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Recently, research has focused on developing efficient wave-guided THz system-on-chip (TSoC) components to reduce physical bulk, loss and cost of free-space THz systems. We recently demonstrated a TSoC platform using a coplanar-stripline (CPS) transmission-line on a 1 μm-thin membrane to generate and detect THz-bandwidth pulses with low loss and low dispersion up to 1.5 THz. In this paper, we demonstrate experimentally an in-phase THz power divider (TPD) at frequency 0.65 THz using the CPS transmission line defined by photolithography on a thin membrane. Measured pulses show close agreement with simulation results. The spectral power density of the measured THz-bandwidth pulses at the output ports are identical at the frequency of 0.65 THz with less than 1 dB power imbalance over a wide spectrum up to 1 THz.

Background and Objectives: In this paper, a new design strategy was proposed in order to enhance bandwidth and efficiency of power amplifier.Methods: To realize the introduced design strategy, a power amplifier was designed using TSMC CMOS 0.18um technology for operating in the Ka band, i.e. the frequency range of 26.5-40GHz. To design the power amplifier, first a power divider (PD) with a very wide bandwidth, i.e. 1-40GHz, was designed to cover the whole Ka band. The designed Doherty power amplifier consisted of two different amplification paths called main and auxiliary. To amplify the signal in each of the two pathways, a cascade distributed power amplifier was used. The main reason for combining the distributed structure and cascade structure was to increase the gain and linearity of the power amplifier.Results: Measurements results for designed power divider are in good agreement with simulations results. The simulation results for the introduced structure of power amplifier indicated that the gain of proposed power amplifier at the frequency of 26-35GHz was more than 30dB. The diagram of return loss at the input and output of power amplifier in the whole Ka band was less than -8dB. The maximum Power Added Efficiency (PAE) of the designed power amplifier was 80%. The output p 1dB of the introduced structure was 36dB, and the output power of power amplifier was 36dBm. Finally, the IP3 value of power amplifier was about 17dB.Conclusion: The strategy presented in this paper is based on usage of Doherty and distributed structures and a new wideband power divider to benefit from their advantages simultaneously.

A triple band Compact Cylindrical Dielectric Resonator Antenna (CCDRA) array is designed, analyzed, fabricated and presented in this paper. A high dielectric material is utilized in the proposed structure to achieve adequate compactness with moderate gain. The overall size of a proposed antenna array is 50 × 60 × 1.6 mm3. The array utilizes Flame Retardant (FR4) material as a substrate which is commercially available. The unequal microstrip line power divider excitation technique is introduced to obtain satisfactory bandwidth. The presented antenna operates at 1.5 GHz, 2.4 GHz and 5.8 GHz frequencies with the gain values of 2.8 dBi, 3.4 dBi and 5.8 dBi. The Defected Ground Structure (DGS) boosts the antenna efficiency above 75%. The VSWR of presented prototype is well below the need of 1.5.The adequate response from an antenna at targeted frequencies makes it suitable for GPS / Wi-Fi /WLAN applications.

An admittance‐inverter‐based two‐section topology is proposed for filtering power dividers in this article aiming at high and wideband output isolation. Different from the classic two‐section Wilkinson power dividers, the bulky quarter‐wave transmission lines are removed and replaced by using two pairs of admittance inverters, which are realized by the input external quality factor (Qe‐in) and coupling coefficient (k12), respectively. Since the electric size of these coupling effects (Qe‐in and k12) are negligible, a significant size reduction is easily realized. In addition, two isolation elements are added between the input resonators and the output ones, respectively. Two‐prefect absorption points are accordingly realized in |S23|, indicating wider and higher output isolation compared with the reported designs using one isolation element. For demonstration, one two‐section filtering power divider is designed and fabricated. The circuit size is only 0.009λg2, while the output isolation exceeds 41.5 dB over the passband. [ABSTRACT FROM AUTHOR]

In this paper, a center‐fed four‐way power divider with wideband harmonic suppression is proposed. A distinguishing feature is the use of sectorially modified Gielis curves (SMGCs) for open stubs, shorted stubs, and stub‐loaded coupled‐line structures, providing more degrees of freedom in the designs to suppress the wideband harmonics. The expressions for the SMGCs, along with the ABCD matrix elements of the stub‐loaded coupled‐line structure having different even and odd mode electrical lengths (θec ≠ θoc) are another distinguishing features presented in this work. The novelty is to use two stages (first and second) with a combination of open, shorted, coupled‐line stubs and tapered transmission lines to achieve good impedance matching and wideband harmonic suppression for center‐fed antenna arrays. The proposed center‐fed four‐way power divider achieves a wideband harmonic suppression of up to 4fo and a relatively wide −10 dB impedance bandwidth of 52%. The proposed power divider is used in a horizontally‐polarized antenna array for wireless L‐band applications. [ABSTRACT FROM AUTHOR]

We propose a power divider comprising of two parallel λ/4 coupled lines with a shared input signal line. An isolation resistor R is included to enhance the output-port reflection coefficients (S22 and S33) and the isolation between the output ports (S32 and S23). In theory, the power divider can achieve perfect input-port reflection coefficient (S11) and equal power coupling from the input to the outputs (i.e. S21 = S31). To achieve compact chip area, three prototyped power dividers with single-spiral- structure are designed and implemented. Tapered width from 8 to 3 μm is used at the output port transmission lines (TLs) (the first power divider) or the input port TL (the second and the third power dividers) to compensate for the single spiral structure for its non-ideality. This leads to enhancement of the reflection coefficients, and amplitude imbalance (AI) and phase difference (PD) of S21 and S31 of the power dividers. Prominent results are obtained. For instance, the second power divider (divider-2) occupies a chip area of 0.02 mm2 (i.e. 2.4 × 10–4λ02), one of the smallest normalized chip areas ever reported for millimeter-wave power dividers. At 33 GHz, divider-2 achieves decent S11 of −13.4 dB, S22 of −17.6 dB, S33 of −22.1 dB, S32 of −17.1 dB, S21 of − 4.68 dB, S31 of − 4.37 dB, AI of −0.31 dB, and PD of − 1.1°. The remarkable results of the power divider indicate that it is suitable for Ka-band communication systems. [ABSTRACT FROM AUTHOR]

A new planar 3‐band composite right/left‐handed (CRLH) unit cell is presented using an interdigital capacitor, two grounded stubs and etching a defected ground structure on the ground plane. A 3‐band filter is designed using this CRLH unit cell. In addition, with nonlinear dispersion relation of the 3‐band unit cell, it can be used as a hexa‐band quarter wave impedance transformer. Using this functionality, a planar hexa‐band power splitter is designed with relatively good performance. A fabricated prototype of the power divider is measured and the experimental results indicate that the power divider achieved better than 10 dB of return loss and the insertion loss is better than 6 dB over six‐frequency bands. [ABSTRACT FROM AUTHOR]

In this paper, a W-band T-junction power divider based on rectangular microcoaxial structure is proposed. Rectangular microcoaxial line is a threedimensional (3D) structure with the merits of wide operation bandwidth, low loss, and high integration, which is suitable for the design of radio frequency (RF) devices. A two-way power divider is designed based on the rectangular microcoaxial structure. And the two-way power divider is expanded into a four-way power divider to further illustrate the design method. Moreover, a back-to-back configuration including two identical two-way power dividers is fabricated and measured. The insertion loss of the back-to-back configuration is about 0.11-1.18 dB in W band, which agrees with the simulation one reasonably and shows good performance. [ABSTRACT FROM AUTHOR]

In this article, a class of dual‐band filtering power dividers is proposed with simultaneous realization of good designable port‐to‐port isolation. A filtering branch, including two cascaded stub‐loaded half‐ wavelength resonators and coupled‐line sections, are introduced together with the proposed isolation network to simultaneously achieve controllable bandwidth, frequency ratio in dual‐band power division, as well as the port‐to‐port isolation. To construct dual‐wideband power division, two coupled multimode resonators could be used to form the filtering branches, while the proposed isolation network with additional open stub at each output port is utilized to obtain a wide port‐to‐port isolation band. Theoretically, a design method for analyzing the dual‐band frequency response of the power division is presented, while a dual‐ or wide‐band isolation is achieved by introducing multiple transmission zeros in the S32‐magnitude. Finally, two prototype power dividers on the microstrip‐line structure are designed and fabricated. The simulated and measured results agree well with each other, which verify the theoretical predications. [ABSTRACT FROM AUTHOR]

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In this article, a novel $n$ -way topology is proposed to design a class of multiway wideband filtering power dividers (FPDs). It consists of $n$ -coupled multimode resonators and $n$ resistors. To achieve a wideband filtering response, the stub-loaded multimode resonator is first employed. A good port–port isolation can then be obtained by electrically connecting the original open end of the two half-wavelength stubs of the two adjacent multimode resonators, and amounting a shunt resistor in-between the two adjacent stubs, which is allocated a quarter-wavelength away from the electrical connection point. The frequency responses of power division and isolation are analyzed based on even–odd mode, aiming to carry out theoretical analysis for wideband $n$ -way power dividers. To verify the proposed design method, a prototype three-way wideband FPD and a four-way wideband FPD are designed and fabricated. The simulated and measured results show a good agreement from each other, thus verifying the feasibility of this proposal. [ABSTRACT FROM AUTHOR]

We propose a novel power splitter (or divider) comprising two back-to-back quarter-wavelength (λ/4) coupled lines (i.e. coupler). To improve the isolation between the output ports (i.e. ports 2 and 3), an isolation resistor R is included. Three power dividers are designed and implemented. To enhance the reflection coefficients, and S21 and S31 and their amplitude imbalance (AI) and phase difference (PD), the output ports transmission lines (TLs) of the first power divider (i.e. divider-1) with R of 100 Ω adopt tapered width from 8 to 3 μm. For contrast, the second power divider (i.e. divider-2) with R of 100 Ω uses tapered width from 8 to 3 μm for the input port (i.e. port 1) TL. To study the effect of R on the performance of the power divider, the third power divider (i.e. divider-3) has the same layout with divider-2 except R equal to 50 Ω. Prominent results are obtained. For instance, divider-1 occupies a small chip area of 0.026 mm2 (i.e. 2.3 × 10−4λ02), one of the smallest normalized chip areas ever reported for millimeter-wave power dividers. Moreover, at 33 GHz, divider-1 achieves excellent S11 of − 13.1 dB, S22 of − 14 dB, S33 of − 14.2 dB, and S32 of − 17.9 dB, S21 of − 4.22 dB, S31 of − 3.99 dB, AI of − 0.23 dB, and PD of 2.1°. The remarkable results of the proposed power divider structure indicate that it is suitable for Ka-band and even higher frequency transceivers. [ABSTRACT FROM AUTHOR]

This paper communicates the design and experimental validation of dual-band SIW power dividers (single-stage and double-stage) with arbitrary power division. The dual-band power dividers are developed for WiMAX (3.5 GHz) and WLAN (5 GHz) applications. The proposed SIW power dividers are realized by a rectangular cavity, two rows of metallic-vias and one pair of unequal complementary split-ring resonators (CSRRs). Two resonating frequencies are produced below the waveguide cut-off frequency due to the unequal CSRRs etched-out on the top-surface of the cavity, which results in size reduction. To realize arbitrary power division, two output-ports are configured asymmetric with respect to input-port. The power division is varied by altering the distance between the two output-ports. Finally, two compact dual-frequency power dividers (single-stage and double-stage) working at 3.5 and 5 GHz are designed and validated through fabrication and measurement. The fabricated prototype exhibits dual-band operation, compact size (0.027 λ g 2 ${\lambda }_{g}^{2}$), good magnitude imbalance, return loss and isolation. [ABSTRACT FROM AUTHOR]

This paper proposes a miniaturized multi-section power divider with parallel resistor and capacitor isolation circuits. Each of the section transmission lines constituting the proposed multi-section power divider has a length less than a quarter wavelength and the impedance of the transmission lines can be controlled within a certain range while avoiding high impedance. In addition, each circuit connected between the transmission lines consists of a parallel resistor and capacitor to satisfy the matching and isolation characteristics between output ports. To validate the proposed power divider, two circuits at a frequency of 2 GHz were designed with two- and three-section dividers. In comparison to a conventional power divider, the proposed divider showed broadband performances with a small structure.

This paper proposed an integrated conical conformal array antenna (CCAA) for versatile application to the unmanned aerial vehicles. The CCAA consists of five flexible linear gradient subarrays with a uniform circumferential arrangement around the conical surface. It is also embedded with a pyramid reflective back-cavity (PRBC) within the conical carrier. The implementation for the three different elements of the linear gradient subarray toward impedance match and high isolation was investigated, and their identity resonant frequency (9.8 GHz) principle was developed and demonstrated. Furthermore, the PRBC was presented to improve the radiation null of the elements. A numerical 5-bit phase shifter manipulating phase difference of 72° was then combined with an 8-way power divider to obtain a fixed beam with a half power bandwidth (HPBW) of less than 24°, which indicated the backward endfire direction (θ = 180°) in terms of three circumferential arrays (R#X). Finally, the measurements with the aid of the designed phase shifter and power divider (model SHPDW4-040140S) were conducted. The experimental results show one omnidirectional coverage (360°) in the H-plane through the switching working mode of the elements with a wide scanning solid angle (≥72°) when these elements of the subarray hold an identity resonant frequency and exhibit a uniform performance in the point-to-point communication. The measurements of a narrow HPBW of less than 27.5° and the gain over 10.7 dBi in the endfire direction of the three circumferential arrays show great potential in backward blind space detection simultaneously.

This paper presents a novel wide-band filtering three-port coupler with inherent DC-blocking function, which is simply comprised of a power divider with wideband filtering function and a broadband phase shifter with a modified coupled line. For demonstration, a designed prototype operating at 3 GHz is simulated, fabricated, and measured. From the simulated and measured results, the coupler shows a 49% filtering bandwidth with 12-dB return loss and 90° ± 590°phase shifting. The amplitude imbalance between the two output ports is less than 0.5 dB. The all-passband isolation is below -13 dB and the 25.7-dB upper stopband rejection is up to 5.4 GHz. Good agreement between the simulated and measured results validates the proposed idea. Hence, the proposed coupler is well suited for the applications of wideband, filtering, and single-layer circuitry integration.

In this paper, a tri-band impedance transformer (TBIT) using a coupled line and a dual-band to tri-band transformer is proposed, which can transform frequency-dependent complex impedances to a real-value impedance. In order to explain how to determine circuit parameters, closed-form equations are derived in detail. Based on the TBIT, a compact T-junction power divider (TTPD) is designed. This TTPD works at three different frequencies with independent controllable power division ratios. Simple steps to design the TTPD are listed. To demonstrate the validity of the theory, this paper exhibits a prototype operating at 2, 4.4, and 5 GHz with different power division ratios. Moreover, the simulated and measured results prove that this TTPD has the features of tri-band operation, independent controllable power division ratios, enhanced bandwidths, and small size.

A novel compact quasi-planar four-way power divider with a wide isolation bandwidth is proposed in this paper. The signal is fed through the coplanar waveguide and then divided to the four microstrip-line output ports through a metal via. To realize the high output isolation, the multi-layer circuit structure is used. The isolation network is composed of four isolation resistors and a metal via (common node). Equivalent circuits are given to analyze and design the novel power divider. The detailed analyses are given according to the equivalent circuits. A four-way high-isolation power divider with the center frequency of 2.1 GHz is designed and fabricated. The measured 20-dB relative isolation bandwidth between the output ports is about 58%, while 30-dB relative isolation bandwidth between the output ports is about 10%. The measured results agree well with the simulated ones. The total size of the fabricated four-way power divider is 0.17λg × 0.22λg (λg is the wavelength of the center frequency). It shows that the proposed power divider has not only the advantages of high output isolation and compact size but also the advantages of excellent output and input impedance matching and very low insertion loss. The presented power divider can be used in antenna feed, power-combining amplifier, and so on.

A power divider (PD) with a wide stopband and simple symmetric structure using open- and short-ended stubs is analyzed and implemented in this paper. In the proposed power divider, for the first time, the output resistor is divided into two sections and open- and short-ended stubs are used between the resistors. The incorporated open- and short-ended stubs have resulted in a controllable bandwidth for the proposed PD, which resulted in 40% of the fractional bandwidth considering 3 dB attenuation of insertion loss. The proposed PD operates at 2 GHz, which shows more than 20 dB attenuation for the return and isolation losses. In addition, the obtained insertion loss at the operating frequency is approximately 0.3 dB, which shows a minor loss, and also, high isolation is achieved in the device. Moreover, 20 dB and 30 dB attenuation levels have been achieved for second and third harmonics. The results show high performance for the proposed power divider.

A new analytic design for multilayer stripline devices in planar circuit technology is presented. The Complementary Split Ring Resonator (CSRR) is used as a sub-wavelength resonant particle, which provides high-Q resonances in a compact size. The electromagnetic field distribution achieved along the stripline enables enhanced excitation of the resonators. An optimal solution for multilayer power dividers is presented, in a configuration in which each output is obtained in different layers and also in a different layer than the input line. The solution is expanded to design different devices, such as diplexers, resonators, and multi-frequency resonators, leading to vertical filters. As the resonances are achieved by stacking resonators, the effective circuit footprint is very compact. The proposed devices can be implemented in a volumetric chip fashion, allowing integration with planar transmission line circuits and flexible output connection placement. A complete analysis of the different devices is proposed, extracting and verifying their equivalent circuit models.

In this article, a novel ultra‐wideband four‐way power divider based on spoof surface plasmon polaritons (SSPPs) is proposed. The study of the transition structure indicates that the wave supported by unilateral SSPPs possesses the similar dispersion relation to the ones restricted by bilateral SSPPs and effective transmission of electromagnetic wave can be realized in this structure. Owning to these features, waves propagating along the bilateral SSPPs can be equally divided into two unilateral SSPPs and the power divider can be realized by loading this structure, which solves the problem of power distribution in multi‐way or even arbitrary ways. With the help of HFSS, the microstrip‐fed power divider is simulated and results show that it performs well. In order to verify the simulation effect, a object is fabricated and the measured results are in good agreement with simulation results. This power divider has the advantages of ultra‐wideband, low insertion loss and arbitrary‐way of power distribution, which opens up a new avenue for the application of SSPPs in power divider and has a great application prospects in photonics integrated circuits. [ABSTRACT FROM AUTHOR]

In this article, a feasible design of an ultra‐wideband power divider (PD) based on spoof surface plasmon polariton (SSPP) is proposed. A quasi T‐junction transmission structure is composed of the sub‐wavelength corrugated grooves drilled on the up metal layer, realizing the wideband and low loss for the propagation of the odd‐mode SSPP wave. The consistency of the dispersion curves between the H‐shaped and the U‐shaped unit cells under the same dimension parameters ensures the smooth transition at the bifurcation point and out‐of‐phase property further. The odd‐mode SSPP is effectively excited by using the microstrip‐to‐slotline convertor. Some design details like gradient corrugations and stepped slotlines are employed to achieve high‐coupling efficiency from the input electromagnetic energy. The simulated and measured results show that the proposed PD achieves 180° ± 5° phase difference over an ultra‐wideband from 3.3 to 9.8 GHz (a relative bandwidth of 99.24%) with high‐transmission efficiency. The ultra‐wideband out‐of‐phase property of this design has potential applications in the differential feed network. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

In this brief, the design methodology of high- performance lumped-distributed Wilkinson power divider with extremely small chip area is proposed. A parallel capacitor is included at the input port (port 1) to compensate the imaginary part of the input admittance for input matching. A parallel RC network is connected between the output ports (ports 2 and 3) to attain perfect input matching and isolation of the output ports in the odd- and the even-mode excitations. Dual spiral structure with transmission line length of about λ/10 and symmetrical layout is adopted to achieve miniature area and small amplitude imbalance (AI) and phase difference (PD). At 33 GHz, the prototyped power divider achieves S11 of −17.8 dB, S22 and S33 of −22.7 dB, S32 of −34.7 dB, S21 of −4.1 dB, and S31 of −4.07 dB. The corresponding AI is −0.03 dB and PD is −0.08°. The chip area is only 1.2 × 10−4 λ02, one of the smallest normalized chip area ever reported for millimeter-wave (mm-wave) power dividers. The superb results of the power divider indicate that it is suitable for power division/combination in mm-wave transceivers. [ABSTRACT FROM AUTHOR]

When quadrature couplers and power dividers are implemented in integrated circuits, accurate isolation networks can not be realized due to the nonideal resistors and the process variations. We present an isolation network design technique which cancels the resistor parasitic effects and also increases the tolerance to variations in the resistance values. A Lange coupler and a power divider are designed at Ka-band using the proposed accurate and process-tolerant isolation networks. The improvement is analytically shown and empirically verified with our in-house GaN-based microstrip MMIC process. For the coupler, the measured return losses and isolation are better than 20 dB from DC to 40 GHz. The power divider achieves 20 dB return losses and isolation in a fractional bandwidth of 50%. Both devices maintain 20 dB performance even when the variation in sheet resistance is as high as 30%. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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]

In this article, a simple and effective method based on the metamaterial concept is proposed to achieve very high isolation between the output ports of a millimeter-wave power divider (MWPD). The proposed MWPD is designed for use in 5G applications (28–32 GHz). In order to increase the isolation, three metamaterial rows are used, each row containing eight proposed unit cells. These metamaterial unit cells are loaded between two dielectric layers. By using this method and without isolating resistors, isolation is improved by more than 36 dB, as compared with a prototype power divider in which no metamaterial element was used. The maximum measured isolation is 43 dB at 30 GHz. The final dimensions of the proposed MWPD are $8 \times 8\,\,\times0.582$ mm3 or $0.9\,\,\lambda _{\mathbf {g}} \times 0.9\,\,\lambda _{\mathbf {g}} \times 0.08\,\,\lambda _{\mathbf {g}}$ where $\lambda _{\mathbf {g}}$ is the guided wavelength at 30 GHz. The simplicity of design, its compactness, and most importantly, high isolation between output ports without any lumped resistor are the key advantages of the proposed MWPD. [ABSTRACT FROM AUTHOR]

In this paper, a directional‐coupler‐based wideband three‐way waveguide power divider is demonstrated. The proposed power divider consists of tapered rectangular waveguide, six‐port directional coupler and iron pentacar‐bonyl terminations. Its fractional bandwidth is 10.99% at 12.9 to 14.4 GHz. In addition, the return loss of all input and output ports is better than 20 dB and the isolation of the three output ports is more than 20 dB. Moreover, the insert loss is better than 5.19 dB including the power division ratio of 4.8 dB and the amplitude imbalance among the three output ports of less than ±0.4 dB. The experimental results agree well with the simulation ones, which indicates the validity of our method. With the above‐mentioned characteristics, the proposed device can be widely used in Ku band communication systems. [ABSTRACT FROM AUTHOR]

A coupled-line based dual-band power divider using substrate integrated suspended line (SISL) for WLAN application is proposed in this brief. Two-section cascaded coupled line in each output path is used for dual-band response. One coupled line loaded at the input port is to improve the frequency selectivity. Two lumped resistors placed between two pairs of the two-section coupled line are used for isolation enhancement. Multi-layer SISL structure is introduced to realize tight broadside coupling, as well as for low loss, miniaturization and self-packaging. To further reduce the dielectric loss, the suspended substrate is cut out in specific pattern. The proposed dual-band power divider (DBPD) is analyzed using the even- /odd- mode method, the S-parameters are derived, and the design procedure is exhibited. For verification, a DBPD prototype working at 2.45 / 5.13 GHz is implemented. The measured results agree well with the simulated ones. The two passbands are from 1.7 GHz to 3.1 GHz and from 4.6 GHz to 5.5 GHz, with fractional bandwidth (FBW) of 58.3% and 17.8%, respectively. The measured return loss and isolation are both better than 15 dB in both passbands. [ABSTRACT FROM AUTHOR]

This paper presents a polarization agile antenna design that can be helpful for underwater communication, using the integrated structure of power divider and phase shifter to feed a square patch antenna. The purpose of this research is to discover new ways of communication by developing a polarization agile antenna, integrated feeding structure that can generate two equal-amplitude signals with fast phase switching between 90 ∘ and 270 ∘ , realizing the agility control for the dual circular polarization of the square patch antenna. Compared with the traditional polarization-agile antennas with the individual power divider and phase shifter networks, the proposed design has the advantages of good amplitude, phase and polarization imbalance performances, a simple control circuit, low insertion loss, and compact design which proves it to be best underwater communication. [ABSTRACT FROM AUTHOR]

A multi‐section ultra‐wideband Wilkinson power divider is presented in this article. The proposed device is developed based on a coplanar waveguide (CPW) to coplanar strip (CPS) transition, which is realized on a two‐layer printed circuit board without using via holes. Equivalent circuit model of the proposed power divider is presented, and on that basis a three‐section power divider with an ultra‐wideband performance, ranging from 3 to 16 GHz is designed and numerically validated. Finally, prototypes of the proposed device is fabricated and measured to provide an experimental verification on the numerically predicted features, namely the operating bandwidth, input/output impedance matching, insertion loss, isolation between output ports, and amplitude/phase balance at output ports. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

This article introduces two-way broadband air-filled substrate integrated waveguide (AFSIW) isolated power dividers/combiners based on surface mounted absorbing materials. The proposed structures take advantage of the AFSIW multilayer feature. The absorber implementation is found highly tolerant of variations in dimensions and positioning. Three different power dividers/combiners topologies are analyzed theoretically, simulatively, and experimentally. The measurement results validate the broadband responses of the fabricated Ka-band demonstrators. The proposed power dividers/combiners are intended to exploit high-power AFSIW system on substrate (up to few hundred watts). [ABSTRACT FROM AUTHOR]

A novel structure for a four-port microstrip magic-T junction is presented. The device is composed of microstrip and slotline circuits etched onto two sides of a dielectric substrate. The device is extremely compact and occupies an area more than three times smaller than similar structures recently reported in the literature. The novelty of the device lies in the use of microstrip/slotline transitions for both input ports: summation (in-phase) port and difference (out-of-phase) port. This ensures electrical separation for DC signals between all four ports, a wide operation band and a very small size for the device. The fabricated prototype operates in a 95% fractional bandwidth with reflection losses better than 10 dB and isolation between input ports better than 35 dB. The insertion losses for the excitation at the summation port are about 0.8 dB and for the excitation at the difference port are about 1.4 dB. In the operation band of the device, the maximum amplitude imbalance is equal to +/-0.3 dB, whereas the maximum phase imbalance is equal to +/-4 deg.

This paper presents a novel dual-band filtering balanced-to-unbalanced impedance transforming out-of-phase power divider using a simple admittance inverter with an extreme high frequency ratio and arbitrary power division, which is composed of stepped-impedance transmission lines. Based on the traditional transmission-line theory and ABCD/V matrix, the closed-formed analytical equations and complete design procedure are derived and provided for the filtering differential-mode transmission with high frequency ratio and good dual-band common-mode suppression. For demonstration, a designed prototype operating at 1 and 6.4 GHz are simulated, fabricated, and measured. The measured results agree well with the EM simulation perfectly.

In this paper, a balanced-to-balanced power divider with a wideband filtering function is proposed. The power divider is simply composed of coupled-line sections, λ/4 lines and isolation resistors, and explicit design methodology is given. From the simulated and measured results, the power divider shows 49% differential-mode filtering bandwidth with two additional transmission zeros introduced, and the common-mode transmission is suppressed below -12 dB over 141% frequency bandwidth. This power divider can be a candidate for constructing fully-balanced systems.

A wideband half-mode substrate integrated waveguide (HMSIW) power divider with bandpassfiltering response using the slotline isolation technology is presented in this paper. Resistive slot on the bottom layer is employed to improve the output isolation. To obtain filtering response, L-type slot line and two multimode SIR resonators loaded symmetrically at two sides of the input transmission line are employed to generate transmission zeros at upper stop band. In addition, filtering response is achieved by combining the inherent high-pass characteristic of the HMSIW and the TZs. The equivalent circuits are presented and analyzed by using evenand odd-mode method, and the relative design equations are derived. The measured return loss of the HMSIW power divider is about 10 dB and its isolation is greater than 15 dB from 3.8 to 5.8 GHz. All measured results show reasonable agreement with the simulated ones.

Based on the concept of conventional Gysel power divider, a novel concept of half-mode substrate integrated waveguide (HMSIW) Gysel power divider was reviewed and developed, by simply combining a traditional HMSIW power divider and a microstrip isolation network. The proposed concept was reviewed, investigated, and analyzed thoroughly, after that, Y-type, T-type, and Parallel-type HMSIW Gysel power divider were designed and analyzed, respectively. Furthermore, based on Parallel-type design, a developed version using two isolation networks was proposed for frequency bandwidth enhancement. All the four prototypes were fabricated and measured for verification and comparison. The good electrical performances and compact configuration indicate the advantages of the proposed concept and an excellent candidate for high power-handling HMSIW/SIW circuits or systems.

An exact design for seven‐way Bagley power divider (7‐way BPD) is introduced. The objective of this article is to derive general closed‐form expressions for the impedances between adjacent ports for unequal‐split 7‐way BPD. The values of the impedances control the output power ratio. Full derivation of S‐parameters followed by exact impedance equations will be presented. A parametric study in addition to several examples will be given to validate the proposed derivation including: 7‐way BPD with output power splitting ratios of: 1:6:15:20:15:6:1, 1:2:3:4:3:2:1, and 1:3:1:3:1:3:1 operating at 1 GHz. An experimental value for the reflection coefficient (S11), at the design frequency is found to be −40.1 dB. A very good agreement between theoretical, simulated, and experimental results is achieved which proves the correctness of the presented approach. Therefore, it can be used to design 7‐way BPDs for any output power ratio. [ABSTRACT FROM AUTHOR]

In a conventional power divider, power dividing network and isolation network are usually independent of each other. To reduce the size of out-of-phase power divider with arbitrary power ratio, coupled microstrip lines are proposed to facilitate power dividing and isolation of a power divider simultaneously in this article. Formulations have been derived for the proposed out-of-phase power divider with arbitrary ratio. Two compact power dividers are implemented on the printed circuit board (PCB) with power ratio $k^{2} = 9$ and $k^{2} = 1000$. It can be observed that there is a satisfactory agreement between the simulated and measured results. [ABSTRACT FROM AUTHOR]

We present the design and analysis of a Ka-band (26.5–40 GHz) CMOS quadrature coupler (QC) and four Ka-band CMOS power dividers. To reduce the chip area of these devices, spiral coupled-line- based structure (or spiral QC-based structure) is adopted. A QC on 90 nm CMOS (with top metal thickness of 3.4 μm) is designed. The QC achieves phase difference (PD) of – 90.015° at 28 GHz, and excellent S21 and S31 of – 3.65 dB and – 3.738 dB, respectively, at 28 GHz. The corresponding amplitude imbalance (AI) is 0.088 dB. Based on the QC structure, a novel power divider structure with in-phase divided signals is proposed. Four power dividers are designed and implemented. At 33 GHz, the miniature square 3-turn power divider on 90 nm CMOS (i.e. divider-4) achieves excellent S11 of – 21 dB, S22 of – 17.8 dB, S33 of – 17.4 dB, and S32 of – 20.9 dB. Moreover, divider-4 achieves S21 and S31 of – 4.029 dB and – 4.008 dB, respectively, at 33 GHz. The corresponding AI and PD are – 0.021 dB and 0.369°, respectively. The chip area is 0.186 × 0.188 mm2 (i.e. 0.035 mm2 or 4.2 × 10–4λ02), one of the smallest normalized chip areas ever reported for millimeter-wave power dividers. The prominent results of the proposed power divider structure indicate that it is suitable for power division/combination in Ka-band and even higher frequency systems. [ABSTRACT FROM AUTHOR]

A new power divider is proposed with a compact size. In 50- $\Omega $ systems, impedance transformation is of great importance for power dividers. Coupled microstrip lines with capacitor loaded and two short-circuited ports are introduced to properly transform impedance and increase degrees of freedom in power divider designs. Image impedance and image transfer constant of coupled microstrip lines with capacitor loaded are derived. The main structural parameters of the power divider are calculated accordingly. A special design procedure is illustrated for the proposed power divider with the capacitor loaded, which is implemented on a printed circuit board. A good agreement between the simulated model and the fabricated sample is observed, which demonstrates the validity of the proposed circuit model and the design scenario. [ABSTRACT FROM AUTHOR]

A four-way suspended-stripline power divider is presented in this letter. The power dividing network is designed by using the suspended stripline, while the isolation network is designed by using the microstrip line. The vias are used to connect the power dividing network and the isolation network. The even- and odd-mode analysis method is applied to design the presented power divider. The simulated and measured results of the presented power divider show reasonable agreement with each other. The measured input return loss in the band is greater than 28 dB (7.92 to 9.53 GHz), while the measured insertion loss is less than 0.37 dB. The measured output return loss is greater than 20 dB from 7.82 to 9.86 GHz. Besides, the measured output isolation is greater than 20 dB. [ABSTRACT FROM AUTHOR]

Package-integrated and ultrathin power dividers with footprint smaller than unit $\lambda ~_{0}~^{\mathrm{ 2}}$ at the operating frequency of 28-GHz 5G new radio (NR) n257 and n258 bands are presented for the first time for small-cell applications. These power dividers are also configured as antenna arrays using endfire Yagi–Uda antenna elements. Utilizing minimal matching techniques, two-, three-, and four-element antenna arrays are designed without compromising on the bandwidth of operation or electrical performance. These thin-film power dividers exhibit a cross-sectional height of $147~\mu \text{m}$ and can be implemented in the top metal layer of front-end module packages. Panel-compatible semiadditive patterning (SAP) process is utilized to realize these structures, which yields precise line space dimensions required for millimeter-wave (mm-wave) applications. This results in power dividers with low added insertion loss, low VSWR, and minimal phase difference between output ports. The added insertion loss is 25% less than similar structures reported on integrated fan-out architectures. The antenna arrays exhibit high gain and efficiency. Excellent model-to-hardware correlation is observed with multiple coupons of the same structure. Package-integrated power dividers and antenna arrays based on ultrathin laminated glass substrate represent a major step toward realizing compact mm-wave antenna-in-package for 5G small-cell applications. [ABSTRACT FROM AUTHOR]