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The paper introduces a class of two-way, 3 dB narrowband power dividers (combiners), closed on complex termination impedances, that generalizes a number of topologies presented during past years as extensions of the traditional Wilkinson design. Adopting even-odd mode analysis, we demonstrate that, under very broad assumptions, any axially symmetric reactive 3-port can be designed to operate as a 3 dB two-way power divider, by connecting a properly designed isolation impedance across two symmetrically but arbitrarily located additional ports. We show that this isolation element can be evaluated by a single input impedance or admittance CAD simulation or measurement; moreover, an explicit expression is given for the isolation impedance. The theory is shown to lead to the same design as for already presented generalizations of the Wilkinson divider; further validation is provided through both simulated and experimental case studies, and an application of the theory to the design of broadband or multi-band couplers is suggested.

A spiral-coupled-line-based Ka-band (26.5–40 GHz) CMOS Wilkinson power divider with a shunt capacitor (C) at the input and a shunt RC (or C) between the outputs is reported. The spiral coupled line, i.e., two noninverting spiral transmission lines (TLs) with magnetic coupling, has a positive mutual inductance. This leads to a significant TL-length reduction (from about λ/7 to λ/12) for a specific TL series inductance. At 33 GHz, the power divider achieves prominent S11 of −21.5, S22 of −22.1, S33 of −22.1, S32 of −26.1, S21 of −4.063, and S31 of −4.052 dB. The corresponding amplitude imbalance (AI) and phase difference (PD) are −0.011 dB and −0.336°, respectively. Moreover, S11 is smaller than −10 dB for 0–45.3 GHz, corresponding to 137.3% fractional bandwidth (FBW). S32 is smaller than −10 dB for 24.1–40.2 GHz, covering the Ka-band and corresponding to 48.8% FBW. The power divider occupies a normalized area of 1.2 ×10−4λ02, one of the smallest normalized chip areas ever reported for millimeter-wave power dividers. [ABSTRACT FROM AUTHOR]

A diplexer with different-frequency power dividers cascaded to its output ports can split a signal into different frequency bands for power dividing functions. However, the design of a diplexer usually requires two different frequency filters. This paper presents three new microstrip diplexing power dividers (DPDs) to achieve duplexing power division without requiring additional filters. Moreover, to increase selectivity, each of the proposed DPDs has the flexibility of adding a dual-band filter to its input port. In particular, the proposed DPDs have matching circuits integrated in the dividers, enabling each divider with imaginary input impedance to reach the required open condition; this is achieved by designing a 50-Ω transmission line of appropriate length or a quarter-wavelength (λ/4) transmission line.

This paper presents four compact lumped-element Wilkinson power combiners (WPC) operating at 5 GHz in 28-nm bulk CMOS. To minimize the chip area, the inductances in the designs are implemented using mutually coupled coils. Two designs use star inverting coupled coils (SICC), while the other two employ delta noninverting coupled coils (DNICC). One of the two SICC-based designs (and similarly for the DNICC-based designs) incorporates a second harmonic (2f0) trap to lower the total harmonic distortion and reduce the required inductances by 25%, further reducing the circuits footprint. A design methodology for effectively exploiting the mutual coupling and nullifying the coupling parasitics is presented. The coupling parasitic in the DNICC-based design is exploited to provide the WPC isolation resistance, resulting in a lumped-element WPC requiring only three components: a coupled coil and two capacitors. The measurement and simulation results are presented to confirm the theory validity. The SICC-based WPC with an area of 0.13 mm2 achieved input return losses (RL) >17.5 dB, output RL > 11.8 dB, isolation >11.2 dB, and insertion losses (IL) <1.5 dB across 3.5–5.4-GHz frequency range. Its variant with a 2f0 trap achieved, from 3.5–5.35 GHz, input RL >18.2 dB, output RL >11.6 dB, isolation >11 dB, IL <1.4 dB, and peak 2f0 rejection of 18 dB at 10.2 GHz in an area of 0.13 mm2.The DNICC-based WPC with an area of 0.11 mm2 achieved input RL and isolation >10 dB, output RL >15.3 dB, and IL <1.2 dB across 4.1–5.45-GHz frequency range. Its variant with a 2f0 trap achieved, from 4.3–5.3 GHz, input RL and isolation >10.1 dB, output RL >14.6, IL <1.2 dB, and peak 2f0 rejection of 23 dB at 10.4 GHz in an area of 0.09 mm2. [ABSTRACT FROM AUTHOR]

This letter presents a low-loss compact 60-GHz power divider/combiner (PD/C) for phased array systems. It is based on the Wilkinson power divider and employs coupled inductors with a shunt capacitor for low insertion loss and compact design. The power divider with a coupled inductor reduces the insertion loss by 0.4 dB at 60 GHz. The insertion loss is less than 0.7 dB, and the return loss is better than 10 dB over a range of 50–67 GHz. The measured isolation of the fabricated PD/C is up to 28 dB at 67 GHz. The fabricated PD/C has a compact core size of 0.0012 mm2. To the best of our knowledge, this power divider achieves the lowest insertion loss and the smallest core area of all published 60-GHz Wilkinson PDs/Cs. [ABSTRACT FROM AUTHOR]

This paper proposes and presents a class of substrate integrated waveguide (SIW) power dividers/combiners based on a modified Wilkinson architecture. The proposed design consists of a ring-type circuit of \(1.5~\lambda _{g}\) length with three waveguide ports. Impedance variation without affecting cutoff frequency and integration of isolation resistance are the two major limitations in connection with the design of SIW Wilkinson structures. Central ring part with different thickness ensures different impedance in the first proposed scheme while the half-mode SIW in the second option. As for the second limitation, the optimal configuration of integrating the isolation resistance is studied. A version without resistance is also examined using a broad-wall series slot. To validate the proposed concept, a bilayered circuit with standard Printed circuit board prototype was fabricated and measured. A table summarizing performances of all the proposed circuits shows a bandwidth of around 25% at the 10 dB reference. A negligible additional insertion loss is observed. The proposed design techniques are found useful at millimeter-wave frequencies where reduced physical dimensions make a circuit configuration suitable for low-cost implementation. This concept is also valid for rectangular waveguide counterparts. [ABSTRACT FROM AUTHOR]

A generalized model of a two-way dual-band Wilkinson power divider (WPD) with a parallel LC circuit at midpoints of two-segment transformers is proposed and compared with that of a conventional two-way dual-band WPD with a parallel LC circuit at the ends of two-segment transformers. The sum of power reflected at an output port and power transmitted to an isolation port from another isolation port in the proposed divider is smaller than that in the conventional divider. Therefore, wide bandwidths for S22, S33, and S32 can be expected for proposed dividers. In the case of equal power division, frequency characteristics of return loss at output ports and isolation of the proposed divider are wider than those of the convention one. The resonant frequencies of LC circuits in the proposed divider and a conventional divider are equal; however, the inductance L used in the proposed divider is always smaller than that in the conventional divider. Design charts and calculated bandwidths as a function of frequency ratio from 1 to 7 are presented. In experiments, two symmetrical and two asymmetrical circuits were fabricated. The experimental results showed good agreement with theoretical results. [ABSTRACT FROM PUBLISHER]

A generalized two-way two-section dual-band Wilkinson power divider with two absorption resistors and its size-reduced model are presented. Design equations for dual-band and arbitrary power division are derived from modified even- and odd-mode analysis. The frequency ratio of the lower and upper band frequencies must be lower than three. The channel bandwidth is presented as a function of frequency ratio with mathematical expressions. A coupled line section is introduced to reduce circuit size based on the assumptions of linear phase characteristics and equal phase velocities of the even and odd modes. Two two-way dual-band power dividers, one three-way planar dual-band power divider, and one size-reduced dual-band power divider were fabricated. Experimental results were in good agreement with predicted values. [ABSTRACT FROM AUTHOR]

In this letter, we propose an $N$-way unequal power division Wilkinson power divider (PD) with physical output port separation. These PDs employ isolation impedances at arbitrary positions within quarter-wave-long transmission lines, and hence both electrical isolation and physical separation can be obtained between output ports. Design equations are derived, meeting the impedance matching and isolation requirements of the PD. The fabricated 2-way (1:2) and 3-way (1:2:1) PDs operating at 2.0 GHz exhibit excellent insertion loss, return loss, and isolation performance with the output ports physically separated. [ABSTRACT FROM PUBLISHER]

This letter presents a fully differential and integrated transformer-based Wilkinson power divider with a broad bandwidth, low loss, high isolation, and an ultra-compact form factor. Two differential transformers connected in parallel serve as the impedance transforming and power combining network in the proposed Wilkinson power divider. Shunt capacitors are added between the output ports for matching and isolation enhancement. A proof-of-concept transformer-based Wilkinson power divider is designed at 60 GHz and implemented in a standard 130 nm SiGe BiCMOS process with the core chip area of 270\ \mu\textm \times 107\ \mu\textm and the simulated 1 dB-magnitude fractional bandwidth of 64% at the 60 GHz center frequency. Measurement results of 4 independent samples demonstrate the passive loss of 1.32 dB at 62 GHz with standard deviation of 0.1 dB and the peak isolation of 28 dB at 65 GHz with magnitude and phase imbalance within 0.2 dB and 5 ^\circ, respectively. [ABSTRACT FROM PUBLISHER]

In this letter a novel power divider (PD) structure with uniformed characteristic impedance lines and a fixed isolation resistor equal to source and load impedances has been proposed. Unlike traditional power dividers, the electrical lengths of the uniformed 50 $\Omega$ branches are the only parameters that need to be adjusted to achieve any required power division ratios, which makes it a flexible and adaptable layout for most desires. Arbitrary power division ratio, especially large dividing ratio that is difficult to achieve by conventional Wilkinson PD, can be obtained easily by applying the proposed structure. For verification, the measured results of a 2 : 1, a 4 : 1 and a 9 : 1 PDs operating at 3 GHz are shown in this letter. [ABSTRACT FROM PUBLISHER]

It is common practice to design multiway power dividers by interconnecting two-way power dividers. Transmission lines are used to link the two-way dividers. This paper investigates the performance of the interconnected power divider and the effects of the interconnecting transmission lines. In particular, it will be shown that the performance of multiway dividers constructed by interconnecting even-number-section two-way dividers deteriorates significantly as the number of output ports increases. The interconnecting lines can be used to improve the performance of such dividers. [ABSTRACT FROM AUTHOR]

In this letter, a compact modified n-way Wilkinson power divider that allows physical isolation between output ports is presented. In the proposed power divider, the isolation impedances are positioned within quarter-wave transmission lines so that part of the lines can be used for interconnection and impedance transformation. Theoretical analysis is performed to derive the design equations of the proposed n-way power divider. Further, measurements show that the proposed power divider can reduce the insertion loss and circuit size when compared with a conventional Wilkinson power divider. [ABSTRACT FROM PUBLISHER]

A modified Wilkinson power divider structure is presented for the dual-band operation. The divider has two output ports shifted away from the isolation resistor to the middle of the divider and an open stub at the input port. The dual-band operation can be achieved over a wide range of band-ratios with the open stub advantage. [ABSTRACT FROM PUBLISHER]

A new scheme is proposed for the dual-band operation of the Wilkinson power divider/combiner. The dual band operation is achieved by attaching two central transmission line stubs to the conventional Wilkinson divider. It has simple structure and is suitable for distributed circuit implementation. [ABSTRACT FROM PUBLISHER]