Tunable Power Divider Research Articles

Simultaneous Amplitude- and Phase-Tunable Coupler With Wide Phase Tuning Range

In this article, a coupler with simultaneously tunable power division ratio (PDR) and phase difference is proposed based on a multivector summation method. Two groups of varactor diodes are installed on the cross-shaped quarter-wavelength coupled lines to realize the proposed tunable coupler. The horizontal coupled lines serve as the subcouplers to generate multiple vectors, while the vertical coupled lines serve as the phase-tunable units (PTUs) to control the phase of the vectors. The phases of the PTUs can be therefore tuned by the varactor diodes. With a proper combination of the capacitance of the varactor diodes, the amplitude and phase characteristics of the proposed coupler can be controlled independently. For demonstration, a highly tunable coupler operating at 1.8 GHz is designed, fabricated, and measured. The PDR of the coupler can be tuned from <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$-$</tex-math> </inline-formula> 7 to 1 dB with a 90 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{\circ}$</tex-math> </inline-formula> phase difference, while the phase difference of the coupler can be tuned within a wide range from 10 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{\circ}$</tex-math> </inline-formula> to 165 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{\circ}$</tex-math> </inline-formula> with equal power division. Better than 10-dB return loss and 15-dB isolation can be observed under different states.

Design of a broadband frequency-tunable planar filtering power divider

ABSTRACT In order to meet the development requirements of multi-frequency and functional integration of radio frequency (RF) modules, a broadband tunable filtering power divider with center frequency is designed. A new structure is composed of open branch line, step impedance resonator, and double branch resonator. The filter response is realized by branch line and double branch resonator. The resonant frequency of the device can be adjusted flexibly by controlling the varactor diode loaded on the two resonators with external voltage. The double branch resonator can realize the broadband frequency adjustability, the step impedance resonator can improve part of the return loss performance of the device, so that the central frequency can achieve high performance in a wide tuning range. The research results show that the center frequency of the designed filtering power divider is adjustable in the range of 1.6 GHz to 2.7 GHz, the tuning bandwidth is 51.2%, the input return loss of each center point is better than 20 dB, and the isolation between output ports is better than 19 dB. The device is expected to be widely used in RF communication systems such as array antennas and transceiver components.

Graphene-based terahertz reconfigurable printed ridge gap waveguide structure

Graphene-based microwave devices have enabled reconfigurability, thus paving the way to the realization of flexible wireless terahertz systems with featured performances. Despite great progress in the development of graphene-based terahertz devices in the literature, high insertion loss and wide tunable range are still significant challenges at such high frequencies. In this work, we introduce the use of graphene to implement a reconfigurable printed ridge gap waveguide (RPRGW) structure over the terahertz frequency range for the first time. This guiding structure is suitable for both millimeter and terahertz wave applications due to its supporting quasi-TEM mode, which exhibits low dispersion compared to other traditional guiding structures. The presented solution is featured with low loss as the signal propagates in a lossless air gap, which is separated from the lossy graphene elements responsible for the reconfigurable behavior. In addition, this guiding structure is deployed to implement a tunable RPPGW power divider as an application example for the proposed structure.

Novel Gysel power dividers with tunable power dividing ratio and central frequency

Novel power dividers based on Gysel architecture with tunable power dividing ratio (TPDR), tunable central frequency (TCF), perfect port matching and isolation are proposed. The regulatory mechanism of traditional Gysel Power Divider (GPD) is studied, and a novel electrical tunable method is presented to tune the power divider ratio by only the electrical length of the GPD section, which simplifies the design of tunable power dividers. Tunable T-type networks are used to tune the power dividing ratio and central frequency by tuning this electrical length parameter, and the TPDR range can be pre-defined by setting the characteristic impedance of the transmission lines in the tunable power divider. The tunable mechanism of the circuits was theoretical studied. Two power dividers operating at 950 MHz with TPDR of 0.3:1 ∼ 35.9:1 and 1.1:1 ∼ 35.4:1, and a GPD with TCF in 1.1 GHz ∼ 1.6 GHz were designed and fabricated. All the measured results are in good agreement with the simulation.

Multifunctional resonant graphene four-port for THz and far IR regions

A new multifunctional resonant device for THz and far-infrared regions based on surface plasmon-polariton graphene resonator and waveguides is suggested and analyzed in this paper. The device consists of a circular graphene resonator and four nanoribbons serving as waveguides. Every waveguide is front-coupled to the resonator with a small gap between them. The waveguides are oriented with the angle 90∘ between them. The graphene elements are deposited on a dielectric substrate. The Fermi energy of graphene can be dynamically varied by applying an electrical potential difference between the graphene and a thin polysilicon layer which acts as an electrode. The resonator can work with dipole and quadrupole resonant modes. They are used to provide the functions of tunable band-pass filter, tunable power divider and switch. Using the scattering matrix description of the four-port, the circuit theory representation and full-wave analysis, we show that for the central frequency 14.52 THz the parameters of the developed device are as follows: the Q-factor due to use of resonant structure is (6÷8), the matching in the pass-band with return loss of − 17 dB and low insertion loss of about − 1.0 dB. The component provides a tunability of the central frequency and the power ratio between the three output ports can be projected in a wide range. In the OFF regime, the transmission coefficients to output ports are lower than − 42 dB.

Nonreciprocal dynamically tunable power dividers by three (1x3) based on graphene for terahertz region

This paper presents two new types of dynamically tunable THz nonreciprocal power dividers based on graphene. These components fulfill division of the input power between three output ports. Besides, they possess isolation properties, i.e., a source connected to the input port is protected against unwanted reflections from the output ports. The components consist of a disk-shaped graphene resonator and six graphene waveguides connected to it. The graphene elements are deposited on a dielectric substrate. The resonator is subject to an external electric and DC magnetic field. The dipole mode resonance in the magnetized resonator is excited by surface plasmon–polariton waves propagating in the graphene waveguides. Numerical simulations and the analytical temporal coupled-mode theory are used in the analysis. The division level of the input power between the three output ports of dividers is about −8 dB and the isolation of the source in relation to the output ports is higher than −15 dB with the central frequency 7.45 THz and the bandwidth 3%. DC magnetic field is 0.29 T and Fermi energy is 0.15 eV. The central frequency of the dividers can be dynamically adjusted by an external electric field.

Π-type reconfigurable coupler based on a complementary tunable method

A complementary tunable method is proposed based on the Hybrid coupler. The odd-even mode analysis shows that the method can achieve continuously tunable power division ratio by changing two transmission lines in the circuit, and it can achieve larger tunable range by improving the complementary tunable method based on the cascaded Hybrid coupler. Using the improved method, a novel π-type reconfigurable coupler, which works at 2.45 GHz, is designed by replacing transmission lines with π-type circuit. The power division ratio of the fabricated reconfigurable coupler is changed in the range of −20.5–21.3 dB, with the bias voltage being 0∼6 V; meanwhile, the isolation and return loss are above 20 dB.

A novel reconfigurable PD based on complementary hybrid circuit

ABSTRACT Reconfigurable methods including areflective phase-shifter circuit are proposed based on complementary hybrid network power divider (PD). The analysis shows that this method can achieve continuously tunable power division ratio (PDR) and wide phase difference by changing the two horizontal transmission lines of the complementary hybrid network. In this way, areconfigurable PD based on acomplementary hybrid circuit-based reflective phase-shifter is designed to work at 2.45 GHz by replacing two horizontal transmission lines with 50 Ω reflective phase-shift circuits. The PDR of this fabricated reconfigurable PD is changed to the range of −29.12 to −0.24 dB, with the bias voltage being 0–8 V; meanwhile, the return loss and isolation are better than 23.2 dB.

Tunable Balanced Power Dividers: An Overview of Recently Developed Balanced Power Dividers and Couplers With Fixed and Tunable Functions

Signal crosstalk and common-mode noise are two issues for engineers when designing today's increasingly complicated microwave integrated circuits [1]. Compared with single-ended circuits, balanced circuits can provide high immunity to environmental noise and broadband common-mode rejection capability [2]. Over the past few years, various balanced passive circuits, such as filters [3], antennas [4], power dividers, and couplers [5]-[17], have been extensively studied. Power dividers and couplers are widely used in microwave integrated circuits, such as antenna feeding networks, balanced mixers, and amplifiers. Balanced couplers are used in double-balanced mixers [18] and balanced frequency doublers [19] to achieve higher efficiency and lower loss.

A Phase Distribution Network Using 2 × 4 Butler Matrix for Linear/Planar Beam-Scanning Arrays

A new $1\times $ 4 phase distribution network (PDN) featuring a fully controllable progressive phase shift between outputs is proposed for continuous beam-scanning arrays. The PDN is made up of two parts: a modified $2\times $ 4 Butler matrix integrated with four phase shifters (PSs), and a tunable power divider (TPD) whose power division ratio can be controlled over a wide tuning range. The synthesis equations show that the relative phase shift between PDN outputs can be fully controlled by the TPD and embedded PSs without using an external single-pole quad-throw (SP4T) switch. The proposed PDN is demonstrated at 2.4 GHz as the feed network of a 4-element linear array. The experimental results display a fully controllable progressive phase shift (from −180° to 180°) between PDN outputs over a 20% bandwidth with good performance of matching, power division, and relative phase shifts. A spatial coverage of 116° with the feature of continuous beam scanning and negligible dc power consumption is achieved. Benefitting from the single-input topology, a planar 16-element phased array for 2D beam scanning is then realized by simply stacking and cascading five instead of eight PDN modules. It removes the high-cost and bulky SP16T switch. Experimental results demonstrate the uniqueness of the proposed designs.

W‐band out‐of‐phase active power divider with continuously tunable power division ratio and invariant phase difference

In this study, a W-band out-of-phase active power divider, with continuously tunable power division ratio, has been presented. Out-of-phase signal is generated by the compact transform balun with accurate phase and amplitude response. To stabilise the phase difference in different power division ratio, phase-invariant cascode variable gain amplifier (VGA) is designed in the two paths of the active power divider and 4-bits proportional to absolute temperature current source is designed to control voltage of VGA. The active power divider is implemented in SiGe BiCMOS process with measured tunable power division ratio from 1:16 up to 16:1, the phase shift from 74 to 90 GHz is about 10° as the gain changes up to 12 dB, which guarantees a good phase-invariant performance.

Comments on “Two Novel Reconfigurable PDs Based on Cascaded Transmission Lines”

In the mentioned article, Peng et al. proposed a three-port power divider (PD) and four-port coupler with tunable power division ratio based on: 1) cascade connection of 3-dB in-phased PD, matched tunable difference phase transmission lines (TLs), and 3-dB quadrature branch line coupler (QBLC) and 2) cascade connection of QBLC, mismatched in-phased TLs, and QBLC. However, the proposed four-port coupler provides an undesired phase difference of 90° between the output signals. Also, the scattering parameter analysis of the second design seems to be incorrect. In this letter, a correct approach is provided to analyze S-parameters.

A Wideband Tunable Power Divider for SWIPT Systems

A two-way tunable power divider for Simultaneous Wireless Information and Power Transfer (SWIPT) is proposed in this paper. The power divider divides the incoming power in such a way that maximum power is utilized for energy harvesting purposes and the rest of the power is used for information decoding purposes. This unequal distribution of power is realized by tuning the varactor diode's reverse biasing voltages. A good matching performance is attained using the radial and short stubs at the input and one of the output ports, respectively. High isolation is achieved with the help of the resistor used for connecting the output ports of the power divider. The achieved power division ratios vary from 13:1 to 28:1. The tunable power divider is designed and fabricated at 2.4 GHz. The bandwidth measured at 10 dB return loss is 3.2 GHz and the isolation better than 12 dB is achieved between the output ports. The designed structure is compact and good consistency is observed between the simulated and measured results. The designed power divider may be used for future 5G wireless networks.

Two Novel Reconfigurable PDs Based on Cascaded Transmission Lines

Two reconfigurable methods including phase superposition method and power reflection method are proposed based on the cascaded power divider (PD). The analysis shows that these two methods can achieve continuously tunable power division ratio by changing the cascaded transmission lines. Using these two methods, the superposition- and reflection-type reconfigurable PDs, which work at 2.45 GHz, are designed by replacing the cascaded transmission lines with the R- and T-type circuits, respectively. The power division ratios of the two fabricated reconfigurable PDs are changed to the ranges of -12.4 to 14.8 dB and -8.6 to 22.5 dB, respectively, with the bias voltage being 0-12 V; meanwhile, the return loss and isolation are better than 20 dB.

A Filtering Power Divider with Tunable Center Frequency and Wide Stopband

AbstractIn this paper, a tunable power divider (PD) with a good band-pass filtering response using quarter-wavelength stepped impedance resonators (SIRs) is presented. By appropriately adjusting the impedance and electrical length ratio of SIR, the proposed structure can achieve wide stopband performance. Meanwhile, four varactor diodes are loaded to the external resonators to achieve electrical reconfiguration. In addition, a pair of transmission zeros (TZs) can be generated by applying source and load coupling on each side of the passband, which can effectively improve passband selectivity and out-of-band rejection. In order to verify the feasibility of the proposed design method, a prototype circuit of the proposed filtering power divider (FPD) with tunable center frequency is simulated, fabricated and measured. A good agreement between the simulation and measurement results is observed.

Quad‐polarization reconfigurable antenna with wideband operation

AbstractA design for quad‐polarization‐agile antenna is described. A multiport crossed dipole that can provide dual orthogonal linear polarizations is used as the radiating element of the design. When the crossed dipole is fed with a tunable power divider, the two linear polarization radiations can be simultaneously excited with same amplitudes and difference phases. The resultant polarization modes include ±45° linear polarizations, right‐handed circular polarization, and left‐handed circular polarization. The overlapped operation bandwidth of the four polarization modes is about 49%, and the antenna operating in each polarization mode has almost the same radiation patterns. These patterns are also stable against frequency. Moreover, the occupied area of the polarization reconfigurable antenna is about 0.43λ0 × 0.43λ0.

Comments on “A Continuously Tunable Unequal Power Divider With Wide Tuning Range of Dividing Ratio”

The power-dividing ratio analysis by Ye et al. is based on an inadequate equivalent circuit and neglects the effect of the isolation resistor. It is shown that the isolation resistor should be included for the power-dividing analysis and the exact analysis results are presented for the power-dividing ratio. According to the exact analysis, the wide tuning range of the power division ratio claimed by Ye et al. is sharply reduced including the effect of the isolation resistor.

Magnon Straintronics to Control Spin-Wave Computation: Strain Reconfigurable Magnonic-Crystal Directional Coupler

The effect of electrical field control of the spin-wave spectrum in adjacent magnonic crystals stripes was investigated by micromagnetic simulation, microwave spectroscopy, and Brillouin light scattering (BLS). The electric-field-induced dipolar coupling between magnetic stripes leads to the formation of symmetric and antisymmetric collective modes in the spectra of propagating spin waves. In particular, the strain-induced variation of the spin-wave coupling length in the stripe, predicted by micromagnetic simulation and measured by BLS, show the possibility of application of a lateral array of magnonic crystals as tunable microwave directional couplers, power dividers, and spin-wave demultiplexers, which can be used simultaneously as an interconnection unit in reconfigurable magnonic networks.

SIW‐based microfluidically tunable PD with wide‐frequency‐tuning range

A passive microfluidically tunable power divider (PD) with a wide-frequency-agile range based on substrate integrated waveguide (SIW) has been presented. The proposed structure consists of two SIW resonators loaded on the same complementary split-ring resonator and five identical filling-water tubes placed on the top plane. By injecting water into five tubes, the effective permittivity of the substrate can be controlled, and thus the operating frequency of the PD can be precisely tuned. For demonstration, the proposed PD is designed and fabricated. The measured and simulated results are given, showing good agreement.

Review of Recent Developments in Microwave Power Divider

In previous years, different objectives and designs of power divider (PD) were proposed for modern wireless communication systems, such as filtering power divider (FPD) and tunable power divider. In this paper, a review on various sorts of filtering and tunable power divider is presented. There are several designs which are novel in their techniques, while others are motivated from previous works. This paper begins with an introduction on power divider, followed by the description of available designs for tunable power divider and filtering power divider. Furthermore, the designs' size, measurement, performance and technology used are also discussed. Most of the existing designs for tunable power divider use varactors for tunable properties. Meanwhile, for filtering power divider, the designs mostly focus on fixed operational bands and frequencies of filtering power divider due to simple design procedures. Therefore, an alternative design for filtering power divider is suggested which integrates the tunable power divider and filtering power divider. However, there are a few works that focus on tunable filtering power divider. From previous works, varactors or pin diodes are used to make tunable filtering power divider.