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In this article, a new design approach for the wideband transformer with frequency-dependent complex loads is proposed, which is based on the least-square method and the generalized modified small reflection theory (MSRT) with proper electrical parameters. Compared with the wideband transformers based on other approaches such as the generalized MSRT and transmission line theory, the proposed ones feature easy design, compact size, and wide bandwidth. For validation, several wideband transformers with frequency-dependent complex loads are designed, simulated, and measured. The measured results are consistent with the calculated and simulated results, and a wideband transformer with a fractional bandwidth of 68.5% (defined by 15-dB return loss) and an overall size of $0.025\lambda _{g}^{2}$ is achieved. In addition, when applied to the design of wideband Wilkinson power divider, a fractional bandwidth of 110% (defined by 25-dB isolation) and an overall size of $0.069\lambda _{g}^{2}$ are attained.

Breast cancer is the most common cancer of women in the globe. Microwave imaging has low power and longer wavelength signals to receive information about breast tissues and guarantees a safer and more accurate modality for regular breast control. So, the antenna is a crucial element in the microwave imaging system. This study involves analysis of the simulation results of the linear and planar microstrip array antennas in terms of high gain. In the series antenna design stage, the antenna models with high gain and directional radiation are aimed. 1x4 and 2x2 array antenna models are prepared with PLA/Carbon insulating material. Array antennas, three-dimensional full-wave electromagnetic structure analysis are designed using the CST (Computer Simulation Technology) Microwave Studio program. In the design phase, the transmission line losses of the array antennas are tried to be optimized by using T-junction and Wilkinson power divider techniques and impedance matching is realized. Also, the redundant areas in the turns are removed to minimize the undesirable reflections in the transmission line and to reduce the capacitive loading. Since the 1x4 array antenna performs better than the 2x2 array antenna, it was preferred for breast cancer simulation.

Bu makalede, ultra-kompakt mikrodalga tektaş Wilkinson güç bölücü entegre devre tasarımı X-bant uygulamaları için gerçekleştirilmiştir. Tasarımın boyutunun küçültebilmesinde minyatürleştirme tekniği kullanılarak, teorik olarak hesaplamaları anlatılmıştır. Teorik analizlerin tamamlanmasından sonra, tasarımın serim tasarımı yapılarak elektromanyetik benzetimleri gerçekleştirilmiştir. Önerilen devre tasarımı, galyum nitrür tümdevre pasif devre teknolojisi kullanılarak üretilmiştir. Ölçüm sonuçlarına göre, giriş ve çıkış (I/O) yansıma katsayılarının 8-12 GHz frekans bandı içerisinde -15 dB’den daha iyi olduğu görülmüştür. Ek olarak, X-bantta (8-12 GHz) araya iletim katsayısının -4 dB’den düşük olarak ölçülmüştür. Ayrıca, elde edilen ölçüm sonuçlarına göre prototipin 15-dB bant genişliği %40 olarak hesaplanmıştır ve çalışma frekans bandı içerisinde çıkış portları arasındaki izolasyonun -15 dB’den daha iyi olduğu görülmüştür. Ayrıca, önerilen Wilkinson güç bölücü tasarımının boyutu, 𝜋-tipi minyatürleştirme tekniğinde tümdevre devre elemanları kullanılarak 700 m  700 m (0.0023 λg x 0.0023 λg, burada λg merkez frekanstaki (10 GHz) dalga boyu değeridir) boyutlarına kadar düşürülmüştür. Geliştirilen güç bölücünün ölçüm sonuçlarına göre, minyatür boyutuna rağmen, elektriksel performansında herhangi bir kötüleşme olmadan geniş bantlı bir karakteristik sergilediği görülmüştür., In this article, an ultra-compact monolithic microwave integrated Wilkinson power divider (WPD) was accomplished for X-band applications. So as to reduce the size of the design, the miniaturization technique was illustrated with the theoretical analysis. After the theoretical analysis, the layout of the design and electromagnetic simulation were performed. The proposed Wilkinson power divider was manufactured with utilizing gallium nitride integrated passive device technology. In the measurement results, it was seen that the input and output (I/O) reflection coefficients were better than -15 dB in the frequency bandwidth of 8-12 GHz. In addition, the transmission coefficient was measured less than -4 dB in the X-band (8-12 GHz). Moreover, the 15-dB fractional bandwidth is 40% and the isolation between the outputs are better than -15 dB. The size of the proposed Wilkinson power was reduced to the dimensions of 700 m  700 m (0.0023 λg x 0.0023 λg, where λg is the wavelength value at the center frequency (10 GHz)), as 𝜋-type miniaturization technique was employed with monolithic lumped components. Beside its miniaturized size, the proposed power divider exhibits broadband characteristics while having any degradation in the electrical performance.

In this article, a tunable lowpass filter (LPF) with a hexagonal stepped impedance resonator and multi open stubs is designed. The − 3 dB cut-off frequency for the proposed LPF is 2.2 GHz. Insertion loss (IL) and return loss (RL) in the passband zone are 0.3 dB and 15 dB, respectively. The frequency response slope (roll-off rate) for the proposed LPF is very sharp and equal to 142.4 dB/GHz. The tuning range of − 3 dB cut-off frequency for the presented LPF is very wide and equal to 2.7 GHz [from 0.5 to 3.2 GHz (84.3%)]. To achieve the desired structure and harmonics suppression, a conventional power divider was designed initially, then the transmission lines (with length of λ/4) were replaced with two LPFs. The isolation, IL, and input RL for the proposed modified Wilkinson power divider are better than 20.1 dB, 3.1 dB and 21.2 dB, respectively, at operating frequency of 1.8 GHz (GSM band). The proposed modified Wilkinson power divider eliminates the 2nd–11th harmonics with high levels of attenuation. The feature selective validation method depicts that the simulation and measurement results for the proposed LPF are in good agreement with each other.

In the design and development of front-end communication systems, the arbitrary impedance environments are encountered frequently. In this article, a three-port dual-band equal power divider is proposed which also transforms all types of impedance environments at its ports inherently. The power divider is suitable for a wide range of arbitrary frequency ratios and impedance terminations at each of the input and output ports. A systematic design procedure with a design flow graph is provided. The closed-form design equations make the design process simple and quick for prototyping purposes. The proposed design approach enhances the design flexibility significantly with the presence of multiple independent variables. Design examples with distinct design specifications are provided to demonstrate the effectiveness and flexibility of the architecture. A prototype working at 1/2.6 GHz and with frequency-dependent complex load (FDCL) terminations at the input and output ports is fabricated and measured to validate the proposed architecture and design methodology. The proposed dual-band impedance transforming power divider exhibits controllable bandwidths, planar structure without any reactive element, compact size, and the ability to provide port matching for any real, complex, and frequency-dependent complex impedance terminations.

The microwave power transfer (MPT) system requires a massive Tx array for building a focused radio wave to efficiently transfer power to the Rx. Beamforming IC is one of the core elements for the massive Tx array. This paper presents a 5.8 GHz 4-channel beamforming Tx IC based on a CMOS process. The beamforming Tx IC includes a resistive 4-way power splitter, 5-bit differential phase shifters, drive amplifiers, and power amplifiers. Each channel is designed to transmit a power of no less than 100 mW. To verify the Tx IC, a 16-channel beamforming Tx module based on 16 patch antennas and four 4-channel Tx ICs was designed. The module also includes a PLL, a frequency doubler, and a 4-way Wilkinson power divider. MPT experiments to verify the beamforming IC and module were carried out using the implemented 16-channel Tx module at 5.8 GHz. Received power levels of 13 dBm and 2.1 dBm were achieved at distances of 0.4 and 1.4 m, respectively. The results are almost similar to the values acquired from the calculation using the Friis equation.

In this article, a systematic procedure is presented for the design of a dual-band unequal-split Wilkinson power divider (WPD) with high frequency and power division ratios. The design methodology is based on replacing the impractical high-impedance transmission line in the conventional divider with cascaded T-section structures with short-circuited stubs. The proposed methodology is simple and adopts distributed elements without reactive components to achieve a large power division ratio. The use of short-circuited stubs allows for circuit miniaturization in comparison to counterpart open-stub techniques. Furthermore, a high frequency ratio is obtained through optimizing the electrical and physical parameters of the T-sections based on a transmission lines theory framework as demonstrated in a simulated and measured prototype. To validate the proposed procedure, two WPD prototypes operating at 1/2.7 GHz and 1/4.4 GHz with a 1:10 power division ratio are simulated and measured. The theoretical response, supported by electromagnetic simulations and measurements, justifies the design concept.

This article presents a superconducting material based planar broadband 3-way Wilkinson power divider which can be used in the Josephson quantum voltage device for the voltage standards. The 3-way Wilkinson power divider aims to improve the integration of Josephson voltage device compared to the commonly used 2-way power divider. A two-stage λ /4 section on each branch is used to increase the bandwidth, and a π model with lumped equivalent elements are used to further decrease physical dimension in device area. Different from the conventional spatial design of N-way Wilkinson power divider, this work designs a planar broadband 3-way divider to be compatible with the on-chip fabrication process. Simulation results show that the insert loss is below 0.18 dB at working bandwidth of 16.7∼23 GHz, the division imbalance of each branch is below 0.044 dB, and the input and output reflection is better than 15 and 11.9 dB, respectively. The isolation between any of the three output ports is better than 11.8 dB. All these indexes satisfy the requirement of the Josephson voltage standard application. To further prove the validity of our design, real device based on superconducting material is realized and characterized. Devices with a 3-way power divider and three 2-stacked Josephson junction arrays with 256 junctions in each array are fabricated. The experiment results indicate the potential usage of our design in quantum voltage standard devices for high-voltage output.

In this paper, a novel miniaturized microstrip Wilkinson power divider (WPD) using squared resonators and open-ended stubs is designed, fabricated, and measured. The proposed divider is designed at 1.9 GHz, which suppresses 2nd, 3rd, and 4th harmonics with high attenuation levels. Moreover, the size of the proposed divider is only 0.1 λg × 0.07 λg, which reduces the circuit size by more than 55%, compared to the conventional Wilkinson divider. In the design process, the neural network model and LC-equivalent circuit model are used to predict the transmission zeros of the circuit. These transmission zeros are used to provide the suppression at the desired harmonics. Also, the main circuit elements could be predicted with the neural network model, which results in a performance improvement of the proposed divider. The results show that the proposed model can predict the frequency response of the designed WPD, accurately.

In this brief, we present a low power sub-harmonic I/Q mixer using the current re-used technique for WiGig at 60 GHz. A transformer integrates the RF trans-conductance stage and LO switching stage by the current re-used technique to save dc power. We only adopt a single transistor at RF stage to replace differential RF amplifier to save die area as only half of the RF matching network is required. The trans-conductance of the RF stage is increased by the $g_{m}$ -boost technique. In addition, since the current re-used technique gathering the dc current from both ${I}$ and ${Q}$ mixer cores, the transconductance of the RF stage is also increased. In order to reduce the die area of passive components, we use mutually coupled inductors to implement lumped element Wilkinson power divider. We also add extra capacitors on all ports of the coupler to improve return loss. The measured peak gain is −7.9 dB at 61 GHz under LO power of 5 dBm at 30 GHz. The measured IP1dB is better than −9.5 dBm in four channels. The measured 3-dB RF bandwidth is from 56.5-67 GHz and 3-dB IF bandwidth is 1.5 GHz. Total dc power consumption is only 3.45 mW and each mixer consumes 1.73 mW for 1.1 V supplied voltage. To our best knowledge, this current re-used I/Q mixer has the lowest dc power and good conversion gain among active I/Q mixers at ${V}$ -band.

In this article, a miniaturized and harmonics suppressed Wilkinson power divider (WPD) is analytically designed. In the proposed divider composite transmission lines and resonator cells are utilized to eliminate unwanted harmonics and reduce circuit size. This structure has a 52% size reduction, compared to the typical WPD. According to the measured results, more than 22, 42, 45 and 40 dB suppression for 3rd, 4th, 5th and 6th harmonics are achieved. The presented WPD has lower than 0.15 dB insertion loss, more than 30 dB output ports isolation and more than 20 dB return losses in all ports at the operating frequency of 1.5 GHz is obtained.

In this paper, a circularly polarized frequency, pattern, and polarization switching antenna is proposed. The antenna consists of an octagonal patch, a narrow octagonal ring and four diamond-shaped parasitic patches on the top layer. Two feed points of the radiating patch are connected to a Wilkinson power divider loaded with the phase reconfigurable transmission lines on the bottom layer. Reconfiguration of the polarization and pattern is realized by using PIN diodes as switching components. By controlling the bias voltage across the varactors, various narrow frequency bands can be achieved. The proposed antenna operates at a frequency tuning range from 1.96 to 2.03 GHz. The radiation pattern can be switched among five cases in yoz-plane and xoz-plane, with the switchable polarization between left- and right-hand circular polarization. In addition, these three types of reconfiguration can be controlled independently.

A new ultra-wideband millimetre-wave passive balanced duplexer (DUX), employing a lumped-element Wilkinson power divider and grounded-centre-tap transformer, has been developed using 0.18- μ m BiCMOS process for fifth generation operations at 28, 37, 39 GHz, and beyond. The developed DUX is configured single-ended transmitter (TX) and antenna (ANT) ports and differential receiver (RX) port. It has an inherent matching at TX, RX and ANT ports, high TX–RX isolation, and highly balanced differential RX waveforms, and is ready for direct integration with a differential low-noise amplifier. Analysis has been performed to confirm the DUX's characteristics and assess its performance. Measured isolation from TX to each single-ended RX port is higher than 50 and 40 dB from dc-20 GHz and dc-60 GHz, respectively. Measured insertion loss from TX to antenna is better than 6.3 dB across 13–53 GHz. Measured insertion loss from ANT to differential RX port is lower than 13.8 dB from 25 to 57 GHz with 10.8 dB at 40 GHz. The core chip only occupies 0.3 mm2.

In this article, compact N-way Ultra Wide Band (UWB) equal and unequal split Wilkinson Power Dividers (WPDs) using exponentially λ/4 Tapered Transmission Line Transformers (TTLTs) are designed. First, 2-way WPDs are designed, simulated and then cascaded to get 4-way (equal and unequal split) and 8-way (equal split) UWB WPDs. 2- and 4-way (equal and unequal split) WPDs are fabricated and tested. The simulated and measured results of all the designed dividers are good in terms of insertion, return losses and group delay through UWB frequency band. The analysis of these dividers is carried out using the commercial ANSYS High Frequency Structure Simulator (HFSS) software package which is based on the Finite Element Method (FEM). Moreover, A MATLAB built-in function “fmincon.m” is used to find the optimum values of the three resistors chosen for perfect isolation. To validate the results, the simulation results are compared with the measured ones.

In this letter, an ultrawideband (UWB) bandpass Wilkinson power divider (WPD) is introduced. By using filter synthesis theory and proposed optimization algorithm, all the S-parameters (S 11 , S 21 = S 31 , S 22 = S 33 and S 32 ) of the proposed topology could provide an equal-ripple response, and their equal-ripple level and bandwidth can be controlled, respectively. For verification purposes, a prototype UWB WPD has been simulated, fabricated, and measured. The measured and simulated results are matched reasonably well.

In this article, a wideband decoupling network (DN) is presented based on the Wilkinson power divider (WPD). The DN is composed of 2 two-way unequal WPDs, three transmission lines (TLs), and two reactive components. Two techniques are introduced for the wideband performance: 1) by using the WPD with high output isolation, the antenna matching becomes independent of antenna decoupling. So, the decoupled antennas with the proposed DN could perform broad impedance bandwidths without using matching networks and 2) the DN is designed to minimize antennas’ coupling coefficients at two frequencies, which collectively contribute to a broader decoupling bandwidth. In addition, rigorous design formulas are presented along with systematic design procedures. Based on this, the TL lengths and component reactances can be precisely calculated instead of being fitted to achieve high antenna isolation. Two decoupling cases using the proposed DN and its simplified model are presented and compared to give an intuitive illustration of the wideband mechanism. The measurement results for decoupling case #1 show that a very wide isolation bandwidth of 23.7%, total efficiency over 65%, and the envelope correlation coefficients (ECCs) less than 0.05 can be achieved simultaneously using the proposed DN.

In this brief, a tunable Wilkinson power divider (WPD) with port match and isolation is proposed based on a reconfigurable compact structure. The reconfigurable unit is composed of one varactor cascaded by a transmission line (TL) with specific characteristic impedance and electrical length. Each unit can be alternately connected with two cascaded varactors to constitute a T-type structure, where the operating frequency can be selected by providing proper bias voltages for the three varactors. By adjusting the characteristic impedance and electrical length of the transmission line in each unit, the continuous tuning range can be easily extended to exceed 120% tunability. The reconfigurable units can also be flexibly configured to work in designated discrete tuning range as well. An experimental reconfigurable WPD with wide continuous tuning range of 0.96-1.73 GHz (57.3% tunability) is designed and fabricated. The measured results show that more than −20dB return losses and isolations can be realized in the entire tuning range.

In this paper, a reconfigurable modified Wilkinson Power Divider (WPD) was proposed. The operating frequencies of the proposed design were either at 2.5 GHz or 3.5 GHz for Worldwide Interoperability for Microwave Access (WiMAX) applications. This proposed design is reconfigurable in terms of its operating frequency by using PIN diode switches. PIN diode switch was used in this design to reconfigure the microstrip line length. By varying the bias voltage of the PIN diode to +5 V or -5 V, the proposed modified WPD can either operate at 2.5 GHz or 3.5 GHz. Rogers RO4350 (er=3.48, h=0.508 mm) was chosen as the substrate material and copper (thickness=0.035 mm) related to patch of design. Based on simulation results obtained from the Advanced Design System (ADS) software, the modified WPD shows good S-parameter performances at 2.5 GHz and 3.5 GHz. However, the measurement results exhibit frequency shifted. Even though there is a correlation between measurement results and simulation results, the resonant frequency was shifted due to parasitic reactance of the PIN diode.

In this paper, a new Wilkinson Power Divider ‎‎(WPD) using open and short stubs is proposed. ‎Open and short stubs are utilized instead of 1/4 wave transmission lines in initial ‎structure to achieve harmonics suppression. The proposed WPD is designed for ‎operational frequency of 0.9 GHz and creates 3 transmission ‎zeros at 1.8 GHz, 2.7 GHz and 3.6 GHz, for suppressing second, third and fourth harmonics. The proposed WPD has been fabricated and the ‎measurement results are in good accordance with simulation results. The designed ‎WPD has a 22 % fractional bandwidth with 0.1 dB insertion loss.‎

In this paper, a lightweight printed dipole antenna array with 3 × 2 beamforming network for wide unmanned aerial vehicle (UAV) communication coverage is presented. The proposed antenna consists of an upper substrate, a lower substrate, and two supports with a microstrip feeding. The upper substrate has a two-element printed dipole antenna array, and the lower substrate includes a beamforming feeding circuit and a ground plane as a reflector of the proposed antenna array for gain improvement. For wide beam coverage, the proposed feeding network consists of three RF switches, one Wilkinson power divider, and one 90° hybrid coupler, and generates the wide beam using one broadside beam and two end-fire beams. Measured impedance bandwidth, peak gain, and half-power beamwidth (HPBW) of the proposed array operated from 5.03 to 5.15 GHz are approximately 2 GHz, 4.3 dBi, and 155°, respectively.

Purpose This purpose of this study is to present a novel four-element array antenna in combination with a modified Wilkinson power divider feeding network. Design/methodology/approach The two covering bands of this planar array antenna are achieved by an Elephant trunk shape (ETS) radiating element; therefore, two frequency bands for Bluetooth (2.4 GHz) and the wireless local area network (WLAN) band (5.15-5.825 GHz) are obtained. Findings An improved design of the power divider with curved corners rather than the sharp edges and certain new modifications in the length of matching stubs are implemented. Originality/value This paper describes an improved four-way Wilkinson power divider with excellent loss of insertion and adequate return loss for all ports and good isolation performance within two frequency bands (2.4 and 5.5 GHz) and when loaded with array components; the modified power divider complies with the design requirements. To comprehend its behavior, numerical and experimental results are provided. The simulated and measured results indicate a proper bandwidth coverage of the suggested antenna, stable radiation patterns and high gain.

In this article, a novel topology is proposed to design a class of power dividers with the simultaneous realization of wideband power division and port-to-port isolation. On the one hand, in order to achieve a wideband power dividing response, two wideband filtering branches, including multimode resonators and parallel-coupled lines, are formed to replace the quarter-wavelength impedance transformers in the Wilkinson power divider. On the other hand, two output ports are at first electrically connected in shunt, stretched by quarter-wavelength transmission lines and then shunt-connected via one resistor, aiming to achieve the highly desired wideband port-to-port isolation. After the theoretical analysis on frequency responses of power division and port-to-port isolation is carried out, a prototype power divider on the microstrip-line structure is designed and fabricated. Good agreement between the simulated and measured results is obtained, exhibiting an extremely wide operating band of 78% fractional bandwidth, over which 3 ± 0.3-dB power division and 17.5-dB port-to-port isolation have been simultaneously achieved.

In this research work, a design of different Microwave Components for the proposed beam steering-switching array is presented. In order to achieve beam steering, two different schemes namely Beam S...

This article examines implementations of the recently introduced metamaterial-based electromagnetic bandgap (MTM-EBG) structure, which may be embedded directly into the transmission-line (TL) segments of microstrip (MS) networks and whose dispersion properties may be accurately determined using multiconductor TL (MTL) theory. Two methods of imparting dual-band behavior to MS-based networks are introduced: utilizing stopband and passband regions of the EBG for frequency-selective signal routing, and using the phasing properties of the EBG to provide equal phase shifts at two separate frequencies. Two topological variants of the MTM-EBG are introduced and shown to provide different bandgap sizes, suiting each proposed application. A dual-band Wilkinson power divider, a dual-band quadrature hybrid coupler, and a dual-band impedance transformer are designed with embedded MTM-EBGs, which due to their ability to be realized in an entirely uniplanar form without vias and using a single dielectric layer, allow these devices to be entirely printable as well. The performance characteristics of all three devices are simulated and demonstrate excellent agreement with measurements. The design methodology is general and based on a rigorous MTL circuit model, making this approach amenable to a variety of MS networks, beyond what is presented.

Development of 5G and beyond technologies brings wireless communications systems to operate at higher frequencies and makes them more compact and integrated in nature. This places further challenges for component and system design, but at the same time the need for reliable RF interconnections becomes more and more important. This work investigates passive RF structures implemented on a low-permittivity Panasonic dielectric substrate up to a frequency of 110 GHz with simulations and measurements. Two different test cases are considered: a simple transmission line with a TRL calibration structure as well as a Wilkinson power divider. Agreement between simulations and measurements is rather good, and the results show that the used substrate material is a viable alternative for RF applications around 100 GHz.

This paper represents a broadband 2-ways Wilkinson power divider for S-band (2-4 GHz), C-band (4-8 GHz) and X-bands (8-12 GHz) applications. The broadband design is proposed by dint of a multisection Wilkinson power divider topology with utilizing the microstrip technology on a single layer printed circuit board. The proposed design has a 7-sections to achieve an operating frequency bandwidth of 2-12 GHz. The surface mount resistors are utilized in the design to enhance the isolation between the output ports. In addition, a prototype of the proposed design is manufactured on a Rogers 4003C and the 0402 package surface mount resistors are soldered between the output ports of each section. The prototype has input reflection coefficient better than -15 dB, -20 dB and -10 dB, respectively in the S-, C-, X-bands. Moreover, the prototype has output reflection coefficients better -17 dB, -20 dB and -10 dB, respectively in the S-, C- and X-bands. The measured insertion loss is less than -5 dB. Furthermore, the isolation between the output ports is better than -10 dB, -17 dB and -15 dB, respectively in the S-, C- and X-bands. Furthermore, the total phase variation between the output ports are less than 1.8° in the frequency range from 2 to 12 GHz. The prototyped multisection 2-way power divider illustrates a broadband characteristic with better phase imbalance and the measurement and simulation results are close to each other. The total size of the prototype is 4x41 mm2., This paper represents a broadband 2-ways Wilkinson power divider for S-, C- and X-bands applications. The broadband design is proposed by dint of a multisection Wilkinson power divider topology with utilizing the microstrip technology on a single layer printed circuit board. The proposed design has a 7-sections to achieve an operating frequency bandwidth of 2-12 GHz. The surface mount resistors are utilized in the design to enhance the isolation between the output ports. In addition, a prototype of the proposed design is manufactured on a Rogers 4003C and the 0402 package surface mount resistors are soldered between the output ports of each section. The prototype has input reflection coefficient better than -15 dB, -20 dB and -10 dB in the S-band (2-4 GHz), C-band (4-8 GHz) and X-band (8-12 GHz), respectively. Moreover, the prototype has output reflection coefficients better -17 dB, -20 dB and -10 dB in the S-band, C-band and X-band, respectively. The measured insertion loss is less than -5 dB. Furthermore, the isolation between the output ports is better than -10 dB, -17 dB and -15 dB in the S-band, C-bands and X-band, respectively. Furthermore, the total phase variation between the output ports are less than 1.8° in the operating frequency bandwidth of 2-12 GHz. The prototyped multisection 2-way power divider illustrates a broadband characteristic with better phase imbalance and the measurement results are in good agreement with the simulation results. The total size of the prototype is 4x41 mm.

Flexible design schemes for single- and dual-band power dividers terminated in arbitrary port impedances are proposed in this paper. The proposed architecture provides the inherent impedance transformation to real, complex, and frequency-dependent complex impedances at the input and output port terminations. Furthermore, the proposed design is supported by flexible design procedures with independent design variables to enhance rapid prototyping in microstrip technology. It is demonstrated that the presence of independent design variables enhances the design flexibility for varied ranges of frequency and impedance transformation ratios. Two different prototypes, one each demonstrating single- and dual-band performances, are developed to validate the performance of the reported designs with real and frequency-dependent complex port impedances. The prototypes exhibit excellent agreements between the simulated and measured results. The single-band impedance transforming power divider (ITPD) possesses a low-amplitude imbalance of 0.5 dB, a phase imbalance of less than ±0.5∘, and an isolation of −26 dB at the design frequency of 5.8 GHz. The dual-band prototype also exhibits a low-amplitude imbalance of 0.5 dB and a phase imbalance of less than ±0.5∘ at both the design frequencies of 1 GHz and 2.6 GHz. The isolation is also better than −30 dB at both design frequencies. It is thus shown that the overall performance advances the state of the art in the design schemes of ITPDs.

This letter presents a K-band compact Wilkinson power divider/combiner (WPDC) with 50-dB configurable isolation in 65-nm CMOS. The WPDC is implemented by LC -based spiral transmission lines (LCSTLs), switched capacitors, and a DAC with a core area of 0.09 mm2. The measured insertion loss was 2.5 dB with 0.2 dB fluctuation in the passband. The measured amplitude and phase error are within 0.2 dB and 0.7° from dc to 50 GHz, respectively. The proposed WPDC supports four operation modes, in which the isolation of more than 35 dB from 20.2 to 27 GHz can be maintained with a peak isolation of 60 dB (@ 22.4 GHz). To the best of our knowledge, the WPDC is the only millimeter-wave power divider/combiner (PD/C) that can achieve an isolation of more than 35 dB within a 29% relative bandwidth in CMOS process.