Unequal Power Division Ratio Research Articles

Miniaturized filtering equal/unequal Wilkinson power dividers

In this paper, two miniaturized Wilkinson power dividers with equal and unequal power division ratios capable of suppressing spurious harmonics over a wide frequency range are presented. First, an asymmetric high-low impedance resonator with coupled open-stubs and folded structure is employed to design the equal power divider. Then, how connecting an inductor in series with the introduced resonator can lead to affecting the transmission coefficient of the power divider branch and achieving an unbalanced power division ratio at output ports, is analytically clarified. In the third step, a combination of the resonator with folded structure and the inductor is utilized to design an unequal 2:1 divider. To validate the performed analysis, two equal and unequal Wilkinson power dividers at 900 MHz are fabricated and measured. Regarding S31, both dividers can suppress the 4th to 13th spurious frequencies and with respect to S21 of the unequal case, the 2nd-harmonic to 14th-harmonic are omitted. The occupied areas of the equal and unequal structures are 7.35 mm × 18.9 mm and 7.5 mm × 17.9 mm, respectively, which indicate almost 84 % size reduction in each case.

Wideband Filtering Power Divider With Unequal Power Division Ratio and All-Frequency Input Absorptive Feature

Wideband Filtering Power Divider With Unequal Power Division Ratio and All-Frequency Input Absorptive Feature

Unequal Power Division Ratio Nonreciprocal Filtering Power Divider With Arbitrary Termination Impedance and Center Frequency Tunability

Unequal Power Division Ratio Nonreciprocal Filtering Power Divider With Arbitrary Termination Impedance and Center Frequency Tunability

DESIGN AND ANALYSIS OF 1:8 RADIO FREQUENCY FEEDING NETWORK USING STEP-DOWN IMPEDANCE TRANSFORMER FOR C-BAND AIRBORNE SYNTHETIC APERTURE RADAR APPLICATIONS

In this research, we developed a unique power divider circuit construction that suppresses harmonic components while providing unequal power division ratios. In antenna arrays, a power divider is used to divide the power among the array's elements. Depending on the design, different power dividers have distinct properties. The purpose of this project was to create a design and examine a 1:8 unequal power divider for C-band applications that operates at 5.3 GHz. The prototype was built on a single board using a duroid RT5880 substrate with relative permittivity of 2.2 and thickness of 1.6 mm. A quarter-wave transformer was utilized to evenly distribute the entire incident power. This design involves adding an extra transmission line to the input side, which is known as a step-down transformer. The input impedance values were reduced and outstanding performance was achieved by using the step-down transformer. Advanced design system software was used in the simulations. The isolation network, which consisted of resisters between the transmission lines, was critical in implementing the radial layout styles and also improved the output port matching and port-to-port isolation. In the operating frequency range, the return loss parameters (S<sub>11</sub>–S<sub>99</sub>) and the isolation were greater than −17 and −37 dB, respectively. The intended structure is compact. The simulated results were in good agreement and demonstrated that all of the ports had matching impedance and the isolation matched the application's requirements.

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.

Arbitrary terminated negative group delay circuit using signal interference concept

In this article, we demonstrate signal interference concept based wideband negative group delay (NGD) circuit with an arbitrary termination port impedance. The proposed circuit consists of unequal power division ratio 180° hybrid and in-phase combiner. The NGD can be generated by controlling power division ratios of 180° hybrid and combiner. For experimental verification, the circuit is designed and fabricated at a center frequency of 2 GHz. The experiment results show that the proposed NGD circuit can provide 460 MHz NGD bandwidth (bandwidth of group delay <0 ns) with group delay of −0.8 ns at 2 GHz.

Dual‐band filtering power divider with unequal power division ratio and low‐loss characteristic

In this article, a dual-band filtering power divider with unequal power-division ability is proposed. Different from conventional equal power dividers constructed by filters or coupled resonators, noncoupled structures are employed in this design. As a result, low-loss characteristic is realized for the proposed power divider. In this proposed structure, the dual-band unequal power allocation is realized by replacing conventional single-band λ/4 transformers with dual-band ones (T-junction structures). Three identical λ/4 stepped impedance resonators are properly attached to all the three ports of the proposed power divider to generate an extra transmission zero between two operational bands. Therefore, a filter-like shaping in its S-parameter results is obtained. A resistor is located between two outputs for output isolation. Mathematical derivations of the overall design procedure are also provided based on the circuit models and transmission line theory. Meanwhile, a resistor for output isolation is also included between two outputs, whose value can be calculated using given equations. For validation, a prototype operating at 0.9 and 2.1 GHz are designed, fabricated, and measured. The isolations between two outputs are 30 and 26 dB while the phase differences are only 2.5°and 4.9° at 0.9 and 2.1 GHz in the measurement, indicating good consistence of outputs. Measured |S21| and |S31| are −(1.76 + 0.3) dB, −(4.77 + 0.2) dB at 0.9 GHz and −(1.76 + 0.6) dB, −(4.77 + 0.5) dB at 2.1 GHz.

A Flexible Quadrature Coupler With Reconfigurable Frequency and Coupling Ratio in Switchable Coupling Direction

A highly reconfigurable and switchable quadrature coupler with simultaneous control in terms of operating frequency, coupling ratio, and coupling direction is presented. To start with, a prototype coupler based on an ideal admittance-inverter model is investigated, and a method to obtain the admittance-inverter values for an arbitrary coupling ratio is described. Next, a tunable-admittance-inverter network implemented with lumped inductors and varactors, which features reconfigurable operating frequency, and tunable-admittance-inverter value is discussed. The conceived reconfigurable coupler is then realized by replacing the ideal admittance inverters with the proposed tunable-admittance-inverter circuit to provide it with operating-frequency and coupling-ratio controllability. Furthermore, when exchanging the admittance-inverter values in the coupler, the coupling direction is switched from forward to backward. The proposed technique is further developed into a general design procedure for reconfigurable-coupler implementations with an arbitrary admittance-inverter-based network. Wilkinson power dividers with equal and unequal power-division ratios are also shown as examples. For experimental/demonstration purposes, a reconfigurable coupler prototype is fabricated and characterized. It demonstrates a tunable operating frequency from 1 to 1.5 GHz, a controllable power-division ratio between output ports from 1 to 0.7, and switchable operational direction between forward and backward.

Six-port balanced network with high unequal power division ratio using shorted coupled lines

A novel 6-port balanced network with high unequal power division ratio using shorted coupled lines is proposed in this letter. The design parameters of the proposed power divider are analyzed according to transmission line theory. Two double-sided parallel-strip line 180° phase inverters loaded with 4 isolation resistors are used to realize high isolation for the power dividing output ports. A planar balanced network with bandwidth of 40.5% (power division ratio: 1:10) for the differential mode and wideband 23% common mode suppression is designed and fabricated. The measured results show good agreement with the theoretical expectations.

Multi-Band Bandpass and Bandstop RF Filtering Couplers With Dynamically-Controlled Bands

This paper reports on multi-band bandpass and bandstop RF filtering four-port couplers with programmable bands in terms of center frequency and number of passbands/stopbands. They are based on four multi-resonant bandpass/bandstop-type modules that are inter-coupled by means of 90°/270°-long transmission lines. Each multi-resonant module is shaped by K in-parallel-cascaded resonators through impedance inverters. The center frequency of each band is controlled by the resonant frequency of each resonator and its bandwidth by the interconnecting impedance inverter. The proposed multi-band coupler with co-integrated spectrally adaptive filtering capability can be designed for symmetrically and asymmetrically located bands, passbands/stopbands with equal or unequal bandwidths, output signals with 0° or 180° phase difference, and equal or unequal power-division ratios at its output ports. For practical-validation purposes, microstrip prototypes of reconfigurable dual-band bandpass and bandstop filtering couplers have been designed, manufactured, and measured. They exhibit two bands that can be independently tuned in frequency and additionally merged to create a wider band within the frequency range between 1.3 and 1.8 GHz.

A Dual-Band Port-Extended Branch-Line Coupler and Mitigation of the Band-Ratio and Power Division Limitations

In this paper, enhanced designs of port-extended branch-line coupler (BLC) are presented. Initially, the analysis of the conventional dual-band port-extended equal-division BLC is presented to deduce its operation from Riblet’s viewpoint. Subsequently, it is shown that extending the Riblet’s concept to dual-band design results in a novel dual-band BLC with arbitrary power division ratios. It has also been identified that the proposed design possesses a free design variable that allows realization of BLC with higher band-ratio. Furthermore, another BLC structure, capable of achieving enhanced band-ratio, utilizing two-section transmission line at each port is also proposed. All the reported design equations are in closed form and are very simple and do not go beyond a second-degree polynomial. The effectiveness of the proposed technique is demonstrated through test cases for equal and unequal power division ratio and for numerous band-ratio ( $= f_{2}/f_{1})$ . The good agreement between the electromagnetic simulated results and the measured results from the two unequal power division BLC prototypes, on Rogers RO4003C substrate, operating at 1.2 GHz/2.52 GHz and 1 GHz/2 GHz validate the proposed approach.

Optimum design of a wideband planar N-way fork power divider with arbitrary power division and input-to-output impedance matching

An effective design procedure based on method of least squares is proposed for multi-section and multi-output fork power divider/combiner with arbitrary power division ratios among its outputs in a specified frequency bandwidth together with impedance matching among its arbitrary source/load impedances. Transmission and scattering matrices are obtained for its equivalent circuit. An error function is constructed based on design specifications on its output power division ratios, isolations among output ports, return losses at its input and output ports and source/load impedances in a desired frequency bandwidth. The design procedure is fully developed, which determines the widths and lengths of microstrip line sections and resistor values. A design example is described for unequal power division ratio and unequal input/output impedances. A 3-section and 3-output fork power divider is designed for equal power division and load/source impedances for 2–12GHz band. It is fabricated and measured. Variations of its transmission coefficients are less than 0.5dB, isolations at its outputs are better than −15dB and reflection coefficients at its ports are better than −10dB. Excellent agreement is observed among the results of the proposed design procedure, full wave computer software and measurement data.

Systematic Design Technique for Dual-Band Branch-Line Coupler Using T- and Pi-Networks and Their Application in Novel Wideband-Ratio Crossover

In this paper, a generalized analysis and design methodology of a dual-band branch-line coupler (BLC) is presented. The proposed design, although based on the prevalent method of replacement of various arms of a single-band BLC with an equivalent T-/Pi-network, simplifies the design approach by only replacing either pair of arms and therefore provides four distinct topologies. Closed-form design equations along with insightful comments are reported for all the four topologies of the BLC. A number of cases are investigated to demonstrate the effectiveness of the proposed design for equal and unequal power division ratio and band-ratio ( $= f_{2}/f_{1}$ ). As an application, a novel dual-band crossover as a cascade of BLCs is also presented. While investigating the limitations of previous designs, a strategy to obtain the crossover with so far the widest band-ratio and simple layout is also presented. An unequal power division dual-band BLC and a dual-band crossover are designed which operate at 1/2 and 1/4 GHz, respectively. These designs are validated from the electromagnetic simulations and prototypes implemented on RT/Duroid 5880 substrate.

A Nonstandard Phase-Difference Ring Coupler for Unequal Power Division

ABSTRACTA planar ring coupler with nonstandard phase difference and an unequal power division ratio is proposed in this article. The circuit topology of this coupler is similar to the traditional coupler, which consists of four arms in microstrip implementation. The design parameters of this coupler can be determined easily by closed-form equations. Based on standard microstrip technology, the interrelated constraint between phase difference and realizable power division ratio has been investigated. The fractional bandwidth analysis in terms of phase difference and power division is provided. Two prototypes with this proposed structure, operating at 1 GHz, have been designed, simulated, and implemented using microstrip lines. The measurement shows good agreement with the numerical results, which demonstrates the validity of this design.

FIVE PORTS POWER DIVIDER DESIGNS WITH CONTROLLABLE POWER DIVISION AND SWITCHING CAPABILITIES

Two new 5-port power divider designs capable of controlling the power division ratios between the output ports are proposed. In the first design, the input power is switchable between two pairs of the output ports. This is implemented by terminating the dividers’ two open-ended stubs with varactor diodes. In the second design, the power division is controlled by a single varactor diode that terminates one of the dividers two open-ended stubs. With judicious choice of dc bias voltage, it is possible to realize equal as well as unequal power division ratios between the four output ports. High power division ratios was achieved without the necessity of involving transmission lines with high impedances. It is demonstrated that this design is capable of generating amplitude modulated signals. Simulation and measurement results are presented for the designs to show their power division and matching performance.

BROADBAND ASYMMETRICAL MULTI-SECTION COUPLED LINE WILKINSON POWER DIVIDER WITH UNEQUAL POWER DIVIDING RATIO

The uniform asymmetrical microstrip parallel coupled line is used to design the multi-section unequal Wilkinson power divider with high dividing ratio. The main objective of the paper is to increase the trace widths in order to facilitate the construction of the power divider with the conventional photolithography method. The separated microstrip lines in the conventional Wilkinson power divider are replaced with the uniform asymmetrical parallel coupled lines. An even-odd mode analysis is used to calculate characteristic impedances and then the per-unit-length capacitance and inductance parameter matrix are used to calculate the physical dimension of the power divider. To clarify the advantages of this method, two three-section Wilkinson power divider with an unequal power-division ratio of 1 : 2:5 are designed and fabricated and measured, one in the proposed conflguration and the other in the conventional conflguration. The simulation and the measurement results show that not only the specifled design goals are achieved, but also all the microstrip traces can be easily implemented in the proposed power divider.

Optimum Design of Asymmetrical Multisection Two-Way Power Dividers With Arbitrary Power Division and Impedance Matching

A general analysis and design procedure is developed for the asymmetrical multisection power divider with arbitrary power division ratio and arbitrary specifications of input and output impedance matching over any desired frequency bandwidth. The even- and odd-mode analysis, which was previously applied to the design of multisection Gysel power dividers, required that the unequal power division ratios be accompanied with appropriately proportional output impedances. This requirement is relaxed here. The equivalent circuits are first obtained for the divider and then their scattering parameters are determined. Some error functions are then constructed by the method of least squares. Their minimization determines the geometrical dimensions of the optimum divider. An approximate method based on the even and odd modes is developed for its initial design of the divider. Two examples of single- and double-section dividers are designed. Their frequency responses of isolation and transmission coefficients are obtained by the proposed method, HFSS software, fabrication, and measurement. They agree within the approximate assumptions. A two-section and two-way power divider is designed and fabricated by the proposed method for the case of unequal port impedances in the <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex Notation="TeX">$L$</tex></formula> -band. The measured isolation between the outputs is better than <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$-{\hbox {22 dB}}$</tex></formula> in 44% of the band.

COMPACT WIDEBAND GYSEL POWER DIVIDER WITH ARBITRARY POWER DIVISION BASED ON PATCH TYPE STRUCTURE

A novel Gysel power divider based on patch type structure is presented in this paper. The proposed power divider possesses broad bandwidth, small physical occupation and arbitrary power division. More than 30% bandwidth enhancement is achieved based on the i15dB input return loss criteria, while 55% size reduction is realized compared with conventional Gysel power divider. What's more, ∞at dividing is obtained in the design without using additional transmission line sections. Based on the novel structure, a design procedure of power dividers with unequal power division ratios is provided without using narrow microstrip line. To verify the design approach, the proposed power dividers with equal and unequal (2:1 and 4:1) power divisions at the centre frequency 1.5GHz are fabricated and measured. The results demonstrate that the design can fulfll our goals.

기판 집적 도파관 기술을 이용한 위성 통신용 4분기 전력 분배기

Equal/unequal 4-way power divider suitable for satellite communication using SIW technology is presented in this paper. The control of positions of guiding posts provides equal or unequal power division ratios by maintaining the width of the SIW unchanged. In addition, the detailed descriptions for the proposed power divider include the general characteristics of radial waveguide, feeding part using coaxial cable, simple SIW structure, power-guiding posts, and transition for measurement. The comparison between the simulated and measured data shows a good agreement at a center frequency of 10 GHz. The measured input impedance bandwidths for equal and unequal power divisions are about 2.1 GHz and 3 GHz under the condition of less than VSWR 2:1, respectively.

A new class of wideband multisection 180/spl deg/ hybrid rings using vertically installed planar couplers

A new class of wideband multisection 180/spl deg/ hybrid rings using the vertically installed planar (VIP) coupler is proposed. On the basis of the reconfigured ideal single-section 180/spl deg/ hybrid ring (i.e., the 180/spl deg/ hybrid ring with an ideal phase inverter), the multisection 180/spl deg/ hybrid rings can be realized by properly cascading of single-section 180/spl deg/ hybrid rings. Compared with the conventional hybrid ring, the two-section hybrid rings exhibit wide bandwidth, size reduction, and easily achievable high power-division ratios. Design equations based on the equal-ripple functions are derived. Design curves for the equal and unequal power-division ratio are also described. In addition, a cascade of single-section cascadable hybrid rings with a unit element at each I/O port can be used for bandwidth enhancement. Good agreement is obtained between the experimental and simulated results.