formula> -band power amplifier (PA) with 32-way power combining in 55-nm bulk CMOS. A new hybrid power combiner (HPC) is proposed and utilized to output combination network of PA. Incorporating the impedance matching requirements, a general model and analysis equations are given, from which it can be seen that HPC increases the design flexibility and reduces the difficulty of multiway power combiner using a single approach, while simultaneously considering asymmetry caused by parasitic capacitance and chip layout distribution. The adoption of HPC also takes into account the inconsistencies between the internal and external channels of the chip due to thermal distribution, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$I$ </tex-math></inline-formula> – <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$R$ </tex-math></inline-formula> drop, and so on. To the best of our knowledge, this is the first time that the challenges and considerations of high-power PA design in silicon-based process are comprehensively presented, and two test printed circuit boards (PCBs) are used to compare and improve the thermal problem of high-power PAs during testing. The PA achieves a small-signal gain of 21.9 dB at 60 GHz and a saturated output power of 24.42–25.06 dBm at 57–62 GHz with a maximum output 1-dB compression point of 21.87 dBm and a peak power-added efficiency (PAE) of 11%. The core area is 1.77 mm2.

Topology and Design Formulas for Four-Way Filtering Power Divider With Wide Isolation Range

In this paper, we present a topology with design equations for the rigorous design of multiway power dividers having a pre-defined filtering response featuring broadband isolation between any pair of output ports. Hence, a filtering power divider designed using the presented topology and design formulas can suppress undesired oscillations at the spurious frequencies when used as a combiner. More importantly, we provide complete mathematical design equations for designing filtering power dividers with various pre-defined filtering responses. Therefore, it is possible to design a filtering power divider without relying on time-consuming parametric sweeps or heuristic approaches. The presented filtering power divider topology and design equations have been verified by designing, fabricating, and measuring a four-way second-order filtering power divider.

Performance study of multi-source driving yaw system for aiding yaw control of wind turbines

Multi-source driving (MSD) yaw system is widely used in large-scale wind turbines. However, due to the complex coupling effect of mechanical, electrical, and hydraulic, there is a knowledge gap on the dynamic process of the MSD yaw system. To fill this gap, a dynamic coupling model of the MSD yaw system is established. In this model, multi-way power source subsystems, transmission gearbox subsystems, and hydraulic brake subsystems are established, and the coupling of multi-way yaw subsystems are realized. Based on this model, different yaw angle control modes are studied, including comparison control and servo control. To further reflect the dynamic process in-service condition, the MSD yaw system model is integrated into a wind turbine model. An approximate solution for calculating yaw load is also presented. Through this study, the results show the established MSD yaw system model can work effectively. The difference of gear meshing gaps directly affects the distribution of yaw load. The dynamic response of the yaw system, including yaw position, yaw speed, and yaw acceleration, is affected by the changing amplitude and frequency of yaw load, but the large inertia of yaw system can restrain the fluctuation of yaw dynamic response to some extent.

Multi-way differential power divider with microstrip output interfaces

Abstract The design and implementation of planar multi-way differential power dividers remain a challenge in terms of the compactness and especially, for the achievable characteristic impedance of the quarter-wavelength transformer when considering large number of outputs. In this work, the double-sided parallel stripline is recommended to realize such a power divider with out-of-phase outputs, and explicit design methods are provided. The proposed multi-way power divider was developed without the use of lump elements on a single substrate. For system applications, a prototype operating at 41.6 MHz with 12 pairs of out-of-phase outputs that utilize the microstrip line as the output interfaces was fabricated and examined. At the center frequency of 41.6MHz, the developed prototype measured insertion losses akin to 14.3 dB as compared with the theoretical data of 13.8 dB. The attainable impedance bandwidth ranges from 10 MHz to 80 MHz under a magnitude imbalance of ±0.3 dB. The isolations of the adjacent outputs are about 13.1 dB as compared with the theoretical values of 14.428 dB, and are better than 34 dB for more distant ones. Parameter measurements are in good agreement with the numerical predications, thus demonstrating the realization of the proposed multi-way power divider.

Multi-Way Quasi-Optical Waveguide Power Divider with 2D Diffraction Approximation and Experimental Verification at Millimeter Wave

In this paper, multi-way quasi-optical parallel-plate waveguide power dividers/combiners are designed and fabricated using the 2D diffraction approximation. Shape optimization technology is applied to shape the cylindrical reflector surface to reconstruct the diffraction field to improve the magnitude and phase balance of the parallel-plate waveguide power dividers. Both a 1-to-6 way quasi-optical waveguide power divider with H-plane horn antenna array and a 1-to-10 way power divider with gap waveguide transition are analyzed and designed, respectively. We fabricated the two designed power devices at millimeter wave for verifying the validity of the design method. The measured average transmission coefficient of the 1-to-6 way power divider is − 10.8 dB from 81 to 110 GHz, corresponding to 50% power combining efficiency, while the measured back-to-back structure of the 1-to-10 way power divider/combiner features an average transmission coefficient to − 2.83 dB corresponding to 72.2% power combining efficiency over the entire W-band. The proposed power dividers/combiners and the efficient optimization method used in their design are believed to be of importance for future power device applications in millimeter wave and terahertz range.

Design of multiway power dividers including all connecting lines

This study proposes a method of designing a multiway power divider including all connecting lines. The multiway power divider is based on several interconnected two-way power dividers. The connecting lines comprise the interconnecting sections, used for interconnecting the two-way power dividers, and the input/output extension lines, used for connecting the internal circuit to the on-board feeding ports. In the proposed method, the length of each interconnecting section can be flexibly partitioned to best fit the layout requirement. Every transmission line used for any purpose of connection in the layout is included as part of design and contributes to improvement of matching bandwidths. Therefore, a multiway power divider adopting the design method will result in better bandwidth performance for the same circuit size. The background principle of the proposed method and several simulated design scenarios are provided. A prototype of a four-way power divider is designed and fabricated. The measurement results, decently matching the simulations, validate the proposed idea. This study for the first time discusses on design and optimisation of an entire multiway power divider including all portions of connecting lines. The proposed method can make a multiway power divider achieving an improved bandwidth and more efficient layout.

A Radial Four-Way Power Divider With the Proposed Isolation Network

A radial multiway power divider is used to distribute microwave signals to the next stages located radially around all directions. It has been a challenging task to implement a radial multiway power divider on a planar circuit board without sacrificing the bandwidth performance. In this letter, a radial four-way power divider with the proposed isolation network is presented. The isolation network, composed of several combined RLC and LC networks, plays the crucial role of making the radial layout style easy to realize, and meanwhile improves the output matching and port-to-port isolation. The background principle of the proposed topology and the guideline of designing the isolation network are provided. The fabricated radial four-way power divider results in the measured −20-dB output matching and isolation bandwidths as large as 35% and 65%, respectively, exhibiting the best bandwidth performance among all the published radial power dividers of the same type.

Design of a High-Isolation n-Way Power Combiner Based on a 2n + 1 Port Mode Network

This paper proposes a design method for high-isolation n-way power combiners based on 2n + 1 port mode networks. The scattering matrix of a 2n + 1 port mode network is obtained by rigorously deriving the voltage and current relations. Following the proposed method, a compact four-way coaxial power combiner based on a nine-port mode network is designed and fabricated. Measurements show that from 7.8 to 10.3 GHz, the return losses of the input and output ports are better than −18 and −21 dB, respectively, the isolation levels between the input ports are higher than 21 dB, the insertion loss for power combination is less than 0.2 dB, and the amplitude and phase imbalances of the power combiner are less than approximately 0.15 dB and 2°, respectively. The simulated results agree well with the measured results. Moreover, the combiner has compact cross-sectional dimensions of $1.2 \lambda \times 1.2\lambda $ . It is clear that the designed four-way power combiner is superior in terms of its compact cross-sectional dimensions, high degree of isolation, low return loss, low insertion loss, and output amplitude and phase imbalance, which make it well suited for solid-state power combination. In addition, the power combiner is easy to fabricate and assemble. The proposed method shows great potential for realizing multi-way power combination with high isolation, low return loss, and compact cross-sectional dimensions.

Design of Length-Saving Multiway Wilkinson Power Dividers

A conventional multiway Wilkinson power divider must include transmission lines with a quarter of the wavelength. The prior miniaturized versions can further shorten the quarter-wave lines by adopting synthesized transmission lines, but the resulted shrunk operation bandwidth has not been considered as part of design. This paper introduces a method of designing the proposed length-saving multiway power divider to achieve targeted bandwidth performance with the minimum required total length. The proposed multiway power divider, including transmission lines with flexible lengths and additional matching capacitors, has the adjustable total length that can be set to the optimum value according to the generated plot mapping the corresponding bandwidths to the selected total lengths. The background principle, the theoretical analyses, and the design procedure of the proposed idea are addressed in detail. The design examples of the four-way, eight-way, and 32-way power dividers are provided. A 1-GHz eight-way power divider prototype based on the proposed design method is fabricated. The measurements, decently matching with simulations and the theoretical prediction, show an expected 51% operation bandwidth with the total length reduced to 72% of the conventional value.

Miniaturized Multiway Unequal Power Divider With Controllable Characteristic Impedances

A design method for miniaturized multiway unequal power divider (PD) is proposed. Compared with conventional multiway PD, each power dividing section in the proposed circuit uses transmission lines of less than quarter-wavelength, while the characteristic impedance in each power dividing section can be controlled in a certain range to avoid high-impedance lines. To demonstrate the validity of the proposed design strategy, a four-way unequal prototype working at 1.5 GHz was designed and measured. A good agreement can be observed between the theoretical simulation and the measured results.

Three-dimensional multiway power dividers based on transformation optics.

The two-dimensional (2D) or three-dimensional (3D) multiway power dividers based on transformation optical theory are proposed in this paper. It comprises of several nonisotropic mediums and one isotropic medium without any lumped and distributed elements. By using finite embedded coordinate transformations, the incident beam can be split and bent arbitrarily in order to achieve effective power division and transmission. In addition, the location of the split point can be employed to obtain unequal power dividers. Finally, several typical examples of the generalized power divider without limitation in 3D space are performed, which shows that the proposed power divider can implement required functions with arbitrary power division and arbitrary transmission paths. The excellent simulated results verify the novel design method for power dividers.

Development of multi-way high-voltage nanosecond rectangle wave pulsed power generator

Development of multi-way high-voltage nanosecond rectangle wave pulsed power generator

Millimetre‐wave broadband waveguide‐based power combiner using lossy planar lines

A lossy waveguide-based power combiner is proposed for broadband low-loss symmetrically combining with good port matching and isolation at millimetre-wave frequencies. In the combiner, lossy planar transmission lines are used to provide attenuation to even-mode excitations and to achieve broadband low-loss power combining with good port matching and isolation. The experimental results show that the lossy waveguide-based power combiner has a loss of about 0.14 dB and a reflection coefficient and isolation of about –15 dB in 26.5–40 GHz, respectively. The lossy waveguide-based power combiner can be used in a multi-way power amplifying–combining system to obtain millimetre-wave broadband high solid-state power with high efficiency and good stability.

Lossless Multiway Power Combining and Outphasing for High-Frequency Resonant Inverters

A lossless multi-way power combining and outphasing system have recently been proposed for high-frequency inverters and power amplifiers that offers major performance advantages over traditional approaches. This paper presents outphasing control strategies for the proposed power combining system that enable output power control through effective load modulation of the inverters. It describes a straightforward power combiner design methodology and enumerates various possible topological combiner implementations. Moreover, this study presents the first-ever experimental demonstration of the proposed outphasing system. The design of a 27.12 MHz, four-way power combining and outphasing system is described and used to experimentally verify the power combiner's characteristics. The proposed outphasing law is shown to be effective in controlling the output power over a 10-100 W (10:1) power range.

Broadband multi-way substrate integrated waveguide radial power divider using novel probe transition

A compact broadband multi-way radial power divider based on substrate integrated waveguide (SIW) technology is presented and a novel probe transition is employed to obtain broadband performance. An equivalent circuit model and a simplified design approach are also proposed in this paper. An eight-way broadband multi-way SIW radial power divider is designed, fabricated, and measured. Good agreement between simulated and measured results is achieved for the proposed power divider. The measured insertion loss of the eight-way power divider is approximately 9.5 dB and return loss is greater than 15 dB over entire C-band.

Design of Multiway Power Divider by Using Stepped-Impedance Transformers

In this paper, the design of multiway power dividers by interconnecting power dividers with fewer output ports is studied by transforming them into multisection stepped-impedance transformers. By using this approach, it is easy to design multiway power dividers with required equal ripples of input reflection ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">S</i> 11 ) within a wide passband. The interconnecting lines can be used as additional matching sections to improve the input matching. General properties of this type of multiway power dividers can be easily obtained. Design of multiway power divider with required input reflection level can be readily performed by using the published data and tables of stepped-impedance transformer in the literature. Both even- and odd-mode analyses are performed to obtain the optimal isolation resistor values. A prototype of a wideband four-way power divider with a rhombic architecture is designed, fabricated, and measured. Simulation and measurement results are in good agreement and validate the proposed approach.