Arbitrary Power Division Ratio Research Articles

An Ultra-Compact and Wideband Transformer-Based Coupler With Arbitrary Phase Difference and Arbitrary Power Division Ratio

An Ultra-Compact and Wideband Transformer-Based Coupler With Arbitrary Phase Difference and Arbitrary Power Division Ratio

Balanced-to-Single-Ended Filtering 180° Hybrids With Arbitrary Power-Division Ratio

In this article, a balanced-to-single-ended (BTSE) 180 <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> hybrid with arbitrary power-division ratio and bandpass filtering response is presented based on the 2-D square patch resonators. With resorting to the TM <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{01}$</tex-math> </inline-formula> and TM <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{10}$</tex-math> </inline-formula> orthogonal degenerate modes in a square patch cavity, the desired in-phase and out-of-phase characteristics between output ports can be simultaneously accomplished. The electric field distributions on the patch under operation of TM <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{01}$</tex-math> </inline-formula> and TM <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{10}$</tex-math> </inline-formula> modes are inspected to guide the design process. Theoretical analysis results demonstrate that the proposed hybrid flexibly allows for effective control of arbitrary power-division ratio by arranging two output ports at proper positions. Meanwhile, the filtering response can be realized using two stacked patch resonators with proper coupling strengths according to the filter specification. Moreover, the isolation performances between balanced input ports and single-ended output ports are evaluated for all the power-division ratios. For validation, two 2nd-order filtering BTSE hybrids with different power ratios of 1:1 and 10:1 are designed. Measured results of both two fabricated circuits exhibit good performances in terms of filtering response, power splitting distribution, common-mode suppression, in-phase and antiphase difference, as well as isolation and port matching.

Balanced-to-Unbalanced Quadrature Couplers With Wide-Band Common-Mode Suppression

In this paper, two types of balanced-to-unbalanced quadrature couplers with six hybrid ports and arbitrary power division ratio are proposed. For Type 1, the quadrature coupler can realize two power division functions, including balanced/unbalanced to balanced-unbalanced-hybrid, and for Type 2, the quadrature coupler contains balanced -to-unbalanced and unbalanced-to-balanced power division functions. To reduce the circuit size, double-sided parallel-strip line (DSPSL) swap structure is used to replace the half-wavelength transmission line, and compact circuit size can be easily achieved. To validate the performance of the quadrature couplers, two types of the balanced-to-unbalanced quadrature couplers centered at 1 GHz with power division ratios 1:1 and 3:1 are fabricated and measured, respectively. The common mode suppression higher than 10 dB (bandwidths over than 176%) can be realized, the isolation and in-band matching level can be also improved.

A compact dual‐band coupled‐microstrip‐slotline coupler with arbitrary power division ratios

In this paper, a novel dual-band coupler with arbitrary power division ratios using coupled-microstrip-slotlines (CMSLs) is proposed. It consists of only four CMSL sections and occupies a small circuit area due to the centric arrangement of the excitation ports. Different from the microstrip implemented edge-coupled-line, the odd and even modes of the CMSL are physically separated, this feature enables the compensation of their phase velocities, facilitates the control of their characteristic impedances, and reduces the design complexity of the dual-band coupler. Explicit design formula for the proposed coupler is developed. To verify the proposed concept, a dual-band CMSL coupler with an unequal power division ratio is designed and characterized.

Miniaturized Balanced Filtering Power Dividers With Arbitrary Power Division Ratio Using Multimode Dielectric Resonator in Single Cavity

In this brief, miniaturized balanced-to-unbalanced (BTU) and balanced-to-balanced (BTB) filtering power dividers (FPDs) are proposed. Using one multi-mode dielectric resonator with multiple feeding probes, a single-cavity structure for BTU FPD is constructed, showing a compact size. Then, the circuit topology is analyzed, where the impedance in each branch can be adjusted to distribute the input power to two outputs with different ratios by only controlling the coupling coefficients. In this way, a BTU FPD with a very simple structure can be designed with arbitrary power division ratio. Besides, by replacing the two unbalanced output feeding probes in the BTU FPD as balanced ones, a BTB FPD can also be realized with controllable power division ratios. The working mechanism of the proposed designs is detailed. The proposed circuits are verified with good simulated and measured results.

Highly Miniaturized Dual-band Power Divider based on HMSIW for 5G/ WLAN Applications

A highly compact dual-band power divider (PD) based on the HMSIW structure is investigated in this paper. The dual-band operation is achieved by incorporating an inner modified circular complementary split-ring resonator (MC-CSRR) and outer circular CSRR on the top metal layer of HMSIW. The operating frequency of the PD decreases due to evanescent mode propagation. This assists in miniaturizing the structure apart from the 50% size reduction offered by the HMSIW. By asymmetric placement of two output ports of a PD, it is possible to achieve an unequal PD with an arbitrary power division ratio. To exhibit the proposed idea, two dual-band PD prototypes, one with equal power division and the other with unequal power division are designed, fabricated and experimentally verified. The PD occupies a compact size of 0.128 λg× 0.122 λg, where λg being the guided wavelength at the first operating frequency. The proposed PD with advantages of lower insertion loss, better return loss, minimum amplitude and phase imbalance between the output ports is beneficial for 5G FR1 n78 (3.3- 3.8 GHz) and WLAN (5.17 GHz) communications.

Multisection Combined Gysel–Wilkinson Power Divider With Arbitrary Power Division Ratios

This article presents the design of a microwave multisection combined Gysel–Wilkinson (MSCGW) power divider (PD) with arbitrary power division ratios, wide bandwidth (BW), and high power-handling capability (PHC). Exact design formulas for the $N$ -section PD are derived in the form of closed-form equations through even- and odd-mode analysis. In addition to the novelty of the structure itself, a straightforward design approach is presented based on the known analytical techniques to offer a guaranteed optimum design. The design approach is validated theoretically, analytically, and experimentally through measurements for simultaneously large BW and high PHC for several cases with different number of sections and power division ratios. Results confirm the BW of two-, three-, and four-section PDs as $\text {BW}_{N = 2} = 75$ %, $\text {BW}_{N = 3} = 90$ %, $\text {BW}_{N = 4} = 100$ %. Besides, compared with other similar works, the presented PD proves to be superior in terms of isolation, insertion loss, and compactness; making the proposed PD a very good candidate for microwave/mm-wave power divider/combiner applications.

N-Port Equal/Unequal-Split Power Dividers Using Epsilon-Near-Zero Metamaterials

In this article, a type of multiport power divider is proposed based on the concept of epsilon-near-zero (ENZ) metamaterials. An arbitrarily shaped ENZ metamaterial comprising a dielectric impurity is connected to N waveguides, and the incident power can be efficiently delivered to output waveguides, with transmitted fields being exactly equal in both amplitude and phase for output branches. Hence, the proposed power divider allows a balanced power allocation independent on its geometrical symmetry. This design philosophy can further be extended to generic dividers with arbitrary power division ratios by modifying the widths of the output waveguides. The experimental verification is carried out in waveguide-emulated ENZ structures. The fabricated eight-way equal-split divider is measured with an average insertion loss of 0.6 dB, a transmission amplitude imbalance of 0.7 dB, and a phase imbalance of 10°, over the 10-dB return-loss bandwidth from 5.35 to 5.56 GHz. The ten-way unequal-split divider with two different groups of outputs is also prototyped, providing a custom-designed power division ratio.

Novel Miniature Dual-Band Rat-Race Coupler With Arbitrary Power Division Ratios Using Differential Bridged-T Coils

In this article, a novel miniature dual-band rat-race coupler design is proposed. The proposed dual-band rat-race coupler employs differential bridged-T coils (DBTCs) as building blocks such that a very compact circuit size and a dual-band response can be achieved at the same time. Especially, through the proposed dual-band design of DBTC, arbitrary power division ratios over the two operating bands can also be realized. Explicit design equations of the proposed dual-band rat-race coupler are presented, and practical limitations on the achievable frequency ratio, power division ratio, and bandwidth are thoroughly investigated. As design examples, two 2.45-/5.5-GHz dual-band rat-race couplers with 0-/0- and 3-/0-dB power division ratios for the two bands are implemented in a silicon-based integrated passive device process. Very compact circuit sizes of less than 4.4 mm $\times \,\, 3.1$ mm as well as good measured performance are achieved. To the best of our knowledge, these are the smallest dual-band rat-race couplers ever reported.

A high-efficiency near-field focused transmitting antenna based on the equal power divisions

For microwave power transmission (MPT), the transmitting (Tx) array with a tapered amplitude distribution can achieve a maximum beam collection efficiency, but it needs a feeding network with an arbitrary power division ratio; thus, it is complicated and costly in practical applications. This work explores realizing high transmission efficiency by a Tx array with the equal-ratio steps amplitude distribution (ERSAD). By using the ERSAD, the amplitude value of the central units of the Tx array is uniform, and the amplitude feeding of the edge units only needs equal power divisions. Thus, the amplitude feeding is greatly simplified. Besides, a compensated phase distribution is used to focus the radiating beam on the receiving aperture. To validate the proposed design, a Tx antenna consisting of 8 × 8 units with a total aperture size of 1 × 1 m2 is designed. The operating frequency and the focused distance are 5.8 GHz and 10 m, respectively. A 64-way microwave power source is used to adjust the amplitude and the phase of the Tx array, and an MPT experiment is conducted. The measurement shows that, compared with the 10 dB Gaussian amplitude array, the proposed array nearly has the same transmission efficiency against different receiving apertures.

A Tunable Vector-Sum Filtering Power Divider With Continuously Tuned Frequency and Arbitrary Output Phase Difference

A novel tunable vector-sum filtering power divider (FPD) with arbitrary output phase difference is proposed. It is constructed by a tunable FPD [which has reconfigurable in-/out-of-phase output and arbitrary power division ratios (PDRs)] on the left and a wideband branch-line coupler (BLC) on the right. The output wave from the left FPD forms two orthogonal vectors at each output port of the BLC. The orthogonal vectors are summed up and result in a new vector with phase that is purely determined by the amplitude ratio of the orthogonal vectors. As a result, the phase difference between the new vectors at the outputs of the BLC can be continuously tuned by adjusting the PDR of the left FPD. Detailed theoretical analysis has been given. It shows that the phase difference between the output ports can be flexibly tuned from 0 °C to 360 °C within the full frequency tuning range.

A balanced-to-balanced directional coupler based on branch-slotline coupled structure

Abstract In this paper, a balanced-to-balanced (BTB) branch-slotline directional coupler (DC) is firstly presented, which can realize an arbitrary power division ratios (PDRs). The coupler is composed by microstrip-to-slotline (MS) transition structures and branch-slotline coupled structures. The single-ended to balanced-ended conversion is simplified and easy to implemented by the MS transition structures, which intrinsically leads to the differential-mode (DM) transmission and common-mode (CM) suppression. Moreover, the different PDRs which are controlled by the widths of branch-slotlines can be achieved. In order to verify the feasibility of the proposed design method, two prototype circuits of the proposed coupler with different PDRs are fabricated and measured. The return loss and the isolation of two designs are all better than 10 dB. Moreover, the CM suppressions are greater than 35 dB. A good agreement between the simulation and measurement results is observed.

A generalized broadband coupled-line based rat-race coupler with arbitrary power division ratios and free terminated impedances

A generalized broadband coupled-line based rat-race coupler with arbitrary power division ratios and free terminated impedances is proposed in this paper. Besides, rigorous closed-form equations with respect to electrical parameters are derived in the section of analysis. Furthermore, one shorted coupled-line section and two identical open-circuited stubs are employed to achieve the requirement of wideband and miniaturization. Owing to additional design freedom, the calculation of parameters becomes much more flexible. For demonstration, a prototype for 6-dB wideband rat-race coupler centered at 1 GHz with the fractional bandwidth of 51.69% and free terminated impedances is designed, fabricated, and measured. Good agreement between the simulated and measured results can be observed, which can verify the validity of the proposed design principle.

Unlimited Power Division Ratio of Microstrip Balanced-to-Unbalanced Gysel-Type Arbitrary Power Divider

A microstrip balanced-to-unbalanced (BTU) Gysel-type arbitrary power divider without the high-impedance transmission-line (TL) section is proposed to eliminate the power division ratio (PDR) limit of the conventional microstrip BTU power dividers. The proposed circuit includes five moderate-impedance TLs having the same characteristic impedance in addition to a grounded resistor. The arbitrary PDR is easily obtained by varying the electrical length of the TLs without changing the characteristic impedances, especially the large PDR, which is difficult to achieve by means of conventional BTU power dividers. When the PDR is ∞, the proposed circuit becomes a balun. The closed-form design equations are derived and discussed. To verify the proposed circuit, three prototypes I, II, and III are designed and fabricated for PDRs of 10 dB, 20 dB, and ∞ dB, respectively. The measured PDRs are in good agreement with the simulations. The measured isolation between the output ports is higher than 31 dB for prototypes I and II. The measured insertion loss of the balun prototype is 0.194 dB. Furthermore, the common-mode suppression of greater than 32 dB and the return loss of higher than 22 dB are obtained for various PDRs.

Novel Tunable Isolation Network Used in Ring-Type Single-to-Balanced, Power-Dividing, and Single-Ended Filter With Arbitrary Power-Division Ratios

In this article, a novel tunable isolation network and a novel ring-type reconfigurable single-to-balanced (SE-BAL), power-dividing (PD), and single-to-single-ended (SE) bandpass filter is proposed. The tunable isolation network consists of a simple $\pi $ -type resistive network with tunable varactors, while the proposed filter consists of three ring-type stepped impedance resonators (SIRs) connected by varactors in between. By simply combining the proposed tunable isolation network and the proposed ring-type reconfigurable filter, it can achieve multiple reconfigurable functions among SE-BAL filtering, PD filtering, and conventional SE filtering with fully matched three ports, arbitrary power-division ratios (PDRs), high output isolations, and excellent amplitude and phase balance, in addition to continuous frequency and independent bandwidth tuning. The proposed filter is demonstrated using the microstrip line technology. The measured results show that the SE-BAL, PD, and two SE filtering functions can continuously cover the frequency ranges of 1.03–1.61, 1.01–1.53, 1.03–1.56, and 1.06–1.48 GHz with −1-dB bandwidth tuning of 35–80, 50–140, 60–130, and 70–140 MHz, respectively; the 1-, 3-, and 5-dB PDRs have been demonstrated for both SE-BAL and PD filtering modes. The measured output return losses and isolation are better than 19 and 18 dB, respectively, for SE-BAL filtering mode and 20 and 16 dB, respectively, for PD filtering mode. Good agreement is obtained between the simulated and measured results.

Design of balanced‐to‐balanced filtering power divider with arbitrary power division ratio based on circular patch resonator

Here, a new balanced-to-balanced filtering power divider with an arbitrary power division ratio is proposed by utilising the circular patch resonator. To clarify the working principle, the resonant property of the circular patch resonator is firstly investigated. A prototype of the balanced-to-balanced power divider with arbitrary power division ratio is then developed. This prototype consists of only one circular patch resonator, three pairs of balanced ports, and two ports terminated with matching impedances. With this simple arrangement, the desired performance of a balanced-to-balanced power divider with an arbitrary power division ratio can be satisfactorily achieved at the resonant frequency of TM 11 . Afterwards, a second-order filtering circuit is constructed. In this context, two circular patches are arranged at the two sides of the ground and good signal transmission is realised by virtue of proper coupling apertures etched on the ground. Apart from coupling, the apertures can be further used for harmonic suppression. Therefore, this proposed structure not only has improved in-band and out-of-band performances, but also has good harmonic suppression. To verify the design concept, two balanced-to-balanced filtering power dividers with division ratios of 1:1 and 15:1 are finally designed and fabricated. All the measured results agree well with the simulated ones.

Miniature Dual-Band Quadrature Coupler With Arbitrary Power Division Ratios Over the Two Bands

In this article, the design of miniature dual-band quadrature coupler that is capable of achieving arbitrary power division ratios over the two bands is presented. By employing the dual-band design of bridged-T coils, the proposed dual-band quadrature coupler features a very compact circuit size, and its power division ratio for each band can be designed with the desired value. Explicit design equations are given and practical limitations on the achievable frequency ratio and power division ratio are investigated in detail. As design examples, two 2.45/5.5-GHz dual-band quadrature couplers, one with 0/3-dB and the other with 3/3-dB power division ratios for the two bands are implemented in a commercial GaAs pHEMT process. Very compact circuit sizes of less than 2.2 mm $\times1.3$ mm are achieved. To the best of our knowledge, these are the smallest dual-band quadrature coupler ever reported.

RF Reflectionless Filtering Power Dividers

A new class of Wilkinson-type power dividers with co-integrated bandpass-filter (BPF) functionality and input-reflectionless behavior is presented. They make use of a resistively terminated bandstop-filter (BSF) branch that is connected at their input terminal and exhibits a quasi-complementary transfer function with regard to the ones of the BPF-type power-divider arms. Thus, the RF-input-signal energy that is not transmitted by this triple-function reflectionless filtering power divider (FPD) to its output ports is dissipated by the loading resistor of its input BSF-type branch. Design formulas and theoretical synthesis examples for first-to-fourth-order FPD schemes and arbitrary power-division ratios are given. Furthermore, the extension of this concept to FPD realizations with multi-passband response and reflectionless capabilities at both the input and output accesses is shown. Theoretical design guidelines and limitations of center-frequency-tunable reflectionless FPD implementations are also provided. For experimental-demonstration purposes, a frequency-tunable 3-dB microstrip prototype with second-order transfer function is also manufactured and tested.

A Simple and General Method for Filtering Power Divider With Frequency-Fixed and Frequency-Tunable Fully Canonical Filtering-Response Demonstrations

This paper proposes a general method to design the power divider (PD) with the arbitrary filtering response. The proposed model allows coupling matrix-based filter synthesis to be adopted in the Wilkinson PD (W-PD) design so that two-order, high-order, single-band, multiband, frequency-fixed, and frequency-tunable responses are all available for the W-PD. Meanwhile, benefiting from the generalized W-PD topology, the general model can be employed to design the PD with arbitrary termination impedances (TIs), arbitrary power division ratios (PDRs), and the highly favorable isolation. To demonstrate the proposed Wilkinson filtering PD (W-FPD), a series of resonator-coupled BPFs with open-end coupling feeding line and their corresponding coupling matrices are considered and applied to the W-FPD design. Accordingly, four frequency-fixed W-FPDs are designed to achieve four fully canonical responses with a full number of transmission zeros (TZs). In addition, two highly selective frequency-agile W-FPDs with the nearly constant absolute bandwidth (ABW) are designed to achieve the very wide frequency tuning range. The excellent simulation and measurement results experimentally validate that the proposed model can be utilized to realize W-FPD with two-order, high-order, single-band, multiband, equal, unequal, equal tunable, and unequal tunable filtering responses.

Balanced‐to‐unbalanced power dividers for arbitrary power division ratios and forarbitrary real termination impedances

Novel balanced-to-unbalanced power divider (BUPD) is introduced for arbitrary power division ratios and for arbitrary real termination impedances. It consists of one 180° transmission-line section (TL), two different 90° TLs and one isolation circuit comprising two different resistances and two different 90° TLs. Due to the arbitrary termination impedances, the conventional ways for the even- and odd-mode excitation analyses are impossible, requiring a new design method. Under the assumption of the perfect isolation between two output ports, the BUPD can be divided into two, based on which the design formulas for the characteristic impedances of all the TLs can be successfully derived. Then, the scattering parameters are inversely derived, which is quite different from the conventional ways where the design formulas are derived based on the scattering parameters. For the verification of the suggested theory, one prototype for the power division ratio of 5 dB and for the termination impedances of 60, 40 and 50 Ω is tested. The measured frequency responses are in good agreement with the predicted ones.