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In this paper, a half‐mode substrate integrated waveguide (HMSIW) power divider with bandpass response and good frequency selectivity is proposed. The proposed power divider includes input/output microstrip lines, four HMSIW resonators, cross‐coupling circuits, and an isolation resistor. The dual‐band bandpass‐filtering response is obtained by using the dual‐mode slotted HMSIW. To get good frequency selectivity, the input/output cross‐coupling circuits have been used, and several transmission zeros can be observed. A dual‐band filtering‐response HMSIW power divider is designed, fabricated and measured. The total size of the fabricated power divider is 0.58λg × 0.45λg. The measured results show a reasonable agreement with the simulated ones. The measured central operating frequencies of the dual‐band HMSIW power divider are at 2.43 and 3.50 GHz, respectively. The measured 3‐dB fractional bandwidth is about 13.3% and 6.3% in the two passbands, and the measured output isolation is about 20 dB. [ABSTRACT FROM AUTHOR]

The design and implementation of planar multi-way differential power dividers remain a challenge in terms of the compactness and especially, for the achievable characteristic impedance of the quarter-wavelength transformer when considering large number of outputs. In this work, the double-sided parallel stripline is recommended to realize such a power divider with out-of-phase outputs, and explicit design methods are provided. The proposed multi-way power divider was developed without the use of lump elements on a single substrate. For system applications, a prototype operating at 41.6 MHz with 12 pairs of out-of-phase outputs that utilize the microstrip line as the output interfaces was fabricated and examined. At the center frequency of 41.6MHz, the developed prototype measured insertion losses akin to 14.3 dB as compared with the theoretical data of 13.8 dB. The attainable impedance bandwidth ranges from 10 MHz to 80 MHz under a magnitude imbalance of ±0.3 dB. The isolations of the adjacent outputs are about 13.1 dB as compared with the theoretical values of 14.428 dB, and are better than 34 dB for more distant ones. Parameter measurements are in good agreement with the numerical predications, thus demonstrating the realization of the proposed multi-way power divider. [ABSTRACT FROM AUTHOR]

A 1x4 cylindrical dielectric resonator antenna (CDRA) array is successfully developed and presented in this paper. The claimed structure has introduced quarter wavelength transformer with power divider network. The adopted concept gives adequate response in terms of appropriate suppression, phase distribution and power division. By utilizing the aforesaid geometry, tri-band response has been achieved for various frequency ranges from 0.87 GHz to 1.04 GHz with 18% bandwidth, 2.37 GHz to 2.78 GHz with 17% bandwidth and 4.17 GHz to 5.21 GHz with 22% bandwidth, having peak gain of 2.43dBi, 7.72dBi, and 8.39dBi respectively. 1x4 element dielectric resonator antenna array are designed for comparison in terms of return loss, gain and radiation pattern. The proposed array is modelled using CST software. In order to verify the simulated result, the designed antenna is fabricated on FR-4 substrate and tested using VNA and anechoic chamber. The parametric analysis is carefully completed in order to fix key parameters such as microstrip line length, dielectric resonator height, and Defected Ground Structure (DGS). The analysis said that there is close agreement between the simulated and fabricated response. As the claimed antenna model resonates for the triple-band with aforesaid frequencies, it would be the appropriate candidate for GPS navigation/Wi-Fi, Bluetooth and satellite applications. [ABSTRACT FROM AUTHOR]

This article introduces analysis of the new configuration; inductor loaded left‐handed composite right‐/left‐handed transmission line ((L‐CRLH TL). Compared to conventional CRLH and dual CRLH, this configuration has the advantage of very slow phase (almost constant) and nonlinear propagation coefficient which enables it to be very effective in designing compact size and ultra‐wideband (UWB) microwave components. The theoretical and circuit model of the L‐CRLH TL is discussed. As an application, a compact UWB (3.1‐10.6 GHz) L‐CRLH power divider is designed using only one L‐CRLH cell with size of 2.7 × 8.6 mm2 whereas the whole power divider photoprint is 12.14 × 18.83 mm2. The size is 58.5% smaller compared to the conventional narrow band T‐junction power divider designed at the mid frequency. The results reveal good insertion losses (3.2 ± 0.2 dB for both S21 and S31), and good return losses (better than 10 dB within the passband). [ABSTRACT FROM AUTHOR]

A new three‐way planar power divider, based on recombinant structure and multisection impedance transformers achieving equal division ratio and high isolation is presented. The new design structure comprises of unequal impedance multisections, and achieves higher isolation than planarized Wilkinson dividers and smaller structure than recombinant designs. The divider is completely modeled analytically using transmission line theory, followed by verification through simulation and measurements. With an overall size of 23.5 mm × 29 mm, the divider demonstrates a bandwidth from 1.8 GHz to 2.8 GHz with measured 20 dB isolation bandwidth of 43%, peak isolation of 31 dB, insertion loss of 4.99 ± 0.5 dB and return loss better than 13 dB at 2.4 GHz. The planar structure, small size and highest reported isolation at 2.4 GHz, makes the design suitable for MMICs, antenna feed networks and power amplifier applications. [ABSTRACT FROM AUTHOR]

Microwave power dividers play important roles in microwave circuit systems. As an in‐phase divider, the Wilkinson power divider which consists of two quarter‐wavelength transmission lines and an isolation resistor connected between two output ports is well known. However, the circuit size becomes large because this divider is designed based on a distributed circuit theory. This problem is extremely serious at low frequency regions such as VHF/UHF bands. Although some lumped‐element power dividers utilizing Π‐ or T‐networks have been reported in order to overcome this problem, these dividers have relatively narrow bandwidths about 16%. On the other hand, authors have been also proposed broadband lumped‐element power dividers utilizing LC‐ladder circuits. This article describes a design method of a multisection LC‐ladder divider at VHF band. The multisection LC‐ladder divider is a broadband lumped‐element power divider composed of multisection LC‐ladder circuits and an isolation resistor. By designing the divider based on multisection impedance transformer and L‐type matching techniques, broadband characteristics of a relative bandwidth of over 100% can be obtained at VHF band. Electromagnetic simulation and experiment for the designed divider have been performed in order to verify the design procedure. The measured results of the fabricated LC‐ladder divider at a center frequency of 178 MHz utilizing commercial chip elements are good agreement with simulation results. It is analytically and experimentally clarified that broadband characteristics can be realized with lumped‐element power dividers using multisection LC‐ladder circuits. [ABSTRACT FROM AUTHOR]

A Wilkinson power divider (WPD) with good novelty has been presented in this letter. To achieve this design, each quarter‐wavelength lines of the conventional WPD have been replaced by two symmetrical comb‐shaped resonators. These resonators create two rejection bands near their passbands, which can guarantee a good harmonics suppression for a power divider. By applying and computing the even‐/odd‐modes analysis, the suggested PD has been analyzed. In the proposed PD, the extra harmonics from second to 10th are suppressed. The normalized circuit size for operation in the center frequency of 1.1 GHz is about 0.06 × 0.07 λg. Eventually, fabrication of the power divider has been done on Rogers type RT‐Duroid 5880 substrate and tested. The measured return loss is about 16 dB in the fundamental frequency. The obtained experimental S‐parameters validated the primal design results. Therefore, the proposed WPD is a high performance one, which can be applied for applications such as the signal splitter in a Doherty power amplifier. [ABSTRACT FROM AUTHOR]

A novel high-isolation microstrip diplexing power divider with high-frequency selectivity is presented in this paper. Miniaturization of the circuit by integrating the diplexer and the power divider. The presented diplexing power divider consists of input matching circuit, two bandpass filters, and two microstrip-line power dividers. By introducing source-load cross coupling, two transmission zeros at both sides of each channel can be obtained. The diplexing power divider has been fabricated and measured, and the design has been demonstrated. The measured results show a reasonable agreement with the simulated ones. The measured results show that the presented diplexing power divider exhibits sharp selectivity, high isolation, and good input/output impedance matching. [ABSTRACT FROM AUTHOR]

A compact broadband eight‐way substrate integrated waveguide (SIW) based radial power divider at C‐band is presented in the article. Bandwidth enhancement is achieved by employing planar impedance transformer consisting of an annular slot and circular patch at the input and output feed positions. The equivalent circuit analysis helps in the optimization of the annular slot and circular patch on the substrate. The proposed compact power divider has fractional bandwidth of 53.5% for 15 dB input return loss. Broadband characteristics are achieved without using any bulky mechanical arrangement for feed matching. It has a size of 0.72 λg2 and the measured amplitude imbalance is within 0.5 dB at the center frequency of 6.6 GHz. [ABSTRACT FROM AUTHOR]

This article demonstrates the feasibility of a novel waveguide dual-mode two-way power divider that is based on an evolved junction having a dedicated T-shaped central matching element (scatterer). This scatterer, with matching sections facing all three ports, provides equal power division and routes the two TE10/TE01 orthogonal modes of a square waveguide toward the corresponding output ports. The proposed design is compact, easily scalable and can be cascaded to obtain $2^{N}$ output ports, being $N$ the number of division stages. Moreover, this structure represents the first waveguide dual-mode two-way reactive power divider (three physical ports) reported in the scientific literature. An exemplary has been manufactured showing an 11% relative bandwidth at 12 GHz and less than −50 dB of cross-coupling. Transmission loss and isolation between output ports are in good agreement with electromagnetic (EM) simulations. [ABSTRACT FROM AUTHOR]

We present the design and analysis of coupled-line-based Ka-band CMOS power dividers. A single spiral structure with a symmetrical layout is adopted to achieve a miniature area and small amplitude imbalance (AI) and phase difference (PD) performance. The first divider (divider-1) achieves ${S} _{21}$ and ${S} _{31}$ of −4.029 and −4.008 dB, respectively, at 33 GHz. The corresponding AI and PD are −0.021 dB and 0.369°, respectively. Moreover, the second divider (divider-2) achieves ${S} _{21}$ and ${S} _{31}$ of −4.093 and −4.055 dB, respectively, at 33 GHz. The corresponding AI and PD are −0.038 dB and 0.148°, respectively. The chip area is $1.7\times 10^{-4} \lambda _{0}^{2}$ , one of the smallest normalized chip area ever reported for millimeter-wave (mm-wave) dividers. The prominent results of the dividers indicate that they are suitable for power division/combination in mm-wave transceivers. [ABSTRACT FROM AUTHOR]

In this article, a miniaturized dual-band dual-polarized slot antenna array is proposed for base station applications. It consists of two closely located $1 \times 4$ subarrays for the digital cellular system (DCS) and wideband code division multiple access (WCDMA) operations. The band-notched slot antenna (BNSA) is designed and adopted as the subarray element with radiation-suppression characteristic at notch frequencies. The notch frequency for one subarray is designed at the center operating frequency of the other subarray. As a result, the radiation from DCS subarray could be effectively suppressed within the WCDMA band and vice versa, resulting in high isolation between two subarrays with a small separation distance. By using the artificial magnetic conductor (AMC) reflector, the array height could be reduced by half, as compared with the perfect electric conductor (PEC) counterpart. In addition, a four-way unequal power divider is designed for the array’s beam-pattern synthesis. For the demonstration, the proposed array is fabricated and measured. The measurement results show that the dual-band array achieves the impedance bandwidths of 1.65–1.88 and 1.89–2.22 GHz, the isolations over 25 dB, the realized boresight gains of 12.2–12.8 and 12.3–13.2 dBi, and the sidelobe levels below −18 dB. The results indicate that the proposed array is a promising candidate for base-station applications. [ABSTRACT FROM AUTHOR]

In this letter, a switchable phase inverter is presented for the design of the reconfigurable in‐phase/out‐of‐phase power divider. Firstly, the in‐phase and out‐of‐phase power dividers are designed based on the finite‐ground microstrip line (FGMSL). Next, two FGMSL‐based switchable phase inverters are designed and installed at two sides of output ports, respectively. After compensating the parasitic effects of the switches and DC blocking capacitors, a wideband reconfigurable in‐phase/out‐of‐phase power divider is constructed. To validate this proposal, a prototype with power‐dividing ratio of 2:1 is finally designed, implemented, and fabricated. The measured and simulated results show a good agreement under both in‐phase and out‐of‐phase states. A measured bandwidth of 64% with better than 15 dB return loss and 20 dB isolation is obtained. Phase unbalances are less than 2.4° for in‐phase state and 4° for out‐of‐phase state, respectively, over a wide concerned frequency range. [ABSTRACT FROM AUTHOR]

In this paper, a novel design of highly compact power divider employing substrate-integrated waveguide (SIW) is proposed for dual-band applications. The double-ring asymmetric complimentary split-ring resonators (CSRRs) are utilized to obtain dual-band operation. The asymmetric double-ring CSRRs create mixed magnetic and electric coupling resulting two distinct resonating frequencies which exhibits bandpass behaviour below the resonating frequency of the cavity. The resonating passbands can be designed individually by varying the dimensions of the proposed CSRRs. In addition, the position ofoutput ports can be varied to achieve arbitrary power division. To demonstrate the proposed analysis, three prototypes (two equal power division and one unequal power division) of dual-band SIW power dividers are designed and fabricated. Measurement performance provides a good consistency with that of simulated one. The circuit areas of the fabricated prototypes 1, 2 and 3 excluding microstrip transitions are 0.053λg², 0.088λg² and 0.033λg², respectively. The proposed design process exhibits dual-band performance with smaller circuit-area, suitable isolation and hence appropriate for dual-band communication services. [ABSTRACT FROM AUTHOR]

Side lobe level (SLL) reduction has a great importance in recent communication systems. It is considered as one of the most important applications of digital beamforming since it reduces the effect of interference arriving outside the main lobe. This interference reduction increases the capacity of the communication systems. In this paper, the hardware implementation of an antenna array system for SLL reduction is introduced using microstrip technology. The proposed antenna array system consists of two main parts, the antenna array, and its feeding network. Power dividers play a vital role in various radio frequency and communication applications. A power divider can be utilized as a feeding network of an antenna array. For the synthesis of a radiation pattern, an unequal-split power divider is required. A new design for a four ports unequal circular sector power divider and its application to antenna array SLL reduction is introduced. The amplitude and phase of the signals emerging from each power divider branch are adjusted using stub and inset matching techniques. These matching techniques are used to adjust the branches impedances according to the desired power ratio. The design of the antenna array and the power divider are made using the software package CST MICROWAVE STUDIO. The power divider is realized on Rogers R03010 substrate with dielectric constant εr=10.2, loss tangent of 0.0035, and height h=1.28mm. In addition, a design for ultra-wide band (UWB) antenna element and array are introduced. The antenna elements and the array are realized on the FR4 (lossy) substrate with dielectric constant εr=4.5, loss tangent of 0.025, and height h=1.5mm. The fabrication is done using thin film technology and photolithographic technique. The experimental measurements are done using the vector network analyzer (VNA HP8719Es). Good agreement is found between the measurements and the simulation results.

In this paper, a simple and compact planar balanced-to-unbalanced in-phase power divider with arbitrary terminated impedances is proposed based on the coupled-line structure and a single grounded resistor. By using the even-/odd-mode analysis and the traditional transmission-line theory, the complete design procedure and analytical equations are obtained to achieve good performances for differential-mode transmission, common-mode suppression, phase difference, arbitrary terminated impedances, and isolation. For demonstration, two different prototypes with 50-to-50 Ω matching and complex impedance transformation are designed, fabricated, and measured. Good agreement can be observed between simulated and measured results.

In this study, a novel high-isolation wideband divider based on multi-layer elliptical defected ground structure coupler is presented along with its analytical theory and design procedure. The proposed divider could be conveniently applied for high- power applications with less loss for the absence of isolation resistors. The simulation results show that in 3.1–10.6 GHz, the return loss S(11) and S(22) are −4 dB within 4–9 GHz, and the amplitude and phase difference between port 2 and port 3 is

A new method to design wideband differentially driven dual-polarized antenna with high common-mode suppression and high port isolation is presented. The presented antenna can be equivalent as a combination of a six-port power divider and four crossed folded dipoles. The six-port power divider is composed of two orthogonal input ports and four equal magnitude output ports. Detailed analysis illustrates that the six-port power divider can have wide bandwidth and high isolation under odd-mode excitation and high common-mode suppression under even-mode excitation. Therefore, based on the wideband and high even-mode suppressed six-port power divider, a wideband differentially driven dual-polarized antenna is developed with high common-mode suppression. To validate the design concept, the proposed antenna was designed, fabricated, and measured. The measured results prove that the antenna has a wide impedance bandwidth of 1.64–3.0 GHz (58.6%) for the return loss higher than 15 dB and isolation higher than 35.4 dB. In addition, very high common-mode suppression is achieved for the measured common-mode reflection coefficient higher than −0.87 dB over the entire bandwidth. With stable antenna gain and half-power beamwidth, the developed antenna is suitable for base station applications. [ABSTRACT FROM AUTHOR]

In this article, a vertical four-way rectangular waveguide to microstrip power divider is proposed. The power divider achieves perfect power division from 10.1 to 11 GHz with a 20-dB return loss and a short longitudinal length. Based on the four-way power divider, two microstrip ports are added, and a compact improved four-way rectangular waveguide to microstrip power divider is constructed. The 20-dB return loss bandwidth of the power divider can be extended from 9.9 to 12.4 GHz. If all the output microstrip ports are connected to resistive loads, the power dividers become rectangular matching terminations. Thus, the four-way power divider can achieve a rectangular matching load with an 8% bandwidth and a 2-mm matching length. The improved four-way power divider can achieve a rectangular matching load with a 22.4% bandwidth and a 2.5-mm matching length. The measurements agree well with the simulations. The proposed designs of the rectangular loads are superior in their compact volume, high power capacity, and ease of fabrication. [ABSTRACT FROM AUTHOR]

A compact wideband out-of-phase power divider (PD) with improved isolation performance is proposed. This divider is formed by connecting an additional stub for isolation to output ports of a traditional Marchand balun with a defected ground structure (DGS) been used. To verify the design, a prototype divider is fabricated and tested. The measured results validate the 53.86% band-width centered at 3.43 GHz with more than 15 dB return loss at all ports, more than 17 dB isolation, respectively. [ABSTRACT FROM AUTHOR]

A novel symmetric two layer six ports multi-functional microwave component was designed and presented in the present study. The proposed component consists of two 90-degree broadband double layer substrate integrated waveguide couplers and two T-shape power dividers. By exciting each port, the component could act as a −6 dB equal power divider, an unequal −3/−6 dB 90-degree coupler, as well as a −3 dB equal coupler. This component with mentioned conditions covers 23% frequency bandwidth with maximum magnitude and phase error of ±0.5 dB and ±0.6 degree in all bandwidths, respectively. [ABSTRACT FROM AUTHOR]

In this communication, a substrate integrated wave (SIW) cavity is applied in feeding dielectric resonator antennas (DRAs) and designing reconfigurable circuits for multifunction applications. The TE120 mode of the SIW cavity is utilized to differentially feed a dielectric resonator (DR) for high-performance antennas with low cross-polarization and symmetrical patterns. The TE110 mode is used to design a filter or a power divider with continuously tunable operating frequency. Considering the characteristics of the field distributions, the filter or power divider part shows no effect on the antenna part, meaning that different functions are independent. The proposed multifunction applications of the SIW cavity are listed, simulated, and verified by experiments. [ABSTRACT FROM AUTHOR]

This article proposes a compact design of a two-section power divider, which operates over an ultra wideband frequency range of 3-11 GHz. The design approach of microtrip with slotline at the ground plane is applied to reduce the size of the circuit and to achieve wide bandwidth coverage. The rectangular slots are implemented at the ground plane, which is positioned symmetrically underneath the second and third arms of each microstrip quarter-wave transformer to reduce its length up to 33.34%. These attributes lead to an easily fabricated 20 mm x 23 mm compact power divider with a reduced size (by 23.33%). The bandwidth performance is improved up to 19.4% compared to a conventional divider. The design is realized by implementing the Rogers TMM4 substrate and simulated by using CST Microwave Studio. The power divider is verified by using a vector network analyzer (VNA). A good agreement between simulation and fabrication is achieved in terms of return loss, isolation and transmission coefficients across the UWB frequency range. [ABSTRACT FROM AUTHOR]

This article presents a novel design of substrate integrated waveguide (SIW) dual‐band power divider loaded with double‐circular complementary split‐ring resonators (CSRRs). The double‐circular CSRRs are etched on the top layer of the proposed structure to obtain the dual‐band characteristic. The proposed geometry provides a passband frequency below the cut‐off frequency of the SIW due to the electric dipole nature of the CSRRs. By changing the dimensions of the CSRRs, various passband characteristics are studied. To validate the design idea, a compact dual band power divider with equal power division operating at 8.4 and 11.7 GHz is designed, fabricated, and tested. A good steadiness is found between simulated and tested results. The proposed idea provides features of compact size, dual‐band operation, and good isolation. The size of the fabricated prototype excluding microstrip transition is 0.473λg × 0.284λg, where λg is the guided wave length at the center frequency of first band. [ABSTRACT FROM AUTHOR]

Summary: A novel compact arbitrary terminated power divider with bandwidth‐enhanced negative group delay (NGD) characteristics is proposed. The NGD characteristics are controlled by characteristic impedances of transmission lines and the coupled line between two output ports. Flat and wide NGD bandwidth is produced by using the combination of a series resistor and short‐circuited coupled‐line section. The complete closed‐form equations are presented. For experimental demonstration, a prototype is designed and fabricated at f0 of 2.14 GHz. The measured results indicate that the proposed power divider is able to realize wide NGD bandwidth and good NGD flatness. [ABSTRACT FROM AUTHOR]

This paper presents a novel numerical approach to simulate H-plane rectangular-waveguide microwave circuits considering a reduced quasi-2D simulation domain with benefits for computational cost and time. With the aim to evaluate the attenuation of the full height 3D component, we propose a modified expression for the waveguide top/bottom wall conductivity. Numerical 2D simulations are validated against results from full wave 3-D commercial electromagnetic simulator. After a benchmark on a simple straight waveguide model, the method has been successfully applied to an asymmetric un-balanced power splitter, where an accurate power loss prediction is mandatory. Simulation time and memory consumption can be reduced by a factor ten and seven respectively, in comparison with complete 3D geometries. Finally, we show that, also for quasi-2D E-bend waveguide, a case where the translational H-plane symmetry is broken, the error on conductor losses computation is mitigated by our approach since the method remains still valid in a first approximation. [ABSTRACT FROM AUTHOR]

This article proposes a six-port network design with an ultra-wideband operation from 3.1 to 10.6 GHz. The proposed six-port configuration is constructed by two types of power dividers with different phase characteristics of 0° (in-phase) and 90°. The new proposed configuration eliminates one unused port of the conventional six-port. Both components forming the proposed six-port are designed utilizing the microstrip-slot technique to accomplish the designated UWB operating frequency. The six-port is designed via the use of CST Microwave Studio (CST MWS) and realised by applying Rogers TMM4 substrate. Comparable simulated and measured performances are achieved in terms of S-parameters and phase differences between each consecutive port across UWB frequency range. [ABSTRACT FROM AUTHOR]

The power splitter is an important device for applications such as microwave signal separation and array antenna feeding. After the emergence of the right and left hand transmission lines, most of the miniaturized power splitters are designed by utilizing the miniaturization characteristics of the left and right hand transmission lines. This paper summarizes the application of left and right hand transmission lines in the power splitter, and analyzes the advantages and disadvantages of different implementation methods. [ABSTRACT FROM AUTHOR]

A new class of in-phase and out-of-phase power dividers with constant equal-ripple frequency response and wide operating bandwidth is presented in this paper. The proposed design is based on microstrip-to-slotline transitions and slotline resonators. A slotted T-junction is adopted to split the power into two parts and obtain wideband isolation between the two output signals at the same time. The characteristic impedance of the transitions and resonators determines the operating bandwidth and in-band magnitude response. By reversing the placement direction of the slotline-to-microstrip transition, the electrical field is reversed, thus resulting in out-of-phase responses between output ports. A thorough analysis of the relations between the structure and the characteristic functions is provided to guide the selection of parameters of the structure in order to meet the design objectives. In the structure, simulation and measurement are conducted to verify the design method. For both in-phase and out-of-phase cases, more than 110% bandwidth has been achieved with excellent matching at all ports and isolation of output signals. Constant in-band ripple is obtained within the operating band of the power dividers, indicating that the proposed design can realise minimal power deviations, which is extremely desired in wireless systems. [ABSTRACT FROM AUTHOR]

A new vertical guiding structure in low-temperature cofired ceramics (LTCC) substrates is proposed. This vertical LTCC integrated waveguide (V-LIW) allows transmitting signals and realizing components in the body of the LTCC substrate perpendicular to its surface. This vertical integration leads to considerable footprint reduction while opening the door to higher frequency coverage as well as easy implementation of $E$ -plane structures. Discontinuities in V-LIW and transitions between the proposed V-LIW and conventional horizontal guiding structures such as coplanar waveguides, standard rectangular waveguides, and substrate integrated waveguides are also introduced. Applications to the design of V-band and W-band filters, couplers, and power dividers are presented. Several prototypes are fabricated with measurement results showing a good agreement with simulation data. [ABSTRACT FROM AUTHOR]

A high output power fully integrated V-band power amplifier (PA) is developed using a 0.18- $\ {\mu }\text{m}$ SiGe BiCMOS technology. The developed PA makes use of four-way parallel power dividing and combining structures to feed and combine powers from four identical unit-PA cells, respectively. Especially, the parallel power combiner and divider are developed by integrating a low-loss wideband Wilkinson structure and two transformers connected in parallel, which achieve broad bandwidth and minimum phase and amplitude mismatches between ports. The unit-PA is designed as a pseudo-differential two-stage cascode amplifier, which employ transformers for both matching and impedance transformation. The PA achieves measured broadband small-signal gain of 19 dB at 60 GHz and 3-dB bandwidth of 56.8–67.5 GHz, which encompasses the overall unlicensed V-band spectrum (57–64 GHz). In addition, it delivers 18.8 dBm of saturated output power and 15.3 dBm of output 1-dB compressed power at 60 GHz. Across 55 to 65 GHz, the PA achieves a very flat power performance with maximum output power between 17–19.1 dBm. [ABSTRACT FROM AUTHOR]

In this paper, performance analysis of switching and matching stubs was done to a reconfigurable power divider with Single Pole Double Throw (SPDT) switch function. Two designs (Design A and Design B) with different positions of switches and matching stubs were proposed. Rogers RO4350 (er=3.48, h=0.508 mm) was used in this analysis as a substrate material with copper thickness of 0.035 mm. The performance analysis was carried out based on insertion loss, return loss and isolation parameters. The simulated results showed that Design B had a better performance than Design A and was able to work as a reconfigurable power divider with SPDT switch function. [ABSTRACT FROM AUTHOR]

A new microstrip balanced-to-unbalanced power divider with dual bandpass filtering response is presented in this paper. The generalized mixed-mode scattering matrix for the filtering balanced-to-unbalanced power divider is derived to guide the design. Differential-mode (DM) dual-band filtering response is analyzed under the odd-mode excitation to show that the frequency ratio ($k = f_{2}/f_{1}$) and bandwidth of these two passbands could be flexibly controlled. For the even-mode excitation, two intrinsic transmission zeros generated by additional open-ended stub are introduced, aiming to achieve the enhancement of in-band common-mode (CM) suppression. In addition, good in-band isolation and port matching are realized by introducing a grounded resistor. To validate the design concept, two prototypes centering at 1 and 2.5 GHz ($k = 2.5$), as well as 0.76 and 2.75 GHz ($k = 3.62$) are implemented following the given design procedure. Tested results of the two fabricated circuits, well agreeing with the simulated ones, exhibit high performances in terms of DM response, in-band CM suppression, port-to-port isolation, and port matching. [ABSTRACT FROM AUTHOR]

This paper presents a wideband multilayer balanced-to-unbalanced (BTUB) power divider consisting of three metallic layers and two substrate layers with inherent common-mode (CM) suppression. With very simple structure, the working mechanism of the proposed power divider is investigated through even- and odd-mode equivalent circuit analysis, and the designed procedure is also summarized. For demonstration, an example of wideband BTUB power divider is implemented through standard printed circuit board process. The bandwidth of 63% of the fabricated BTUB power divider can be obtained with the best differential-mode transmission coefficient of −3.45 dB. The isolation bandwidth of approximately 63% can also be achieved. Good agreement between the simulated and measured results is observed, where the measured −15-dB CM suppression bandwidth is about 95%. Moreover, the performance is stable after adding the shielding cavity. [ABSTRACT FROM AUTHOR]

A novel circuit is proposed to design filtering power dividers (FPDs) with bandpass filtering responses and out-of-band rejection performances. The presented circuit is constructed of two transmission line sections, four short-circuited sections and one resistor. Based on the introduced novel circuit, FPD1 is designed by selecting transmission line sections and short-circuited sections as quarter-wave transmission lines. The FPD2 is proposed to realize more compact size, enhanced bandpass selectivity and improved out-of-band rejection performance by replacing the quarter-wave transmission lines in FPD1 with dual transmission lines. The corresponding equations are derived to calculate the initial parameter values of FPD1 and FPD2 by adopting even-odd mode method. For verification, two FPDs centered at 2.0 GHz are designed and fabricated. The measured 3-dB fractional bandwidths of FPD1 and FPD2 achieve up to 63.2% and 52.3%, while the measured rejections with the level better than 20 dB extend to 2.4f0 and 4.0f0, respectively. [ABSTRACT FROM AUTHOR]

This article presents the wideband compact 4-port fractal MIMO antenna array for Ku-band applications. It incorporates the Koch snowflake fractal in combination with a complementary split-ring resonator (CSRR) to achieve both miniaturization and a broad bandwidth. Further, to improve the effectiveness of the single-driven element, the 2-element linear array is constructed, fabricated, and tested. The single-driven element and the constructed array give good performance results. For pattern diversity, a 4-port MIMO configuration is developed and tested. The proposed MIMO array geometry realizes a wide bandwidth of 13. 6 − 17. 5 GHz, fractional bandwidth of 25.08%, a maximum gain of 6.95 dBi, and radiation efficiency of beyond 90% with superior isolation (> − 30 dB). It provides better diversity performance parameters (Envelope correlation coefficient < 0. 001) over the resonating band. Also, channel capacity loss (CCL) < 0. 11 bit/s/Hz and the total active reflection coefficient (TARC) < − 10 dB, parameters are perceived to be within adequate range. Therefore, the designed compact fractal antenna, 2-element array, and 4-port MIMO array are applicable for wide Ku-band applications. [ABSTRACT FROM AUTHOR]

In this paper, a set of general constraint conditions of 3 port power divider is newly established for arbitrary power ratio and arbitrary phase difference, where, the relationship between power ratio and phase difference can be newly summarized as a very simple equation. To verify this theory, a novel power divider with three standard 50 Ω ports is presented, and it consists of an isolation resistor and seven transmission lines. From the design charts and several design examples, the proposed power divider could not only provide arbitrary power ratio and arbitrary phase difference, but also independently control their fractional bandwidths (FBW S 11 or FBW S 32) under various combinations of power ratio and phase difference. In final, two prototypes are fabricated, and the measured results matched very well with simulated results. [ABSTRACT FROM AUTHOR]

This paper introduces a novel antenna array synthesis for radar systems based on the concept of a virtual antenna array (VAA) and the method of moments/genetic algorithm (MoM/GA) synthesis method. The VAA concept is applied to both scanning and fixed radiation pattern arrays. The proposed VAA is introduced to simultaneously support the medium-range radar (MRR) and the long-range radar (LRR) with beam width ±7° for LRR and ±37° for MRR. The proposed VAA is distinguished by its minimum number of antenna elements, simple feeding network, high efficiency, and gain, but all of these are at the expense of a large aperture antenna size compared to the planar antenna array (PAA). The VAA has the ability to have the feeding network and the radiating elements on the same layer, as compared to the multilayer PAA. The newly proposed concept is analyzed and verified analytically and experimentally. Two orthogonal (16 elements) VAAs are designed to operate in the frequency range from 23.55 to 24.7 GHz and to support a flat-shoulder shape (FSS) radiation pattern for LRR/MRR. The antenna was fabricated and tested experimentally, and good agreements between the simulated and measured results were noticed. The proposed VAA is introduced to solve the problems of large size, low isolations, low efficiency, feeding network, low resolution, and small coverage range for the antenna arrays of automotive radars. The proposed antenna array is introduced for automotive radar applications at 24 GHz.

In this reply, we refer to comments made by a reader on our publication “Overlapped phased array antenna for avalanche radar.” The authors would like to thank the reader for reading this article. In this article, the authors provided detailed answers to the comments made by the reader. [ABSTRACT FROM AUTHOR]

In this paper, we present a novel compact three-way power divider with bandpass responses. The proposed power divider utilizes folded net-type resonators to realize dual functions of filtering and power splitting as well as compact size. Equal power ratio with low magnitude imbalance is achieved due to the highly symmetric structure. For demonstration, an experimental three way filtering power divider is implemented. Good filtering and power division characteristics are observed in the measured results of the circuit. The area of the circuits is 14.5 mm x 21.9 mm or 0.16 λg x 0.24 λg, where the λg is the guide wavelength of the center frequency at 2.1 GHz.