Wilkinson Power Divider Research Articles

2 n -Way Wideband Filtering Power Dividers With Good Isolation Enhanced by a Modified Isolation Network

In this article, a class of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2^{n}$ </tex-math></inline-formula> -way wideband filtering power dividers (FPDs) is presented and designed with a wide isolation band. It consists of ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2^{n}-1$ </tex-math></inline-formula> ) two-way power-dividing units and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$n$ </tex-math></inline-formula> three-line coupled lines. The basic two-way power divider is achieved by replacing a simple isolation resistor of the conventional Wilkinson power divider with a modified isolation network, so as to improve the bandwidth of better-than-20-dB isolation band from 40% to 120%. The modified isolation network is composed of one quarter-wavelength coupled line, two quarter-wavelength transmission lines, and one resistor. The three-line coupled line is introduced at each output of the proposed FPD to improve its frequency selectivity and passband bandwidth. Furthermore, after placing one additional isolation resistor on each three-line coupled line, the number of output ports in the proposed power divider could be doubled without introducing more two-way power-dividing units. Finally, a prototype two-way and two prototype four-way wideband FPDs with different occupied sizes are designed and fabricated. The feasibility of the proposed design method is verified by the good agreement between the simulated and measured results.

A Simple Approach for Improving Bandwidth and Isolation of Wilkinson Power Divider

A Simple Approach for Improving Bandwidth and Isolation of Wilkinson Power Divider

An Unequal Wilkinson Power Divider Based on Integrated Passive Device Technology and Parametric Model

A new on-chip unequal Wilkinson power divider (WPD), developed on a silicon-based integrated passive device (IPD) process and parametric model, is proposed. The central operating frequency is at 4.8 GHz for sub-6G applications. The design process achieves a balance between circuit simulation efficiency and full-wave simulation accuracy based on the parametric model. The size of a fabricated sample for the proposed unequal WPD is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1.6\times2.1$ </tex-math></inline-formula> mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . A good agreement between the simulated and measured results is achieved.

Wideband Circularly Polarized Stacked Patch Antenna Based on TM₁₁ and TM₁₀

A wideband circularly polarized (CP) stacked patch antenna based on TM₁₁ and TM₁₀ is proposed in this article. This four-port antenna consists of a circular patch and a square patch, where the square patch is located above the circular patch. Taking into account the mutual coupling between four ports, the active reflection coefficient (ARC) is adopted to describe the impedance matching of the antenna, and a simplified form of ARC is derived. The abnormal electric field distribution generated in the square patch is attributed to the superposition of the electric fields of two orthogonal TM₁₀ modes, which is theoretically verified. Due to the coupling between TM₁₁ mode and TM₁₀ mode, a new resonance mode appears in a square patch, where the abnormal electric fields on the two diagonals are generated simultaneously. The effect of the square patch on the circular patch is equivalent to a capacitor at the lower frequency end and the higher frequency end of &#x2212;10 dB impedance bandwidth, while it acts as an inductor at the middle frequency band. Besides the horizontal patch of <inline-formula> <tex-math notation="LaTeX">$\lceil $ </tex-math></inline-formula>-shaped feed is sandwiched between two radiators to enhance coupling. Finally, a wideband feed network composed of Wilkinson power divider and phase shifter is devised to provide four signals of equal magnitude and quadrature phase for proposed antenna. To verify the design concept, a prototype is fabricated and measured. The results show that left-hand circularly polarized (LHCP) radiation is achieved. The 3 dB gain variation bandwidth is 44.6&#x0025;, ranging from 1.48 to 2.33 GHz, in which VSWR &#x003C; 1.5 and AR &#x003C; 1.5 dB. Besides the peak gain is 9.5 dBic and antenna efficiency is not less than 64&#x0025;.

A novel 10MHz-4GHz Wilkinson power divider using lumped compensation elements

A novel 10MHz-4GHz Wilkinson power divider using lumped compensation elements

Neural network inverse model for multi-band unequal Wilkinson power divider

PurposeThe purpose of this paper is to build a neural network (NN) inverse model for the multi-band unequal-power Wilkinson power divider (WPD). Because closed-form expressions of the inverse input–output relationship do not exist, the NN becomes an appropriate choice, because it can be trained to learn from the data in inverse modeling. The design parameters of WPD are the characteristic impedances, lengths of the transmission line sections and the isolation resistors. The design equations used to train the NN inverse model are based on the even–odd mode analysis.Design/methodology/approachAn inverse model of a multi-band unequal WPD using NNs is presented. In inverse modeling of a microwave component, the inputs to the model are the required electrical parameters such as reflection coefficients, and the outputs of the model are the geometrical or the physical parameters.FindingsFor verification purposes, a quad-band WPD and a penta-band WPD are designed. The results of the full-wave simulations verify the validity of the design procedure. The resulting NN model outperforms traditional time-consuming optimization procedures in terms of computation time with acceptable accuracy. The designed WPDs using NN are implemented by microstrip lines and verified by using full-wave analysis based on high-frequency structure simulator (HFSS). The results of the microstrip WPDs have good agreements with the corresponding results obtained by using ideal transmission line sections.Originality/valueThe associated time-consuming procedure and computational burden in realizing WPD through optimization are major disadvantages; needless to mention the substantial increase in optimization time because of the multi-band design. NNs are one of the best candidates in addressing the abovementioned challenges, owing to their ability to process the interrelation between electrical and geometrical/physical characteristics of the WPD in a superfast manner.

Compact wideband Wilkinson power divider on gallium arsenide integrated passive device technology

In this article, a novel topology of wideband on-chip Wilkinson power divider (WPD) with good insertion loss (IL) performance is proposed and demonstrated on gallium arsenide (GaAs)-based integrated passive device (IPD) technology. The proposed WPD is further analyzed by the even and odd method. To verify the advantage of the proposed WPD against the conventional one, two examples are numerically investigated, showing that the proposed one achieves better performance in terms of IL and isolation. In addition, the proposed design achieves a miniature area and small amplitude and phase imbalance (AI) performance. The fractional bandwidth (FBW) of the proposed WPD is 100% (6–18 GHz), where the magnitude imbalance is less than 0.08 dB and phase imbalance is better than 0.4°. Furthermore, the minimum IL is better than 0.96 dB and return loss is better than 13.7 dB within the core passband. Meanwhile, the isolation of the WPD is better than 17.6 dB. Finally, to further demonstrate our design conception, the proposed WPD has been fabricated on GaAs IPD technology with size of 1.5 × 0.9 mm2, and measured by on-wafer probing. All the simulated and measured results of the proposed WPD are matched reasonably well with each other, thus firmly validating the claimed superior performance of the proposed WPD in the wide operating bandwidth, low IL and high isolation.

Miniaturization of microwave planar circuits using composite microstrip/coplanar-waveguide transmission lines

The rapid development of modern communication systems propels the demand of high performance and miniaturization of RF/microwave components. Power dividers and filters are indispensable circuit components in amplifiers and antenna feed-networks which occupy large footprint of circuit broads, particularly at low frequency. The purpose of this study is to initiate a new type of planar transmission line with unique dual signal-path characteristics and ultimately achieve circuit miniaturization. In this paper, a novel technique of consolidating microstrip lines (MLs) and coplanar waveguide (CPW) lines on a single dielectric substrate, designated as the composite microstrip/CPW line (CM/CPW line), is proposed. With reference to the average line length of ML and CPW, it warrants a physical length reduction of 48.3% and further achieves a reduction of 80.8% after zigzagging CM/CPW line. The proof-of-concept design example of a two-way Wilkinson power divider (WPD) has demonstrated the effectiveness of the miniaturization technique. The simulation, in combination with the experimental results, validates that a size reduction factor of 86.9% when compared to conventional one has been achieved while maintaining a fractional bandwidth of 57.7% for the WPD.

A 65‐nm 28‐GHz CMOS Wilkinson power divider with improved isolation

AbstractIn this study, we implemented a Wilkinson power divider/combiner composed of lumped elements suitable for 28‐GHz of fifth‐generation mobile communication technology. To improve the isolation of the system, signal perfect cancellation analysis is used with optimized values of the lumped elements of the Wilkinson power divider, which is fabricated using bulk complementary metal–oxide–semiconductor (CMOS) 1P9M 65‐nm process and the fabricated circuit area was 0.046 mm2. The measured insertion loss of this system is less than 0.62 dB, input/output matching exceeds 16.9 dB, and isolation between the output ports exceeds 19.6 dB in the operating frequency range of 25.5–29.5 GHz. The circuit thus has low insertion loss and good isolation compared to conventional Wilkinson power dividers manufactured for use in the similar frequency bands.

Design and Implementation of a Dual-Band Filtering Wilkinson Power Divider Using Coupled T-Shaped Dual-Band Resonators

The paper introduces a novel structure of a dual-band filtering Wilkinson power divider (WPD). Its essential component is a dual-band bandpass filter (BPF), implemented using coupling lines and two T-shaped resonators. The BPF is incorporated into the divider structure to suppress the unwanted harmonics within the circuit. The latter is achieved owing to a wide stopband of the filter. The designed dual-band WPD can suppress third unwanted harmonics in both channels with high levels of attenuation. The designed dual-band WPD operates at 2.6 GHz and 3.3 GHz with a return loss of 22.1 dB and 22.3 dB at the operating frequencies. Furthermore, the insertion loss and isolation are 0.3 dB and 20.2 dB at 2.6 GHz and 0.9 dB and 24.5 dB at 3.3 GHz. The analysis and simulation results are corroborated by the measurements of the fabricated divider prototype. The competitive performance of the proposed circuit is also demonstrated through comparisons with state-of-the-art divider circuits from the literature.

Integrated-Designs of Filtering Circuits Based on Adjustable Dielectric Waveguide Resonators

This brief presents a new kind of adjustable dielectric waveguide resonator (DWR), based on which integrated designs of filtering circuits are conducted. The DWR is composed of a dielectric part as the main resonating body and a printed circuit board (PCB) part as the cover. An unmetallized blind hole is carved at the upper surface of the dielectric part. A tuning screw is installed on the PCB and inserted into the unmetallized blind hole to adjust the resonant frequency the DWR. This adjusting method is flexible and reversible. By using the proposed adjustable DWR, a fourth-order bandpass filter (BPF) is designed, fabricated and measured. The measured results show that the BPF is with an in-band insertion loss of 0.8 dB and an in-band return loss better than 19 dB. A capacitive cross coupling structure is constructed on the PCB so that two transmission zeros are introduced close to the passband to improve the filtering selectivity. In addition, a Wilkinson power divider is realized on the PCB and integrated with the above BPF, forming a filtering power divider. The measured in-band insertion loss of the filtering power divider is 1.1 dB. The isolation is better than 24 dB and the maximum phase imbalance is 1° in the passband.

Wideband Monostatic Co-Horizontally Polarized Simultaneous Transmit and Receive Antenna Subsystem With Integrated Beamforming Network

A wideband monostatic simultaneous transmit and receive (STAR) antenna subsystem with high isolation and Co-horizontally polarized (Co-HP) omnidirectional radiation is presented. The antenna subsystem consists of a STAR antenna and a beamforming network (BFN). The STAR antenna consists of a planar circular array having four printed dipole elements surrounded by two groups of parasitic strips. The parasitic strips are used to improve the impedance bandwidth (IMBW) and reduce the gain variation in transmit (TX) and receive (RX) modes. To achieve high isolation, the four ports of the STAR antenna are excited with two orthogonal phase modes for TX and RX using the BFN. The BFN is a six-port network consisting of two 180&#x00B0; hybrid couplers, one 90&#x00B0; hybrid coupler, and a Wilkinson power divider. The 180&#x00B0; hybrid coupler is elaborately designed with low imbalances since it is most key to achieve high TX/RX isolation. Measured results show that the proposed STAR subsystem achieves a TX/RX overlapping IMBW of 4.71&#x2013;6.2 GHz, and a 40 dB TX/RX isolation bandwidth of 4.81&#x2013;5.88 GHz, while maintaining horizontally polarized omnidirectional radiation patterns for TX and RX over the entire operating frequency band.

Novel Passive Vector-Sum Reconfigurable Filtering Phase Shifter With Continuous Phase-Control and Tunable Center Frequency

In this article, a novel reconfigurable filtering vector-sum phase shifter (RFPS) with a continuous phase shift range of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\ge 300^{\circ }$ </tex-math></inline-formula> and tunable operating frequency range from 1.05 to 1.3 GHz is proposed. It consists of two identical wideband Wilkinson power dividers (or power combiners) (WPDs) and a reconfigurable filtering quadrature coupler (RFQC) that is connected between the two WPDs. Through the first WPD, the split waves are fed into the RFQC and are then combined at the output ports of the RFQC. The phase of the combined waves can be continuously tuned by adjusting different combinations of coupling types between interstage resonators of the RFQC, and the resulted output waves are then summed up through the second WPD with the desired output phase. Different from the conventional active vector-sum phase shifter, the vector summing is realized by the proposed RFQC and is a pure passive design, resulting in a low-cost, low-noise, easy-design, and highly flexible system. A prototype is designed and fabricated to demonstrate the proposed technique. Detailed theoretical analysis and design procedure have been given. The experimental results show that the proposed RFPS features the continuous phase-control range of more than 300° with a tunable filtering response covering the frequency range from 1.05 to 1.3 GHz.

Design and analysis of noninverting single-spiral CMOS Wilkinson power dividers and their quadrature couplers and baluns

Design and analysis of noninverting single-spiral CMOS Wilkinson power dividers and their quadrature couplers and baluns

Electronically Steered MIMO Patch Antenna with Conformal Feeding for 5G Applications

Multiple input multiple output antenna is the key technology which enables the design of 5G networks. In order to achieve desired beam forming and side lobe reduction capabilities, antennas used in MIMO technology are required to feed with signals having different phase and amplitude. It is possible to achieve variable phase shift and variable attenuation using phase shifter and amplitude limiters. However when these devices are used between source and antenna, they makes the system non planner and non-conformal. This research presents a 16 element, multiple user MIMO Patch antenna with conformal and planner power divider network to achieve electronically steered beam along with the desired side lobe level reduction. Wilkinson power divider is used to achieve conformal and planner power divider for MIMO antenna. Desired beam forming capabilities are achieved by controlling the phase of input signal to antennas by controlling the length of microstrip line and desired side lobe reduction capabilities are achieved by controlling the amplitude of input signal to antenna by controlling the width of microstrip line used in Wilkinson power divider. This provides an overall planner and conformal structure. In this research same antenna is used to generate two major beams by controlling the phase and amplitude of input signal. The designed structure is simulated and analyzed using HFSS. Simulated results for the designed MIMO antenna are verified by analyzing the fabricating structure using vector network analyzer and horn antenna. The novelty in this research is to design power divider, phase shifter and amplitude limiter in single unit.

Compact Dual-Band Wilkinson Power Divider Design Using Via-Free D-CRLH Resonators for Beidou Navigation Satellite System

A compact dual-band Wilkinson power divider (WPD) using the via-free dual-composite right/left-handed (D-CRLH) resonators is presented for application in the Beidou navigation satellite system in this brief. First, by establishing an equivalent circuit model and using Bloch theory, a dual-band resonator is further analyzed to gain insight into its working mechanism, which can exhibit −90° phase shift at lower frequencies and +90° phase shift at upper frequencies, respectively. Then, to facilitate the design, ignoring parasitic parameters, a simplified circuit model retaining the physical meaning is presented, and the closed-form formulas for determining lumped element values of a dual-band characteristic are derived. Next, there is a significant rejection performance between two operating frequencies due to the inherent band-stop filtering effect of the D-CRLH resonator. Following that, the WPD is verified through experiments, showing excellent performance. Finally, based on this property, a dual-band feeding network (FN) is constructed by the combination of a WPD and a phase shifter with the proposed resonator. The simulated and measured results are found in good agreement with each other, which further demonstrated our proposed design conception.

Rigorous Analysis and Investigation of the Bandwidth Broadening Mechanism in a Compact Power Divider With Physical Port Isolation

This paper proposes a compact power divider with simultaneous physical port isolation and wideband operation based on the simple Wilkinson power divider (WPD) configuration. Rigorous analysis based on the even- and odd-mode bisected networks has been performed to investigate the relationship between the design parameters and the overall performance. Theoretical analysis revealed that the impedance and isolation bandwidth are directly related to the reflection coefficients of the even- (Γ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">e</sub> ) and odd-mode (Γ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">o</sub> ) bisected networks. Simultaneous broadening of the impedance and isolation bandwidth is possible through the optimum choice of design parameters which confines the trajectories of the Γ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">e</sub> and Γ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">o</sub> in the low constant-Q region on the Smith Chart. Experimental verification by the prototype designed at 1 GHz exhibited the widest overall system bandwidth (43.2%) and the lowest total electrical length (140.8°) as compared to the previous state-of-the-art WPD’s with physical port isolation.

Design of a High-Efficiency Doherty Power Amplifier for 5G Applications Using Wilkinson Power Divider

In this paper, a novel Doherty Power Amplifier DPA based on a 10 W gallium-nitride high-electron-mobility transistor (GaN-HEMT) technology is designed using Advanced Design System (ADS) software. In the design, two different single Power Amplifiers (PAs) are combined using a Wilkinson power divider which is also used to connect the power to the load. The designed DPA operates in the range of 2.0-3.0 GHz and aims to achieve high efficiency, wide bandwidth and high output power for 5G applications. Simulation results showed a 40% fractional bandwidth and more than 44 dBm of saturated output power. In addition, the Power-Added Efficiency (PAE) and Drain-efficiency (Deff) are about 77% and 84%, respectively. A comparison with the other previous works shows enhancement in the maximum large-signal gain (L_S_Gain) in the average of 2.5 dB and an average PAE of about 10%. This improvement can be attributed to the deployment of the power divider/combiner proposed in the design and also the optimization of the components during the design.

Millimeter-Wave Multi-Band Reconfigurable Differential Power Divider for 5G Communication

A differential four-way power divider for 24 to 30 GHz and a frequency reconfigurable differential four-way power divider for 24 to 30 GHz and 37 to 43.5 GHz are presented. The differential structure provides sound virtual grounds in a multiple-channel chip. Both circuits have a four-way Wilkinson power divider (WPD) configuration based on lumped elements that provide small chip sizes. The first one has a small core chip area of 0.09 mm², a small insertion loss of 0.93 to 1.94 dB, and the port-to-port isolation of 19.1 to 25.6 dB from 24 to 30 GHz. It has a small amplitude and phase differences at four outputs. The second one allows frequency-reconfigurable operation by switching inductances and capacitances to cover widely separated frequency bands (5G NR n257-n261 bands). In addition, switched capacitors (SCs) are inserted to resonate out the parasitic series inductances in isolation resistors at both bands of 24-30 GHz and 37-43.5 GHz. It has a core chip area of 0.168 mm², insertion losses of 1.65-1.89 dB at 24 to 30 GHz and 2.04-2.70 dB at 37 to 43.5 GHz, respectively. The port-to-port isolations are 23.4-37.6 dB at 24 to 30 GHz and 22.6-28.4 dB at 37 to 43.5 GHz.

Teaching Scattering Matrix in Electrical Engineering—Misconceptions and Clarifications

This paper presents a new approach to introducing scattering parameters for dispelling doubts and misconceptions. Normalization of voltage and current is first introduced for the subsequent descriptions of normalized matrices. The analogy with lossless transmission lines is used to define voltage waves in terms of circuit voltages and currents. Scattering parameters are interpreted as reflection and transmission coefficients for real normalizing impedance. Power considerations are made to interpret scattering parameters as power ratios. The condition for the lossless circuit is derived, and it is shown that the definitions of the voltage waves satisfy maximum power transfer conditions for real input impedance. Reciprocity conditions are derived to show that the normalized, not the unnormalized scattering matrix, is symmetric. The application of losslessness and reciprocity in filter design is clarified. Next, it is shown why definitions of forward and reverse voltage have to be changed for complex normalizing impedances. The relationships of matrices for complex normalizing impedance are shown to reduce to those for real normalizing impedance. The procedure for changing normalizing impedance is given, and its application for amplifier design is briefly described. The difference between circuit symmetry and physical symmetry is pointed out. Finally, it is shown how odd and even mode analysis arises from a mathematical consideration of symmetrical two-port networks. A straightforward discussion of Wilkinson power divider is given to illustrate the application of these modes.